how can i use clarity factor with gaussian kernel in image processing

i apply the gaussian gradient kernel to image for bubble detection

after that i trying to find the clarity of image and remove out of focused bubble. like this article

(Sci-Hub | A fully-automated image processing technique to improve measurement of suspended particles and flocs by removing out-of-focus objects. Computers & Geosciences, 52, 189–198 | 10.1016/j.cageo.2012.08.018)

at the part 3.2.

but i can't find the code for clarity in matlab. so i use the binarize fuction and threshold but it didn't work perfectly so i want to find how i can use

clarity of the image

can anyone help me?

this is my cord

C=imread('30130170023.jpg');
C2=imread('back.jpg');
C1=C2-C;
C3 = imcomplement(C1);
[gx,gy]=gaussgradient(C1,2.0);
[gx1,gy1]=gaussgradient(C3,2.0);
M=abs(gx)+abs(gy);
M1=abs(gx1)+abs(gy1);
MU=M+M1;
Bi=imbinarize(MU,0.3);
BWdfill = imfill(Bi,'holes');
% imshow(MU);
si=imread('sisi.jpg');
si=si(:,:,1:3);
si=im2gray(si);
si=imbinarize(si);
BWdfill=BWdfill-si;
BWdfill=imcrop(BWdfill,[299 0 687 796]);
% imshow(BWdfill);
se = strel('disk',2);
ie = imerode(BWdfill,se);
ie = imerode(ie,se);
ie = imerode(ie,se);
% ie = imerode(ie,se);
% ie = imerode(ie,se);
id =imdilate(ie,se);
id =imdilate(id,se);
id =imdilate(id,se);
% id =imdilate(id,se);
% id =imdilate(id,se);
imshow(id);

[centers,radii] = imfindcircles(id,[3 80],'ObjectPolarity','bright','Sensitivity',0.85);
viscircles(centers, radii,'Color','b');

Answer 1

[Image Analyst]

Looks like they define clarity as the max of the gradient in each floc blob:

"The maximum value of Ig associated with each floc i is a

quantitative measure of how close to the plane of focus a given

floc is, and this value is defined here as the ‘‘clarity value’’ a

a(i) = max(Ig(ROI(i))

A threshold......"

[chang hoon oh]

yeah i think you are right... but can you give me another advice? i think using gaussian gradient kernel is suit for bubble detection and remove out of focused bubble but sometime it didn't work. apply the threshold to picture some case that erase not out of focused bubble but focused bubble....

[Image Analyst]

It's possible expecially if the bubble had a smooth exterior boundary and is smooth inside. I'd try adjusting parameters like the window side and threshold level.