location of pixel from minimum and maximum value is in histogram

can you help me, please? I want to know where the location of pixel from minimum and maximum value is in histogram ?

Answer 1

[Image Analyst]

See if this is what you want:

% Read in image.
grayImage = imread('pout.tif');
subplot(2, 1, 1);
imshow(grayImage);
% Get histogram.
[counts, grayLevels] = imhist(grayImage);
subplot(2, 1, 2);
bar(grayLevels, counts, 1);
grid on;
title('Histogram of image', 'FontSize', 20);

% Get the min and max gray levels directly from the image.
minGLImage = min(grayImage(:))
maxGLImage = max(grayImage(:))
% Get the min and max gray levels from the histogram (instead of directly from the image).
minGL = grayLevels(find(counts, 1, 'first'))
maxGL = grayLevels(find(counts, 1, 'last'))
% Should be the same as from the image.
% Get the rows and columns where these occur in the image.
[minRows, minColumns] = find(grayImage == minGL);
[maxRows, maxColumns] = find(grayImage == maxGL);
% Plot these locations over the image in the graphical overlay.
subplot(2, 1, 1);
hold on; % Don't blow away image.
plot(minColumns, minRows, 'b.', 'MarkerSize', 25);
plot(maxColumns, maxRows, 'r.', 'MarkerSize', 25);
title('Red = max.  Blue = min.', 'FontSize', 20);

Answer 2

[Yudawan Hidayat]

this is can't work in rgb image bro :(

[Image Analyst]

If you want the min and max location for each color channel separately you have to process each color channel separately. Here is how you can separate the RGB image into 3 monochrome images.

% Extract the individual red, green, and blue color channels.

redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);

Then use each one of those in turn instead of "grayImage".

Otherwise if you want the intensity of the RGB image, you'll need to convert it to gray scale:

grayImage = rgb2gray(rgbImage);

[Yudawan Hidayat]

how to show of location value bro? not point?

[Image Analyst]

Not sure what that means. If you want to plot a dot over the point, use plot().

hold on;
plot(xBro, yBro, 'r.', 'MarkerSize', 30);

If you want text, you can use sprintf() and then text(), title(), xlabel(), or ylabel() depending on where you want it placed.

txtInfo = sprintf('(xBro, yBro) = (%.4f, %.4f)', xBro, yBro);
title(txtInfo, 'FontSize', 15);
xlabel(txtInfo,  'FontSize', 15);
text(xBro, yBro, txtInfo, 'FontSize', 15);

[Yudawan Hidayat]

I want to find the matrix value of the min and max histogram

[Image Analyst]

I really don't know what this means. I've given you several guesses. Please define what a "max histogram" is because I don't know. All I know is that an image has one histogram, not several - no min histogram, no max histogram, no "any-kind-of-other" histogram, just one simple gray level histogram. And do you want the number of counts in the histogram bin? Or the values of pixels in the bins? Or the edges (min gray level and max gray level) that define one of the bins (like the one with the most counts in it)? Please give an example.