How to increase the contrast in an image, using imagesc, with removal of outliers.

6 次查看（过去 30 天）
Ronni BIng
Ronni BIng 2012-6-30
Hi,
I have data from a fits file that is displayed with the help of imagesc. The image is very dark (data range in [20 2200]). When I use imcontrast(gca) i can manually remove outliers, and if 0.01% of the outlieres is removed, the data range is [59 1175], and I get the desired contrast.
Is there any way to remove the outliers in the command window, as I have many files to be analysed?
p.s. I know i can use the command imagesc(data, [cmin cmax]),colormap(gray), but the problem is that I dont know cmin and cmax for the different images.
Any help appriciated,
Thank you
Ronni
  1 个评论
Image Analyst
Image Analyst 2012-6-30
Do you really want to remove outliers from your data, or do you want to keep them but just scale your image for display? Have you tried imadjust()? Or just passing in the display limits into imshow like imshow(yourImage, [42 123])?

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Walter Roberson
Walter Roberson 2012-6-30
Something like:
ndev = 3;
data_mean = mean(data(:));
data_std = std(data(:));
data_min = min(data(:));
data_max = max(data(:));
cmin = max( data_min, data_mean - ndev * data_std );
cmax = min( data_max, data_mean + ndev * data_std );
imagesc( data, [cmin, cmax] )
  3 个评论
显示 1更早的评论
Image Analyst
Image Analyst 2012-6-30
So go ahead and specify your own limits, using fixed values like I did, or come up with some algorithm like Walter did to derive the value. No one says you need to use his method.
Walter Roberson
Walter Roberson 2012-6-30
cutout = 0.0001;
num_to_cut = ceil( numel(data) * cutout / 2);
sorted_data = sort(data(:));
cmin = sorted_data( num_to_cut );
cmax = sorted_data( end - num_to_cut + 1);
imagesc(data, [cmin, cmax]);

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 2-D and 3-D Plots 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by