Multiple Focus Points: Combining them into one image.

This question is using digital microscopy, so it may be a bit different than

what most of you are used to. I have about 10 images that are all focused on

different planes (layers) of a specimen, and I was wondering if it is possible,

using photoshop, to layer these images together and output one image that is

completely in focus. Each image has a section that is in focus, and I'd like to

keep the in focus areas from each image and combine them into one. Anyone have

any ideas as to how to go about this?

 

Thanks,

 

Steve

It doesn't sound possible using Photoshop. For every pixel in the final image you would need to know which of the 10 source images has the best focus on that pixel. Photoshop wouldn't have the information needed to make that decision (you could do it manually but it would take a very long time for every pixel). I'm sure other image processing software could be written to perform this task (maybe that's how medical CAT and MRI images are created).

There is a free piece of software that does this. I wish I could remember what it's called; I tried it out on a couple images. The developer's goal was to get increased depth of focus on macro images while keeping a pleasing blurred background. It should work fine for what you want to do, too.

 

I can't find the software with a quick google, but I did just stumble across this:

http://www.photomigrations.com/articles/0603200.htm

 

Is that what you're after?

I think this has most of the links:

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00E55Q

I should have added that, to look further, you'll need to use the right nomenclature. By searching for <i>blending</i>, <i>DOF</i> and/or <i>depth-of-field</i> and <i>focus</i>, you should be able to find what's out there. Adding <i>microscopy</i> wouldn't hurt, as it's a classic problem.

It's certainly possible. Basically you just put each image in its own layer and remove the area out of focus. Merge the layers and you should have one image that is sharp. Registration is important though.

I think it depends on the complexity of your subject. What you could do, as the previous poster said, is stack your images in layers and make sure they're aligned right. For example, your background layer might be, say, an amoeba with the center in focus but the squishy sides blurry.

 

Put the picture in which the squishy sides are blurry on top and then use the erase tool, on a soft setting, to get rid of the middle part of the top layer.

 

Again, it depends on how complicated the image is, how "uniform" the depth levels are, and of course, how similar all the images are.

http://www.heliconfocus.com/pages/index.php?focus_overview

If the illustration will be on the net, rather than printed, then you have other approaches. One is to make one image with each picture as an aligned layer. Then use Flash or an animated gif to pan through the object. I have an example of a microscope slide done in that manner that I can post.

 

Another is to use Flash (again) so that the user can navigate manually, or even choose a particular layer to study.

 

There are 'infinite DOF' programs but they generally use well separated items, or an angle of view that helps separate the objects as they would appear in real life. A perfectly flat object of each layer in focus might, depending upon the subject, be virtually opaque.

I'm unfamiliar with "digital microscopy". Are your final combined images intended for monitor or prints? If a combined image needs to be precise and accurate in fine details, then the individual images must be aligned perfectly with one another. Otherwise, you will spend lots of time aligning them in PS, and may never get a perfect alignment. Merging unaligned layers will result in soft edges in the details, and/or distort them. I will be weary of sw that merge "automatically". If they cannot align the layers perfectly withan explicit step before merging, the end result will have the same problems. Check this related thread:

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00JYJH