Hi Wei-Hao (@whwang),
“1. I believe I used equirectangularProjection instead of the standard rectlinearProjection. I might be wrong.”
Okay, the equirectangular projection only becomes possible after calibrated projective registration. Let me know if this works tomorrow ;-)
“2. I also did try a small subset of the panels to start with. APP can process them successfully. Please see the attached image. Here, my question is whether I can control the orientation of the FOV, to be either horizontal or vertical. The tilted angle like this doesn’t look quite comfortable.”
Currently, the orientation is the result of the orientation of the chosen reference frame. To control this orientation, I need to do some more programming, but this should be possible. I would scan the borders of the whole mosaic and rotate it in such a manner that either the widest/smallest part will be either horizontally or vertically directed. I think that’s what you are referring to? I can add it to my list as a new feature.
“3. I believe what PI did for image stacking is to register every image to the reference frame. If all of the images are taken with identical optics, then the stacked result can be considered as having no distortion correction at all. It should have identical distortion pattern of the reference frame.”
This is rather complicated. An optical distortion pattern is described by a center of distortion, that is a certain spot on the sensor of your camera and dependent on your optics, like you describe. But if you have made several stacks, theses central points of distortion are definitely not at the same spot in the stacks. So these distortions patterns in the stacks can’t be considered the same, although the data is shot with the same camera. (Technically speaking, PI is the camera now for the stacks that you created, and I am quite convinced that PI doesn’t do correct distortion correction since PI uses thin plate splines for this. Pi doesn’t correct the distortion pattern in your reference frame, the thin plates just bend arbitrarily to the distorted reference. This is a fundamentally wrong approach in my opinion. That’s why I am worried about stacks that were created in PI with Pi’s so called distortion correction. )
“4. I have another project to mosaic the 2pi sky. Do you think either of the current two projection methods in APP can do that? When I started the project, I had fisheye projection in mind.”
The equirectangular projection should be able to do 360 degrees x 180 degrees, the full sphere. Rectilinear is limited to 120 degrees x 120 degrees. A fish-eye projection is something that I can implement as a new feature for sure ;-) Other projection types as well. There are a lot of possibilities. The technical requirement for these other projections is that APP knows the focal lengths and principal points of the frames, which it should know after the calibrated projective registration.
“5. It takes couple of minutes for my computer to launch APP. This is more than 10x slower than any other programs I have. Is this normal?”
No, this is not normal at all, on my windows desktop, and Macbook 2016 it takes just a couple of seconds. The seconds are basically time in which APP connects to the license server using a high degree of TLS encryption, this takes a few seconds for the encryption. It shouldn’t take a couple of minutes. Can you share your OS and hardware specifics? Let me know if it takes a couple of minutes each time that you start APP, then something is not allright..