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熵风格

Local entropy of grayscale image

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Syntax

J = entropyfilt(I)
J = entropyfilt(I,nhood)

Description

example

J=熵filt（I)returns the arrayJ, where each output pixel contains the entropy value of the 9-by-9 neighborhood around the corresponding pixel in the input imageI。

For pixels on the borders ofI,熵风格uses symmetric padding. In symmetric padding, the values of padding pixels are a mirror reflection of the border pixels inI。

J=熵filt（I,nhood)执行输入图像的熵过滤Iusing the neighborhoodnhood。

Examples

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打开实时脚本

This example shows how to perform entropy filtering using熵风格。Brighter pixels in the filtered image correspond to neighborhoods in the original image with higher entropy.

在工作区中阅读图像。

I = imread('电路.tif');

Perform entropy filtering using熵风格。

J = entropyfilt(I);

Show the original image and the processed image.

imshow（i）标题（'Original Image')

Figure contains an axes object. The axes object with title Original Image contains an object of type image.

figure imshow(J,[]) title('Result of Entropy Filtering')

Figure contains an axes object. The axes object with title Result of Entropy Filtering contains an object of type image.

Input Arguments

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Image to be filtered, specified as a numeric array of any dimension. If the input image has more than two dimensions (ndims(I) > 2), such as for an RGB image, then熵风格filters all 2-D planes along the higher dimensions. For data typesdouble和single,强度values ofImust be in the range [0, 1].

Data Types:double|uint8|uint16|uint32|logical

Neighborhood, specified as a numeric or logical array containing0s and1s. The size ofnhood在每个维度中必须奇怪。

By default,熵风格uses the neighborhoodtrue(9)。The center element of the neighborhood isfloor((size(nhood) + 1)/2)。

To specify neighborhoods of other shapes, such as a disk, use thestrel函数创建所需形状的结构元素对象。然后，从结构元素对象的对象中提取邻域neighborhoodproperty.

Data Types:single|double|int8|INT16|int32|int64|uint8|uint16|uint32|uint64|logical

Output Arguments

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Filtered image, returned as a numeric array the same size as the input imageI。The data type ofJisdouble。如果输入图像Iis a binary image (data typelogical), then the values ofJ在[0，1]范围内。对于所有其他数据类型I, the values ofJare in the range [0, 8].

Data Types:double

More About

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Entropy

Entropy is a statistical measure of randomness that can be used to characterize the texture of the input image.

熵定义为-sum（p。*log2（p））, wherep包含从imhist。

Tips

  • By default,熵风格uses two bins for logical arrays.熵风格converts any other class touint8for the histogram count calculation and uses 256 bins so that the pixel values are discrete and directly correspond to a bin value.

  • 如果输入图像I是灰度图像，然后是Jcan exceed the range [0, 1] that some Image Processing Toolbox™ functions expect for images of typedouble。通过J作为这些功能的输入参数，请使用恢复function to rescale the values ofJto the range [0, 1].

参考

[1]Gonzalez, R. C., R. E. Woods, and S. L. Eddins.Digital Image Processing Using MATLAB。新泽西，Prentice Hall，2003年，第11章。

Version History

在R2006a之前引入

See Also

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