com.google.zxing.common
Class HybridBinarizer

java.lang.Object
  com.google.zxing.Binarizer
      com.google.zxing.common.GlobalHistogramBinarizer
          com.google.zxing.common.HybridBinarizer

public final class HybridBinarizer
extends GlobalHistogramBinarizer

This class implements a local thresholding algorithm, which while slower than the GlobalHistogramBinarizer, is fairly efficient for what it does. It is designed for high frequency images of barcodes with black data on white backgrounds. For this application, it does a much better job than a global blackpoint with severe shadows and gradients. However it tends to produce artifacts on lower frequency images and is therefore not a good general purpose binarizer for uses outside ZXing. This class extends GlobalHistogramBinarizer, using the older histogram approach for 1D readers, and the newer local approach for 2D readers. 1D decoding using a per-row histogram is already inherently local, and only fails for horizontal gradients. We can revisit that problem later, but for now it was not a win to use local blocks for 1D. This Binarizer is the default for the unit tests and the recommended class for library users.

Since:

BlackBerry API 7.0.0

Constructor Summary

HybridBinarizer(LuminanceSource source)

Method Summary
Binarizer	createBinarizer(LuminanceSource source) Creates a new object with the same type as this Binarizer implementation, but with pristine state.
BitMatrix	getBlackMatrix() Converts a 2D array of luminance data to 1 bit data.

Methods inherited from class com.google.zxing.common.GlobalHistogramBinarizer

getBlackRow

Methods inherited from class com.google.zxing.Binarizer

getLuminanceSource

Methods inherited from class java.lang.Object

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

Constructor Detail

HybridBinarizer

public HybridBinarizer(LuminanceSource source)

Since:

BlackBerry API 7.0.0

Method Detail

getBlackMatrix

public BitMatrix getBlackMatrix()
                         throws NotFoundException

Description copied from class: Binarizer

Converts a 2D array of luminance data to 1 bit data. As above, assume this method is expensive and do not call it repeatedly. This method is intended for decoding 2D barcodes and may or may not apply sharpening. Therefore, a row from this matrix may not be identical to one fetched using getBlackRow(), so don't mix and match between them.

Overrides:

getBlackMatrix in class GlobalHistogramBinarizer

Returns:

The 2D array of bits for the image (true means black).

Throws:

NotFoundException

Since:

BlackBerry API 7.0.0

createBinarizer

public Binarizer createBinarizer(LuminanceSource source)

Description copied from class: Binarizer

Creates a new object with the same type as this Binarizer implementation, but with pristine state. This is needed because Binarizer implementations may be stateful, e.g. keeping a cache of 1 bit data. See Effective Java for why we can't use Java's clone() method.

Overrides:

createBinarizer in class GlobalHistogramBinarizer

Parameters:

source - The LuminanceSource this Binarizer will operate on.

Returns:

A new concrete Binarizer implementation object.

Since:

BlackBerry API 7.0.0