SharpCap Forums

Hi Robin,

I've just had a quick go with the new Auto Sharpen function using a saved Jupiter capture from a while ago.

Is there a reason why Auto Sharpen doesn't use the Fine sharpening setting?

Normally I mostly use the Fine adjustment, with just a bit of Level 1 and sometimes a little bit of Level 2. Comparing what I normally do, the Auto Sharpen function is using no Fine, quite a bit more Level 1 and Level 2 than I would use (twice the amount), and some Level 3 and 4 which I don't normally use at all.

Peter

Hi Peter,

the way the auto sharpen works is linked to the different levels of gaussian wavelet sharpening, so the calculations that it does leads to a set of values for the various levels that seem to give good results in a wide range of cases. The 'Fine' adjustment doesn't come in to the calculations, so the auto sharpen doesn't try to set that value (except that it brings the value down if it is set to a high value, otherwise the combination of level 1 sharpening and fine sharpening tends to produce a mess).

In a way, the auto sharpen is not aimed at more experienced images who have some experience in adjusting the various level sliders and the other adjustments (except as a quick starting point) - it's aimed at the inexperienced... It all came from seeing so many Jupiter images posted online and in many cases my immediate reaction is either "that will easily take more sharpening" or "overdone it on the coarse levels of sharpening" (the latter leads to distinctive excessive contrast between the belts and zones).

cheers,

Robin

Hi folks,

another update this week - version 4.1.13041 has just been uploaded. A couple of significant new features - 'Time Travel Auto Capture' and 'Freeze/Resume'...

Time Travel Auto Capture

This feature is intended to help combine traditional 'Capture an SER and process later' planetary imaging with SharpCap live planetary stacking. When enabled, SharpCap will do two things...

• Continually monitor the stack quality, looking for peaks in quality that indicate that the frames leading up to that point have been particularly high quality
  
  and
• Use memory to store the most recent hundreds or thousands of frames that have contributed to the current state of the stack

That means that when the stack quality *does* peak, SharpCap can make the decision to save those stored frames to SER, knowing that they are of better than average quality. It's like being able to press the 'Start Capture' button *after* a period of good seeing rather than before - that's why the 'Time Travel' name. Once a peak has occurred and a batch of frames saved to SER, SharpCap just goes back to watching the quality and storing frames, waiting for a new, even higher, peak in quality...

To get started with auto capture, get the stack going as normal and then go to the 'Auto Capture' tab in the Planetary Stacking area - once the stack has reached target length, a graph will start to appear showing how the stack quality is changing over time. This is the quality before sharpening/adjustments, so those settings will not affect the graph.
Higher values in the graph indicate a higher quality (more contrasty) stacked image, which in turn means that the frames that have recently been stacked are higher quality (better seeing or focus typically). A peak in the graph occurs after a period of good quality frames that have come to an end, a trough after a period of poor quality frames that have now improved.

Activating Auto Capture and Memory Requirements

You will see the 'Activate' button to turn on auto capture - if this is not available then it almost certainly means that there is not enough memory allocated to 'High Speed Frame Cache' in the memory settings. The number of frames that need to be stored in memory to activate this feature is calculated as:
The 'Filter Factor' is a factor that corrects for the 'Frame Filtering' option being active - if it is inactive, the filter factor is 1. If it is active and you are selecting the best 50% of frames, the filter factor is 2; for the best 33% it would be 3 and for the best 25% it would be 4.

The decision buffer allows SharpCap 10 seconds extra time to decide if a high quality score is a peak (time to capture) or is just part of a gradual and continuing rise in quality (don't capture just yet - quality is still improving).

If you cannot activate this feature and cannot further increase the memory allocation, then consider turning down the target stack length or disabling frame filtering to reduce the amount of memory required.

How Auto Captures Happen

Once activated, you will first see the stored frame count begin to increase up to the calculated number of frames - the frame gauge will be orange while filling (insufficient frames to capture) and change to green when there are sufficient stored frames.
Once there are enough frames and the gauge turns green, SharpCap will also draw two lines onto the quality graph:

• A horizontal green dashed line - this indicates the quality threshold for capturing - a capture will happen when the stack quality peaks above this level (note - it must be a peak, not just rising above the level)
• A vertical green dashed line leading to a recent measurement - this is the decision point indicator - the measurement that SharpCap is looking at to consider whether to capture. A capture will start when the decision point quality matches the threshold line *and* all the more recent quality measurements than the decision point are lower values than the decision point value

When a capture happens, it will usually happen *very* quickly, since the frames needed are already in memory, and SharpCap just has to save them to file. The frame gauge level will drop when a capture happens and the gauge will also turn pink during capture, but this might be hard to spot if the capture finished rapidly. To make it easy to tell that a capture has happened, SharpCap shades the area of the quality graph red to show the time period of the capture that has been saved.
Over time, more captures will automatically happen each time the stack quality peaks to a new higher level.
Note the adjustment to change how much of the history SharpCap includes in its calculation of the quality threshold level - in the screenshots it is set to 15 minutes, which means that high quality peaks in the stack are ignored after they are more than 15 minutes old. This helps ensure that a high quality peak early in a session does not prevent any more captures at all for the rest of the session.

