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ISSUE: http://code.google.com/p/zxing/issues/detail?id=110

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Renamed ITF14Reader to ITFReader. ITFReader now reads arbitrary number of digits. Added a QuietZone check. Removed checksum validation. Added more test cases.

git-svn-id: https://zxing.googlecode.com/svn/trunk@744 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
kev.sully 2008-11-20 17:26:34 +00:00
parent 4928f6bd07
commit 233ae565fe
4 changed files with 343 additions and 282 deletions
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4
core/src/com/google/zxing/BarcodeFormat.java
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@ -49,8 +49,8 @@ public final class BarcodeFormat {
/** Code 39 1D format. */
public static final BarcodeFormat CODE_39 = new BarcodeFormat("CODE_39");
/** ITF-14 1D format. */
public static final BarcodeFormat ITF_14 = new BarcodeFormat("ITF_14");
/** ITF (Interleaved Two of Five) 1D format. */
public static final BarcodeFormat ITF = new BarcodeFormat("ITF");
private final String name;

280
core/src/com/google/zxing/oned/ITF14Reader.java
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@ -1,280 +0,0 @@
/*
* Copyright 2008 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.zxing.oned;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.ReaderException;
import com.google.zxing.Result;
import com.google.zxing.ResultPoint;
import com.google.zxing.common.BitArray;
import com.google.zxing.common.GenericResultPoint;
import java.util.Hashtable;
/**
* <p>Implements decoding of the ITF-14 format.</p>
* <p/>
* <p>"ITF" stands for Interleaved Two of Five. The "-14" part indicates there are 14 digits encoded in the barcode.</p>
* <p/>
* <p><a href="http://en.wikipedia.org/wiki/Interleaved_2_of_5">http://en.wikipedia.org/wiki/Interleaved_2_of_5</a>
* is a great reference for Interleaved 2 of 5 information. </p>
* <p/>
* <p>TODO: ITF-14 is an implementation of
* <a href="http://en.wikipedia.org/wiki/Interleaved_2_of_5">Interleaved 2 of 5</a> barcode.
* It stipulates that there is 14 digits in the bar code. A more abstract class should be implemented
* which will scan an arbritary number of digits encoded in two of five format.</p>
*
* @author kevin.osullivan@sita.aero
*/
public final class ITF14Reader extends AbstractOneDReader {
private static final int MAX_AVG_VARIANCE = (int) (PATTERN_MATCH_RESULT_SCALE_FACTOR * 0.42f);
private static final int MAX_INDIVIDUAL_VARIANCE = (int) (PATTERN_MATCH_RESULT_SCALE_FACTOR * 0.7f);
private static final int W = 3; // Pixel width of a wide line
private static final int N = 1; // Pixed width of a narrow line
private final int DIGIT_COUNT = 14; // There are 14 digits in ITF-14
/**
* Start/end guard pattern.
* <p/>
* Note: The end pattern is reversed because the
* row is reversed before searching for the END_PATTERN
*/
private static final int[] START_PATTERN = {N, N, N, N};
private static final int[] END_PATTERN_REVERSED = {N, N, W};
/**
* Patterns of Wide / Narrow lines to
* indicate each digit
*/
static final int[][] PATTERNS = {
{N, N, W, W, N}, // 0
{W, N, N, N, W}, // 1
{N, W, N, N, W}, // 2
{W, W, N, N, N}, // 3
{N, N, W, N, W}, // 4
{W, N, W, N, N}, // 5
{N, W, W, N, N}, // 6
{N, N, N, W, W}, // 7
{W, N, N, W, N}, // 8
{N, W, N, W, N} // 9
};
public final Result decodeRow(int rowNumber, BitArray row, Hashtable hints) throws ReaderException {
StringBuffer result = new StringBuffer(20);
/**
* Find out where the Middle section (payload) starts & ends
*/
int[] startRange = decodeStart(row);
int[] endRange = decodeEnd(row);
decodeMiddle(row, startRange[1], endRange[0], result);
String resultString = result.toString();
if (!AbstractUPCEANReader.checkStandardUPCEANChecksum(resultString)) {
throw ReaderException.getInstance();
}
return new Result(resultString, null, // no natural byte representation
// for these barcodes
new ResultPoint[]{new GenericResultPoint(startRange[1], (float) rowNumber),
new GenericResultPoint(startRange[0], (float) rowNumber)},
BarcodeFormat.ITF_14);
}
/**
* @param row row of black/white values to search
* @param payloadStart offset of start pattern
* @param resultString {@link StringBuffer} to append decoded chars to
* @throws ReaderException if decoding could not complete successfully
*/
protected void decodeMiddle(BitArray row, int payloadStart, int payloadEnd, StringBuffer resultString)
throws ReaderException {
// Digits are interleaved in pairs - 5 black lines for one digit, and the 5
// interleaved white lines for the second digit.
