# Reverse color blob detection

**URL:** <https://forums.openmv.io/t/reverse-color-blob-detection/282>\
**Category:** OpenMV Boards\
**Created:** [June 5, 2017, 4:31am UTC](https://forums.openmv.io/t/reverse-color-blob-detection/282 "2017-06-05T04:31:00Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![tedmeyers](https://avatars.discourse-cdn.com/v4/letter/t/a183cd/32.png) [@tedmeyers](https://forums.openmv.io/u/tedmeyers)\
**Post date:** [June 5, 2017, 4:31am UTC](https://forums.openmv.io/t/reverse-color-blob-detection/282/1 "2017-06-05T04:31:00Z")

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Not quite sure how to describe this, but I’m looking for a way to do color blob detection on objects that are not a specific color. To put it more directly, if I have a green wall, is there a way to detect anything in view that is not green? I know how to get the camera to find green objects, but I want it in this case to find everything that is not green.

This will eventually be used for robotic object avoidance; my idea is to look at the floor and find anything that is a different color than the floor. I just figure that a green (or white, or gray) wall is a good way to test things before I move on to the floor.

Thanks in advance!

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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:** [June 5, 2017, 5:11am UTC](https://forums.openmv.io/t/reverse-color-blob-detection/282/2 "2017-06-05T05:11:51Z")

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Pass invert=True to find blobs. It’s right in the docs. 😀