Registax Lowest Quality Estimate

[Chrissyo]

Hey everyone,

Lately, I found myself changing my processing style in Registax - more specificly by decreasing the 'lowest quality estimate' value. I used to keep it around 80/85, but have lately found myself bringing it down to 55/60. However, last night whist playing around with an old avi of saturn I had (in fantastic seeing etc), I found that using the 55/60 estimate greatly hurt the overall quality of the shot. I was a little suspicious of this, as the 55/60 estimate has lately been giving me some good quality (compared to my standards :P ) shots. I decided to test the function with a shot of Mars I took on the 1st of this month.

The first mars on the left was processed with quality estimate at 60. Around 700 frames were used. The middle mars was processed with quality esimate at 90. The last was processed at 95. To me, it seems that the lower the quality, the better the picture (in this example anyway). Yet the Saturn avi from the other night is annoying me.

Therefore, my question is this: does increasing the total number of frames (by decreasing the quality estimate) give better quality than decreasing the total number of frames (by increasing the quality estimate). I had an idea that in excellent seeing etc, increasing the quality estimate would have a positive effect on the end result, where as in bad seeing etc, decreasing the quality estimate would have a positive effect.

Any thoughts on this?

[asimov]

This part of registax has always puzzled me actually. So for the last couple of months I've been doing a lot of experimenting of my own in this area.

I have'nt come to any definite conclusions as yet though. But I will say I have better success If I use 80% (default) onlyif the seeing conditions were fairly average. If the seeing was good, I go with 50%. It seems to me how many frames you have to stack initially in the AVI has a lot to do with what % to give it as well.

If I have a fairly short AVI (800 frames or less) I will nominate 100% which bypasses optimization totally then go to the stacking area & hand pick the good frames & then stack. Not many people have time for this though!

As I said, I'm still experimenting in this area so no definite conclusions yet.

[Robert_T]

I'd tend toward Asi's approach myself with the intent to stack a greater % of the frames captured when seeing is good compared to when seeing is bad - in other words I'd set quality lower for an avi with good seeing an vice versa. The rationale is to use as many of the good seeing frames as possible and in the poor seeing avis to exclude as many of the poor frames as possible. Other factors are how much grain I have incurred via gain, which will lead me to select a quality estimate that gives sufficient frames to overcome grain regardless of seeing quality. Seeing I think though is key.


cheers,

[[1ponders]]

From what I understand Chris, if you have good seeing and/or the quality of each image frame is similar then by selecting more images you get an improved signal to noise ratio so the image looks cleaner, but the final image may not show more detail than a higher quality setting.

However if you have a avi with only a few dozen/couple of hundred good frames then selecting a higher quality will weed out the poor one and only stack the good ones. The down side of this is that you wont have as good signal to noise ratio. The better the signal to noise ration the harder you can push the waveletting, within moderation, if you want to.

That's how I understand it :shrug: (did any of that make sense :) )

[Chrissyo]

Yup, I understand what you're saying, and it seems to fit with my trails. I only had 100 or 200 frames in the avi of saturn in good seeing, and setting a higher quality would result in a clean shot, where as a lower quality left the shot blurry.

@Asi: I've never actually tried hand picking frames, I might have a go at that now and seeing how it goes =)