Code detecting false objects

On the left is the original image and on the right objects are being detected. Please advise. Also, there is another image in which I use the same code and it detects only one object. Why is this happening? I have attached that image as well.

clear all
close all
img= imread("C:\Users\0000_012_14px_prergb.tif");
imshow (img)
img=rgb2gray(img);
b=imbinarize(img); %binary image
imshow(b)
img1 = bwareafilt(b,[20 1000]); %retains objects pixel area
c=bwlabel(img1);
imshow(c)

measurements = regionprops(c,img, 'MeanIntensity'); %measurements = regionprops(labeledImage, grayscaleImage, 'MeanIntensity');
stats = regionprops('table',img1,'Centroid','MajorAxisLength','MinorAxisLength') %object detection
centers = stats.Centroid;
diameters = mean([stats.MajorAxisLength stats.MinorAxisLength],2);
radii = diameters/2;
hold on
viscircles(centers,radii); %drawing around the object
hold off
num_obj=height (stats)%finding the number of objects

Answer 1

[darova]

Use threshold to find appropriate objects

th = threshold(img);
% bw = im2bw(img,th);
bw = im2bw(img,th+0.1);

[Image Analyst]

Do you mean my interactive thresholding tool: https://www.mathworks.com/matlabcentral/fileexchange/29372-thresholding-an-image

[learningmatlab]

I have to analyze a set of images, will it work on all of them? These two images are from the same set. Also, there is no such function as "threshold" in Matlab.

[darova]

• I have to analyze a set of images, will it work on all of them?

Yes

• Also, there is no such function as "threshold" in Matlab.

Sorry, i mean graythresh()