net.sourceforge.javaocr.filter
Class HistogramFilter

java.lang.Object
  net.sourceforge.javaocr.filter.AbstractSinglePixelFilter
      net.sourceforge.javaocr.filter.HistogramFilter

All Implemented Interfaces:

ImageFilter

public class HistogramFilter
extends AbstractSinglePixelFilter

collect image histogram and perform useful calculations on it

Author:

Konstantin Pribluda

Field Summary

(package private) int	amount_bins
private static int	DEFAULT_BINS
(package private) int[]	defaultSmooth
(package private) int[]	histogramm
(package private) int	totalCount

Constructor Summary

HistogramFilter()

HistogramFilter(int amount_bins)

Method Summary

int	adaptiveThreshold() compute adaptive threshold in iterative way starting from the middle of histogramm.
int	adaptiveThreshold(int threshold) recursively compute adaptive threshold
private int	computeM(int from, int to) compute meadian out of defined span
void	fold(int[] folder) Deprecated. does it makes sense at all?
int[]	getHistogramm()
int	getTotalCount()
protected void	processPixel(Image image) process single image pixel subclass shall retrieve current pixel value with image.next() and store it with image.put() after processing
void	reset()
void	smooth() Deprecated. does it makes sense at all?

Methods inherited from class net.sourceforge.javaocr.filter.AbstractSinglePixelFilter

process

Methods inherited from class java.lang.Object

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

Field Detail

defaultSmooth

int[] defaultSmooth

histogramm

int[] histogramm

totalCount

int totalCount

DEFAULT_BINS

private static final int DEFAULT_BINS

See Also:

Constant Field Values

amount_bins

final int amount_bins

Constructor Detail

HistogramFilter

public HistogramFilter()

HistogramFilter

public HistogramFilter(int amount_bins)

Method Detail

getHistogramm

public int[] getHistogramm()

getTotalCount

public int getTotalCount()

reset

public void reset()

processPixel

protected void processPixel(Image image)

Description copied from class: AbstractSinglePixelFilter

process single image pixel subclass shall retrieve current pixel value with image.next() and store it with image.put() after processing

Specified by:

processPixel in class AbstractSinglePixelFilter

smooth

public void smooth()

Deprecated. does it makes sense at all?

perform historgramm smoothing woth default coeefficitns { 1,2,1}

fold

public void fold(int[] folder)
          throws IllegalArgumentException

Deprecated. does it makes sense at all?

perform folding (smoothing, sharpening... depending on coeff array). TODO: what do we do with border conditions? zero them? let in peace? assume folding coefficients outside border to be 0?

Parameters:

folder - array contaning folding coefficients. must have odd length

Throws:

IllegalArgumentException

adaptiveThreshold

public int adaptiveThreshold()

compute adaptive threshold in iterative way starting from the middle of histogramm. for the best results image shall be normalised or enhanced befode doing this

Returns:

adaptiveThreshold

public int adaptiveThreshold(int threshold)

recursively compute adaptive threshold

Parameters:

threshold - start value for threshold computation

Returns:

computeM

private int computeM(int from,
                     int to)

compute meadian out of defined span

Parameters:

from - value (inclusive)

to - too value (exclusive)

Returns: