Talk:Color histogram

Table needs clarification

In my opinion, the example table isn't thorough enough. By reading the article, I really have no idea what it means... is that a table for some sample image, or what? Mattpat 12:43, 26 September 2006 (UTC)

Seems to be an example from who knows where. I kept it, but put some words in front of it for what it might mean. Dicklyon 01:17, 9 February 2007 (UTC)

Poor article

This is a very poor article. It does not explain the graph shown, why there is a red and a grey solid part, and what the grey graph line is. It should show a sample image that matches the sample color table values shown. And it only covers histograms used as a highly compressed representation of the image. But the main use of histograms is as a tool for editors who are manipulating images, to understand the pixels in the image, and to decide what adjustments to make in the color values.--69.87.200.66 21:54, 8 February 2007 (UTC)

Yes, it's pretty awful. I just took a step toward making it better. Enough for now. Hopefully others will help. Dicklyon 01:16, 9 February 2007 (UTC)

I second the above comment. I was interested in finding out about image editing, which is barely mentioned here. Even a less abstract explanation of what a histogram actually represents, and how, would be helpful. The article is also very poorly written, especially the paragraph on object recognition, which repeats itself without actually clarifying anything. We could do without such redundant phrases as "adding additional information", as well...

Sorry to criticise rather than contribute - I don't really know enough about the subject to risk re-writing anything myself. I hope somebody out there does! Jethrobrice 11:25, 4 May 2007 (UTC)

It's OK. But the "color histogram" is not what you're looking for. It's not the same kind of histogram that you see in image editing. You should be looking for an image histogram or something like that (it redirected here, so I made a new stub there instead). Dicklyon 14:43, 4 May 2007 (UTC)

Color histogram vs. image histogram

The article says that "color histogram should not be confused with image histogram", implying that the former is used only for color spaces with two or more dimensions, while the latter is exclusively for monochromatic images (or a single channel of a color image).
Methinks that this distinction is false. Perhaps some authors define things that way; but Wikipedia should follow common usage, not the favorite definition of a particular author or community.
IMHO, if we consider the views of all people who use those terms, we can only say that "image histogram" is a generic term for any histogram derived from the image pixels; while "color histogram" is a histogram of the color values of the image, whatever its color space is. So:

• for monochromatic images, "color histogram" and "image histogram" are both valid and mean the same thing;
• for images with N≥2 color channels, "color histogram" usually means an N-dimensional histogram; and "image histogram" may be either the same thing, or any lower-dimensional histogram of some color attribute(s), such as luminance, single channel, hue/sat pairs, etc..

Would you agreee?
All the best, --Jorge Stolfi (talk) 13:08, 17 November 2009 (UTC)

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