// Therefore, need to scan 10 lines and then
// split these into two arrays
int[] counterDigitPair = new int[10];
int[] counterBlack = new int[5];
int[] counterWhite = new int[5];
for (int x = 0; x < DIGIT_COUNT / 2 && payloadStart < payloadEnd; x++) {
// Get 10 runs of black/white.
recordPattern(row, payloadStart, counterDigitPair);
// Split them into each array
for (int k = 0; k < 5; k++) {
counterBlack[k] = counterDigitPair[k * 2];
counterWhite[k] = counterDigitPair[(k * 2) + 1];
}
int bestMatch = decodeDigit(counterBlack);
resultString.append((char) ('0' + bestMatch % 10));
bestMatch = decodeDigit(counterWhite);
resultString.append((char) ('0' + bestMatch % 10));
for (int i = 0; i < counterDigitPair.length; i++) {
payloadStart += counterDigitPair[i];
}
}
}
/**
* Identify where the start of the middle / payload section starts.
*
* @param row row of black/white values to search
* @return Array, containing index of start of 'start block' and end of 'start block'
* @throws ReaderException
*/
int[] decodeStart(BitArray row) throws ReaderException {
int endStart = skipWhiteSpace(row);
return findGuardPattern(row, endStart, START_PATTERN);
}
/**
* Skip all whitespace until we get to the first black line.
*
* @param row row of black/white values to search
* @return index of the first black line.
* @throws ReaderException Throws exception if no black lines are found in the row
*/
private int skipWhiteSpace(BitArray row) throws ReaderException {
int width = row.getSize();
int endStart = 0;
while (endStart < width) {
if (row.get(endStart)) {
break;
}
endStart++;
}
if (endStart == width)
throw ReaderException.getInstance();
return endStart;
}
/**
* Identify where the start of the middle / payload section ends.
*
* @param row row of black/white values to search
* @return Array, containing index of start of 'end block' and end of 'end block'
* @throws ReaderException
*/
int[] decodeEnd(BitArray row) throws ReaderException {
// For convenience, reverse the row and then
// search from 'the start' for the end block
row.reverse();
int endStart = skipWhiteSpace(row);
int end[];
try {
end = findGuardPattern(row, endStart, END_PATTERN_REVERSED);
} catch (ReaderException e) {
// Put our row of data back the right way before throwing
row.reverse();
throw e;
}
// Now recalc the indicies of where the 'endblock' starts & stops to accomodate
// the reversed nature of the search
int temp = end[0];
end[0] = row.getSize() - end[1];
end[1] = row.getSize() - temp;
// Put the row back the righ way.
