Extract pixels inside the area between 2 edge lines

2 次查看（过去 30 天）
Riccardo Rossi
Riccardo Rossi 2023-6-5
编辑： Matt J 2023-6-6
Hello,
I would like to detect all the pixels of an BW image which are enclosed into the area of a polybuffer. About the polybuffer, I have got the x and y coordinates of the 2 edge lines whcih constitute the polybuffer itself. How can I do it?
Thank you so much for your help!
  2 个评论
Matt J
Matt J 2023-6-5
编辑：Matt J 2023-6-5
What is a polybuffer? Please show us the image and the input variables that you have, so we can better demonstrate solutions..
Riccardo Rossi
Riccardo Rossi 2023-6-5
编辑：Matt J 2023-6-5
Hi Matt,
I have uploaded the image I and the POLYOUT (with x and y coordinates). Basically I would like to select all the pixels of I which are enclosed inside the area of polyout., as you can easily see by running the following code:
imshow(I)
hold on;
plot(POLYOUT.Vertices(:,2),POLYOUT.Vertices(:,1),'g','LineWidth',3);

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Matt J
Matt J 2023-6-5
编辑：Matt J 2023-6-5
[m,n]=size(I);
mask=poly2mask(POLYOUT.Vertices(:,2),POLYOUT.Vertices(:,1), m,n);
pixels=I(mask)
  2 个评论
Riccardo Rossi
Riccardo Rossi 2023-6-6
It is run, and how can i get the x y coordinates of "pixels" variable? Thank you so much again
Matt J
Matt J 2023-6-6
编辑：Matt J 2023-6-6
[y,x]=find(mask);
Once you have the mask, you can also get both together with,
stats = regionprops(mask,I, 'PixelList','PixelValues')

请先登录，再进行评论。

更多回答（1 个）

Diwakar Diwakar
Diwakar Diwakar 2023-6-5
Ran in:
% Create a black and white image
image = zeros(500, 500);
image(200:300, 200:300) = 1; % Add a square shape
% Display the original image
subplot(1, 2, 1);
imshow(image);
title('Original Image');
% Coordinates of the edge lines
edge_line1 = [100, 100; 200, 100; 200, 200; 100, 200];
edge_line2 = [150, 150; 250, 150; 250, 250; 150, 250];
% Detect enclosed pixels
enclosed_pixels = detect_enclosed_pixels(image, edge_line1, edge_line2);
% Display the enclosed pixels
subplot(1, 2, 2);
imshow(enclosed_pixels);
title('Enclosed Pixels');
function enclosed_pixels = detect_enclosed_pixels(image, edge_line1, edge_line2)
% Create binary mask
mask = false(size(image));
% Define the polygon points using edge lines
polygon_points = [edge_line1; flip(edge_line2, 1)];
% Get the minimum and maximum coordinates for the polygon
min_x = min(polygon_points(:, 1));
max_x = max(polygon_points(:, 1));
min_y = min(polygon_points(:, 2));
max_y = max(polygon_points(:, 2));
% Create a binary mask for the polygon region
polygon_mask = poly2mask(polygon_points(:, 1), polygon_points(:, 2), size(image, 1), size(image, 2));
% Extract the region of interest using the polygon mask
roi = image(min_y:max_y, min_x:max_x);
% Apply the polygon mask to the region of interest
roi_masked = roi & polygon_mask(min_y:max_y, min_x:max_x);
% Create a new binary mask with the enclosed region
enclosed_pixels = false(size(image));
enclosed_pixels(min_y:max_y, min_x:max_x) = roi_masked;
end

类别

在 Help Center 和 File Exchange 中查找有关 Region and Image Properties 的更多信息

标签

产品


版本

R2020b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by