More sensor analysis questions

[galljj]

Thanks Robin.

In the camera controls there is a debayer preview box. If set to off does that mean SC thinks it is a mono camera?

I dont recall that it always have me two peaks, and it seemed like something to do with illumination. I'll play with it

If I do both 8 and 12 bit analysis, does the smart brain know which one to use, assuming I switch between bit modes?

Thanks again for a great product!

John

[admin]

Hi John,

yes, the debayer preview overrides the info that comes from the camera (ASCOM cameras seem to be wrong more often than right, so that control is a must). If you set it to off you will be working as if it was a mono camera and see a grid pattern of the individual pixels when you zoom in.

SharpCap keeps track of the 8 and 12 bit analyses properly and uses the one for the mode you are in. Also it compares in the background to the results from the other mode and suggests when to change to 12 bit from 8 or the other way round via the histogram colour bars.

cheers,

Robin

[galljj]

Robin: SEE LAST POST OF MINE BELOW

I picked up the latest version of the beta and reran some of the sensor analysis tests. Well, I tried to.

I set the debayer preview to macth the mask of the 224 chip - rggb.

When running, i got a single humped histogram - no doubles.

But repeated attempts to get the analysis to come to closure failed. I was able to get through the dark measurements relatively simply. But when measuring the relative gain, it kept failing with the comments that the minimum exposure had been reached and it was giving up.

Attached is the log from the session.

Question - are the results from my previous analysis still available, even though I have updated the beta version ? And, even though the previous analysis may have been made under odd circumstances, the derived relationships looks very much like the expected 224 curves. That being he case, I think the smart histogram analysis would give me useful information. What do you think ?

j

in the dark tests.txt

(277.31 KiB) Downloaded 127 times

[galljj]

Robin:

I solved the illumination problem. I had a maximum frame rate set, and had the USB transfer set to low, both were there because I typically do DSO and didn't need high frame rates.

Also, I went back and followed your instruction about sizing, and illumination.

But now, when the the analysis gets to the end of the relative gain work, it says checking binning, and shortly thereafter the program stops. A screen pops up and says Sharpcap has stopped. Windows will now close the program an let you know if a solution is found. Unfortunately, I cannot access the log file at that time.

I'll keep plugging away.

john

[galljj]

BTW, when it is measuring the darks (with the objective covered) it no longer shows the histogram, although the log file shows that it is computing the mean and sigma at each gain level.

j

[galljj]

OK, I got it to work !

Here's some tips:

Your suggestions about pretesting the illumination were good.

But, I would suggest that the minimum size sensor area should be something like 320x240, from which you select a 100x100 test area. I had several runs using a 100x100 sensor area, and used the whole frame for analysis. I suspect that it got hung up when it tried to check the binning - that appears to be the point at which it simply stopped working.

When i reverted to the 320x240, all was well.

Make sure your frame rates are set to maximum across the board.

For this sensor, force debayer to rggb

here is the 12 bit output

Now to try in the real world, and not my basement !

success 4713 12 bit.png (460.61 KiB) Viewed 2203 times

[admin]

Hi John,

I think that my suggestion of 100x100 was what led you in the wrong direction - I was meaning to use the red selection are box to pick an area of 100x100, not to set the camera resolution to 100x100 - sorry. You should be able to leave the camera basically at full resolution and select your 100x100 sub-area from that.

Remember that once you have done the sensor analysis for the camera there is no need to repeat it - it gets saved to your PC and re-used in future sessions. With an ASCOM camera, SharpCap doesn't really understand the difference between 8 and 12 bit mode, so it is best to just run the analysis once in 12 bit mode (since you are planning on using that). With cameras that are natively supported then you would be better running in both 8 and 12 bit modes to get the full camera parameter set saved.

cheers,

Robin