Why is Photoshop not merging my panorama?

Question

It's not something i am planning on doing often but I wanted to try to do a panorama and use Photoshop's "Merge to Panorama" feature to stitch the images. Previously I have only done this manually. I think I have a decent overlap in my images but Photoshop is unable to stitch my images. I have 2 sets of images and it stitches the middle group fine but not the first and the last image. This is similar with my other group of images where it stitches 2 middle groups and not the first and the last image. Below is a screen capture of what i usually get:

What am I doing wrong?

Answer 1

The framing of the first and last images seems to be significantly different from the others (it took a while for me to see that the top pic was the last and the bottom the first, assuming left-to-right sequence). There may simply be too much ambiguity for Photoshop to deal with in this particular sequence, since the main differentiator is colour (something PS autocorrects to a degree in stitching), with the darkness of the islands and clouds being the "anchor", and both of the pics left out have the horizon in a significantly different place than their next-door neighbors.

I don't know how the panoramic merge works in PS these days (I'm still running CS3), but this looks to me like one of those instances where manual tiling would be necessary, and I'd expect to lose (or have to synthesize) a significant part of the vertical after the stitching because of the framing issue.

Answer 2

Automatic stitching is not perfect, it works by identifying a set of salient image features, corners, junctions, dots, lines etc. and then searching for a transformation that causes a good number of features to match up with the feature set of an adjacent image.

In your case there are simply not enough features in the two unmatched images. The top image contains a large amount of featureless sky. In the bottom image, all the features are concentrated in the shoreline area - which isn't present in any of the other images, and the water is devoid of the dark ripples that I'm guessing provided the features to match the middle images.

You haven't really done anything wrong, it's just your chosen subject doesn't contain enough detail. If I were you I'd try and add the spare images manually, and try and bear in mind the need for distinguishable features when shooting panos.

Answer 3

Photoshop's Photomerge is relatively limited as panorama stitching packages go. And most auto stitching programs require enough overlap and significant enough features to be able to match the images together. Shots where there may not be enough distinguishing detail in the overlap areas to anchor accurately can be problematic. In your scene, the ocean and horizon is very similar from shot to shot, and chances are good Photomerge simply can't figure out where to attach the images together.

There may not be any way to save this is Photoshop. You may have to use a specialized panostitching program, such as Hugin.

The autostitching algorithms in specialized panorama stitching programs can be more sophisticated, but in addition, they allow you to manually correct issues that can lead to stitching errors. In the case of Hugin, you can manually specify control points--that is the specific spots that match between the images, and where you want to pin the member images together to form your pano.

The procedure goes something like this:

1. In Hugin, after loading up the images and aligning them (i.e., letting the software automatically find control points), if the software can't find control points between pairs of images, it notifies you with a message.
2. Go to the Control Points tab.
3. In the window, select the pair of images that don't have control points defined. The window will have two panes in it, one for the first image in the pair, and one for the second.
4. Click on the point in the first image to define where to place the control point, and then click at the same point in the other image to finish defining the point.
5. Define three to six pairs of control points.

6. Repeat Step 5 for every pair of images that didn't have any control points.

7. Check on the stitch by looking at the GL preview window (you can also correct bowed or slanted horizons here by simple dragging under the Move/Drag tab to reset yaw, pitch, and roll.)

8. Save your project (File → Save).
9. Stitch the image (Stitcher tab; Stitch! button).

Answer 4

I am not sure if you can rescue the panorama above in Photoshop; manual work is problematic since Photoshop transforms the images to fit a chosen "layout".

(An aside - it seems your horizon is not level, and normally this is crucial for these types of panos; your stand and head must be properly leveled. If you try to correct this in Photoshop the height of your pano will very small indeed.)

I have used Photoshop for stitching panoramas earlier - with up to nine images and have sold copies of the panoramas. But I suddenly ran into problems in Photoshop without being able to really identify why.

I shoot with a Manfrotto 303 SPH head to ensure good alignment, and also to adjust for nodal point. I shoot both landscapes and architecture.

My experience is as follows:

1. Use good overlap between the images, at least 25% (I normally use 30%) with lots of extra room on either side and above/below the panorama you wish to cut down to (again 25% is a good measure).

2. Ensure there is some clearly identifiable structure in each of the images that overlap, this helps Photoshop to identify where the merging can be done.

3. Sometimes Photoshop just cannot seem to figure things out even if great care is taken.

As far as I can tell there is no good way to solve this in Photoshop. I had my first issues with Photoshop about two months ago, having spent a weekend walking and shooting landscapes. Photoshop would not handle any of them.

I ended up downloading Autopano from Kolor and it handled all of the panoramas, so I ended up buying the program.

My workflow now is:

1. Batch process all images in Adobe RAW (manually setting white balance, noise reduction, exposure compensation, highlight and shadow compensation etc., the same for all files), save the resulting files as TIF.

2. Import into Autopano, and adjust the panorama; crop and render to Photoshop format.

3. Open in Photoshop and do further editing and printing there.

To be able to handle the panoramas (in reasonable time) I upgraded my PC with a new motherboard, CPU and RAM. I have two SSDs (one for OS and programs and one for images and Photoshop scratch disk), 32 GB RAM and an i5 6500 CPU running at 3,2 GHz. I still on occasion run out of memory if I have Autopano and Photoshop open at the same time.