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git-svn-id: https://zxing.googlecode.com/svn/trunk@2712 59b500cc-1b3d-0410-9834-0bbf25fbcc57
895 lines
42 KiB
C#
895 lines
42 KiB
C#
// /*
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// * Copyright 2009 ZXing authors
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// *
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// * Licensed under the Apache License, Version 2.0 (the "License");
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// * you may not use this file except in compliance with the License.
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// * You may obtain a copy of the License at
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// *
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// * http://www.apache.org/licenses/LICENSE-2.0
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// *
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// * Unless required by applicable law or agreed to in writing, software
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// * distributed under the License is distributed on an "AS IS" BASIS,
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// * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// * See the License for the specific language governing permissions and
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// * limitations under the License.
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// */
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using ZXing.Common;
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using ZXing.PDF417.Internal.EC;
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using Log = System.Diagnostics.Debug;
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using System.Text;
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namespace ZXing.PDF417.Internal
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{
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/// <summary>
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///
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/// </summary>
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/// <author>Guenther Grau (Java Core)</author>
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/// <author>Stephen Furlani (C# Port)</author>
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public static class PDF417ScanningDecoder
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{
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private static readonly int CODEWORD_SKEW_SIZE = 2;
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private static readonly int MAX_ERRORS = 3;
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private static readonly int MAX_EC_CODEWORDS = 512;
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private static readonly ErrorCorrection errorCorrection = new ErrorCorrection();
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/// <summary>
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/// Decode the specified image, imageTopLeft, imageBottomLeft, imageTopRight, imageBottomRight, minCodewordWidth
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/// and maxCodewordWidth.
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/// TODO: don't pass in minCodewordWidth and maxCodewordWidth, pass in barcode columns for start and stop pattern
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/// columns. That way width can be deducted from the pattern column.
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/// This approach also allows to detect more details about the barcode, e.g. if a bar type (white or black) is wider
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/// than it should be. This can happen if the scanner used a bad blackpoint.
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/// </summary>
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/// <param name="image">Image.</param>
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/// <param name="imageTopLeft">Image top left.</param>
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/// <param name="imageBottomLeft">Image bottom left.</param>
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/// <param name="imageTopRight">Image top right.</param>
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/// <param name="imageBottomRight">Image bottom right.</param>
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/// <param name="minCodewordWidth">Minimum codeword width.</param>
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/// <param name="maxCodewordWidth">Max codeword width.</param>
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public static DecoderResult Decode(BitMatrix image,
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ResultPoint imageTopLeft,
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ResultPoint imageBottomLeft,
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ResultPoint imageTopRight,
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ResultPoint imageBottomRight,
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int minCodewordWidth,
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int maxCodewordWidth)
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{
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BoundingBox boundingBox = new BoundingBox(image, imageTopLeft, imageBottomLeft, imageTopRight, imageBottomRight);
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DetectionResultRowIndicatorColumn leftRowIndicatorColumn = null;
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DetectionResultRowIndicatorColumn rightRowIndicatorColumn = null;
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DetectionResult detectionResult = null;
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for (int i = 0; i < 2; i++)
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{
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if (imageTopLeft != null)
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{
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leftRowIndicatorColumn = GetRowIndicatorColumn(image, boundingBox, imageTopLeft, true, minCodewordWidth, maxCodewordWidth);
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Log.WriteLine("Before setRowNumbers\n" + leftRowIndicatorColumn);
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leftRowIndicatorColumn.SetRowNumbers();
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Log.WriteLine("After setRowNumbers\n" + leftRowIndicatorColumn);
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}
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if (imageTopRight != null)
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{
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rightRowIndicatorColumn = GetRowIndicatorColumn(image, boundingBox, imageTopRight, false, minCodewordWidth, maxCodewordWidth);
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Log.WriteLine("Before setRowNumbers\n" + rightRowIndicatorColumn);
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rightRowIndicatorColumn.SetRowNumbers();
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Log.WriteLine("After setRowNumbers\n" + rightRowIndicatorColumn);
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}
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detectionResult = Merge(leftRowIndicatorColumn, rightRowIndicatorColumn);
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if (detectionResult == null)
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{
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// TODO Based on Owen's Comments in <see cref="ZXing.ReaderException"/>, this method has been modified to continue silently
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// if a barcode was not decoded where it was detected instead of throwing a new exception object.
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// return null;
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throw ReaderException.Instance;
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}
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if (i == 0 &&
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(detectionResult.Box.MinY < boundingBox.MinY || detectionResult.Box.MaxY > boundingBox.MaxY))
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{
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boundingBox = detectionResult.Box;
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} else
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{
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detectionResult.Box = boundingBox;
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break;
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}
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}
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int maxBarcodeColumn = detectionResult.ColumnCount + 1;
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detectionResult.DetectionResultColumns[0] = leftRowIndicatorColumn;
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detectionResult.DetectionResultColumns[maxBarcodeColumn] = rightRowIndicatorColumn;
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bool leftToRight = leftRowIndicatorColumn != null;
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for (int barcodeColumnCount = 1; barcodeColumnCount <= maxBarcodeColumn; barcodeColumnCount++)
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{
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int barcodeColumn = leftToRight ? barcodeColumnCount : maxBarcodeColumn - barcodeColumnCount;
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if (detectionResult.DetectionResultColumns[barcodeColumn] != null)
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{
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// This will be the case for the opposite row indicator column, which doesn't need to be decoded again.
