imshow update in realtime, colorbar causing it to slow down

Question

Shane 2013-4-17

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/72481-imshow-update-in-realtime-colorbar-causing-it-to-slow-down

I am updating a display ~15 times a second using imshow. I want to display the colorbar on the side, but that seems to slow down the displaying greatly, causing other problems.

Here is my code, and how I am doing it. So this code is called multiple times over and over in a loop until the user stops something (it is taking data in from an acquisition card and displaying it). Can I make the colorbar more efficient somehow?

                            imshow(squeeze(sum( RawData((1:2:7),:,:,2)< ChannelD_Threshold ,1)),[],'Parent',imagePlot1, 'border','tight');
                           imshow(squeeze(sum( RawData((2:2:8),:,:,2)< ChannelD_Threshold ,1)),[],'Parent',imagePlot2, 'border','tight');
                            colormap cool
%                             colorbar('location','southoutside')

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Answer 1

Adam Filion 2013-4-17

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https://ww2.mathworks.cn/matlabcentral/answers/72481-imshow-update-in-realtime-colorbar-causing-it-to-slow-down#answer_82604

编辑：Adam Filion 2013-4-17

在 MATLAB Online 中打开

You can make visualizations inside of loops more efficient by using handle graphics to update the underlying data rather than recreating the visualization. For example, the following piece of code creates a visualization with imshow, saves the handle to it, retrieves the color data, then sets it to a new value.

im = imread('rice.png');
h = imshow(im);
cd = get(h,'CData');
set(h,'CData',cd/4);

This speeds things up because commands like imshow and plot are doing a lot things behind the scenes that aren't necessary when you're just revisualizing inside of a loop. It can also let you set the colorbar once before the loop and not need to reissue it at every iteration.