How can we detect the image properties

[tonyfkchu]

Dear Expert,

Anyone can help me to convert the following CMDLine of Image Adjustment process to .Net API

A) Detect Image Background and Remove it
[Convert CMDLine]

1. convert input.tiff -format "%[pixel:u.p{0,0}]" info:
2. convert input.tiff -fuzz 50% +transparent <bgColor result from step1> -scale1x1! -alpha off -format "%[pixel:u.p{0,0}]" info:
3. convert input.tiff -channel rgb -fill white -fuzz 50% -opaque <bgColor result from step2> output.tiff

B) Detect Low Contrast Level and Enhance the Contrast

1. Identify -verbose input.tiff
2. Extract the Line "STANDARD DEVIATION:" under "Overall: " section
3. if the result in Step 2 lower then 40 Apply Step 4 Otherwise Step 5
4. convert input.tiff -channel RGB -level 50%,80% output.tiff
5. convert input.tiff -channel RGB -auto-level output.tiff

Thanks for any help!

Best Regards
Tony Chu

[tonyfkchu]

Dear Expert,

After more study, I find a way to convert the code of Remove Background Color For Item A as follow:

Public Function RemoveBG(Fuzz As Integer) As Stream
    Dim result As Stream = New MemoryStream()
    Dim bgColor = IMImage.BackgroundColor

    IMImage.ColorFuzz = New Percentage(Fuzz)
    IMImage.Settings.FillColor = bgColor
    IMImage.Opaque(bgColor, MagickColors.White)

    IMImage.Write(result)
    Return result
End Function

[dlemstra]

A) You can get the name of the MagickColor that you need to call the Transparent method on the image with the following call image.FormatExpression("%[pixel:u.p{0,0}]").

B) You can get the STANDARD DEVIATION with image.Statistics().Composite().StandardDeviation.

I hope this will help you get started.

[tonyfkchu]

I have tested the Standard Deviation with this image https://app.box.com/s/3ihciqfhbgbanzovu8kg5qiknxzhkhqy

For the API, it return the result as 6402.11455673883

but with the identify -verbose function it just return 24.5184 as show below

Image statistics:
Overall:
min: 0 (0)
max: 255 (1)
mean: 239.587 (0.939559)
standard deviation: 24.5184 (0.0961508)
kurtosis: 46.5539
skewness: -6.03602
entropy: 0.428667
So what cost the difference ?

Best Regards
Tony Chu

[dlemstra]

You are using Q8 on the command line and Q16 in .NET. The Q8 version use a range of 0 to 255 and the Q16 version uses a range from 0 to 65535. Percentage wise this is around the same value.

[tonyfkchu]

I have found 1 more way to detect contrast level with CMDLine

magick zelda1.jpg -colorspace LAB -channel 0 -separate +channel
( -clone 0 -statistic maximum 5x5 )
( -clone 0 -statistic minimum 5x5 )
( -clone 1 -clone 2 +swap -define compose:clamp=off -compose minus -composite )
( -clone 1 -clone 2 +swap -define compose:clamp=off -compose plus -composite )
-delete 0-2
+swap -define compose:clamp=off -compose divide -composite
-scale 1x1! -format "%[fx:100*u]%" info:

How can we convert it to API ?

Best Regards
Tony Chu

[dlemstra]

What have you tried so far?

[tonyfkchu]

So Far, I just try the following only

image.Statistics().Composite().StandardDeviation.

[dlemstra]

You have added multiple samples. I am no longer following what you want to accomplish.