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Why this incongruency happens regarding number of pixels?

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Stelios Fanourakis
Stelios Fanourakis on 24 Feb 2019
Closed: MATLAB Answer Bot on 20 Aug 2021
Hi
I use the image I attached.
I use this line to get the sum of pixels from row 307 to 366, at columns from 464 to 490
for col = 464 : 490
heights(col) = sum(rgbImage(366,col) - rgbImage(307,col));
end
This subtraction would give us 59 pixels and with a calibration factor of 0,042 it would give us around 2,48 mm for all the columns.
When I export the values to an excel file I get
If you multiply the below values with 0,042 you only get around 6 values acceptable and the closest to 2,5mm.
Why this incongruency???
By measuring heights(col), I should get 59 pixels multiplied by 0,042 I would get around 2,47 mm. Why I don't get those values when I export them to Excel??
Any ideas?
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  11 Comments
Stelios Fanourakis
Stelios Fanourakis on 24 Feb 2019
Image Analyst. Can you please give me an example of how I could use the improfile command at my specific issue?
How I define X1,X2,Y1,Y2 and embed image as well. I have tried it in the past with no luck

Answers (1)

Image Analyst
Image Analyst on 24 Feb 2019
See attached spatial calibration demo. Adapt as needed.
  5 Comments
Stelios Fanourakis
Stelios Fanourakis on 24 Feb 2019
I see. It is a subtraction of pixels values (intensity values), not the pixel as a number.
I double checked it.
Thanks for your time Image Analyst.

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