imshow produces error when used in subplot

Question

F Sp 2020-6-6

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/543350-imshow-produces-error-when-used-in-subplot

评论： F Sp 2020-6-7

采纳的回答： Ameer Hamza

Hello,

I had a working code using:

figure, imshow(I);

Then I wanted to put all the displayed images into one figure using subplot in this way:

figure;

h = [];

h(1) = subplot(2,4,1); etc.

and calling the image via:

imshow(I,'Parent', h(2))

The problem is that this now produces the error:

"Unable to perform assignment because dot indexing is not supported for variables of this type.

Error in images.internal.basicImageDisplay (line 78)

ax_handle.Colormap = map;

Error in imshow (line 330)

hh = images.internal.basicImageDisplay(fig_handle,ax_handle,..."

Also the image now appears blue and yellow instead of black and white.

Being new to MatLab I can only assume something went wrong with the colormap interfering with multiple images in one figure.

Any help would be appreciated a lot :)

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Ameer Hamza 2020-6-6

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/543350-imshow-produces-error-when-used-in-subplot#answer_447218

在 MATLAB Online 中打开

From your code, it is not clear how did you assign the 2nd element of vector h. However, I recommend initializing 'h' with 'gobjects'.

Replace

h = [];

with

h = gobjects;

3 个评论
显示 1更早的评论隐藏 1更早的评论

Image Analyst 2020-6-6

What page gave that incorrect information? Not this one.

F Sp 2020-6-7

somewhere on MatLab Answers, of course not in this particular question. Thank you guys

请先登录，再进行评论。

Answer 2

Image Analyst 2020-6-6

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/543350-imshow-produces-error-when-used-in-subplot#answer_447287

编辑：Image Analyst 2020-6-6

在 MATLAB Online 中打开

You do not need to initialize h to anything, not [] nor gobjects. This works perfectly fine:

figure;
h    = []; % Unnecessary.
h(1) = subplot(2,4,1);
% and calling the image via:
I = imread('peppers.png');
imshow(I,'Parent', h(1))

Just make sure you haven't assigned h to anything in advance, like h is not already a cell array or structure or some other complicated non-numerical variable. If h does already exist when you get to h=[], then it might be a mistake to use the same variable h because setting it to null would blow it away and if you ever needed that original h again you would not have it anymore.

Just make sure whatever index you're using in h exists, like you can't use h(2) if you haven't called h(2) = subplot yet.