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Given this RGB image

enter image description here

I want to find the number of points that are, or almost, black ؟

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  • $\begingroup$ Please double check your question. $\endgroup$
    – anderstood
    Commented Feb 18, 2018 at 13:11
  • $\begingroup$ I cannot find the ؟. Moreover, what does "near" mean? $\endgroup$
    – Henrik Schumacher
    Commented Feb 18, 2018 at 13:28
  • $\begingroup$ Point Near to black color or give me black don’t worry $\endgroup$
    – nwafotb
    Commented Feb 18, 2018 at 14:04
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    $\begingroup$ One approach: binarize the image, then count the number of zeros in the binarized image. $\endgroup$
    – bill s
    Commented Feb 18, 2018 at 15:21
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    $\begingroup$ similarly, (yourimage)// Binarize // ColorNegate // Total $\endgroup$
    – Ali Hashmi
    Commented Feb 19, 2018 at 9:03

2 Answers 2

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First let's convert to grayscale and look at the histogram of colors.

im = Import["https://i.sstatic.net/QPKeW.jpg"];
gdata = Join @@ ImageData[ColorConvert[im, "Grayscale"]];
Histogram[gdata]

enter image description here

We see there's a big divide between 'black' and 'white', so we can just binarize and count the black pixels.

Length @ PixelValuePositions[Binarize[im], 0]

49073
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Indeed the image is RGB

Import["https://i.sstatic.net/QPKeW.jpg", "ColorSpace"]

RGBColor

This gives the positions of the pixels with RGB values from {0,0,0} to {10,10,10}. Change the Round argument to redefine what "almost black" means.

Position[
 Round[Import["https://i.sstatic.net/QPKeW.jpg", "Data"], 10]
 , {0, 0, 0}
 ]

Then you can use Length

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