com.google.zxing.common
Class GlobalHistogramBinarizer
java.lang.Object
com.google.zxing.Binarizer
com.google.zxing.common.GlobalHistogramBinarizer
- Direct Known Subclasses:
- HybridBinarizer
public class GlobalHistogramBinarizer
- extends Binarizer
This Binarizer implementation uses the old ZXing global histogram approach. It is suitable
for low-end mobile devices which don't have enough CPU or memory to use a local thresholding
algorithm. However, because it picks a global black point, it cannot handle difficult shadows
and gradients.
Faster mobile devices and all desktop applications should probably use HybridBinarizer instead.
- Author:
- dswitkin@google.com (Daniel Switkin), Sean Owen
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
GlobalHistogramBinarizer
public GlobalHistogramBinarizer(LuminanceSource source)
getBlackRow
public BitArray getBlackRow(int y,
BitArray row)
throws NotFoundException
- Description copied from class:
Binarizer
- Converts one row of luminance data to 1 bit data. May actually do the conversion, or return
cached data. Callers should assume this method is expensive and call it as seldom as possible.
This method is intended for decoding 1D barcodes and may choose to apply sharpening.
For callers which only examine one row of pixels at a time, the same BitArray should be reused
and passed in with each call for performance. However it is legal to keep more than one row
at a time if needed.
- Specified by:
getBlackRow
in class Binarizer
- Parameters:
y
- The row to fetch, 0 <= y < bitmap height.row
- An optional preallocated array. If null or too small, it will be ignored.
If used, the Binarizer will call BitArray.clear(). Always use the returned object.
- Returns:
- The array of bits for this row (true means black).
- Throws:
NotFoundException
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.
- Specified by:
getBlackMatrix
in class Binarizer
- Returns:
- The 2D array of bits for the image (true means black).
- Throws:
NotFoundException
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.
- Specified by:
createBinarizer
in class Binarizer
- Parameters:
source
- The LuminanceSource this Binarizer will operate on.
- Returns:
- A new concrete Binarizer implementation object.