Re: Removing grill/grate - "horizontal stripes in background"

Posted by Joel Sheffield on
URL: http://imagej.273.s1.nabble.com/Removing-grill-grate-horizontal-stripes-in-background-tp5009203p5009207.html

Hi Kiwa,

Will this help?  This is a crude image, and would need some tweaking.
I ran FFT on the image, and then drew a circle of r=34.4 centered on the
center of the image.  Then I used edit>selection>make inverse to invert the
selection, and then filled it with black (It must be true black, 0,0,0).
This blanked out everything but the central area,  and then I ran an
inverse FFT on the result.  The grid is mostly gone, but there is something
of a halo around each of the pieces of food.

Joel

[image: Inline image 1]



Joel B. Sheffield, Ph.D
Department of Biology
Temple University
Philadelphia, PA 19122
Voice: 215 204 8839
e-mail: [hidden email]
URL:  *http://tinyurl.com/khbouft <http://tinyurl.com/khbouft>*


On Thu, Aug 14, 2014 at 10:49 AM, Kiwa <[hidden email]> wrote:

> Hello All,
>
> I am trying to process this image:
> <http://imagej.1557.x6.nabble.com/file/n5009203/Food.jpg>
>
> I would like to remove the background to keep only the "food".
> The color doesn't matter since I basically want to calculate the surface of
> the food.
> (I know this image is not really good, I would need to take a picture
> directly above the belt)
>
> I am facing difficulties with the grill/grid in the background.
> I tried several approaches :
> - Grayscale + Thresholding + Bandpass filter
> - Split RBG channel, Threshold min/max on each, Merge
> - Edge detection
> - Watershed ..
>
> So far, the best image I got is after applying good Levels/Windows.. to the
> Red channel image.
> Here :
> <http://imagej.1557.x6.nabble.com/file/n5009203/Food.jpg>
>
>
> Do you guys have any ideas how I could remove the horizontal lines ?
>
> Do you think it's feasible or better to do a detection/object-tracking of
> the large white/colored features to get multiple ROI for each food part and
> then work on them separately ?
>
> I am open to any suggestions,
>
> Thanks a lot,
> K.
>
>
>
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