colour count of an image

Question

I am trying to make an upscale texture mod for an old game "Recoil".

For this, I need to find the height, width, pixel format and colour count of a few 1000 images, so that I can feed this information to excel and find the best textures to be upscaled.

I have been able to get the height, width and pixel format via a PowerShell script, which I can then copy to excel as this script provides a table. the script works on the whole folder.

Function Get-Image{
Param(
     [Parameter(ValueFromPipeline=$true)]
     [System.IO.FileINfo]$file
)
begin{        
     [System.Reflection.Assembly]::LoadWithPartialName("System.Drawing") |Out-Null 
}
process{
      if( $file.Exists){
           $img=[System.Drawing.Image]::FromFile($file)
           $image=$img.Clone()
           $img.Dispose()
           $image | Add-Member `
                          -MemberType NoteProperty `
                          -Name Filename `
                          -Value $file.FUllname `
                          -PassThru
      }else{
           Write-Host "File not found: $file" -fore yellow       
      }   
 }    
end{}
}
dir C:	est\*.png | Get-Image
dir C:	est\*.png -Recurse | Get-Image  | select filename, Width, Height,     PixelFormat | ft -auto

the result of the above code

I need help finding a way to get a colour count of the images. I have found a manual way to do it via a Photoshop filter but it is not a viable way to do all the images. photoshop filter example

If I can get the Colour count in a similar way to the code provided it would be the best.

edit: I need a way to get Colour count of all images in the folder.

the images themselves are small (the biggest being 512x512). I just need the number of colours, no need for the breakdown of RGB.

ps- I have literally no knowledge of programming and scripting ( even the above script someone Reddit helped me out with)

Hopefully, I have been able to explain my query clearly. Thank you for your time and consideration.

user_712649 · Answer

Use the GetPixel() method to fetch the color used for each pixel, then count the unique colors you encounter:

$hashset = [System.Collections.Generic.HashSet[System.Drawing.Color]]::new()

foreach($x in 0..($image.Width - 1)){
  foreach($y in 0..($image.Height - 1)){
    [void]$hashset.Add($image.GetPixel($x, $y))
  }
}

Write-Host "Image has $($hashset.Count) unique colors"

You could add this routine to your existing function like so:

process {
    if ($file.Exists) {
        # Load image
        $img = [System.Drawing.Image]::FromFile($file)
        $image = $img.Clone()
        $img.Dispose()

        # Count colors
        $colorSet = [System.Collections.Generic.HashSet[System.Drawing.Color]]::new()
        foreach ($x in 0..($image.Width - 1)) {
            foreach ($y in 0..($image.Height - 1)) {
                [void]$colorSet.Add($image.GetPixel($x, $y))
            }
        }

        # Add file name and color count properties to image object
        $fileNameProp = @{ MemberType = 'NoteProperty'; Name = 'Filename'; Value = $file.FullName; PassThru = $true}
        $colorCountProp = @{ MemberType = 'NoteProperty'; Name = 'ColorCount'; Value = $colorSet.Count; PassThru = $true}
        $image | Add-Member @fileNameProp | Add-Member @colorCountProp
    }
    else {
        Write-Host "File not found: $file" -fore yellow       
    }   
}

And now you can do:

dir C:	est\*.png -Recurse | Get-Image | ft Filename, Width, Height, PixelFormat, ColorCount -AutoSize

colour count of an image

1 Answers