I have an assignment for my Matlab class in which I have to make a grey matrix (all locations have value 100). In this matrix there should be a filled circle. All the values in the filled circle should be 200. How do I create this? My teacher gave me the following tip: use these functions: rand(), randperm(), indexing, for-loop, gray(), meshgrid(), cart2pol() Some of these functions might not be necessary for creating this circle in the matrix. My assignment is bigger than just creating a filled circle, but i'm not sure which functions are needed, so I decided to show them all.
MATLAB: How to make a grey matrix, that contains a filled circle
cart2polcirclefaqfilledgreymatrix
Related Solutions
Maitham, check out the following:
function my_circ(imageSize, center, radius) % function definition
% Create a logical image of a circle with specified
% diameter, center, and image size.
% First create the image.
imageSizeX = imageSize(1);imageSizeY = imageSize(2);[columnsInImage rowsInImage] = meshgrid(1:imageSizeX, 1:imageSizeY);% Next create the circle in the image.
centerX = center(1);centerY = center(2);circlePixels = (rowsInImage - centerY).^2 ... + (columnsInImage - centerX).^2 <= radius.^2;% circlePixels is a 2D "logical" array.
% Now, display it.
image(circlePixels) ;colormap([0 0 0; 1 1 1]);title('Binary image of a circle');end % end of function
which is called (e.g., from the MATLAB command window) with
my_circ([400 600], [20 30], 50)Here is the code:
% Initialization / clean-up code.
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;
% Create a gradient ramp along the x axis
rampImage = uint8(repmat([0:255], [256, 1]));% Now, display it.
subplot(2,2, 1);imshow(rampImage) ;axis on;title('Ramp Image');% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);% Get rid of tool bar and pulldown menus that are along top of figure.
set(gcf, 'Toolbar', 'none', 'Menu', 'none');% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off') % Create a logical image of a circle with specified
% diameter, center, and image size.
% First create the image.
imageSizeX = 256;imageSizeY = 256;[columnsInImage rowsInImage] = meshgrid(1:imageSizeX, 1:imageSizeY);% Next create the circle in the image.
centerX = 128;centerY = 128;radius = 110;circlePixels = (rowsInImage - centerY).^2 ... + (columnsInImage - centerX).^2 <= radius.^2;% circlePixels is a 2D "logical" array.
% Now, display it.subplot(2,2, 2);imshow(circlePixels, []);axis on;title('Binary image of a circle');% Apply the circle mask to the ramp image.
finalImage = rampImage; % Initialize;
finalImage(~circlePixels) = 0; % Mask
% Now, display it.subplot(2,2, 3);imshow(finalImage, []);axis on;title('Masked Image');
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