Hello,
I am currently working on a GUI to perform several morphological operations on images and am having an issue with ROI's from a rotated rectangle of specified dimensions. I found a similar question here and got to where I am using the documentation from the suggested functions. My goal is taking a series of images of a tube under magnification, taking pictures and rotating it under the camera between each shot, then concatenating segments from each image into a flat map of the surface. However, this tube is not perfectly straight and has somewhat of a curve so I was testing methods on cropping out a diagonal region of an image
The functions 'customWait' and 'clickCallback' are from the mathworks documentation on using a wait funciton with an ROI example here. The relevant code is: [file,path] = uigetfile({'*.jpg';'*.jpeg';'*.tiff'});
image = imread([path file]);
S = [1 1 2500 120];
imshow(Scomp);
h = drawrectangle(gca,'Position', S, 'Rotatable', true);
position = customWait(h);
I2 = imcrop(Scomp,position);
imshow(I2);
function pos = customWait(hROI)
l = addlistener(hROI,'ROIClicked',@clickCallback);
uiwait;
delete(l);
pos = hROI.Position;
end
function clickCallback(~,evt)
if strcmp(evt.SelectionType,'double')
uiresume;
end
end
ROI selection:
Result:
The method works perfectly when the ROI is perfectly horizontal or vertical. Whenever the rectangle is rotated however, it crops a horizontal segment from the centerline of the rectangle ignoring the rotated position. I imagine this is due to that in rotatted orientations, the diagonal edges cannot be recorded properly in a square or rectangular matrix.
I looked into ROI poly, but could not find how to specify the dimensions of the polygon or how to make it interactable.
I have considered just rotating the images so that the crop fits as best as possible, but since I am working with large image sequences (100+ images for about a dozen subjects) of a subject irregularly occurring bends and curves in it. Finding each image's necessary rotation angle individually would be a very time consuming task to perform image by image. The original idea was to use rotated rectangular crop and the batch image processing app to just cycle through the images and rotate the rectangle as needed.
Is there a way to achieve what I'm looking for, cropping and angled rectangle or region? Or perhaps a method better suited given my application? I am open to revising my methods if a better alternative exists.
