Star Alignment Improvement Requests

[georg.viehoever]

Hi,

I experimented with the latest Star Alignment Module, and have the following improvement requests:

- I sometimes get an "Out of Memory" message, and PI does not recover from this producing out of memories for all following images as well. Only restarting PI helps.
- When the first RANSACs don't succeed, the higher RANSACs require excessive amounts of time. There is no obvious RAM shortage (Vista, 3GB RAM, task manager does not go beyond 2.2 GBytes), although CPU utilization sometimes is very low (<10%), which may be an indicator of some memory management issues. Maybe you can configure RANSAC just to give up after a specified amount of CPU time.
- Is it possible to "uncheck" images successfully processed during a run? That would enable us to reuse the current configuration in a second try.

Georg

[Juan Conejero]

Hi Georg,

I sometimes get an "Out of Memory" message, and PI does not recover from this producing out of memories for all following images as well. Only restarting PI helps.

Unfortunately, there is little I can do to improve this situation. Usually after an out-of-memory condition the heap is heavily fragmented. As a result of fragmentation, PI may be unable to allocate a contiguous block of the required size, even when there are enough free memory bytes in total. Fragmentation usually fixes "by itself" if you continue using the application for a long time. This is because successive allocations and deallocations tend to compact free memory blocks, due to PI's internal design, but you have to have patience to achieve that. It's far easier and faster to exit and re-enter the application.

From my experience, this problem is worse on Windows, mainly due to MS's runtime inefficiencies (malloc()). This problem is not so severe on platforms that depend on glibc (Linux and Mac OS X).

When the first RANSACs don't succeed, the higher RANSACs require excessive amounts of time.

You should be able to abort the ongoing StarAlignment process. I'll try to increase SA's execution granularity to make it more interruptible.

Is it possible to "uncheck" images successfully processed during a run? That would enable us to reuse the current configuration in a second try.

Yes. Just double-click on an image entry on StarAlignment's Target Images list, and the corresponding green check mark will turn into a red cross mark, or click the Toggle Selected button to toggle the state of a multiple-file selection.

[georg.viehoever]

Hi Juan,

Yes. Just double-click on an image entry on StarAlignment's Target Images list, and the corresponding green check mark will turn into a red cross mark, or click the Toggle Selected button to toggle the state of a multiple-file selection.

My idea was that StarAlignment would do the toggling itself when it successfully aligns an image. That would allow to run the same star alignment with different parameters on those images where it failed. Should not be difficult to implement...

Georg

[Juan Conejero]

Hi Georg,

I understand. Yes, this can be implemented quite easily. My intention is to include this feature in the new version.

Thank you for an excellent suggestion.