I'm writing code in which I use MATLAB's fill command to plot 2D shapes. I can specify the fill color of the shape. However, the border line color is always black. I want the border line color the same as the fill color. How can I also specify the border line color?
See this thread:
To set the edgecolor to white do the following.
h = fill([-1 -1 1 1],[-1 1 1 -1],'w');
axis([-2 2 -2 2]);
set(h,'edgecolor','white');
that should take care of the border.
In addition to schnaader's answer, you can also set the edge color in the initial call to FILL:
hPatch = fill(xData,yData,'r','EdgeColor','r'); %# Red patch with red edges
Or stop the edges from being drawn altogether:
hPatch = fill(xData,yData,'r','EdgeColor','none'); %# Red patch with no edges
Related
Hello i need to make background color black and foreground color white. As u can see i did this with transfering image to 2 dimension. I want to make this color changes in 3 dimension, so we are nor allowed to transfer it bw. Is there any way to do this ?
logo=imread('logo.png');
subplot(2,2,1);
imshow(logo);
b=rgb2gray(logo);
subplot(2,2,2);
imshow(b);
c=im2bw(b,0.92)
subplot(2,2,3);
imshow(c);
c = 1-c;
subplot(2,2,4);
imshow(c);
Preface:
To set the pixel to white or black each layer of the pixel needs to be set to an intensity value of 0 (black) or 255 (white).
White Pixel → rgb(255,255,255)
Black Pixel → rgb(0,0,0)
The colon can be used to obtain all the indices in the 3rd dimension (grab all the layers). To grab one RGB-pixel in the top-left corner of the image:
RGB_Pixel = Image(1,1,:);
Method 1:
If you wish to retain the three colour channels you can use matrix indexing to change the white background to black. Matrix indexing can also be used to change anywhere that isn't white to white. This method may, unfortunately, break down if you have a coloured component with a 255 intensity component. This doesn't seem to be the case for your image though. You can use method 2 for a more safe approach.
logo = imread('logo.png');
[Image_Height,Image_Width,Depth]= size(logo);
new_logo = zeros(Image_Height,Image_Width,Depth);
new_logo(logo == 255) = 0;
new_logo(logo ~= 255) = 255;
imshow(new_logo);
Method 2:
Checks each pixel (RGB-triplet) using a set of for-loops that scan through the entire image. If the RGB-intensities of the pixel are rgb(255,255,255) then the pixels are set to 0 (black). If the RGB-intensities of the pixel are anything else the pixels are set to 255 (white). The ~ismember() function is used to check if the RGB-pixel has an intensity that is not 255 (not-white).
logo = imread('logo.png');
%Grabbing the size of the image%
[Image_Height,Image_Width,~]= size(logo);
for Row = 1: Image_Height
for Column = 1: Image_Width
%Grabbing RGB pixel%
RGB_Pixel = logo(Row,Column,:);
if(~ismember(255,RGB_Pixel))
%RGB pixel is white change
logo(Row,Column,:) = 255;
else
%RGB pixel is coloured change to black%
logo(Row,Column,:) = 0;
end
end
end
imshow(logo);
Using the repmat() function is also a great solution that the above comment suggested. Which possibly may be the quickest method since you already have the code that generates one layer from the greyscale image.
Ran using MATLAB R2019b
I'm trying to color code some parameter values on a gray image in MATLAB. I'm wondering how to show gray image, make parameter values colored on the gray appearance image and on some pixels, and finally draw a colorbar aside the image just showing parameter values range.
Unsuccessful Code since now:
I = Igray; % gray image
Icc = zeros(size(I,1),size(I,2),3); % color coded image
Icc(:,:,1) = I;
Icc(:,:,2) = I;
Icc(:,:,3) = I;
Icc('some address in the image',3) = 'some number between 0 and 255';
imshow(Icc,[])
colorbar % colorbar showing colored parts spectrum
Result image that I need:
Try something like this:
I = Igray; % gray image
RGB = [1.0,0.7,0.2]; % color for patch
x = 30:50;
y = 70:90;
% If you gray image is in the range [0,255], make it range [0,1]
I = double(I)/255;
Icc = repmat(I,[1,1,3]);
block = I(y,x);
Icc(y,x,1) = 1 - ((1-block) * (1-RGB(1)));
Icc(y,x,2) = 1 - ((1-block) * (1-RGB(2)));
Icc(y,x,3) = 1 - ((1-block) * (1-RGB(3)));
imshow(Icc)
I'm sure there is a prettier way to encode this, but this way it shows the intent.
