# Need to ignore black rectangluar blobs which are not on the mat

**URL:** <https://forums.openmv.io/t/need-to-ignore-black-rectangluar-blobs-which-are-not-on-the-mat/9812>\
**Category:** OpenMV Boards\
**Created:** [July 12, 2024, 12:34pm UTC](https://forums.openmv.io/t/need-to-ignore-black-rectangluar-blobs-which-are-not-on-the-mat/9812 "2024-07-12T12:34:54Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![aryakhed](https://avatars.discourse-cdn.com/v4/letter/a/ba9def/32.png) [@aryakhed](https://forums.openmv.io/u/aryakhed)\
**Post date:** [July 12, 2024, 12:34pm UTC](https://forums.openmv.io/t/need-to-ignore-black-rectangluar-blobs-which-are-not-on-the-mat/9812/1 "2024-07-12T12:34:54Z")

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We are working on a robotics competition and have to solve a mat using a robot. The mat will be kept on the floor and it will have a black border around it.  
How can i ignore all the black blobs which the camera detects that are not on the mat? Is there any specific parameter to be set in fand\_blobs to do that? Kindly respond.

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**Author:** ![kwagyeman](https://yyz1.discourse-cdn.com/flex029/user_avatar/forums.openmv.io/kwagyeman/32/4_2.png) [@kwagyeman](https://forums.openmv.io/u/kwagyeman)\
**Post date:** [July 12, 2024, 6:53pm UTC](https://forums.openmv.io/t/need-to-ignore-black-rectangluar-blobs-which-are-not-on-the-mat/9812/2 "2024-07-12T18:53:34Z")

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Yeah, you just detect the mat blob using find\_blobs() and then look at all rects of detected blobs that are inside the mat blob. This is a very simple intersection of rects problem.