使用Image.CData在MATLAB中快速重绘图像

Question

I am want to draw once, and then update (very) often and redraw (less) often an image in MATLAB. My image is a vector which is updated and redrawn. To show this image, I used I = imagesc(reshape(data, nVoxels)) to draw and I.CData(:) = data to update. (Redrawing is taken care of seperately.) This worked fine.

Now, in order to make the correspondence to an xy-coordinate system (x horizontal, y vertical - very standard), where the first dimension of reshape(data, nVoxels) is x and the second is y, I need to draw like this:

I = imagesc(reshape(data, nVoxels)');
axis('xy');

But how can I make a quick update of the image data now?

So far, I have found I need to do

I.CData = reshape(data, nVoxels)';

but I would prefer to do something like before, updating CData without having to reallocate and without having to transpose the data.

Is that possible? I am specifically interested in updating very often in a loop; redrawing is handled independently using a timer.

Answer 1

The transpose can be avoided by setting x and y limits when you create the image to flip it, and rotating the axes:

I = imagesc([nVoxels(2) 1], [1 nVoxels(1)], reshape(data, nVoxels));
camroll(90);

then using

I.CData(:) = data;

again.

However, the transpose time is probably negligible compared to updating the figure using drawnow() .