Select a color range

I would like to sel ect a color range in an image. For example, from pink to dark red. Then deleting only these color areas fr om the image or using only these color areas. It is easy to do in Photoshop, but how to do using only Filter Forge?

Thanks so much, Rick.
I check it and see how to adapt it.

Set the threshold to 90 and the feathering to 5. Then go to the Match Color and change colors and watch if it works. It works for me. If not, please show me an example if you could.

It may be that you want more of a color match than a brightness match. Might require looking at the separate channels in the code.

UPDATE: I am looking at using Euclidean distance to compute the color range. This is the distance between each pixel and the "match" color (in 3d space, RGB). If I have time today I will post a less sensitive (and more correct) version using Euclidean distance. Needed to learn about this anyway.

A lot more math to do the 2 color version, it may have to wait... It's been a long time since I did 3d cross products or dot products in code.

It sounds like it is doable. I suspect I need to work in the HSB color space instead of RGB, maybe interpreting each channel separately. Computing the distance in 1 dimension is a whole lot easier I can see how this might work, the sensitivity of the picker can be changed in each channel of the HSB. More later.

Very nice work!

Great! This is surely the best one among the three you made.
Thanks Rick!

Yes, I think so. If you let it only here, after a while, it will become hard to find.

a color range filter was asked for several years ago by me. a couple folks worked on it, including me, but nothing satisfactory was ever done. you might do a search on this in the forums to find that old thread. maybe there's some ideas that could be used with all the new stuff in FF now.

yeah, that's pretty good, but needs more refinement. using the bird picture and picking a green hue as the color picker value, when I adjust the sliders for emphasis and threshold as I pick up and then lose the blue hues, some of the green disappears before all of the blue. not sure of all the hex values here and how this all gets checked internally, but it's still a little off. but, like I said, this is about the best I've seen in all the attempts from years ago and now and is still very helpful. this could easily be incorporated into other filters for color picking ranges.

ok, after more testing, I find that there's a bit of a trouble here. if you take an orange and reddish range but the image also has some greens, and even though your range is in the oranges, some of the reds and oranges and browns will disappear before some of the greens and this seems a bit off.

This color range picker is more sensitive to saturation. Play around in the Match Color with raising and lowering the saturation only and to see if this helps. If not, give me some specific RGB values for match colors and images to look at and I'll give it more thought.

take the above image and start at 50/5/100 and you'll see the greens. these settings also get a large amount of her hair and face. as you move the 50 up, you will start to eliminate the greens but you also start to lose some of the reds and that's what I'd like to fix.

Good news, bad news. The picker is working properly. Yes, the edge of the hair definitely shows the tendency towards green. One problem is the 50 value on color threshold, normally I would consider this too large a color range. Problem is skin and hair are usually very difficult to match, the range of colors is much greater than we perceive. So, I am testing with Photoshop's magic wand at different tolerances (UPDATE: make sure to uncheck Contiguous). Start at tolerance 40 and use the wand. Then move it up to 60 to test the wand. You will see green results creeping in when wanding the hair. Seems in comparing the Magic Wand with the FF color range picker, the FF picker does pretty well.

The question is this, is it worth having a 2 color picker? One color you want, the second a reject color? Also, I have considered a 2 color picker that picks the range of colors between the two, but it is a lot more work (mathematically).

To tell you the truth, the real problem is not the magic wands in editing tools, it is the human perception of color. Humans "perceive" color (hue) more than brightness and saturation in a scene or photograph. Also we take in account areas, so it is somewhat like the Magic Wand with Contiguous checked in Photoshop. I have not found a great simple color range picker, especially for photographs. It's mostly due to the color models not being able to match human perception of color in a "linear" way + the wide dynamic range of many photographs. So the math used to match human perception of color is only an approximation, IMHO.

I'll put the color range picker out on Monday. Thanks for your input Craig

cool beans. in the meantime, you can always post a copy here so I can start playing with it

got your new color picker. thanks

have been revisiting some of the older color range and mask filters and here's what I got using one of those. this one was originally one by me. I altered it, however. I don't recall who the original person was now and there's no record on the filter of the original author.

this one came out pretty good. they don't always. the controls on the filter aren't marked very well and I'm out of practice with the filter. still, this came out fairly well.

I'm wondering, after playing with all these filters, if it wouldn't be easier to make a color range filter based on the HLS component. one could limit the range of each of these qualities and perhaps get something quite refined.

had to save it as a png file. lol. been a while since I've saved with a transparency.

I am putting the Lab color range picker on the shelf. Maybe someday I will find a use for it. Maybe your picker is the solution?!

frankly, rick, yours is MUCH better. I just got lucky. after looking at the guts of the thing again, I'm surprised I even got it that good.

i vote that you release it and make it available wih a note telling this that you have written here, so the possible user will know what to expext fr om it.

As it happens with many other filters, it will not work right with ANY image, and you would to select images carefully, but I think it could very useful and interesting in some situations

also I suggest to have an option to choose contigous color OR similar color range, as it could be possible that if you want to remove a whole gradient background, it whole be needed to be select all of it, and not only the contigous parts, so one checkbox to choose either contigous or similar.

also if possible it would be good and useful to be able to pick wh ere it will start to count the contigous selection of color range

And I wonder if it could be possible to select two different color ranges in the same image, as a gradient may be composed of two colors.

what happens with the edges of the color range? Are they sharp and pixelated? Or maybe a little soft, lime it happen with the antialiasing effect?

Thanks Rick

GOOGLE SEARCH IMAGES

there are possible examples for selected images

gradient background isolated flower

black background isolated flowers

Thanks very much for the detailed answer and comments

Good that you will make it available

I have to say that when i am suggesting possible things, i have no idea how difficult is to be done, and if there may be technical limitations, or if it may need coding to do it, or if it involves additional things that may be complex to do

What i put are just ideas, and you can take the ones you like, can do and want to do

Of course this is all your own decidions and is up to you to do it as you want as these are only possible suggestions, not requests

Seems like a good solution. The only recommendation I can see is a 'precise' switch so that users can save 2/3 the time when high precision and AA is turned off. But hey, you can do like I did and save that for a headline update later on.