Re: Advise on object detection

On May 23, 7:47 pm, aruzinsky <aruzin...@xxxxxxxxxxxxxxxxxxxx> wrote:
On May 22, 10:11 am, serg271 <serg...@xxxxxxxxx> wrote:



On May 22, 6:14 pm, aruzinsky <aruzin...@xxxxxxxxxxxxxxxxxxxx> wrote:

On May 21, 9:48 pm, ImageAnalyst <imageanal...@xxxxxxxxxxxxxx> wrote:

Find the green box with a color classifier, for
example just convert the RGB image into HSI and threshold on the hue
channel.

In my experience, that won't work because there will be numerous
unwanted green (or any) hue regions with S slightly greater than
zero. In other word, these unwanted regions look white or grey but
have green (or any) hue. Hue and saturation must be both examined to
properly detect an object by color.

I found helpful in my project (on low-en cellphone camera) use YUV
based "saturation" and "hue". That is saturation=sqrt(U*U+V*V),
hue=atan(U,V). For some reason it works a lot better for low end
camera than HSV, probably because in HSV hue almost pure R , G and B
take most of the range, and YUV have more place for "transitional"
colors.

Why don't you combine and compare hue and saturation thusly?:

[ (U - U0)*(U - U0) + (V - V0)*(V - V0) ] < threshhold

where Y0 U0 V0 is the reference color.

I don't have any reference color. I'm doing color classification - how
similar colors of different objects, and use both hue and saturation
for kind of hashing.
.

Relevant Pages

  • Re: Advise on object detection
    ... example just convert the RGB image into HSI and threshold on the hue ... unwanted green hue regions with S slightly greater than ... camera than HSV, probably because in HSV hue almost pure R, G and B ... I bet the rationale for these coefficients is far fetched. ...
    (sci.image.processing)
  • Re: Advise on object detection
    ... example just convert the RGB image into HSI and threshold on the hue ... unwanted green hue regions with S slightly greater than ... I found helpful in my project (on low-en cellphone camera) use YUV ... camera than HSV, probably because in HSV hue almost pure R, G and B ...
    (sci.image.processing)
  • Re: Advise on object detection
    ... example just convert the RGB image into HSI and threshold on the hue ... unwanted green hue regions with S slightly greater than ... camera than HSV, probably because in HSV hue almost pure R, G and B ... Why don't you combine and compare hue and saturation thusly?: ...
    (sci.image.processing)
  • Re: Advise on object detection
    ... example just convert the RGB image into HSI and threshold on the hue ... channel. ... unwanted green hue regions with S slightly greater than ...
    (sci.image.processing)
  • Re: Effects of saturation on contrast
    ... Convert the raw shot into a RGB color-space ... make a duplicate of that and convert the duplicate to Lab. ... Luminance, hue, and saturation. ...
    (comp.graphics.apps.photoshop)
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