How to highlight a area in figure

I want to hightlight the defect in croppedImage.mat by convHull.mat.

It's better set transparent.

the size of two figures is same.

[Rik]

What have you tried so far? If you post your code, we can suggest edits more easily.

[xie]

Sorry, I have no idea to combine these two attached figures.

[xie]

maskedImage = croppedImage;

maskedImage(convHull) =0;

imshow(maskedImage)

But I want to change the black portion to transparent. I have no idea. Could you help me?

Answer 1

[prabhat kumar sharma]

To highlight an area in a figure and make it transparent, you can use the alpha data property in MATLAB. Here's a step-by-step guide to achieve this:

1. Load your data: First, load your croppedImage and convHull data.
2. Create a mask: Use the convHull to create a mask that identifies the region you want to highlight.
3. Display the image with transparency: Use the imshow function with the 'AlphaData' property to make the highlighted area transparent.

Here's an example code snippet:

% Load the data
load('croppedImage.mat'); % Assuming this loads a variable named croppedImage
load('convHull.mat'); % Assuming this loads a variable named convHull

% Display the original image
imshow(croppedImage);
hold on;

% Create a mask for the highlighted area
highlightMask = false(size(croppedImage));
highlightMask(convHull) = true;

% Overlay the highlighted area with transparency
h = imshow(croppedImage);
set(h, 'AlphaData', ~highlightMask); % Set the non-highlighted part to transparent

% Optional: Add a color to the highlighted area
highlightedArea = imshow(cat(3, ones(size(croppedImage)), zeros(size(croppedImage)), zeros(size(croppedImage))));
set(highlightedArea, 'AlphaData', highlightMask * 0.5); % Adjust transparency level

[xie]

Very clear! Good teaching!

Answer 2

[Image Analyst]

You can try imoverlay to make the mask overlaid on the image, or you can use plot to plot a red outline at the mask perimeter location in the image.

[xie]

Very good guidance!!!

[Image Analyst]

imoverlay gives opaque overlays. labeloverlay can give transparent/tinted overlays.

Answer 3

[xie]

Maybe I got the simple method: labeloverlay function can meet my request.

imshow(labeloverlay(croppedImage,convHull, 'Colormap','spring','Transparency',0.7));

thank you all!