how can i convert detected grayscale image object back into rgb form?

I have to detect red chilies from plant. I got this result which shown in given figure but now i have to convert this final detected chili image back into red form, how can i do this?

This is the code which i used in this work.

i=imread('IMG_20210825_153633 - Copy.jpg');
subplot(2,2,1);
imshow(i)
G=rgb2gray(i);
subplot(2,2,2);
imshow(G);
A=i(:,:,1);
subplot(2,2,3);
imshow(A);
f=imsubtract(A,G);
subplot(2,2,4);
imshow(f)

Answer 1

[yanqi liu]

clc; clear all; close all;
i=imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/808449/image.jpeg');
i=imcrop(i,[5     8   632   291]);
subplot(2,2,1);
imshow(i)
G=rgb2gray(i);
subplot(2,2,2);
imshow(G);
A=i(:,:,1);
subplot(2,2,3);
imshow(A);
f=imsubtract(A,G);
subplot(2,2,4);
imshow(f)

bw = im2bw(mat2gray(f));
bw = imclose(bw, strel('disk', 5));
bw = bwareaopen(bw, 5);
i2 = i .* uint8(cat(3,bw,bw,bw));
figure; imshow(i2, []);

[Atul Kumar]

Thank you so much, it works.

Answer 2

[Yongjian Feng]

How about changing the red chili area of the last image to alpha = 0 (so it is completely transparent). Then overlay on top of the original image

Answer 3

[Image Analyst]

Use the Color Thresholder app on the apps tab of the tool ribbon. Load your image then choose HSV color space, then adjust the thresholds, then export the function. Easy, but if you have trouble, let us know, but attach the original image 'IMG_20210825_153633 - Copy.jpg'