主要内容

histeq

Enhance contrast using histogram equalization

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Syntax

J = histeq(I,hgram)
J = histeq(I,n)
J = histeq(I)
newmap = histeq(X,map)
newmap = histeq（x，地图，hgram）
[___，t] =组合（___)

描述

example

J= histeq (I,h)转换灰度图像Iso that the histogram of the output grayscale imageJwithlength(hgram)bins approximately matches the target histogramh。

J= histeq (I,n)转换灰度图像Iso that the histogram of the output grayscale imageJwithn箱大约是平的。直方图Jis flatter whennis much smaller than the number of discrete levels inI。

J= histeq (I)转换灰度图像Iso that the histogram of the output grayscale imageJhas 64 bins and is approximately flat.

newmap= histeq (X,地图)transforms the values in the color map so that the histogram of the gray component of the indexed imageXis approximately flat. The transformed color map isnewmap。

newmap= histeq (X,地图,h)将与索引图像相关联的颜色映射转换Xso that the histogram of the gray component of the indexed image (X,newmap）大致匹配目标直方图h。该histeqfunction returns the transformed color map innewmap。length(hgram)must be the same as大小（地图，1）。

[___,T] = histeq(___)also returns the transformationTthat maps the gray component of the input grayscale image or color map to the gray component of the output grayscale image or color map.

例子

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打开直播脚本

将图像读入工作区。

I = imread('tire.tif');

Enhance the contrast of an intensity image using histogram equalization.

j =组合（i）;

Display the original image and the adjusted image.

imshowpair（我，j，'montage') axis关闭

Display a histogram of the original image.

图imhist（我，64）

Display a histogram of the processed image.

图imhist（J，64）

打开直播脚本

加载3-D数据集。

loadmristack

Perform histogram equalization.

enhanced = histeq(mristack);

Display the first slice of data for the original image and the contrast-enhanced image.

figure subplot(1,2,1) imshow(mristack(:,:,1)) title('Slice of Original Image') subplot(1,2,2) imshow(enhanced(:,:,1)) title('Slice of Enhanced Image')

Input Arguments

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输入灰度图像，指定为任何维度的数字数组。

Data Types:single|double|int16|uint8|uint16

目标直方图, specified as a numeric vector.h在适当的范围内具有强度值的平等间隔箱：

  • [0, 1] for images of classdouble要么single

  • [0, 255] for images of classuint8

  • [0, 65535] for images of classuint16

  • [-32768, 32767] for images of classint16

histeqautomatically scaleshso thatsum(hgram)=numel(I)。直方图J更好的比赛hwhenlength(hgram)is much smaller than the number of discrete levels inI。

Data Types:single|double

离散灰度级数, specified as a positive integer.

Data Types:single|double

索引图像, specified as a numeric array of any dimension. The values inXare an index into the color map地图。

Data Types:single|double|uint8|uint16

彩色地图, specified as ac-3个数字矩阵范围内的值[0,1]。每行是一个三个元素的RGB三元组，指定颜色图的单个颜色的红色，绿色和蓝色组件。

Data Types:double

Output Arguments

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Transformed grayscale image, returned as a numeric array of the same size and class as the input imageI。

Grayscale transformation, returned as a numeric vector. The transformationT映射图像中的灰色级别Ito gray levels inJ。

Data Types:double

Transformed color map, specified as ann-3个数字矩阵范围内的值[0,1]。每行是一个三个元素的RGB三元组，指定颜色图的单个颜色的红色，绿色和蓝色组件。

Data Types:double

算法

When you supply a desired histogramh,histeqchooses the grayscale transformationT最小化

| c 1 ( T ( k ) ) − c 0 ( k ) | ,

c0是输入图像的累积直方图I，和c1is the cumulative sum ofhfor all intensitiesk。This minimization is subject to these constraints:

  • T必须是单调的

  • c1（t（a））不能过度c0(a)直方图计数之间的距离超过一半a

histequses the transformationb=T(a）映射灰度级别X(or the color map) to their new values.

If you do not specifyh, thenhisteqcreates a flath,

h= ones(1,n)*prod(size(A))/n;

and then applies the previous algorithm.

Extended Capabilities

See Also

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在R2006A之前介绍

图像处理工具箱Documentation

金宝app

与Matlab引入深度学习

与Matlab引入深度学习

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