How to normalise Image intensity?

39 次查看（过去 30 天）

Kyle 2011-7-1

1
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/10716-how-to-normalise-image-intensity

移动：DGM 2023-3-5

Hi,

I have 2 picture of the same object taken on different time. There are intensity different between the 2 picture(minor changes in lighting condition.)

Is there a way for me to make both to have the same intensity? Eg, Im2's intensity follows Im1's intensity?

Im1:

http://postimage.org/image/bzycpw10/

Im2

http://postimage.org/image/2sy5ler2c/

Thanks

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Dustin 2011-7-3

3
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/10716-how-to-normalise-image-intensity#answer_14830

在 MATLAB Online 中打开

Hi Kyle,

The method suggested by Sean de is fine to normalize the maximum intensity. However, it will not necessarily give you the same appearance for both images (due to the intensity distributions not definitely being scaled by a multiplicative factor).

I suggest you try the histogram transfer method in order to get a somewhat similar appearance. Something along the lines of:

b = histeq(b,imhist(a));

Cheers.

7 个评论
显示 5更早的评论隐藏 5更早的评论

Dustin 2011-7-6

移动：DGM 2023-3-5

You need to find the difference in the intensity values in the histograms of each image. Then, this difference for each intensity level can be transferred to the histogram of the third image, and histogram equalization performed on that image with this histogram.

Basic arithmetic and histeq should let you solve your problem. Look at this for further information about histogram equalization:

http://en.wikipedia.org/wiki/Histogram_equalization

Farah Nadiah 2016-4-2

移动：DGM 2023-3-5

Dustin..can i ask..how to subtract the two histogram that u mean in previous comment...can i have the coding thanx.. :)

请先登录，再进行评论。

更多回答（2 个）

Sean de Wolski 2011-7-1

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/10716-how-to-normalise-image-intensity#answer_14746

在 MATLAB Online 中打开

Inormalized = double(I)./double(max(I(:)));

Doing this to both will give them both the same maximum intensity (1).

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Kyle 2011-7-2

I try the code but the image still looks the same for me.

I uploaded the image,hope u can help me make both the images into same intensity.

请先登录，再进行评论。

Image Analyst 2011-7-9

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/10716-how-to-normalise-image-intensity#answer_15321

If you really want to match intensities of gray scale images, meaning that the histograms of the two images have EXACTLY the same histograms after transforming one image, then you need to look at my "Custom-shaped histogram" File Exchange submission: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862 You could use this on each color channel independently for what will probably give very acceptable results.

If you want to match histograms of a color image, I direct you to the Grundland/Dodgson method: http://www.eyemaginary.com/Portfolio/ColorHistogramWarp.html