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continue;
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}
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DetectionResultColumn detectionResultColumn;
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if (barcodeColumn == 0 || barcodeColumn == maxBarcodeColumn)
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{
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detectionResultColumn = new DetectionResultRowIndicatorColumn(boundingBox, barcodeColumn == 0);
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} else
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{
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detectionResultColumn = new DetectionResultColumn(boundingBox);
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}
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detectionResult.DetectionResultColumns[barcodeColumn] = detectionResultColumn;
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int startColumn = -1;
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int previousStartColumn = startColumn;
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// TODO start at a row for which we know the start position, then detect upwards and downwards from there.
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for (int imageRow = boundingBox.MinY; imageRow <= boundingBox.MaxY; imageRow++)
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{
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startColumn = GetStartColumn(detectionResult, barcodeColumn, imageRow, leftToRight);
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if (startColumn < 0 || startColumn > boundingBox.MaxX)
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{
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if (previousStartColumn == -1)
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{
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continue;
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}
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startColumn = previousStartColumn;
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}
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Codeword codeword = DetectCodeword(image, boundingBox.MinX, boundingBox.MaxX, leftToRight,
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startColumn, imageRow, minCodewordWidth, maxCodewordWidth);
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if (codeword != null)
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{
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detectionResultColumn.SetCodeword(imageRow, codeword);
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previousStartColumn = startColumn;
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minCodewordWidth = Math.Min(minCodewordWidth, codeword.Width);
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maxCodewordWidth = Math.Max(maxCodewordWidth, codeword.Width);
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}
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}
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}
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return CreateDecoderResult(detectionResult);
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}
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/// <summary>
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/// Merge the specified leftRowIndicatorColumn and rightRowIndicatorColumn.
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/// </summary>
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/// <param name="leftRowIndicatorColumn">Left row indicator column.</param>
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/// <param name="rightRowIndicatorColumn">Right row indicator column.</param>
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private static DetectionResult Merge(DetectionResultRowIndicatorColumn leftRowIndicatorColumn,
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DetectionResultRowIndicatorColumn rightRowIndicatorColumn)
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{
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if (leftRowIndicatorColumn == null && rightRowIndicatorColumn == null)
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{
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return null;
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}
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BarcodeMetadata barcodeMetadata = GetBarcodeMetadata(leftRowIndicatorColumn, rightRowIndicatorColumn);
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if (barcodeMetadata == null)
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{
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return null;
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}
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BoundingBox boundingBox = GetBoundingBox(leftRowIndicatorColumn, rightRowIndicatorColumn);
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return new DetectionResult(barcodeMetadata, boundingBox);
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}
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/// <summary>
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/// Gets the bounding box.
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/// </summary>
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/// <returns>The bounding box.</returns>
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/// <param name="leftRowIndicatorColumn">Left row indicator column.</param>
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/// <param name="rightRowIndicatorColumn">Right row indicator column.</param>
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private static BoundingBox GetBoundingBox(DetectionResultRowIndicatorColumn leftRowIndicatorColumn,
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DetectionResultRowIndicatorColumn rightRowIndicatorColumn)
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{
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BoundingBox box1 = AdjustBoundingBox(leftRowIndicatorColumn);
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BoundingBox box2 = AdjustBoundingBox(rightRowIndicatorColumn);
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return BoundingBox.Merge(box1, box2);
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}
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/// <summary>
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/// Adjusts the bounding box.
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/// </summary>
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/// <returns>The bounding box.</returns>
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/// <param name="rowIndicatorColumn">Row indicator column.</param>
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private static BoundingBox AdjustBoundingBox(DetectionResultRowIndicatorColumn rowIndicatorColumn)
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{
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if (rowIndicatorColumn == null)
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{
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return null;
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}
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int[] rowHeights = rowIndicatorColumn.GetRowHeights();
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int maxRowHeight = rowHeights.Max();
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int missingStartRows = 0;
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foreach (int rowHeight in rowHeights)
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{
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missingStartRows += maxRowHeight - rowHeight;
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if (rowHeight > 0)
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{
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break;
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}
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}
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Codeword[] codewords = rowIndicatorColumn.Codewords;
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for (int row = 0; missingStartRows > 0 && codewords[row] == null; row++)
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{
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missingStartRows--;
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}
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int missingEndRows = 0;
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for (int row = rowHeights.Length - 1; row >= 0; row--)
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{
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missingEndRows += maxRowHeight - rowHeights[row];
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if (rowHeights[row] > 0)
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{
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break;
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}
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}
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for (int row = codewords.Length - 1; missingEndRows > 0 && codewords[row] == null; row--)
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{
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missingEndRows--;
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}
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return rowIndicatorColumn.Box.AddMissingRows(missingStartRows, missingEndRows, rowIndicatorColumn.IsLeft);
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}
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/// <summary>
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/// Gets the barcode metadata.
