setBlock
Description
Examples
Write Data to Blocked Image and Read It Back
Create a blocked image to which you can write data. You specify the format of the blocked image in the destination
parameter. To write to memory, specify an empty matrix. You must also specify the size of the image and the size of the blocks into which you want the image chunked. The initial value parameter depends on the format you specified in destination. To create a writable blocked image, specify the 'Mode'
parameter with the value 'w'
for write mode.
destination = []; imgsize = [5 7]; blocksize = [2 2]; initval = uint8(0); bim = blockedImage(destination,imgsize,blocksize,initval, "Mode", 'w');
Write data to the specified blocks in the blocked image by using the setBlock
object function. The blocksubs
parameter specifies the coordinates of the block to which you want to write data. The blockdata
parameter specifies the data to write to the specified block. The size of blockdata must match the block size.
blocksubs = [1 1];
blockdata = ones(2,2,"uint8");
setBlock(bim, blocksubs, blockdata)
Close the image for writing.
Switch the blocked image to read mode by setting the 'Mode' parameter to 'r' for read.
bim.Mode = 'r'
bim = blockedImage with properties: Read only properties Source: " {5x7 uint8}..." Adapter: [1x1 images.blocked.InMemory] Size: [5 7] SizeInBlocks: [3 4] ClassUnderlying: "uint8" Settable properties BlockSize: [2 2]
Create the full image by using the gather
function to collect all the individual blocks.
fullImage = gather(bim);
Display details of the blocked image at the command line.
disp(fullImage)
1 1 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Create Mask from ROI
Create a blocked image.
bim = blockedImage('tumor_091R.tif');
Display the blocked image and draw a circular ROI on the image.
h = bigimageshow(bim); hROI = drawcircle(gca, 'Radius', 470, 'Position', [1477 2284]);
Specify the resolution level at which to create the mask.
maskLevel = 3;
Create a writable blocked image in memory.
bmask = blockedImage([], [200 200], bim.Size(maskLevel,1:2), false, "Mode", "w");
Specify the start and ending points for the mask.
bmask.WorldStart = bim.WorldStart(maskLevel, 1:2); bmask.WorldEnd = bim.WorldEnd(maskLevel, 1:2);
Display the number of blocks.
disp(bmask.SizeInBlocks);
1 1
Convert the ROI coordinates to pixel level.
roiPositionsRC = fliplr(hROI.Vertices); % x,y to row,column roiPosSub = world2sub(bmask, roiPositionsRC, "level", 1); for cSub = 1:bmask.SizeInBlocks(2) for rSub = 1:bmask.SizeInBlocks(1) blockSub = [rSub, cSub]; [pStart, pEnd] = blocksub2sub(bmask, blockSub, "Level", 1); % Create a grid encompassing all pixels in the block in X-Y order [xgrid,ygrid] = meshgrid(pStart(2):pEnd(2), pStart(1):pEnd(1)); % Create in/out mask for this block tileMask = inpolygon(xgrid, ygrid,... roiPosSub(:,2), roiPosSub(:,1)); % Write out the block setBlock(bmask, blockSub, tileMask); end end
Switch the blocked image to read mode.
bmask.Mode = 'r';
Display the mask.
figure bigimageshow(bmask)
Input Arguments
bim
— Blocked image
blockedImage
object
Blocked image, specified as a blockedImage
object.
blocksub
— Block subscript vector
integer-valued vector
Block subscript vector, specified as a 1-by-N integer-valued
block subscript vector. Valid elements range from 1
to the
corresponding element in SizeInBlocks
property.
Example: [3, 2, 1]
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
blockdata
— Block of data
numeric array
Block of data, specified as a numeric array with dimensions that match
BlockSize
. The type matches the type specified by the
ClassUnderlying
property. setBlock
automatically
trims blocks along the edges to fit the Size
property.
Version History
Introduced in R2021a
See Also
MATLAB 명령
다음 MATLAB 명령에 해당하는 링크를 클릭했습니다.
명령을 실행하려면 MATLAB 명령 창에 입력하십시오. 웹 브라우저는 MATLAB 명령을 지원하지 않습니다.
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