sub2world

Convert pixel subscripts from one level to another via the world coordinates.

Create a blocked image from a sample image included with the toolbox.

bim = blockedImage("tumor_091R.tif");

Create a binary mask at the coarsest resolution level.

bmask = apply(bim, @(bs)imbinarize(im2gray(bs.Data)),Level=3);

Define a region of interest (ROI) in the finest resolution level in pixel subscripts.

pixelStartLevel1 = [1700 1550];
pixelEndLevel1 = [2100 2000];
imagePixelSubs = [pixelStartLevel1; pixelEndLevel1];

Get the image data from the ROI at the finest resolution level.

roiImage = getRegion(bim,pixelStartLevel1,pixelEndLevel1,Level=1);
size(roiImage)

ans = 1×3

   401   451     3

Convert the pixel subscripts that define the ROI into world coordinates. By default, sub2world converts the coordinates at the finest resolution level.

worldRegion = sub2world(bim,imagePixelSubs);

Convert the world coordinates of the ROI to pixel subscripts of the mask.

maskPixelSubs = world2sub(bmask,worldRegion);

Get the mask data from the ROI.

roiMask = getRegion(bmask,maskPixelSubs(1,:),maskPixelSubs(2,:));
size(roiMask)

ans = 1×2

    51    58

View the region of interest and the corresponding mask.

montage({roiImage,roiMask})