row.reverse();
return end;
}
/**
* @param row row of black/white values to search
* @param rowOffset position to start search
* @param pattern pattern of counts of number of black and white pixels that are
* being searched for as a pattern
* @return start/end horizontal offset of guard pattern, as an array of two ints
* @throws ReaderException if pattern is not found
*/
int[] findGuardPattern(BitArray row, int rowOffset, int[] pattern) throws ReaderException {
int patternLength = pattern.length;
int[] counters = new int[patternLength];
int width = row.getSize();
boolean isWhite = false;
int counterPosition = 0;
int patternStart = rowOffset;
for (int x = rowOffset; x < width; x++) {
boolean pixel = row.get(x);
if ((!pixel && isWhite) || (pixel && !isWhite)) {
counters[counterPosition]++;
} else {
if (counterPosition == patternLength - 1) {
if (patternMatchVariance(counters, pattern, MAX_INDIVIDUAL_VARIANCE) < MAX_AVG_VARIANCE) {
return new int[]{patternStart, x};
}
patternStart += counters[0] + counters[1];
for (int y = 2; y < patternLength; y++) {
counters[y - 2] = counters[y];
}
counters[patternLength - 2] = 0;
counters[patternLength - 1] = 0;
counterPosition--;
} else {
counterPosition++;
}
counters[counterPosition] = 1;
isWhite = !isWhite;
}
}
throw ReaderException.getInstance();
}
/**
* Attempts to decode a sequence of ITF-14 black/white lines into single digit.
*
* @param counters the counts of runs of observed black/white/black/... values
* @return The decoded digit
* @throws ReaderException if digit cannot be decoded
*/
static int decodeDigit(int[] counters) throws ReaderException {
int bestVariance = MAX_AVG_VARIANCE; // worst variance we'll accept
int bestMatch = -1;
int max = PATTERNS.length;
for (int i = 0; i < max; i++) {
int[] pattern = PATTERNS[i];
int variance = patternMatchVariance(counters, pattern, MAX_INDIVIDUAL_VARIANCE);
if (variance < bestVariance) {
bestVariance = variance;
bestMatch = i;
}
}
if (bestMatch >= 0) {
return bestMatch;
} else {
throw ReaderException.getInstance();
}
}
}

336
core/src/com/google/zxing/oned/ITFReader.java Normal file
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@ -0,0 +1,336 @@
/*
* Copyright 2008 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.zxing.oned;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.ReaderException;
import com.google.zxing.Result;
import com.google.zxing.ResultPoint;
import com.google.zxing.common.BitArray;
import com.google.zxing.common.GenericResultPoint;
import java.util.Hashtable;
/**
*<p>
* Implements decoding of the ITF format.
* </p>
*<p>
* "ITF" stands for Interleaved Two of Five. This Reader will scan an arbritary
* ITF length barcode. The checksum is optional and is not applied by this
* Reader. The user of the decoded value will have to apply a checksum if
* required.
* </p>
*
*<p>
* <a
* href="http://en.wikipedia.org/wiki/Interleaved_2_of_5">http://en.wikipedia.
* org/wiki/Interleaved_2_of_5</a> is a great reference for Interleaved 2 of 5
* information.
* </p>
*
* @author kevin.osullivan@sita.aero
*/
public class ITFReader extends AbstractOneDReader {
private static final int MAX_AVG_VARIANCE = (int) (PATTERN_MATCH_RESULT_SCALE_FACTOR * 0.42f);
private static final int MAX_INDIVIDUAL_VARIANCE = (int) (PATTERN_MATCH_RESULT_SCALE_FACTOR * 0.8f);
private static final int W = 3; // Pixel width of a wide line
private static final int N = 1; // Pixed width of a narrow line
// Stores the actual narrow line width of the image being decoded.
private int narrowLineWidth = -1;
/**
* Start/end guard pattern.
