Package com.google.zxing.qrcode.detector
Class Detector
java.lang.Object
com.google.zxing.qrcode.detector.Detector
- Direct Known Subclasses:
MultiDetector
Encapsulates logic that can detect a QR Code in an image, even if the QR Code is rotated or skewed, or partially obscured.
- Author:
- Sean Owen
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprotected final float
calculateModuleSize
(ResultPoint topLeft, ResultPoint topRight, ResultPoint bottomLeft) Computes an average estimated module size based on estimated derived from the positions of the three finder patterns.detect()
Detects a QR Code in an image.final DetectorResult
detect
(Map<DecodeHintType, ?> hints) Detects a QR Code in an image.protected final AlignmentPattern
findAlignmentInRegion
(float overallEstModuleSize, int estAlignmentX, int estAlignmentY, float allowanceFactor) Attempts to locate an alignment pattern in a limited region of the image, which is guessed to contain it.protected final BitMatrix
getImage()
protected final ResultPointCallback
protected final DetectorResult
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Constructor Details
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Detector
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Method Details
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getImage
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getResultPointCallback
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detect
Detects a QR Code in an image.
- Returns:
DetectorResult
encapsulating results of detecting a QR Code- Throws:
NotFoundException
- if QR Code cannot be foundFormatException
- if a QR Code cannot be decoded
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detect
public final DetectorResult detect(Map<DecodeHintType, ?> hints) throws NotFoundException, FormatExceptionDetects a QR Code in an image.
- Parameters:
hints
- optional hints to detector- Returns:
DetectorResult
encapsulating results of detecting a QR Code- Throws:
NotFoundException
- if QR Code cannot be foundFormatException
- if a QR Code cannot be decoded
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processFinderPatternInfo
protected final DetectorResult processFinderPatternInfo(FinderPatternInfo info) throws NotFoundException, FormatException - Throws:
NotFoundException
FormatException
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calculateModuleSize
protected final float calculateModuleSize(ResultPoint topLeft, ResultPoint topRight, ResultPoint bottomLeft) Computes an average estimated module size based on estimated derived from the positions of the three finder patterns.
- Parameters:
topLeft
- detected top-left finder pattern centertopRight
- detected top-right finder pattern centerbottomLeft
- detected bottom-left finder pattern center- Returns:
- estimated module size
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findAlignmentInRegion
protected final AlignmentPattern findAlignmentInRegion(float overallEstModuleSize, int estAlignmentX, int estAlignmentY, float allowanceFactor) throws NotFoundException Attempts to locate an alignment pattern in a limited region of the image, which is guessed to contain it. This method uses
AlignmentPattern
.- Parameters:
overallEstModuleSize
- estimated module size so farestAlignmentX
- x coordinate of center of area probably containing alignment patternestAlignmentY
- y coordinate of aboveallowanceFactor
- number of pixels in all directions to search from the center- Returns:
AlignmentPattern
if found, or null otherwise- Throws:
NotFoundException
- if an unexpected error occurs during detection
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