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/// </summary>
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/// <returns>The barcode metadata.</returns>
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/// <param name="leftRowIndicatorColumn">Left row indicator column.</param>
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/// <param name="rightRowIndicatorColumn">Right row indicator column.</param>
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private static BarcodeMetadata GetBarcodeMetadata(DetectionResultRowIndicatorColumn leftRowIndicatorColumn,
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DetectionResultRowIndicatorColumn rightRowIndicatorColumn)
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{
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if (leftRowIndicatorColumn == null || leftRowIndicatorColumn.GetBarcodeMetadata() == null)
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{
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return rightRowIndicatorColumn == null ? null : rightRowIndicatorColumn.GetBarcodeMetadata();
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}
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if (rightRowIndicatorColumn == null || rightRowIndicatorColumn.GetBarcodeMetadata() == null)
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{
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return leftRowIndicatorColumn == null ? null : leftRowIndicatorColumn.GetBarcodeMetadata();
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}
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BarcodeMetadata leftBarcodeMetadata = leftRowIndicatorColumn.GetBarcodeMetadata();
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BarcodeMetadata rightBarcodeMetadata = rightRowIndicatorColumn.GetBarcodeMetadata();
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if (leftBarcodeMetadata.ColumnCount != rightBarcodeMetadata.ColumnCount &&
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leftBarcodeMetadata.ErrorCorrectionLevel != rightBarcodeMetadata.ErrorCorrectionLevel &&
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leftBarcodeMetadata.RowCount != rightBarcodeMetadata.RowCount)
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{
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return null;
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}
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return leftBarcodeMetadata;
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}
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/// <summary>
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/// Gets the row indicator column.
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/// </summary>
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/// <returns>The row indicator column.</returns>
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/// <param name="image">Image.</param>
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/// <param name="boundingBox">Bounding box.</param>
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/// <param name="startPoint">Start point.</param>
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/// <param name="leftToRight">If set to <c>true</c> left to right.</param>
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/// <param name="minCodewordWidth">Minimum codeword width.</param>
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/// <param name="maxCodewordWidth">Max codeword width.</param>
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private static DetectionResultRowIndicatorColumn GetRowIndicatorColumn(BitMatrix image,
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BoundingBox boundingBox,
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ResultPoint startPoint,
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bool leftToRight,
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int minCodewordWidth,
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int maxCodewordWidth)
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{
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DetectionResultRowIndicatorColumn rowIndicatorColumn = new DetectionResultRowIndicatorColumn(boundingBox, leftToRight);
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for (int i = 0; i < 2; i++)
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{
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int increment = i == 0 ? 1 : -1;
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int startColumn = (int)startPoint.X;
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for (int imageRow = (int) startPoint.Y; imageRow <= boundingBox.MaxY &&
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imageRow >= boundingBox.MinY; imageRow += increment)
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{
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Codeword codeword = DetectCodeword(image, 0, image.Width, leftToRight, startColumn, imageRow,
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minCodewordWidth, maxCodewordWidth);
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if (codeword != null)
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{
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rowIndicatorColumn.SetCodeword(imageRow, codeword);
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if (leftToRight)
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{
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startColumn = codeword.StartX;
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} else
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{
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startColumn = codeword.EndX;
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}
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}
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}
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}
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return rowIndicatorColumn;
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}
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/// <summary>
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/// Adjusts the codeword count.
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/// </summary>
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/// <param name="detectionResult">Detection result.</param>
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/// <param name="barcodeMatrix">Barcode matrix.</param>
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private static void AdjustCodewordCount(DetectionResult detectionResult, BarcodeValue[][] barcodeMatrix)
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{
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int[] numberOfCodewords = barcodeMatrix[0][1].GetValue();
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int calculatedNumberOfCodewords = detectionResult.ColumnCount *
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detectionResult.RowCount -
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GetNumberOfECCodeWords(detectionResult.ErrorCorrectionLevel);
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if (numberOfCodewords.Length == 0)
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{
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if (calculatedNumberOfCodewords < 1 || calculatedNumberOfCodewords > PDF417Common.MAX_CODEWORDS_IN_BARCODE)
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{
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throw ReaderException.Instance;
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}
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barcodeMatrix[0][1].SetValue(calculatedNumberOfCodewords);
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} else if (numberOfCodewords[0] != calculatedNumberOfCodewords)
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{
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// The calculated one is more reliable as it is derived from the row indicator columns
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barcodeMatrix[0][1].SetValue(calculatedNumberOfCodewords);
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}
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}
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/// <summary>
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/// Creates the decoder result.
