measure the maximum distance in millimeters(mm)

How can I measure the maximum width of the white shape in millimeters(mm) not in pixels ?

Image Analyst

Answer 1

[Image Analyst]

Then you need to multiply by the number of millimeters per pixel:

props = regionprops(binaryImage, 'BoundingBox')
width = props.BoundingBox(3) * mmPerPixel;

See attached demo.

[Dina Abd El-twab]

I dont want to use the demo . I want to write the equation of conversion directly

Image Analyst

[Image Analyst]

Did you overlook this code:

props = regionprops(binaryImage, 'BoundingBox')
width = props.BoundingBox(3) * mmPerPixel;

Now, what is mmPerPixel for your image? Or what is the field of view of your image and the number of pixels across?

mmPerPixel = FOVinMm / size(yourImage, 2)

[Dina Abd El-twab]

I need it to extract features .

Image Analyst

[Dina Abd El-twab]

I applied your (regionprops code), but the value that is obtained is not the right value , I applied (imtool) and I found that the maximum width is 60.07 .

But your code gave me the width is 445.