Hi, anyone can help me how to measure the moon crescent using regionprops and how to remove the unwanted object in the image?
MATLAB: How to measure the moon crescent
Image Processing Toolboximage segmentationmooncrescentregionprops
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Pretty easy. Threshold, fill holes, take the 3 largest.
Solution below. Adapt as needed.
% Initialization steps.
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 = 14;filename = fullfile(pwd, 'image_1.jpg');grayImage = imread(filename);if ndims(grayImage) == 3 % It's really an RGB image, not a gray scale image.
% Convert to gray scale
grayImage = rgb2gray(grayImage);endsubplot(2, 3, 1);imshow(grayImage, []);title('Original Image', 'FontSize', fontSize);% Threshold
subplot(2, 3, 2);imhist(grayImage);grid on;title('Histogram', 'FontSize', fontSize);mask = grayImage < 128; % or whatever value works
subplot(2, 3, 3);imshow(mask, []);title('Initial Binary Image', 'FontSize', fontSize);% Fill Holes
mask = imfill(mask, 'holes');subplot(2, 3, 4);imshow(mask, []);title('After holes filled', 'FontSize', fontSize);% Take 3 largest blobs then invert intensity.
mask = ~bwareafilt(mask, 3);subplot(2, 3, 5);imshow(mask, []);title('Final Image Showing 3 Largest', 'FontSize', fontSize);
Convert to grayscale and then threshold and find the bounding box
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
imtool close all; % Close all imtool figures.
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;% Read in the color image.
folder = pwd;baseFileName = 'm2.bmp';% Get the full filename, with path prepended.
fullFileName = fullfile(folder, baseFileName);if ~exist(fullFileName, 'file') % Didn't find it there. Check the search path for it.
fullFileName = baseFileName; % No path this time.
if ~exist(fullFileName, 'file') % Still didn't find it. Alert user.
errorMessage = sprintf('Error: %s does not exist.', fullFileName); uiwait(warndlg(errorMessage)); return; endendrgbImage = imread(fullFileName);% Get the dimensions of the image. numberOfColorBands should be = 3.
[rows, columns, numberOfColorBands] = size(rgbImage);% Display the original color image.
subplot(2, 3, 1);imshow(rgbImage, []);axis on;title('Original Color Image', 'FontSize', fontSize);drawnow;% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);% Histogram the red channel, but there is a huge spike at 255 so let's not count those.
subplot(2, 3, 2);grayImage = rgb2gray(rgbImage);imshow(grayImage, []);title('Gray Scale version', 'FontSize', fontSize);subplot(2, 3, 3);histogram(grayImage(grayImage<255))grid on;title('Histogram of Gray Scale Image', 'FontSize', fontSize);someThresholdValue = 150;binaryImage = grayImage > someThresholdValue;% Take largest blob
binaryImage = bwareafilt(binaryImage, 1);subplot(2, 3, 4);imshow(binaryImage);grid on;title('Binary Image', 'FontSize', fontSize);% Label the binary image.
labeledImage = bwlabel(binaryImage);props = regionprops(labeledImage, 'BoundingBox');bbox = props.BoundingBoxcroppedImageRGB = imcrop(rgbImage, bbox);subplot(2, 3, 5);imshow(croppedImageRGB);grid on;title('Cropped RGB Image', 'FontSize', fontSize);% Gray scale version of cropped image
croppedImageGray = imcrop(grayImage, bbox);subplot(2, 3, 6);imshow(croppedImageGray);grid on;title('Cropped Gray Scale Image', 'FontSize', fontSize);
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