com.jtm.qrcode.qrcode.detector

Class Detector

java.lang.Object

com.jtm.qrcode.qrcode.detector.Detector

public class Detector
extends java.lang.Object

Encapsulates logic that can detect a QR Code in an image, even if the QR Code is rotated or skewed, or partially obscured.

Constructor Summary

Constructors

Constructor and Description
Detector(BitMatrix image)

Method Summary

Modifier and Type	Method and Description
protected 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.
protected static int	computeDimension(ResultPoint topLeft, ResultPoint topRight, ResultPoint bottomLeft, float moduleSize) Computes the dimension (number of modules on a size) of the QR Code based on the position of the finder patterns and estimated module size.
static PerspectiveTransform	createTransform(ResultPoint topLeft, ResultPoint topRight, ResultPoint bottomLeft, ResultPoint alignmentPattern, int dimension)
DetectorResult	detect() Detects a QR Code in an image, simply.
DetectorResult	detect(java.util.Map<DecodeHintType,?> hints) Detects a QR Code in an image, simply.
protected 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 BitMatrix	getImage()
protected ResultPointCallback	getResultPointCallback()
protected DetectorResult	processFinderPatternInfo(FinderPatternInfo info)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Detector

public Detector(BitMatrix image)

Method Detail

getImage

protected BitMatrix getImage()

getResultPointCallback

protected ResultPointCallback getResultPointCallback()

detect

public DetectorResult detect()
                      throws NotFoundException,
                             FormatException

Detects a QR Code in an image, simply.

Returns:

DetectorResult encapsulating results of detecting a QR Code

Throws:

NotFoundException

FormatException

detect

public DetectorResult detect(java.util.Map<DecodeHintType,?> hints)
                      throws NotFoundException,
                             FormatException

Detects a QR Code in an image, simply.

Parameters:

hints - optional hints to detector

Returns:

NotFoundException encapsulating results of detecting a QR Code

Throws:

NotFoundException

FormatException

processFinderPatternInfo

protected DetectorResult processFinderPatternInfo(FinderPatternInfo info)
                                           throws NotFoundException,
                                                  FormatException

Throws:

NotFoundException

FormatException

createTransform

public static PerspectiveTransform createTransform(ResultPoint topLeft,
                                                   ResultPoint topRight,
                                                   ResultPoint bottomLeft,
                                                   ResultPoint alignmentPattern,
                                                   int dimension)

computeDimension

protected static int computeDimension(ResultPoint topLeft,
                                      ResultPoint topRight,
                                      ResultPoint bottomLeft,
                                      float moduleSize)
                               throws NotFoundException

Computes the dimension (number of modules on a size) of the QR Code based on the position of the finder patterns and estimated module size.

Throws:

NotFoundException

calculateModuleSize

protected 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.

findAlignmentInRegion

protected 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 far

estAlignmentX - x coordinate of center of area probably containing alignment pattern

estAlignmentY - y coordinate of above

allowanceFactor - number of pixels in all directions to search from the center

Returns:

AlignmentPattern if found, or null otherwise

Throws:

NotFoundException