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detect colored bars from an object

asked 2014-03-09 07:01:02 -0500

madmax gravatar image

Hi,

I am trying to filter for the colored bars like you can see in this image:

image description

Right now I try with a mean()over the rgb image and crop all under this threshold.
But then it looks like this:

image description

Do you have any idea what I could do better or other methods for getting the color?
Or should I just search for the colors? (There are about 10 colors that can occur)

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2

You can use the HSV-color wheel here to choose correct color.

Haris gravatar imageHaris ( 2014-03-09 22:55:47 -0500 )edit

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answered 2014-03-09 07:26:28 -0500

wuling gravatar image

updated 2014-03-09 10:29:02 -0500

Hi try to use inRangelink text and cvcolor to coverter color space like hsv,cym etc to solve this problem

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To filter all but the color bars or to filter for each color that can occur?

madmax gravatar imagemadmax ( 2014-03-09 13:06:59 -0500 )edit

There are two soluation here: 1. in color space(RGB ,HSV,CYM.......): use inRange 2. separate each color channel that easy to handle: use threshold. you can use filter to reduce some noise.

wuling gravatar imagewuling ( 2014-03-09 19:48:01 -0500 )edit

Just as a remark. The RBG (or BGR for OpenCV) is the worst color space for efficient color thresholding. I suggest using the HSV color space like suggested!

StevenPuttemans gravatar imageStevenPuttemans ( 2014-03-10 10:03:54 -0500 )edit

Yes, for color detection I am using HSV already, but was wondering how I could segment the bars best.

madmax gravatar imagemadmax ( 2014-03-10 12:10:39 -0500 )edit
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answered 2014-03-10 19:18:57 -0500

wuling gravatar image

updated 2014-03-10 20:46:09 -0500

when you decide to use hsv color space then drawing histogram and try in error to get threshold value Remember that the in each color space min, & max. threshold value may fail in 0<=min<=max<=255 or 0~min & max~255. Finally you use morphology like erode,dilate,region filling etc,and get the shape you want.

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Asked: 2014-03-09 07:01:02 -0500

Seen: 735 times

Last updated: Mar 09 '14