imhist - get the histogram of an image

Calling Sequence

[counts, cells] = imhist(im)

[counts, cells] = imhist(im, bins)

[counts, cells] = imhist(im, bins [,width [,color]])

Parameters

• im: An image, which can be a boolean, uint8, int8, uint16, int16, int32 or double image.
• bins: The number of bins of the histogram. If bins is not specified, the function will used default value which determined by the image type: 2 for boolen, 2^8 for uint8 and int8, 2^16 for uint16 and int16, 2^16 for int32 (2^32 will need huge computer memory), and 10 for double.
• width: This argument will be sent to bar function. It is a real scalar, defines the width (a percentage of the available room) for the bar (default: 0.8, i.e 80%).
• color: This argument will be sent to bar function. It is a string (default: 'blue'), specifing the inside color bar.
• counts: the returned histogram.
• cells: the intervals for bins.

Description

imhist return the histogram of an image. If more than 2 arguments are give, the histogram will be shown in a figure.

If step is the step of scalar cells (cells(i+1)=cells(i)+step), the i'th bin is half-open interval (cells(i)-step/2, cells(i)+step/2] for i > 1, and [cells(1)-step/2, cells(1)+step/2] for i=1.

If more than 2 arguments are given, the function will call bar(cells, counts, ...) and send rest arguments to bar function to display the histogram.

Supported image type

BOOLEAN, UINT8, INT8, UINT16, INT16, INT32, DOUBLE.

Examples

    im = imread('lena.png');
    im = rgb2gray(im);
    [count, cells]=imhist(im);
    [count, cells]=imhist(im, 10);
    scf(0); imhist(im, 10, '');
    scf(1); imhist(im, 10, 0.5);
    scf(2); imhist(im, 10, 'green');
    scf(3); imhist(im, 10, 0.8, 'green');

Authors

Shiqi Yu <shiqi.yu[at]gmail.com>

Availability

http://sivp.sourceforge.net

See Also

mean2,  corr2,