Filtering certain color range

Posted by rasheed-3 on May 12, 2008; 6:29am
URL: http://imagej.273.s1.nabble.com/Filtering-certain-color-range-tp3696226.html

Hi there everyone,

I would like to know if it is possible to subtract or filter a certain color range. I have attached a photograph of a core(acquired while drilling the hole looking for oil). From the image, three different major features (in terms of color) can be seen, light brown, dark brown and gray.

2010.00-2020.00+m.jpg.

What I would like to do is to know the total height of the sand(light and dark brown) in the image removing the gray stuff which is shale/clay. Therefore, if I could filter the gray stuff out, I can then plot a profile, knowing that the low value(or black) is the shale/clay and the rest is sand.

The problem I have now is, when I plot a gray scale profile, it will not be possible to differentiate the shale from sand as the shale seem to be brighter than the dark brown sand.

Any advice on this matter is very much appreciated. Thanks guys/gals.