Matlab needs to calculate distance and find pixel size

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Hi, I need to do image calibration between two known points on an image.
Let's say that we have those two points [130,799] and [602,799], where the first are rows and then the columns. I know I need to use the euclidean distance equation like this
So assuming
y1 = 130
y2 = 602
x1 = 799
x2 = 799
distanceInPixels = sqrt( (x2-x1).^2 + (y2 - y1).^2);
How do I combine all those stuff and finally get the calibration factor of mm/pixel.
Please help.

Accepted Answer

Mark Sherstan
Mark Sherstan on 29 Jan 2019
You need to know the distance between those two points. I attachted part of a presentation where I did just that. I placed three "calibration blobs" at the start of the video. Masked the image for green, then red, then blue to find the "blobs". Using the euclidean distance equation you provided I took the known centroid-centroid distance divided by the pixels for each color mask and then averaged the results. Let me know if you have any further questions but you are almost there!
Screen Shot 2019-01-28 at 10.29.34 PM.png

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