*
* Note: The end pattern is reversed because the row is reversed before
* searching for the END_PATTERN
*/
private static final int[] START_PATTERN = { N, N, N, N };
private static final int[] END_PATTERN_REVERSED = { N, N, W };
/**
* Patterns of Wide / Narrow lines to indicate each digit
*/
static final int[][] PATTERNS = { { N, N, W, W, N }, // 0
{ W, N, N, N, W }, // 1
{ N, W, N, N, W }, // 2
{ W, W, N, N, N }, // 3
{ N, N, W, N, W }, // 4
{ W, N, W, N, N }, // 5
{ N, W, W, N, N }, // 6
{ N, N, N, W, W }, // 7
{ W, N, N, W, N }, // 8
{ N, W, N, W, N } // 9
};
public final Result decodeRow(int rowNumber, BitArray row, Hashtable hints) throws ReaderException {
StringBuffer result = new StringBuffer(20);
/**
* Find out where the Middle section (payload) starts & ends
*/
int[] startRange = decodeStart(row);
int[] endRange = decodeEnd(row);
decodeMiddle(row, startRange[1], endRange[0], result);
String resultString = result.toString();
if (resultString.length() == 0 || resultString.length() % 2 == 1)
throw ReaderException.getInstance();
return new Result(resultString,
null, // no natural byte representation for these barcodes
new ResultPoint[] { new GenericResultPoint(startRange[1], (float) rowNumber), new GenericResultPoint(startRange[0], (float) rowNumber) },
BarcodeFormat.ITF);
}
/**
* @param row
* row of black/white values to search
* @param payloadStart
* offset of start pattern
* @param resultString
* {@link StringBuffer} to append decoded chars to
* @throws ReaderException
* if decoding could not complete successfully
*/
protected void decodeMiddle(BitArray row, int payloadStart, int payloadEnd, StringBuffer resultString) throws ReaderException {
// Digits are interleaved in pairs - 5 black lines for one digit, and the
// 5
// interleaved white lines for the second digit.
// Therefore, need to scan 10 lines and then
// split these into two arrays
int[] counterDigitPair = new int[10];
int[] counterBlack = new int[5];
int[] counterWhite = new int[5];
for (int x = 0; payloadStart < payloadEnd; x++) {
// Get 10 runs of black/white.
recordPattern(row, payloadStart, counterDigitPair);
// Split them into each array
for (int k = 0; k < 5; k++) {
counterBlack[k] = counterDigitPair[k * 2];
counterWhite[k] = counterDigitPair[(k * 2) + 1];
}
int bestMatch = decodeDigit(counterBlack);
resultString.append((char) ('0' + bestMatch % 10));
bestMatch = decodeDigit(counterWhite);
resultString.append((char) ('0' + bestMatch % 10));
for (int i = 0; i < counterDigitPair.length; i++) {
payloadStart += counterDigitPair[i];
}
}
}
/**
* Identify where the start of the middle / payload section starts.
*
* @param row
* row of black/white values to search
* @return Array, containing index of start of 'start block' and end of
* 'start block'
* @throws ReaderException
*/
int[] decodeStart(BitArray row) throws ReaderException {
int endStart = skipWhiteSpace(row);
int startPattern[] = findGuardPattern(row, endStart, START_PATTERN);
/**
* Determine the width of a narrow line in pixels. We can do this by
* getting the width of the start pattern and dividing by 4 because its
* made up of 4 narrow lines.
*/
this.narrowLineWidth = (startPattern[1] - startPattern[0]) / 4;
/**
* The start & end patterns must be pre/post fixed by a quiet zone. This
* zone must be at least 10 times the width of a narrow line.
*
* ref: http://www.barcode-1.net/i25code.html
*/
if (this.narrowLineWidth * 10 > startPattern[0]) {
// Unable to find the quiet zone preceeding the start sequence.
throw ReaderException.getInstance();
}
return startPattern;
}
/**
* Skip all whitespace until we get to the first black line.
*
* @param row
* row of black/white values to search
* @return index of the first black line.
* @throws ReaderException
* Throws exception if no black lines are found in the row
*/
private int skipWhiteSpace(BitArray row) throws ReaderException {
int width = row.getSize();
int endStart = 0;
while (endStart < width) {
if (row.get(endStart)) {
break;
}
endStart++;
}
if (endStart == width)
throw ReaderException.getInstance();
return endStart;
}
/**
* Identify where the end of the middle / payload section ends.
