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Azzera filtri

I would like to know how to convert a binary image to a pseudo color image based on closed regions

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this to this

Risposta accettata

Image Analyst
Image Analyst il 25 Ott 2021
Modificato: Image Analyst il 25 Ott 2021
Try this:
% Demo by Image Analyst
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
clear; % Erase all existing variables. Or clearvars if you want.
workspace; % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 20;
markerSize = 40;
fileName = 'image.png';
grayImage = imread(fileName);
% Get the dimensions of the image.
% numberOfColorChannels should be = 1 for a gray scale image, and 3 for an RGB color image.
[rows, columns, numberOfColorChannels] = size(grayImage)
if numberOfColorChannels > 1
% It's not really gray scale like we expected - it's color.
% Extract the red channel (so the magenta lines will be white).
grayImage = grayImage(:, :, 1);
% Display the image.
subplot(2, 2, 1);
imshow(grayImage, []);
axis('on', 'image');
title('Original Gray Scale Image', 'FontSize', fontSize, 'Interpreter', 'None');
hold on
% Maximize window.
g = gcf;
g.WindowState = 'maximized'
% Get a mask:
binaryImage = grayImage < 128;
% Display the image.
subplot(2, 2, 2);
imshow(binaryImage, []);
axis('on', 'image');
title('Mask/Binary/Logical Image', 'FontSize', fontSize, 'Interpreter', 'None');
hold on
% Label each blob with 8-connectivity, so we can make measurements of it
[labeledImage, numberOfBlobs] = bwlabel(binaryImage, 8);
% Display the image.
subplot(2, 2, 3);
imshow(labeledImage, []);
axis('on', 'image');
title('Labeled Image', 'FontSize', fontSize, 'Interpreter', 'None');
hold on
% Apply a variety of pseudo-colors to the regions.
coloredLabelsImage = label2rgb (labeledImage, 'jet', [0,0,.5]);
% Display the pseudo-colored image.
subplot(2, 2, 4);
axis('on', 'image');
title('Colorized Labeled Image', 'FontSize', fontSize, 'Interpreter', 'None');
hold on
[EDIT] Just a note to say that while this may look pretty, it's not very useful because you cannot tell if nearby blobs are connected because their colors are so similar. You'd be better off with shuffling the colors like this:
coloredLabelsImage = label2rgb (labeledImage, 'jet', 'k', 'shuffle');

Più risposte (3)

yanqi liu
yanqi liu il 26 Ott 2021
sir,please check the follow code to get some information
clc; clear all; close all;
I = imread('');
J = im2bw(I);
J = ~J;
[L,num] = bwlabel(J);
figure; imagesc(L);axis equal; axis off;colormap jet;
  2 Commenti
Akshay Kumar Pakala
Akshay Kumar Pakala il 26 Ott 2021
Hi yanqui liu
Thank you for the help. I think the imagesc command is the reson why the circumference of each cell in the pusedo color image is approximated.
Sure, I will go through the book.
Thank you

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Akshay Kumar Pakala
Akshay Kumar Pakala il 25 Ott 2021
Thank you image analyist for the your answer and the code. I will try to grasp your code and run it, and will let you know my comments.
Neverthelss, thank you for the immediate response.

Akshay Kumar Pakala
Akshay Kumar Pakala il 25 Ott 2021
Hey thanks a lot again. I really appreciate your help. I just have some questions regarding your code.
1st one
from your code "binaryImage = grayImage < 128;"
how does this work.
  10 Commenti
Image Analyst
Image Analyst il 26 Ott 2021
You can get the number of blobs like this:
[labeledImage, numberOfBlobs] = bwlabel(binaryImage, 8);
props = regionprops(labeledImage, 'Area', 'EquivDiameter', 'Perimeter'); % Whatever you want.
numberOfBlobs should be the same as numel(props) which is the number of blobs in the image.
You might want to call
binaryImage = imclearborder(binaryImage);
before calling bwlabel() to get rid of partial blobs being chopped off at the boundary. The areas are not accurate for those blobs because we do not have the entire blob available to measure.

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