It's also worth noting that immediately after a capture, the number of stored frames will be depleted, and SharpCap cannot capture again until the store has refilled - that means that a peak followed by a short dip, followed by a higher peak may mean that the second, higher, peak is not captured due to occurring in this 'refill' period.

Please remember that this is the first version of this functionality, so there are probably still some gremlins to be found and resolved - feedback welcome!

Freeze and Resume

This is much simpler... Currently Planetary Live Stacking resets if you close and then reopen it. In most cases that's fine, but if you want to do something else and then come back to the same stack, there was no way to do it. Now the Freeze and Resume feature gives you that ability.

Freezing a Stack

To freeze a stack, just press the 'Freeze and Close' button - this will keep the current state of the stack active (including any timelapse that is running), but close the live planetary stacking tool so that you can use other tools (focus tools to refocus for instance, or other tools to perform a meridian flip).
Resuming after Freezing

When you want to return to planetary stacking, just re-select it, then press the 'Unfreeze and Resume' button to continue stacking (the button has an attention-grabbing yellow/red flashing background and is the only thing you can press at this point apart from 'Reset Stack').
Note that you should make sure that you have returned to the same image size (width/height) of capture area and the same camera mode before resuming, otherwise the stack may immediately reset due to the mismatch. I will look into warning about that situation in a future update.

If you perform a meridian flip, SharpCap will detect that the flip has occurred since the start of the stack (providing your ASCOM mount reports the side of pier to SharpCap) and will automatically rotate all frames captured after the flip by 180 degrees before adding them to the stack, to align with the existing image. I must admit though that I haven't had the clear sky to test this feature yet!

cheers,

Robin

I just wanted to say how good this software is Robin and to express appreciation. I have not really seriously tried planetary imaging before --tried it for the first time with an appropriate set up using your live stacking software last night under far from ideal unsteady conditions and - but lucky with the timing of the cloud gaps - was quickly rewarded with a great semi-live view of Jupiter red spot and Mars syrtis major. The only catch seemed to be the lack of an ability to record an ongoing SER file at the same time and you already appear to have fixed that above. Loads that I don't understand or know how to optimise yet and still just blundering about wrt settings but the snapshot from a 136 frame live view was actually better than anything I was able to later derive from ser files.

Hi Tim,

glad you had some success with the planetary live stacking

In fact you can capture a normal SER file while planetary live stacking if you want (just press 'Start Capture') - the new auto capture tool above is just to help ensure that the captures are timed optimally with respect to seeing.

Some quick guidelines to get the most out of it:

* Set your exposure to about 15ms or less for Jupiter - aim for 60+fps. If the images from the camera are dim, brighten them by increasing gain
* Stack more frames - 1 to 2 thousand?
* Use the 'Auto Sharpen' / 'Auto Sharpen More' buttons to set a reasonable set of sharpening parameters in most cases
* Jupiter looks nicer with boosted colours - wind the saturation up to about 2.0 and then adjust to taste.

If you have saved SER files then you can play them back again in SharCap (run SharpCap, don't open a camera, drag the SER file into the SharpCap main window area). That lets you practice with the planetary live stacking adjustments before the next clear sky evening.

cheers,

Robin

Tim,

There is a checkbox in the tool that will align the RGB channels to mitigate atmospheric dispersion. If you don't have an ADC, you should leave that on by default.

Cheers,

Mike

WoW! Can't wait to try these new features out.
Thank you so much.

Thanks very much Robin and Mike..

Great tips. Yes I will try honing my Sharpcap skills offline and have a play with quality settings etc using a ser file -- I had the gain down too low on this first attempt.

Yes Mike you are right -- I don't have an ADC yet and Jupiter was getting rather low by the end of the session so a useful tip about aligning the RGB channels - makes perfect sense.

Tim

Hi folks,

a new update for planetary live stacking with this week's release (and possibly the last change for a while - I don't have anything major on my todo list in planetary live stacking any more).

What we have this week is 'Expert Mode' for sharpening, which gives 8 wavelet layers to adjust rather than 4 (the layers are more closely spaced - half the spacing of the normal four layer mode). This gives finer control over sharpening and can give better final images in almost all cases with proper adjustment.
Expert mode can be turned on/off by checking or unchecking the 'Expert' checkbox at the top. The settings for the sharpening levels are independent between expert and normal mode, so the two modes will need to be adjusted separately if you switch back/forward between them (note: 'Fine', 'Denoise' and 'De-ring' are shared between the two modes).

My experience has been that the finest level - level 0.5 - typically doesn't need much boosting in expert mode, but it does serve a purpose as it 'traps' a lot of the pixel noise and prevents it from being boosted so much when you turn up the higher levels.

Other changes in expert mode are:

* Auto Stretch now has a variable strength rather than the two set strengths available in normal mode - this can help a lot in getting just the right amount of auto-sharpening.

* There is a 'Linked Adjustments' checkbox - when that is enabled, moving one of the level sliders will also adjust the neighbouring ones in the same direction, but by a proportionally smaller amount. This can be handy as adjusting 8 levels individually can get a bit tiresome.

cheers,

Robin

Hi Robin,

Is there any chance you could look at making the planetary live stacking file names respond to the template as they do with DSO stacking before you move on to another area of the SharpCap software? I'm still having to manually edit the filenames that I keep.

Peter