Prob: Quick Selection doesn't work on B&W image

[photoken]

Win7 x64 SP1
PL 19.00 x64

The Quick Selection tool is not working on Black & White RGB images. At times, the selection will briefly flash before disappearing.

Here's a screenshot that shows nothing is selected:

BB QS screenshot.jpg

I can send the original JPG to support if necessary. (Even when zipped, the original is 135Kb and is rejected by the forum software as too large.)

[Alan9940]

Hello Ken,

Not sure I'm doing this right since I rarely use Quick Selection, but here's what I did:

1. Open color image (please ignore the uninspired choice as this was simply a test for something!)
2. Create a Gray Mixer adjustment layer at default values.
3. Flattened the layers.
4. Used the Quick Selection tool to select the lower trunk area.

As you can see from the attached, PL was able to provide a pretty good initial selection based on the boundary area specified. I didn't carry it any further to refine the selection. Does this show that it's working for me and not for you?

Best regards,
Alan

QuickSelectionBW.jpg

[photoken]

Does this show that it's working for me and not for you?

I don't know. My original posted image was B&W to start with.

Here's an image that was originally full colour. I used the Gray Mixer to convert it to B&W and saved it as a different file. Then I re-opened that B&W image and used the QS tool. QS did not initially select anything, so I hand-painted the foreground and background areas, which sort of worked:

QS screenshot 02.jpg

I expected QS to do a much better job of selecting on this one. It's as if the QS is looking for Hue differences and ignoring Value differences -- there's certainly enough contrast between the tree and the background (especially against the sky) for a selection to be made....

[Alan9940]

Hello Ken,

Wow, don't know what's happening here. I just opened one of my 16-bit 4x5 B&W film scans that has a palm tree (roughly zones 3 - 5) against a bald sky (about zone 7.) Using QS, I set a border around the top of the palm and, though it took a bit longer to process due to filesize, it did give me a half decent initial selection.

Sorry I couldn't provide any help.

Best regards,
Alan

[Hoogo]

Are you sure that you're working on the correct layer?

[photoken]

There's only one layer.

More info: what's happening (using the BB image as an example) is that everything within the initial selection rectangle is selected as the "Object" -- that's why the yellow Object marks had no effect.

I've now learned that I can force the QS tool to calculate a selection of her head and shoulders by painting as a "Background" mark everything in the background and slightly inside the edges of her head and shoulders. Then, it's a matter of repeatedly alternating between the "Object" and "Background" markers to attempt to get a decent selection. Definitely nothing "Quick" about that process....

If I use a colour image, the QS works much better; and a couple of alternations between marking as "Object" and "Background" gets a decent selection. IOW, the procedure is a lot quicker on a colour image.

If I'm right that the QS is mostly using Hue information to do the selecting, then I propose this feature request for the tool to accommodate making a selection on B&W images:
Add two new sliders to the tool's options:

• A "Bias" slider ranging from "B&W" to "Color" (or, more precisely, from "Value" to "Hue"). This would change the relative importance of Value data and Hue data used by the selection algorithm.
• A "Tolerance" slider. This would set how different the pixel value should be from its neighbor when determining if the pixel should be selected or not.

[bkh]

The Quick Selection tool is not working on Black & White RGB images. At times, the selection will briefly flash before disappearing.

Same here, on OS X 10.10.3, including a better selection showing up briefly after using one of the brushes.

If I switch to 16 bit layers, everything seems to work ok – this may explain why Alan9940 didn't see any problems.

Here's an image that was originally full colour. I used the Gray Mixer to convert it to B&W and saved it as a different file. Then I re-opened that B&W image and used the QS tool. QS did not initially select anything, so I hand-painted the foreground and background areas, which sort of worked:

QS screenshot 02.jpg

I expected QS to do a much better job of selecting on this one. It's as if the QS is looking for Hue differences and ignoring Value differences -- there's certainly enough contrast between the tree and the background (especially against the sky) for a selection to be made....

In that example, you're selecting part of the surrounding (shining through the leaves) as foreground, so that's likely confusing PL. But that's unrelated to the other problem, I suppose.

Cheers

Burkhard.

[Alan9940]

Ken, Burkhard,

Yep, looks like it's an issue with 8-bit vs 16-bit images! Since I rarely work in anything other than 16-bit mode, I modified layer attributes to 8-bit on a couple of my images and had the same issue that Ken initially reported; the proposed initial selection flashes briefly and disappears.

Ken - are you reporting this as a bug?

Best regards,
Alan

[Gerhard Huber]

we read it and will fix it.

[photoken]

I modified layer attributes to 8-bit on a couple of my images and had the same issue that Ken initially reported; the proposed initial selection flashes briefly and disappears.

Alan, Burkhard,
Thanks for the confirmations and follow-ups. Interestingly enough, one of the things I tested was going in the opposite direction -- converting that BB image to 16-bit TIF. That didn't help, so I abandoned the 8-bit vs. 16-bit question.

[photoken]

Ken - are you reporting this as a bug?

Hi Alan,
I'm changing the way I report bugs. Recently, the developers have complained about subject lines containing the word "Bug", and I can understand their concern. It's not up to users to label a behavior as a "bug" -- the developers are the ones who can examine the code and determine what can best be considered a "bug in their opinion, and I accept that.

So, in the future, I'll continue reporting issues as before with the steps to reproduce, etc., but I'll be prefacing the subject line with "Prob" (short for "Problem"). That's a more neutral phrase, and should help smooth the discussions somewhat.

I only preface the subject line with those phrases for my own benefit, anyway. To allow me to be a better tester of PL, when a new version is released, I can more easily search my messages for that phrase to ensure I check if the problems I reported have been solved.

[Alan9940]

Hi Ken,

Yes, I agree that the terminology "bug" is not necessarily correct use of the term. I like your "Prob" label and will use that myself with any issues that I find. However these issues are reported, I'm very happy to see Gerhard jump in on the post to say "We've read it and it will be fixed." Works for me!

Best regards,
Alan

[photoken]

Not quite there, yet....

Win7 x64 SP1
PL 19.01 x64

When using the Quick Selection tool on an 8-bit RGB JPG image, there is now an initial selection; however, attempting to refine that selection doesn't work well at all.

For example, there was an initial selection made on this image which included some of the background. Using the "Background" tool to mark some of that background removed the initial selection, and replaced the selection with a selection of everything but the indicated background.

QS selection.jpg