You're basically multiplying the grey values with the RGB color you want to make the patch. By inverting the patch and the color first, and inverting the result, the multiplication makes the patch brighter, not darker. That way you get the effect you want where the dark parts show the color also. If you multiply directly without inverting first, black stays black and doesn't show the color.
You'll have to figure out how to coordinate with the color bar after that. There are commands in MATLAB to set the limits of the color bar, you can find those reading the documentation.
The color bar you show uses the PARULA color map. You could do this to find the right RGB value to color your patch:
T; % value to color your patch in, in range [0,1]
cm = parula(256);
RGB = interp1(cm,T*255,'linear')
I am using sobel filter for edge detection. How to illustrate the gradient direction with color coding. For example, horizontal edges with blue and vertical edges with yellow?
Thank you.
Since you can specify whether you want horizontal or vertical edge detected (check here), you could perform 2 filtering operations (one horizontal and the other vertical) and save each resulting image, then concatenating them to form a final, 3-channels RGB image.
The RGB color code for yellow is [1 1 0] and that of blue is [0 0 1], so in your case the vertical edge image will occupy the first 2 channels whereas the horizontal edge image will occupy the last channel.
Example:
clear
clc
close all
A = imread('circuit.tif');
[r,c,~] = size(A);
EdgeH = edge(A,'Sobel','Horizontal');
EdgeV = edge(A,'Sobel','Vertical');
%// Arrange the binary images to form a RGB color image.
FinalIm = zeros(r,c,3,'uint8');
FinalIm(:,:,1) = 255*EdgeV;
FinalIm(:,:,2) = 255*EdgeV;
FinalIm(:,:,3) = 255*EdgeH;
figure;
subplot(1,2,1)
imshow(A)
subplot(1,2,2)
imshow(FinalIm)
Output:
There are some white portions in a black object.
I need to cover up the all the white portions in the object with its neighboring black.
The bwlabel function labels the black part as '2' and white part as '1'.
can i somehow change the labels of the required object and cover the white portion with black.
I have isolated the objects individually using the following code:
a=imread('3.jpg');
figure(),imshow(a),title('Original image');
b=im2bw(a, graythresh(a));
figure(),imshow(b),title('Grayscale image');
[c,num]=bwlabel(b);
figure(),imshow(c),title('labelled image');
for i=1:1:num
figure(),imshow(c==i),title('OBJECT');
end
What can i do further ?
Or is there any other way to achieve the same?
Can you do
Find the indices of the white area
ind_white = find(c==1);
Replace the white area with zeros
b(ind_white) = 0;
or you can change the label of the white object to that of the black
c(ind) = 2;
I need to draw vertical lines at regular intervals in a rectangular box. this is what i have used so far:
xmin=000;
xmax=70000;
ymin=0;
ymax=1000;
line1Val=900;
line2Val=600;
line3Val=300;
xlim([xmin xmax])
ylim([ymin ymax])
xl=get(gca,'XLim');
line(xl,[line1Val line1Val],'Color','y');
line(xl,[line2Val line2Val],'Color','y');
line(xl,[line3Val line3Val],'Color','y');
hold on ;
rectangle('Position',[120000,900,(280000-120000),37],'faceColor','k')
so the width of the rectangle is 160000 units i want to divide this into 4 , where the vertical line is of a different color(say red) and the height of the line is 37 units.
any ideas on how i can draw this without drawing 4 rectangles whose edges are red and are filled with black color.
You could use the parameters xstart,ystart,width and height for drawing your rectangle:
rectangle('Position',[xstart,ystart,width,height],'faceColor','k');
After that, you could determine the line positions in a loop and simply draw these lines:
for i = 1:3
x = xstart+i*width/4;
line([x x],[ystart ystart+height],'Color','r');
end
If you want a red line at the start and end of the rectangle, let i = 0:4.