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/// </summary>
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/// <returns>The decoder result.</returns>
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/// <param name="detectionResult">Detection result.</param>
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private static DecoderResult CreateDecoderResult(DetectionResult detectionResult)
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{
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BarcodeValue[][] barcodeMatrix = CreateBarcodeMatrix(detectionResult);
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AdjustCodewordCount(detectionResult, barcodeMatrix);
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List<int> erasures = new List<int>();
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int[] codewords = new int[detectionResult.RowCount * detectionResult.ColumnCount];
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List<int[]> ambiguousIndexValuesList = new List<int[]>();
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List<int> ambiguousIndexesList = new List<int>();
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for (int row = 0; row < detectionResult.RowCount; row++)
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{
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for (int column = 0; column < detectionResult.ColumnCount; column++)
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{
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int[] values = barcodeMatrix[row][column + 1].GetValue();
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int codewordIndex = row * detectionResult.ColumnCount + column;
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if (values.Length == 0)
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{
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erasures.Add(codewordIndex);
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} else if (values.Length == 1)
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{
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codewords[codewordIndex] = values[0];
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} else
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{
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ambiguousIndexesList.Add(codewordIndex);
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ambiguousIndexValuesList.Add(values);
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}
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}
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}
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int[][] ambiguousIndexValues = new int[ambiguousIndexValuesList.Count][];
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for (int i = 0; i < ambiguousIndexValues.Length; i++)
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{
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ambiguousIndexValues[i] = ambiguousIndexValuesList[i];
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}
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return CreateDecoderResultFromAmbiguousValues(detectionResult.ErrorCorrectionLevel, codewords,
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erasures.ToArray(), ambiguousIndexesList.ToArray(), ambiguousIndexValues);
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}
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/**
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* This method deals with the fact, that the decoding process doesn't always yield a single most likely value. The
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* current error correction implementation doesn't deal with erasures very well, so it's better to provide a value
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* for these ambiguous codewords instead of treating it as an erasure. The problem is that we don't know which of
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* the ambiguous values to choose. We try decode using the first value, and if that fails, we use another of the
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* ambiguous values and try to decode again. This usually only happens on very hard to read and decode barcodes,
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* so decoding the normal barcodes is not affected by this.
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* @param ecLevel
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* @param codewords
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* @param erasureArray contains the indexes of erasures
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* @param ambiguousIndexes array with the indexes that have more than one most likely value
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* @param ambiguousIndexValues two dimensional array that contains the ambiguous values. The first dimension must
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* be the same Length as the ambiguousIndexes array
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* @return
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* @throws FormatException
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* @throws ChecksumException
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*/
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/// <summary>
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/// This method deals with the fact, that the decoding process doesn't always yield a single most likely value. The
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/// current error correction implementation doesn't deal with erasures very well, so it's better to provide a value
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/// for these ambiguous codewords instead of treating it as an erasure. The problem is that we don't know which of
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/// the ambiguous values to choose. We try decode using the first value, and if that fails, we use another of the
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/// ambiguous values and try to decode again. This usually only happens on very hard to read and decode barcodes,
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/// so decoding the normal barcodes is not affected by this.
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/// </summary>
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/// <returns>The decoder result from ambiguous values.</returns>
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/// <param name="ecLevel">Ec level.</param>
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/// <param name="codewords">Codewords.</param>
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/// <param name="erasureArray">contains the indexes of erasures.</param>
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/// <param name="ambiguousIndexes">array with the indexes that have more than one most likely value.</param>
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/// <param name="ambiguousIndexValues">two dimensional array that contains the ambiguous values. The first dimension must
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/// be the same Length as the ambiguousIndexes array.</param>
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/// <exception cref="Zxing.ReaderException"></exception>
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private static DecoderResult CreateDecoderResultFromAmbiguousValues(int ecLevel,
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int[] codewords,
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int[] erasureArray,
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int[] ambiguousIndexes,
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int[][] ambiguousIndexValues)
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{
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int[] ambiguousIndexCount = new int[ambiguousIndexes.Length];
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int tries = 100;
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while (tries-- > 0)
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{
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for (int i = 0; i < ambiguousIndexCount.Length; i++)
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{
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codewords[ambiguousIndexes[i]] = ambiguousIndexValues[i][ambiguousIndexCount[i]];
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}
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try
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{
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return DecodeCodewords(codewords, ecLevel, erasureArray);
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} catch (ReaderException ignored)
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{
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//
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}
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if (ambiguousIndexCount.Length == 0)
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{
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throw ReaderException.Instance;
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}
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for (int i = 0; i < ambiguousIndexCount.Length; i++)
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{
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if (ambiguousIndexCount[i] < ambiguousIndexValues[i].Length - 1)
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{
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ambiguousIndexCount[i]++;
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break;
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} else
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{
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ambiguousIndexCount[i] = 0;
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if (i == ambiguousIndexCount.Length - 1)
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{
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throw ReaderException.Instance;
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}
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}
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}
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}
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throw ReaderException.Instance;
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}
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/// <summary>
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/// Creates the barcode matrix.
