iMac crash when atempting to create a masterbias in imageintergration

[DOBR28]

Dear All,

My name is Dominique and just subscribed to the forum.
I am a absolute beginner with Pixinsight, so i figured that the best way for me would be to start to learn how to pre-processe my image sets and take it from there. I shoot my images (subs bias dark and flat frames) on a modified Canon 6D. Last weekend I installed Pixinsight on my iMac Core i5 2,7GHz 16gb DDR3. I copied the folder to my application folder and started the program. All applications seem to be working and directly installed 18 updates.

Guided by the tutorial of Richard Bloch "calibration and stacking in pixinsight 1.8", is tried to give it a go.
The first step in this tutorial is to create a master bias frame. I opened imageintegration and loaded my first 240 bias frames. I took over all settings one on one that Richard showed in his tutorial (sigma clipping) and hit start button.
As the process is running, I found that my computer is getting slower and slower. My computer is able to load all images, but crashes/not responding when it starts to process the 3 integrating channels. This process takes about 3 hours.

As looking for what could have been wrong, I updated my iMac to Sierra and reinstalled the coresponding version of Pixinsight. The problem however reappears, so figured that i need some help. As I am writing this I am trying to reduce the buffer size from 16mb to 10mb, and hope that helps. As it looks that the program is taking a lot of my memory, is there someone that can help me with optimizing my settings, in order that the process might be slower, but my computer is still usable.

Dominique.

[Juan Conejero]

Hi Dominique,

Welcome to PixInsight Forum. There is no bug here, just a logical consequence of trying to load 9 GiB of data in RAM, along with the internal working images and data structures that ImageIntegration generates, the PI Core application, other applications and processes running concurrently, the operating system kernel, and system services. You just don't have enough RAM in your computer to do this.

This happens because you are trying to integrate DSLR raw frames directly. The problem with raw frames is that they use data compression (typically some variant of lossless JPEG compression), which does not allow incremental file reading operations (reading image data by successive strips of pixel rows). This means that all of the data must be loaded in RAM in order to integrate them.

Fortunately, the solution is very easy: convert the raw frames to a format able to perform incremental file access operations, such as PixInsight's native XISF format. Do the following:

- From the main menu, select Script > Batch Processing > BatchFormatConversion

- Click the Add button and select your 240 bias frames.

- Make sure that input format hints are "raw cfa" (without quotes).

- Select an output directory (aka folder) to write converted files.

- Make sure that output extension is .xisf

- Click OK and wait.

Now you can integrate your 240 bias frames (much more if necessary, in fact) in XISF format without problems. Let me know if this works.

[DOBR28]

Hello Juan,

It works. Right now I am processing another badge and my mac is working fine.
Do I need to do this for the other calibration and sub frames as well?
Thank you for the feedback.

Dominique

[Juan Conejero]

Hi Dominique,

Glad to know it works. You only need to convert your raw bias frames when you're going to integrate a relatively large number of them. With your hardware, say about 50 frames or so. For dark, flat and light frames, you already have them in XISF format after calibration and registration.

[DOBR28]

Hi Juan,

Thanks for giving me a kick-start. My first 10 hours of becoming an expert are a fact!
This morning looked thru the forum and found a lot of information and tutorials that are useful in getting started.
Hopefully by the end of the day I have my first stack ready.

Best regards,

Dominique