Ticket #1108 (closed defect: moved)

Opened 8 years ago

Last modified 8 years ago

Channel slider is confusing

Reported by: bdezonia Owned by: curtis
Priority: major Milestone: imagej-2.0.0
Component: Display API Version:
Severity: serious Keywords:
Cc: G.Landini@… Blocked By:
Blocking: #1246


Gabriel Landini reported in the imagej devel mail list::

I do not understand what is the function of the slider under colour images while looking at them in colour mode. Of course I understand that changes the channel, but if that is to set the processing a particular channel (if so, it is not working) shouldn't there a position where all the channels are processed too?

Change History

comment:1 Changed 8 years ago by curtis

For now we focused on having the behavior match ImageJ1, which also has a similar channel slider, with no way to toggle processing of multiple simultaneous channels.

What sort of UI changes would you like to see here? A checkbox next to the slider that does a "select all"? Or do you think it is necessary to allow cherry-picking of channels (so you might select e.g. channels 1, 4 and 7 for visualization and/or processing)? In that case we might need the channels in an explicit list off to the side, similar to Photoshop's layers where you can toggle each one individually.

comment:2 Changed 8 years ago by landinig

The issue I see is that RGB are a special kind of multichannel that do not follow the generalisation of multichannel images (think of other colour spaces if implemented, like HSB or CIE Lab).

Currently IJ1 does not display sliders unless it is a composite image (where you can process a particular channel). But all filters applied to an RGB image will process all the channels one after another. Not sure if changing this behavior might break things?

Will IJ2 have RGB stacks? If so, colour images should not have a slider (because currently it does not do anything). The slider should appear after converting from RGB composite to RGB stack (like in IJ1).

If there is no RBG stack type in IJ2, and colour images are generic stacks, then slider is not working, and filtering (blur, etc) need to be taken care of differently.

Take for example "sharpening". On an RGB image this filter is applied to all channels, but in HSB or CIELab this should be applied only to the "V" or "b" channels. Not that I want to redefine filtering depending on the colour space, but there are new challenges in treating colour spaces as generic multichannel.

Thanks for listening!

comment:3 Changed 8 years ago by curtis

  • Blocking 1246 added

comment:4 Changed 8 years ago by curtis

  • Milestone changed from imagej-2.0.0-beta3 to imagej-2.0.0

comment:5 Changed 5 years ago by curtis

  • Status changed from new to closed
  • Resolution set to moved
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