Check if the code is correct or not for finding the diameter of objects in an image.

Sir here I attached the code for finding the diameter of irregularly shaped objects in an image. Tell me if the code is correct to find the diameter or not .

if true
  % code
end
originalImage = imread('result.jpg');
originalImage=rgb2gray(originalImage);
labeledImage = bwlabel(originalImage, 8);
D=regionprops(labeledImage,'area');
d1=regionprops(labeledImage,'EquivDiameter');

Answer 1

[Image Analyst]

No, you need to create a binary image first, plus you can do it all in one call to regionprops():

originalImage = imread('result.jpg');
originalImage=rgb2gray(originalImage);
binaryImage = originalImage > thresholdValue; % for example 80 or 142 or some value.
labeledImage = bwlabel(binaryImage, 8);
D=regionprops(labeledImage,'area','EquivDiameter');

[ajith]

WHAT IS THE EFFICIENT METHOD FOR CALCULATING THE THRESHOLD VALUE

[Walter Roberson]

See graythresh()

[ajith]

if true
  % code
end
originalImage = imread('result.jpg');
originalImage=rgb2gray(originalImage);
thresholdvalue = graythresh(originalImage);
binaryImage = originalImage > thresholdValue; 
labeledImage = bwlabel(binaryImage, 8);
D=regionprops(labeledImage,'area','EquivDiameter');

sir, if the coding is right to perform the correct operation or not

[Walter Roberson]

Plausible.

[Image Analyst]

You'd have to multiply the value from graythresh by 255 because that gives you a value in the range 0-1. Other than that it looks fine but you'd have to decide if graythresh's method (the "Otsu" method) works in your situation. I find that often it doesn't pick the best threshold and so I have to custom write a method to pick the threshold.