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/// </summary>
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/// <returns>The barcode matrix.</returns>
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/// <param name="detectionResult">Detection result.</param>
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private static BarcodeValue[][] CreateBarcodeMatrix(DetectionResult detectionResult)
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{
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// Manually setup Jagged Array in C#
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BarcodeValue[][] barcodeMatrix = new BarcodeValue[detectionResult.RowCount][];
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for (int row = 0; row < barcodeMatrix.Length; row++)
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{
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barcodeMatrix[row] = new BarcodeValue[detectionResult.ColumnCount + 2];// Enumerable.Repeat(new BarcodeValue(), detectionResult.ColumnCount + 2).ToArray();
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for (int col = 0; col < barcodeMatrix[row].Length; col++)
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{
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barcodeMatrix[row][col] = new BarcodeValue();
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}
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|
}
|
|
|
|
int column = -1;
|
|
foreach (DetectionResultColumn detectionResultColumn in detectionResult.GetDetectionResultColumns())
|
|
{
|
|
column++;
|
|
if (detectionResultColumn == null)
|
|
{
|
|
continue;
|
|
}
|
|
foreach (Codeword codeword in detectionResultColumn.Codewords)
|
|
{
|
|
if (codeword == null || codeword.RowNumber == -1)
|
|
{
|
|
continue;
|
|
}
|
|
barcodeMatrix[codeword.RowNumber][column].SetValue(codeword.Value);
|
|
}
|
|
}
|
|
return barcodeMatrix;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Tests to see if the Barcode Column is Valid
|
|
/// </summary>
|
|
/// <returns><c>true</c>, if barcode column is valid, <c>false</c> otherwise.</returns>
|
|
/// <param name="detectionResult">Detection result.</param>
|
|
/// <param name="barcodeColumn">Barcode column.</param>
|
|
private static bool IsValidBarcodeColumn(DetectionResult detectionResult, int barcodeColumn)
|
|
{
|
|
return (barcodeColumn >= 0) && (barcodeColumn < detectionResult.DetectionResultColumns.Length);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets the start column.
|
|
/// </summary>
|
|
/// <returns>The start column.</returns>
|
|
/// <param name="detectionResult">Detection result.</param>
|
|
/// <param name="barcodeColumn">Barcode column.</param>
|
|
/// <param name="imageRow">Image row.</param>
|
|
/// <param name="leftToRight">If set to <c>true</c> left to right.</param>
|
|
private static int GetStartColumn(DetectionResult detectionResult,
|
|
int barcodeColumn,
|
|
int imageRow,
|
|
bool leftToRight)
|
|
{
|
|
int offset = leftToRight ? 1 : -1;
|
|
Codeword codeword = null;
|
|
if (IsValidBarcodeColumn(detectionResult, barcodeColumn - offset))
|
|
{
|
|
codeword = detectionResult.DetectionResultColumns[barcodeColumn - offset].GetCodeword(imageRow);
|
|
}
|
|
if (codeword != null)
|
|
{
|
|
return leftToRight ? codeword.EndX : codeword.StartX;
|
|
}
|
|
codeword = detectionResult.DetectionResultColumns[barcodeColumn].GetCodewordNearby(imageRow);
|
|
if (codeword != null)
|
|
{
|
|
return leftToRight ? codeword.EndX : codeword.StartX;
|
|
}
|
|
if (IsValidBarcodeColumn(detectionResult, barcodeColumn - offset))
|
|
{
|
|
codeword = detectionResult.DetectionResultColumns[barcodeColumn - offset].GetCodewordNearby(imageRow);
|
|
}
|
|
if (codeword != null)
|
|
{
|
|
return leftToRight ? codeword.EndX : codeword.StartX;
|
|
}
|
|
int skippedColumns = 0;
|
|
|
|
while (IsValidBarcodeColumn(detectionResult, barcodeColumn - offset))
|
|
{
|
|
barcodeColumn -= offset;
|
|
foreach (Codeword previousRowCodeword in detectionResult.DetectionResultColumns[barcodeColumn].Codewords)
|
|
{
|
|
if (previousRowCodeword != null)
|
|
{
|
|
return (leftToRight ? previousRowCodeword.EndX : previousRowCodeword.StartX) +
|
|
offset *
|
|
skippedColumns *
|
|
(previousRowCodeword.EndX - previousRowCodeword.StartX);
|
|
}
|
|
}
|
|
skippedColumns++;
|
|
}
|
|
return leftToRight ? detectionResult.Box.MinX : detectionResult.Box.MaxX;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Detects the codeword.
