draw segment line on image

Question

thoraya 2012-7-13

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/43536-draw-segment-line-on-image

hi, i want to draw a set of segment line in a given image I.each segment line s is defined by: postion of the centre p depending on the size of the image , its length l and its orientation w. please help me.

3 个评论
显示 1更早的评论隐藏 1更早的评论

Walter Roberson 2012-7-14

Please do not use "matlab" as a tag. http://www.mathworks.co.uk/matlabcentral/answers/43073-a-guide-to-tags

Walter Roberson 2012-7-14

Yash, there are a lot of users here whose first language is not English. Please do not use careless English such as "u" or "wana", as it makes it difficult for people to understand.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Image Analyst 2012-7-13

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/43536-draw-segment-line-on-image#answer_53421

在 MATLAB Online 中打开

See my demo:

% Demo to write an ellipse and a line into the overlay of an image,
% and then to burn those overlays into the image.
%----- Initializing steps -----
% Clean up
clc;
clear all;
close all;
workspace; % Display the workspace panel.
hasIPT = license('test', 'image_toolbox');
if ~hasIPT
  % User does not have the toolbox installed.
  message = sprintf('Sorry, but you do not seem to have the Image Processing Toolbox.\nDo you want to try to continue anyway?');
  reply = questdlg(message, 'Toolbox missing', 'Yes', 'No', 'Yes');
  if strcmpi(reply, 'No')
    % User said No, so exit.
    return;
  end
end
% Display images to prepare for the demo.
monochromeImage = imread('pout.tif');
subplot(2, 4, 1);
imshow(monochromeImage);
title('Original Image');
subplot(2, 4, 2);
imshow(monochromeImage);
title('Original Image with ellipse in overlay');
subplot(2, 4, 5);
imshow(monochromeImage);
title('Original Image');
subplot(2, 4, 6);
imshow(monochromeImage);
title('Original Image with line in overlay');
set(gcf, 'units','normalized','outerposition',[0 0 1 1]); % Maximize figure.
set(gcf,'name','Demo by ImageAnalyst','numbertitle','off') 
%----- Burn ellipse into image -----
% Create elliptical mask, h, as an ROI object over the second image.
subplot(2, 4, 2);
hEllipse = imellipse(gca,[10 10 50 150]); % Second argument defines ellipse shape and position.
% Create a binary image ("mask") from the ROI object.
binaryImage = hEllipse.createMask();
% Display the ellipse mask.
subplot(2, 4, 3);
imshow(binaryImage);
title('Binary mask of the ellipse');
% Let's try to add some text.  (Doesn't work)
% hText = text(50, 100, 'Line of Text');
% textMask = hText.createMask();
% binaryImage = binaryImage & textMask;
% imshow(binaryImage);
% Burn ellipse into image by setting it to 255 wherever the mask is true.
monochromeImage(binaryImage) = 255;
% Display the image with the "burned in" ellipse.
subplot(2, 4, 4);
imshow(monochromeImage);
title('New image with ellipse burned into image');
%----- Burn line into image -----
burnedImage = imread('pout.tif');
% Create line mask, h, as an ROI object over the second image in the bottom row.
subplot(2, 4, 6);
hLine = imline(gca,[10 100],[10 100]); % Second argument defines line endpoints.
% Create a binary image ("mask") from the ROI object.
binaryImage2 = hLine.createMask();
% Display the line mask.
subplot(2, 4, 7);
imshow(binaryImage2);
title('Binary mask of the line');
% Burn line into image by setting it to 255 wherever the mask is true.
burnedImage(binaryImage2) = 255;
% Display the image with the "burned in" line.
subplot(2, 4, 8);
imshow(burnedImage);
title('New image with line burned into image');

3 个评论
显示 1更早的评论隐藏 1更早的评论

Ryan 2012-7-13

编辑：Ryan 2012-7-13

y = m*x + b

You know the angle so you know the slope and you know the length (which could give you the number of 'x' values if you do some simple trig). Plot a line starting half the length from the center point.

Image Analyst 2012-7-14

You can use line() or imline(). For both you specify the two endpoint coordinates, which you can determine through regular 9th grade algebra, or 10th grade trigonometry at most.

请先登录，再进行评论。