imhist

Histogram of image data

Syntax

[counts,binLocations] = imhist(I)

[计数，binlocations] = imhist（i，n）

[counts,binLocations] = imhist(X,cmap)

imhist(___)

Description

[计数,binLocations] = imhist(I)calculates the histogram for the grayscale imageI。这imhistfunction returns the histogram counts in计数和垃圾箱位置binLocations。这number of bins in the histogram is determined by the image type.

[计数,binLocations] = imhist(I,n)specifies the number of bins,n, used to calculate the histogram.

[计数,binLocations] = imhist(X,cmap)calculates the histogram for the indexed imageXwith colormapcmap。这直方图has one bin for each entry in the colormap.

example

imhist(___)显示直方图的曲线图。如果输入图像是索引图像，则直方图显示了Colormap的颜色栏上方的像素值的分布cmap。

Examples

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Calculate Histogram

打开直播脚本

Read a grayscale image into the workspace.

I = imread('pout.tif');

Display a histogram of the image. SinceIis grayscale, by default the histogram will have 256 bins.

imhist(I)

Figure contains 2 axes objects. Axes object 1 contains an object of type stem. Axes object 2 contains 2 objects of type image, line.

Display the Histogram of a 3-D Intensity Image

打开直播脚本

加载3-D数据集。

loadmristack

Display the histogram of the data. Since the image is grayscale,imhistuses 256 bins by default.

imhist(mristack)

Figure contains 2 axes objects. Axes object 1 contains an object of type stem. Axes object 2 contains 2 objects of type image, line.

Input Arguments

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`I`—Grayscale image
numeric array

灰度图像，指定为任何维度的数字数组。如果图像具有数据类型single或者double, then values must be in the range [0, 1]. IfIhas values outside the range [0, 1], then you can use therescale.function to rescale values to the expected range.

`n`—Number of bins
positive integer

被指定为正整数的箱数。如果Iis a grayscale image, thenimhistuses a default value of 256 bins. IfIis a binary image, thenimhist使用两个垃圾箱。

Example:50

`X`—Indexed image
numeric array

索引图像，指定为任何维度的数字数组。

数据类型s:single|double|uint8|uint16|logical

`cmap`—Colormap
c-by-3 numeric matrix

Colormap associated with indexed imageX, specified as ac-by-3 numeric matrix with values in the range [0, 1]. Each row is a three-element RGB triplet that specifies the red, green, and blue components of a single color of the colormap.这colormap must be at least as long as the largest index inX。

数据类型s:double

Output Arguments

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`计数`— Histogram counts
numeric array

直方图计数，返回为数字数组。如果针对索引图像计算直方图，则X，然后是长度计数与Colormap的长度相同，cmap。

`binLocations`- 垃圾箱位置
numeric array

Bin locations, returned as a numeric array.

尖端

For grayscale images, then直方图的垃圾箱是宽度的半开放间隔A/（n-1）。In particular, thepthbin is the half-open interval

$\frac{A (p - 1.5)}{(n - 1)} - B \leq x < \frac{A (p - 0.5)}{(n - 1)} - B,$

wherexis the intensity value. The scale factorA和偏移B依赖于图像类的类型如下：

数据类型	A	B
`double`	`1`	`0`
`single`	`1`	`0`
`int8`	`255`	`128`
`INT16`	`65,535`	`32,768`
`int32`	`4,294,967,295`	`2,147,483,648`
`uint8`	`255`	`0`
`uint16`	`65,535`	`0`
`uint32`	`4,294,967,295`	`0`
`logical`	`1`	`0`

To display the histogram from计数和binLocations，使用命令stem（宾馆，计数）。

Extended Capabilities

C/C++ Code Generation
使用MATLAB®Coder™生成C和C ++代码。

Usage notes and limitations:

imhist金宝app支持C代码的生成（需要MATLAB^®Coder™). Note that if you choose the genericMATLAB主机计算机目标平台，imhistgenerates code that uses a precompiled, platform-specific shared library. Use of a shared library preserves performance optimizations but limits the target platforms for which code can be generated. For more information, see图像处理工具箱中的代码生成支持类型金宝app。
如果the first input is a binary image, thennmust be a scalar constant of value 2 at compile time.
不支持非编程语法。金宝app例如，语法imhist(I), whereimhist不支持显示直方图。金宝app

GPU Code Generation
使用GPU编码器™生成NVIDIA®GPU的CUDA®代码。

Usage notes and limitations:

如果the first input is a binary image, thennmust be a scalar constant of value 2 at compile time.
不支持非编程语法。金宝app例如，语法imhist(I), whereimhist不支持显示直方图。金宝app

GPU Arrays
使用并行计算工具箱™在图形处理单元（GPU）上运行，加速代码。

Usage notes and limitations:

imhistdoes not support indexed images on a GPU.
When you omit output arguments on a GPU,imhistdoes not display the histogram. In this case, the function returns the histogram counts in the variableANS.和does not return the histogram bin locations.

For more information, seeImage Processing on a GPU。

imhist

Syntax

Description

Examples

Calculate Histogram

Display the Histogram of a 3-D Intensity Image

Input Arguments

`I`—Grayscale image
numeric array

`n`—Number of bins
positive integer

`X`—Indexed image
numeric array

`cmap`—Colormap
c-by-3 numeric matrix

Output Arguments

`计数`— Histogram counts
numeric array

`binLocations`- 垃圾箱位置
numeric array

尖端

Extended Capabilities

C/C++ Code Generation
使用MATLAB®Coder™生成C和C ++代码。

GPU Code Generation
使用GPU编码器™生成NVIDIA®GPU的CUDA®代码。

GPU Arrays
使用并行计算工具箱™在图形处理单元（GPU）上运行，加速代码。

See Also

图像处理工具箱Documentation

金宝app

与Matlab引入深度学习

imhist

Syntax

Description

Examples

Calculate Histogram

Display the Histogram of a 3-D Intensity Image

Input Arguments

I—Grayscale imagenumeric array

n—Number of binspositive integer

X—Indexed imagenumeric array

cmap—Colormapc-by-3 numeric matrix

Output Arguments

计数— Histogram countsnumeric array

binLocations- 垃圾箱位置numeric array

尖端

Extended Capabilities

C/C++ Code Generation使用MATLAB®Coder™生成C和C ++代码。

GPU Code Generation使用GPU编码器™生成NVIDIA®GPU的CUDA®代码。

GPU Arrays使用并行计算工具箱™在图形处理单元（GPU）上运行，加速代码。

See Also

图像处理工具箱Documentation

金宝app

与Matlab引入深度学习

`I`—Grayscale image
numeric array

`n`—Number of bins
positive integer

`X`—Indexed image
numeric array

`cmap`—Colormap
c-by-3 numeric matrix

`计数`— Histogram counts
numeric array

`binLocations`- 垃圾箱位置
numeric array

C/C++ Code Generation
使用MATLAB®Coder™生成C和C ++代码。

GPU Code Generation
使用GPU编码器™生成NVIDIA®GPU的CUDA®代码。

GPU Arrays
使用并行计算工具箱™在图形处理单元（GPU）上运行，加速代码。