|
|
/// </summary>
|
|
/// <returns>The codeword.</returns>
|
|
/// <param name="image">Image.</param>
|
|
/// <param name="minColumn">Minimum column.</param>
|
|
/// <param name="maxColumn">Max column.</param>
|
|
/// <param name="leftToRight">If set to <c>true</c> left to right.</param>
|
|
/// <param name="startColumn">Start column.</param>
|
|
/// <param name="imageRow">Image row.</param>
|
|
/// <param name="minCodewordWidth">Minimum codeword width.</param>
|
|
/// <param name="maxCodewordWidth">Max codeword width.</param>
|
|
private static Codeword DetectCodeword(BitMatrix image,
|
|
int minColumn,
|
|
int maxColumn,
|
|
bool leftToRight,
|
|
int startColumn,
|
|
int imageRow,
|
|
int minCodewordWidth,
|
|
int maxCodewordWidth)
|
|
{
|
|
startColumn = AdjustCodewordStartColumn(image, minColumn, maxColumn, leftToRight, startColumn, imageRow);
|
|
// we usually know fairly exact now how long a codeword is. We should provide minimum and maximum expected Length
|
|
// and try to adjust the read pixels, e.g. remove single pixel errors or try to cut off exceeding pixels.
|
|
// min and maxCodewordWidth should not be used as they are calculated for the whole barcode an can be inaccurate
|
|
// for the current position
|
|
int[] moduleBitCount = GetModuleBitCount(image, minColumn, maxColumn, leftToRight, startColumn, imageRow);
|
|
if (moduleBitCount == null)
|
|
{
|
|
return null;
|
|
}
|
|
int endColumn;
|
|
int codewordBitCount = PDF417Common.GetBitCountSum(moduleBitCount);
|
|
if (leftToRight)
|
|
{
|
|
endColumn = startColumn + codewordBitCount;
|
|
} else
|
|
{
|
|
for (int i = 0; i < moduleBitCount.Length >> 1; i++)
|
|
{
|
|
int tmpCount = moduleBitCount[i];
|
|
moduleBitCount[i] = moduleBitCount[moduleBitCount.Length - 1 - i];
|
|
moduleBitCount[moduleBitCount.Length - 1 - i] = tmpCount;
|
|
}
|
|
endColumn = startColumn;
|
|
startColumn = endColumn - codewordBitCount;
|
|
}
|
|
// TODO implement check for width and correction of black and white bars
|
|
// use start (and maybe stop pattern) to determine if blackbars are wider than white bars. If so, adjust.
|
|
// should probably done only for codewords with a lot more than 17 bits.
|
|
// The following fixes 10-1.png, which has wide black bars and small white bars
|
|
// for (int i = 0; i < moduleBitCount.Length; i++) {
|
|
// if (i % 2 == 0) {
|
|
// moduleBitCount[i]--;
|
|
// } else {
|
|
// moduleBitCount[i]++;
|
|
// }
|
|
// }
|
|
|
|
// We could also use the width of surrounding codewords for more accurate results, but this seems
|
|
// sufficient for now
|
|
if (!CheckCodewordSkew(codewordBitCount, minCodewordWidth, maxCodewordWidth))
|
|
{
|
|
// We could try to use the startX and endX position of the codeword in the same column in the previous row,
|
|
// create the bit count from it and normalize it to 8. This would help with single pixel errors.
|
|
return null;
|
|
}
|
|
|
|
int decodedValue = PDF417CodewordDecoder.GetDecodedValue(moduleBitCount);
|
|
int codeword = PDF417Common.GetCodeword(decodedValue);
|
|
if (codeword == -1)
|
|
{
|
|
return null;
|
|
}
|
|
return new Codeword(startColumn, endColumn, GetCodewordBucketNumber(decodedValue), codeword);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets the module bit count.
|
|
/// </summary>
|
|
/// <returns>The module bit count.</returns>
|
|
/// <param name="image">Image.</param>
|
|
/// <param name="minColumn">Minimum column.</param>
|
|
/// <param name="maxColumn">Max column.</param>
|
|
/// <param name="leftToRight">If set to <c>true</c> left to right.</param>
|
|
/// <param name="startColumn">Start column.</param>
|
|
/// <param name="imageRow">Image row.</param>
|
|
private static int[] GetModuleBitCount(BitMatrix image,
|
|
int minColumn,
|
|
int maxColumn,
|
|
bool leftToRight,
|
|
int startColumn,
|
|
int imageRow)
|
|
{
|
|
int imageColumn = startColumn;
|
|
int[] moduleBitCount = new int[8];
|
|
int moduleNumber = 0;
|
|
int increment = leftToRight ? 1 : -1;
|
|
bool previousPixelValue = leftToRight;
|
|
while (((leftToRight && imageColumn < maxColumn) || (!leftToRight && imageColumn >= minColumn)) &&
|
|
moduleNumber < moduleBitCount.Length)
|
|
{
|
|
if (image[imageColumn, imageRow] == previousPixelValue)
|
|
{
|
|
moduleBitCount[moduleNumber]++;
|
|
imageColumn += increment;
|
|
} else
|
|
{
|
|
moduleNumber++;
|
|
previousPixelValue = !previousPixelValue;
|
|
}
|
|
}
|
|
if (moduleNumber == moduleBitCount.Length ||
|
|
(((leftToRight && imageColumn == maxColumn) || (!leftToRight && imageColumn == minColumn)) && moduleNumber == moduleBitCount.Length - 1))
|
|
{
|
|
return moduleBitCount;
|
|
}
|
|
return null;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets the number of EC code words.
