jigl.image
Class Histogram

java.lang.Object
  |
  +--jigl.image.Histogram

Direct Known Subclasses:

CumulativeHistogram

public class Histogram

extends Object

Histogram keeps track of histogram information for an image. The range of histogram's grayscale starts from min() and ends with max(). Supports only GrayImage and RealGrayImage.

Field Summary

protected float	inc The "bucket" size for the histogram
protected float	max The minimum grayscale value in the histogram
protected float	min The maximum grayscale value in the histogram
protected int[]	values An array stors the counts for every grayscale

Constructor Summary

Histogram(Image image, int interval)
Creates a Histogram from image.

Histogram(Image image, int interval, int int_min, int int_max)
Creates a Histogram from image.

Histogram(Image image, int interval, ROI r)
Creates a Histogram from this image over a Region of Interest.

Histogram(int[] data, int min, int max, int interval)
Creates a histogram from data.

Histogram(int min, int max, int interval)
Creates an empty Histogram of size (max-min)/interval + 1.

Method Summary

int	count(int value) Returns the count at the given value.
void	decrement(int value) Decrements at the given value.
int[]	getData() Returns a deep copy of the histogram data.
float	inc() Returns the incrementation value (interval).
void	increment(int value) Increments at the given value.
int	length() Returns the size of the data array
float	max() Returns the maximum grayscale value for this histogram.
float	min() Returns the minimum grayscale value for this histogram.
void	setCount(int value, int count) Sets the count for a histogram value.
RealSignal	toSignal() Turns this Histogram into a signal.

Methods inherited from class java.lang.Object

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

Field Detail

values

protected int[] values

An array stors the counts for every grayscale

min

protected float min

The maximum grayscale value in the histogram

max

protected float max

The minimum grayscale value in the histogram

inc

protected float inc

The "bucket" size for the histogram

Constructor Detail

Histogram

public Histogram(Image image,
                 int interval)
          throws ImageNotSupportedException

Creates a Histogram from image. image can only be GrayImage or RealGrayImage.

Parameters:

image - GrayImage or RealGrayImage to create histogram from.

interval - the "bucket" size for the histogram. A value of 1 with a GrayImage will leave a bucket for every grayscale value between image.max() and image.min().

Throws:

ImageNotSupportedException - if image is null or not a GrayImage or RealGrayImage.

Histogram

public Histogram(Image image,
                 int interval,
                 int int_min,
                 int int_max)
          throws ImageNotSupportedException

Creates a Histogram from image. image can only be GrayImage or RealGrayImage.

Parameters:

image - GrayImage or RealGrayImage to create histogram from.

interval - the "bucket" size for the histogram. A value of 1 with a GrayImage will leave a bucket for every grayscale value between image.max() and image.min().

int_min - minimum value in the histogram

int_max - maximum value in the histogram

Throws:

ImageNotSupportedException - if image is null or not a GrayImage or RealGrayImage.

Histogram

public Histogram(Image image,
                 int interval,
                 ROI r)
          throws ImageNotSupportedException

Creates a Histogram from this image over a Region of Interest. image can only be GrayImage or RealGrayImage.

Parameters:

image - GrayImage or RealGrayImage to create histogram from.

interval - the "bucket" size for the histogram. A value of 1 with a GrayImage will leave a bucket for every grayscale value between image.max() and image.min().

r - defines the interest region in the image.

Throws:

ImageNotSupportedException - if image is null or not a GrayImage or RealGrayImage.

Histogram

public Histogram(int min,
                 int max,
                 int interval)

Creates an empty Histogram of size (max-min)/interval + 1.

Parameters:

min - minimum grayscale value.

max - maximum grayscale value.

interval - grayscale values per bucket.

Histogram

public Histogram(int[] data,
                 int min,
                 int max,
                 int interval)
          throws InvalidArgumentException,
                 NullPointerException

Creates a histogram from data. data must be of length (max-min)/interval + 1. If data is null, a NullPointerException will be thrown.

Parameters:

data - histogram data.

min - minimum grayscale value.

max - maximum grayscale value.

interval - grayscale values per bucket.

Throws:

InvalidArgumentException - if data is not the exact length.

NullPointerException

Method Detail

getData

public int[] getData()

Returns a deep copy of the histogram data.

increment

public void increment(int value)

Increments at the given value. Please note, all calculations are internal. For Example, suppose min=-20 and max=20, if you want to increment the value at -20 then pass in -20 not 0.

decrement

public void decrement(int value)

Decrements at the given value. Please note, all calculations are internal. value should be between min and max.

For Example, suppose min=-20 and max=20, if you want to decrement the value at -20 then pass in -20 not 0.

setCount

public void setCount(int value,
                     int count)

Sets the count for a histogram value. value should be between min and max.

count

public int count(int value)

Returns the count at the given value. Please note, all calculations are internal. For Example, suppose min=-20 and max=20, if you want to get the value at -20 then pass in -20 not 0.

toSignal

public RealSignal toSignal()

Turns this Histogram into a signal. The length of this signal is (int)((max-min)/inc) + 1 and may not be 255.

min

public float min()

Returns the minimum grayscale value for this histogram.

max

public float max()

Returns the maximum grayscale value for this histogram.

inc

public float inc()

Returns the incrementation value (interval).

length

public int length()

Returns the size of the data array