making complicated selections

[Optikz]

Hi,

So I have these two photos and I want to replace the tree in the long exposure shot with the tree that doesn't have the motion blur in it from the wind. I can't seem to figure out how to make a really good selection of the tree in either picture. It would take forever to do it with the quick selection brush and refine it. I'm sure there is a way to make this an easier process. Does any one have suggestions?

Cheers,

Jason

[barninga]

i downloaded your examples an tried selecting the tree in the short exposure.

it looks like selecting by tonal range (shadows) also selects the darkest clouds.

at last i found that it could worth the wile to try these methods:

 

- select by color (magic wand tool). dragging the wand on the tree allows to dynamically set the tolerance; you can see what gets selected while you drag.

- sample a color in the tree with the eyedropper and select by sampled color, setting the tolerance in the dialog window.

 

these are at last similar methods; i think i obtained somehow better results creating grayscale layers from the r, g, b channel (red and blue working best) and selecting on these layers.

 

in neither case i could select the whole tree in a single try: it looks like the complete selection has to be obtained as the union of multiple different selections. to sum selections you can create a spare channel from the selection (rightclick on the pixel selection channel at the bottom of the channels panel); then you can sum all the selecions by rightclicking on their respective spare channels and selecting "add to pixel selection".

 

that said, i'm not sure about how you can paste the selected tree in the second picture, since the blur of the branches is likely to appear "around" the branches of the sharper tree silhouette.

maybe you'll have to use the inpaint brush or other healing tools on the second image to fake the sky where the branches are blurred.

[Asha]

I have been trying to use the channel separation method for selecting the tree, and in AP it is a bit convoluted, but it will allow you to get decent separation of the tree from the background. Here is what I did:

 

--convert the file to CMYK (for this photo, RGB and LAB did not have sufficient contrast in any of the channels)

--check for highest contrast channel--in this case it was the black channel

--duplicate the background layer and change the name to something more unique

--right click the black channel of the duplicated layer and select "Invert"

--right click the black channel of the duplicated layer again, and select "Create Grayscale Layer"

--add layer adjustment "Threshold" above the new grayscale layer, adjust so that tree is distinct from the sky, then "Merge Down" so the threshold is applied to the grayscale layer.

 

Since your file has a difference of exposure due to the backlighting, you may need to do 2 grayscale layers with different threshold settings. You can use editing tools to remove most of the the background way more easily once the threshold is applied, and you can use the finalized black and white to create a mask for masking or selection of the tree. Creating a mask has the added benefit of allowing you to refine it with powerful tools within the layers panel ("Refine Mask") to get even better edges around the tree.

 

barninga already answered the issue of the inpainting needed for your 2nd photo--that should be corrected before you merge with the first photo.

[Optikz]

Thanks for help! I will play with both and see which one I think works better. If nothing I have learned something new. :). For the second long exposure shot, ya, it's not likely going to turn out the way I hope, it was just a little too windy...

[crabtrem]

Those have been some really great suggestions. The only thing I might add is the use of the blend options.

 

 

 

I followed Asha's instructions. But just to see how it would look, I copied the threshold layer to the image you want the background for. I didn't even mess with the blur on the tree in this case. Although I would probably recommend going with the stamp tool. I did try the inpainting brush, and it worked. The problem is having a strategy to use it. The inpainting brush has to be able to sample parts of the image, and depending on how you construct your inpainting strokes, they can sometimes come up with some unexpected results. I think you will probably have better luck with the stamp tool, but definitely try every tool at your fingertips.

 

Anyway, I used the blend options and just reduced the top (threshold) layer's highlights to transparent.  The results aren't bad for a first go, doing nothing else to the images.

 

 

Not bad for 5 minutes of work.  Great techniques. Will have to remember these.