How can I find how many colours are there in an image?

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OpenCV

Hi
I am looking for a way to find number of colours are there in an image ? and they are which colours ?

Posted 3-May-13 22:51pm

hor_313

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dev C plus 4-May-13 6:02am

so what???
get color by another software or by API
it's so vague question

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i964682 · Answer 1 · 2013-05-03T22:56:00

Solution 1

You have a vague question but i'll give it a go.

Tip:
You need to know the structure of the file format used by the image.
From here, you will know where the colour data is saved.
You can then just parse through the file and count the unique colour data saved.

Does this answer your question?

Posted 3-May-13 22:56pm

i964682

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hor_313 4-May-13 5:08am

yes , but may you explain more about jpg images?
and if the colours goes more than 100 , how can I decrease them to less than 100 colours?

Style-7 · Answer 2 · 2013-05-03T23:10:00

Solution 2

GetDIBits()
http://msdn.microsoft.com/en-us/library/windows/desktop/dd144879(v=vs.85).aspx[^]

or

GetPixel()

http://msdn.microsoft.com/ru-ru/library/system.drawing.bitmap.getpixel.aspx[^]

Posted 3-May-13 23:10pm

Style-7