|
|
/// </summary>
|
|
/// <returns>The number of EC code words.</returns>
|
|
/// <param name="barcodeECLevel">Barcode EC level.</param>
|
|
private static int GetNumberOfECCodeWords(int barcodeECLevel)
|
|
{
|
|
return 2 << barcodeECLevel;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Adjusts the codeword start column.
|
|
/// </summary>
|
|
/// <returns>The codeword start column.</returns>
|
|
/// <param name="image">Image.</param>
|
|
/// <param name="minColumn">Minimum column.</param>
|
|
/// <param name="maxColumn">Max column.</param>
|
|
/// <param name="leftToRight">If set to <c>true</c> left to right.</param>
|
|
/// <param name="codewordStartColumn">Codeword start column.</param>
|
|
/// <param name="imageRow">Image row.</param>
|
|
private static int AdjustCodewordStartColumn(BitMatrix image,
|
|
int minColumn,
|
|
int maxColumn,
|
|
bool leftToRight,
|
|
int codewordStartColumn,
|
|
int imageRow)
|
|
{
|
|
int correctedStartColumn = codewordStartColumn;
|
|
int increment = leftToRight ? -1 : 1;
|
|
// there should be no black pixels before the start column. If there are, then we need to start earlier.
|
|
for (int i = 0; i < 2; i++)
|
|
{
|
|
while (((leftToRight && correctedStartColumn >= minColumn) || (!leftToRight && correctedStartColumn < maxColumn)) &&
|
|
leftToRight == image[correctedStartColumn, imageRow])
|
|
{
|
|
if (Math.Abs(codewordStartColumn - correctedStartColumn) > CODEWORD_SKEW_SIZE)
|
|
{
|
|
return codewordStartColumn;
|
|
}
|
|
correctedStartColumn += increment;
|
|
}
|
|
increment = -increment;
|
|
leftToRight = !leftToRight;
|
|
}
|
|
return correctedStartColumn;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Checks the codeword for any skew.
|
|
/// </summary>
|
|
/// <returns><c>true</c>, if codeword is within the skew, <c>false</c> otherwise.</returns>
|
|
/// <param name="codewordSize">Codeword size.</param>
|
|
/// <param name="minCodewordWidth">Minimum codeword width.</param>
|
|
/// <param name="maxCodewordWidth">Max codeword width.</param>
|
|
private static bool CheckCodewordSkew(int codewordSize, int minCodewordWidth, int maxCodewordWidth)
|
|
{
|
|
return minCodewordWidth - CODEWORD_SKEW_SIZE <= codewordSize &&
|
|
codewordSize <= maxCodewordWidth + CODEWORD_SKEW_SIZE;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Decodes the codewords.
|
|
/// </summary>
|
|
/// <returns>The codewords.</returns>
|
|
/// <param name="codewords">Codewords.</param>
|
|
/// <param name="ecLevel">Ec level.</param>
|
|
/// <param name="erasures">Erasures.</param>
|
|
private static DecoderResult DecodeCodewords(int[] codewords, int ecLevel, int[] erasures)
|
|
{
|
|
if (codewords.Length == 0)
|
|
{
|
|
throw ReaderException.Instance;
|
|
}
|
|
|
|
int numECCodewords = 1 << (ecLevel + 1);
|
|
Log.WriteLine("EC level: " + ecLevel + ", ec codewords: " + numECCodewords);
|
|
|
|
int correctedErrorsCount = CorrectErrors(codewords, erasures, numECCodewords);
|
|
Log.WriteLine("Corrected errors: " + correctedErrorsCount);
|
|
VerifyCodewordCount(codewords, numECCodewords);
|
|
|
|
// Decode the codewords
|
|
DecoderResult decoderResult = DecodedBitStreamParser.Decode(codewords);
|
|
decoderResult.ErrorsCorrected = (correctedErrorsCount >= 0) ? correctedErrorsCount : 0;
|
|
decoderResult.Erasures = erasures.Length;
|
|
return decoderResult;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Given data and error-correction codewords received, possibly corrupted by errors, attempts to
|
|
/// correct the errors in-place.
|
|
/// </summary>
|
|
/// <returns>The errors.</returns>
|
|
/// <param name="codewords">data and error correction codewords.</param>
|
|
/// <param name="erasures">positions of any known erasures.</param>
|
|
/// <param name="numECCodewords">number of error correction codewords that are available in codewords.</param>
|
|
private static int CorrectErrors(int[] codewords, int[] erasures, int numECCodewords)
|
|
{
|
|
if (erasures != null &&
|
|
erasures.Length > numECCodewords / 2 + MAX_ERRORS ||
|
|
numECCodewords < 0 ||
|
|
numECCodewords > MAX_EC_CODEWORDS)
|
|
{
|
|
// Too many errors or EC Codewords is corrupted
|
|
throw ReaderException.Instance;
|
|
//return -1;
|
|
|
|
}
|
|
return errorCorrection.Decode(codewords, numECCodewords, erasures);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Verifies that all is well with the the codeword array.
|
|
/// </summary>
|
|
/// <param name="codewords">Codewords.</param>
|
|
/// <param name="numECCodewords">Number EC codewords.</param>
|
|
private static void VerifyCodewordCount(int[] codewords, int numECCodewords)
|
|
{
|
|
if (codewords.Length < 4)
|
|
{
|
|
// Codeword array size should be at least 4 allowing for
|
|
// Count CW, At least one Data CW, Error Correction CW, Error Correction CW
|
|
throw ReaderException.Instance;
|
|
}
|
|
// The first codeword, the Symbol Length Descriptor, shall always encode the total number of data
|
|
// codewords in the symbol, including the Symbol Length Descriptor itself, data codewords and pad
|
|
// codewords, but excluding the number of error correction codewords.
|
|
int numberOfCodewords = codewords[0];
|
|
if (numberOfCodewords > codewords.Length)
|
|
{
|
|
throw ReaderException.Instance;
|
|
}
|
|
if (numberOfCodewords == 0)
|
|
{
|
|
// Reset to the Length of the array - 8 (Allow for at least level 3 Error Correction (8 Error Codewords)
|
|
if (numECCodewords < codewords.Length)
|
|
{
|
|
codewords[0] = codewords.Length - numECCodewords;
|
|
} else
|
|
{
|
|
throw ReaderException.Instance;
|
|
}
|
|
}
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets the bit count for codeword.
|
|
/// </summary>
|
|
/// <returns>The bit count for codeword.</returns>
|
|
/// <param name="codeword">Codeword.</param>
|
|
private static int[] GetBitCountForCodeword(int codeword)
|
|
{
|
|
int[] result = new int[8];
|
|
int previousValue = 0;
|
|
int i = result.Length - 1;
|
|
while (true)
|
|
{
|
|
if ((codeword & 0x1) != previousValue)
|
|
{
|
|
previousValue = codeword & 0x1;
|
|
i--;
|
|
if (i < 0)
|
|
{
|
|
break;
|
|
}
|
|
}
|
|
result[i]++;
|
|
codeword >>= 1;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets the codeword bucket number.
|
|
/// </summary>
|
|
/// <returns>The codeword bucket number.</returns>
|
|
/// <param name="codeword">Codeword.</param>
|
|
private static int GetCodewordBucketNumber(int codeword)
|
|
{
|
|
return GetCodewordBucketNumber(GetBitCountForCodeword(codeword));
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets the codeword bucket number.
|
|
/// </summary>
|
|
/// <returns>The codeword bucket number.</returns>
|
|
/// <param name="moduleBitCount">Module bit count.</param>
|
|
private static int GetCodewordBucketNumber(int[] moduleBitCount)
|
|
{
|
|
return (moduleBitCount[0] - moduleBitCount[2] + moduleBitCount[4] - moduleBitCount[6] + 9) % 9;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Returns a <see cref="System.String"/> that represents the <see cref="ZXing.PDF417.Internal.BarcodeValue"/> jagged array.
|
|
/// </summary>
|
|
/// <returns>A <see cref="System.String"/> that represents the <see cref="ZXing.PDF417.Internal.BarcodeValue"/> jagged array.</returns>
|
|
/// <param name="barcodeMatrix">Barcode matrix as a jagged array.</param>
|
|
public static String ToString(BarcodeValue[][] barcodeMatrix)
|
|
{
|
|
StringBuilder formatter = new StringBuilder();
|
|
for (int row = 0; row < barcodeMatrix.Length; row++)
|
|
{
|
|
formatter.AppendFormat("Row {0,2}: ", row);
|
|
for (int column = 0; column < barcodeMatrix[row].Length; column++)
|
|
{
|
|
BarcodeValue barcodeValue = barcodeMatrix[row][column];
|
|
if (barcodeValue.GetValue().Length == 0)
|
|
{
|
|
formatter.Append(" ");
|
|
} else
|
|
{
|
|
formatter.AppendFormat("{0,4}({0,3})", barcodeValue.GetValue()[0], barcodeValue.GetConfidence(barcodeValue.GetValue()[0]));
|
|
}
|
|
}
|
|
formatter.Append("\n");
|
|
}
|
|
return formatter.ToString();
|
|
}
|
|
}
|
|
}
|
|
|