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Class Binarizer

This class hierarchy provides a set of methods to convert luminance data to 1 bit data. It allows the algorithm to vary polymorphically, for example allowing a very expensive thresholding technique for servers and a fast one for mobile. It also permits the implementation to vary, e.g. a JNI version for Android and a Java fallback version for other platforms.

author

dswitkin@google.com (Daniel Switkin)

Hierarchy

Index

Constructors

Protected constructor

Properties

Private source

Methods

Abstract createBinarizer

  • 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.

    Parameters

    • source: LuminanceSource

      The LuminanceSource this Binarizer will operate on.

    Returns Binarizer

    A new concrete Binarizer implementation object.

Abstract getBlackMatrix

  • 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.

    throws

    NotFoundException if image can't be binarized to make a matrix

    Returns BitMatrix

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

Abstract getBlackRow

  • 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.

    throws

    NotFoundException if row can't be binarized

    Parameters

    • y: number

      The row to fetch, which must be in [0, bitmap height)

    • row: BitArray

      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 BitArray

    The array of bits for this row (true means black).

getHeight

  • getHeight(): number

getLuminanceSource

getWidth

  • getWidth(): number

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