# Detect colour ratio on ROIs individually

**URL:** <https://forum.opencv.org/t/detect-colour-ratio-on-rois-individually/12806>\
**Category:** Python\
**Tags:** programming\
**Created:** [April 14, 2023, 5:41am UTC](https://forum.opencv.org/t/detect-colour-ratio-on-rois-individually/12806 "2023-04-14T05:41:56Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![karinca](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/karinca/32/7677_2.png) [@karinca](https://forum.opencv.org/u/karinca)\
**Post date:** [April 14, 2023, 5:41am UTC](https://forum.opencv.org/t/detect-colour-ratio-on-rois-individually/12806/1 "2023-04-14T05:41:56Z")

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![Red area detection](https://us1.discourse-cdn.com/flex020/uploads/opencv/original/2X/4/4bb447daa771b654ef8b260a55b432de410832ed.jpeg)  
Hello boys and girls,

I have a study on selecting 4 ROIs and calculating the red colour ratio on an object.  
I build a process flow in the attached JPEG file.  
I’m a noob python and opencv user.

Is there anyone who can help me about my study?

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<div class="post-metadata">

**Author:** ![karinca](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/karinca/32/7677_2.png) [@karinca](https://forum.opencv.org/u/karinca)\
**Post date:** [May 10, 2023, 8:33am UTC](https://forum.opencv.org/t/detect-colour-ratio-on-rois-individually/12806/2 "2023-05-10T08:33:29Z")

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Dear all,

I’ve completed the study by myself.  
Anyone who needs it, I’ll be happy to share. Just please let me know.