imagingbook.pub.color.statistics

Class ColorHistogram

java.lang.Object

imagingbook.pub.color.statistics.ColorHistogram

public class ColorHistogram
extends Object

This class calculates a color histogram of a set of colors (i.e., a color image). Only the unique colors are accounted for. Colors are supplied as ARGB-encoded integers (A = alpha values being ignored). Colors are internally sorted by their frequency (in descending order).

Version:

2017/01/04

Constructor Summary

Constructors

Constructor and Description
ColorHistogram(int[] pixelsOrig)
ColorHistogram(int[] pixelsOrig, boolean sortByFrequency) Creates a color histogram instance from the supplied sequence of color pixel values (assumed to be ARGB-encoded integers).

Method Summary

Modifier and Type	Method and Description
int	getColor(int index) Returns the unique color with the given index.
int	getCount(int index) Returns the frequency of the unique color with the given index.
int	getNumberOfColors() Returns the number of unique colors.
void	listUniqueColors() Lists the unique colors to System.out (intended for debugging only).

Methods inherited from class java.lang.Object

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

Constructor Detail

ColorHistogram

public ColorHistogram(int[] pixelsOrig)

ColorHistogram

public ColorHistogram(int[] pixelsOrig,
                      boolean sortByFrequency)

Creates a color histogram instance from the supplied sequence of color pixel values (assumed to be ARGB-encoded integers). The original pixel values are not modified.

Parameters:

pixelsOrig - Original pixel values (not modified).

sortByFrequency - Pass true to sort the final colors by descending frequency.

Method Detail

getNumberOfColors

public int getNumberOfColors()

Returns the number of unique colors.

Returns:

The number of unique colors.

getColor

public int getColor(int index)

Returns the unique color with the given index. Colors are sorted by (decreasing) frequency.

Parameters:

index - The color index.

Returns:

The color, encoded as an ARGB integer (A is zero).

getCount

public int getCount(int index)

Returns the frequency of the unique color with the given index. Colors are sorted by (decreasing) frequency.

Parameters:

index - The color index.

Returns:

The frequency of the color.

listUniqueColors

public void listUniqueColors()

Lists the unique colors to System.out (intended for debugging only).