*
* @param row
* row of black/white values to search
* @return Array, containing index of start of 'end block' and end of 'end
* block'
* @throws ReaderException
*/
int[] decodeEnd(BitArray row) throws ReaderException {
// For convenience, reverse the row and then
// search from 'the start' for the end block
row.reverse();
int endStart = skipWhiteSpace(row);
int endPattern[] = null;
try {
endPattern = findGuardPattern(row, endStart, END_PATTERN_REVERSED);
} catch (ReaderException e) {
// Put our row of data back the right way before throwing
row.reverse();
throw e;
}
/**
* The start & end patterns must be pre/post fixed by a quiet zone. This
* zone must be at least 10 times the width of a narrow line.
*
* ref: http://www.barcode-1.net/i25code.html
*/
if (this.narrowLineWidth * 10 > endPattern[0]) {
// Unable to find the quiet zone preceeding the start sequence.
throw ReaderException.getInstance();
}
// Now recalc the indicies of where the 'endblock' starts & stops to
// accomodate
// the reversed nature of the search
int temp = endPattern[0];
endPattern[0] = row.getSize() - endPattern[1];
endPattern[1] = row.getSize() - temp;
// Put the row back the righ way.
row.reverse();
return endPattern;
}
/**
* @param row
* row of black/white values to search
* @param rowOffset
* position to start search
* @param pattern
* pattern of counts of number of black and white pixels that are
* being searched for as a pattern
* @return start/end horizontal offset of guard pattern, as an array of two
* ints
* @throws ReaderException
* if pattern is not found
*
* TODO: This is very similar to implementation in AbstractUPCEANReader. Consider if they can be merged to
* a single method.
*/
int[] findGuardPattern(BitArray row, int rowOffset, int[] pattern) throws ReaderException {
int patternLength = pattern.length;
int[] counters = new int[patternLength];
int width = row.getSize();
boolean isWhite = false;
int counterPosition = 0;
int patternStart = rowOffset;
for (int x = rowOffset; x < width; x++) {
boolean pixel = row.get(x);
if ((!pixel && isWhite) || (pixel && !isWhite)) {
counters[counterPosition]++;
} else {
if (counterPosition == patternLength - 1) {
if (patternMatchVariance(counters, pattern, MAX_INDIVIDUAL_VARIANCE) < MAX_AVG_VARIANCE) {
return new int[] { patternStart, x };
}
patternStart += counters[0] + counters[1];
for (int y = 2; y < patternLength; y++) {
counters[y - 2] = counters[y];
}
counters[patternLength - 2] = 0;
counters[patternLength - 1] = 0;
counterPosition--;
} else {
counterPosition++;
}
counters[counterPosition] = 1;
isWhite = !isWhite;
}
}
throw ReaderException.getInstance();
}
/**
* Attempts to decode a sequence of ITF black/white lines into single
* digit.
*
* @param counters
* the counts of runs of observed black/white/black/... values
*
* @return The decoded digit
*
* @throws ReaderException
* if digit cannot be decoded
*/
static int decodeDigit(int[] counters) throws ReaderException {
int bestVariance = MAX_AVG_VARIANCE; // worst variance we'll accept
int bestMatch = -1;
int max = PATTERNS.length;
for (int i = 0; i < max; i++) {
int[] pattern = PATTERNS[i];
int variance = patternMatchVariance(counters, pattern, MAX_INDIVIDUAL_VARIANCE);
if (variance < bestVariance) {
bestVariance = variance;
bestMatch = i;
}
}
if (bestMatch >= 0) {
return bestMatch;
} else {
throw ReaderException.getInstance();
}
}
}

5
core/src/com/google/zxing/oned/MultiFormatOneDReader.java
View file

@ -49,11 +49,16 @@ public final class MultiFormatOneDReader extends AbstractOneDReader {
if (possibleFormats.contains(BarcodeFormat.CODE_128)) {
readers.addElement(new Code128Reader());
}
if (possibleFormats.contains(BarcodeFormat.ITF)) {
readers.addElement(new ITFReader());
}
}
if (readers.isEmpty()) {
readers.addElement(new MultiFormatUPCEANReader(hints));
readers.addElement(new Code39Reader());
readers.addElement(new Code128Reader());
readers.addElement(new ITFReader());
}
}