How to measure the length of the particular region?

Hi, I am new to image processing field and I want to know how to measure the length and width of the particular image using Matlab.

Answer 1

[Von Duesenberg]

It depends on your goal. If you want the number of pixels, the size of your image in the workspace (with the size function) should give you this info. If you want real world units, you'll have to calibrate your camera: https://fr.mathworks.com/help/vision/ug/camera-calibration.html

Answer 2

[Image Analyst]

Try this:

[rows, columns, numberOfColorChannels] = size(yourImage);

If you need the lengths in real world units, see my attached spatial calibration demo.

[Image Analyst]

Wow, I don't know how we were expected to guess that given what you told us first. Anyway, use find

binaryImage = sobelImage > 128; % Or whatever value works.
topRow = find(binaryImage(:, 240), 1, 'first');
bottomRow = find(binaryImage(:, 240), 1, 'last');
leftColumn = find(binaryImage(300, :), 1, 'first');
rightColumn = find(binaryImage(300, :), 1, 'last');

[Dinesh Kumar Kanagaraj]

This 4 lines is suitable for all sizes of images or only 480*480 images.. And can u give some notes to understand this concept...because I am doing real time project based on this method...