索引图像的背景 [英] Background for indexed image

问题描述

我有一个索引图像(2-D，不是rgb)，并且我使用imagesc来显示图像.此功能提供了从蓝色到红色的范围，可以由colormap设置，并且可以由colorbar查看.

I have an indexed image (2-D, not rgb), and i use imagesc to display the image. This function gives a range from blue to red, which can be set by colormap, and can be viewed by colorbar.

现在，我想将背景(通常为0或NaN)更改为白色或黑色，但不会影响或更改颜色图/颜色条的范围.我尝试将所有图像都转换为3-D rgb，但这会阻止更改对比度或clims的选项，例如在imagesc中. 那么，还有其他方法可以做到吗?

Now, I want to change the background, that is usually 0's or NaN's, to white or black, but that it will not affect or change the range of the colormap/colorbar. I've tried converting all the image to 3-D rgb, but this prevent the option of changing the contrast, or the clims, like in imagesc. So, there is other way to do that?

@Shai的解决方案很好，但引起了其他问题-

@Shai's solution was good, but it caused other problem-

当我的图像具有一定范围的值并且背景是NaN的并且以特定的对比度显示图像时(例如通过imagesc(img, [-1,1]))，我得到的颜色范围是-1到1，并且i在背景中获取白色(因为我将[1 1 1]放置在颜色图的第一项中)，但是所有对比度最小的值(例如，示例中的-1以下)也获得了白色颜色条刻度中最下面的深蓝色的颜色.

When I have an image with a range of values and the background is NaN's, and I display the image in a specific contrast (by imagesc(img, [-1,1]) for example), I get range of colors between -1 to 1, and i get white in the background (because i put [1 1 1] in the first entry of the colormap), but also all the values under the minimum of contrast (i.e., <-1 in the example) also get the white color instead of the bottom dark blue in the colorbar scale.

有什么想法...吗?

Any idea for that...?

非常感谢.

推荐答案

考虑将[1, 1, 1]作为颜色表的第一项，以使背景为白色.

Consider putting [1, 1, 1] as the first entry of your colormap to get the background as white.

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