What causes Simple change the color of an image?

[CsatiZoltan]

I have an input RGB image: If I apply Process -> Filter -> Median on it, I obtain the following filtered image: The median filter in ImagePy inherits from class Filter. However, if I want to replicate the same process using the Simple class, I get a different color: Why is it so? How can I keep the original color? My code is:

class FilterImage(Simple):
    """Median filtering of the current image."""
    title = 'Filter image'
    note = ['all', 'auto_msk', 'auto_snap', 'preview']
    para = {'size': 5}
    view = [(int, 'size', (1, 30), 0, 'window size', 'pixel')]

    def run(self, ips, imgs, para=None):
        out = median_filter(ips.img, para['size'])
        IPy.show_img([out], ips.title + '-filtered')

Additional information:

• motivation: the only reason I subclass Simple and don't use the already available Median class is because I want to show the filtered image on a new tab, not overwriting the original one. Yes, I know, I could first duplicate the original image and perform the filtering on it, but still, I am curious why this color issue happens.
• ImagePy still shows the third image as RGB (first I thought that the change in color is due to the an implicit conversion to an int type)
• I realized that even if I change the above code to

  def run(self, ips, imgs, para=None):
         imgs[0] = median_filter(ips.img, para['size'])

  the same color change happens. It means that it is not IPy.show_img that causes the issue.

[yxdragon]

because median_filter treat the rgb image as a 3d image, So do filter in a cube.

you can loop the z channels yourself, or there is a skimage function can help you to go though the channels, (but I forgot the name).

you can see filter's base class, the 'not_channel' note. That's why the filter can fit multi-channels image.

[yxdragon]

by the way: how to upload image in issue?

[CsatiZoltan]

how to upload image in issue?

Simply drag&drop the image.

[yxdragon]

just have a try

[CsatiZoltan]

@yxdragon Just a tip: you can test whether uploading works without posting a message. After the drag&drop, click on the Preview tab.