Images flipping

[AMIF]

Is images flipping made by SharpCap and requires processor operations, or it is just camera's option? It is important for stable video recording for precise timing.

[admin]

Hi,

if you are using the 'flip after dark/flat' control in the 'PreProcessing' section of the controls on the right then that is being done by SharpCap (the image is being flipped after the camera has delivered it to SharpCap).

For some brands of camera you will also see a separate flip control in the 'Camera Controls' section (or perhaps 'Image Controls'). Those controls pass on a setting to the camera SDK to ask it to flip the image, so with those the image is flipped *before* it gets as far as SharpCap. I would expect that in most cases, this is achieved with a software flip of the image on the PC rather than in hardware on the camera, but I can't be sure about that (the camera manufacturers don't document this sort of thing).

Hope that helps,

Robin

[AMIF]

Oh, thank you, Robin! I asked about camera control, but not about pre-processing calibration. So camera's flip should not affect on speed of recording, I hope

BTW, about pre-processing: at present I use two sets of flats and darks - for flip 0 and flip both images, and do not use 'flip after dark/flat'. I guess, it is not correct way, but results are correct. What would you recommend in this case?

[admin]

Hi,

since you have already created the two sets of darks/flats, there is no real gain by using the 'flip after dark/flat' option (except that it would avoid the possibility of changing the flip and forgetting to switch the dark/flat). For those who are starting from scratch, the use of 'flip after dark/flat' means that they only need to make one set of darks and flats and can then use any orientation without worry.

To be honest, unless the PC you are using has a very very low power CPU, the sort of simple image processing involved in a horizontal or vertical flip will not have much impact on frame rates (probably none at all). If you use the camera control flip option, it may add very slightly to the latency between the frame actually being captured and the frame getting to SharpCap (at which point a timestamp is attached to the image), but even that effect would probably be a small number of milliseconds at most.

cheers,

Robin

[AMIF]

Thank you again, Robin! Would you please kindly explain two last questions:

1. For example, darks and flats were prepared with flip 0, but flip both is needed with calibration. Does it mean, flip in camera control should be 0, but post-processing flip = both? Or post-processing will flip darks and flats according to camera control flip?

2. Is it possible to add flip value to the flats and darks filenames and folders? Or it is not necessary, if post-processing flip is used as above noted?

Mikhail

[admin]

Hi,

if you have captured both darks and flats at flip=Off, but want to image using them with some flip applied, you need to use the 'Flip Post Dark/Flat' option to flip the image (otherwise the images will be flipped by the camera SDK before the dark/flat correction and then those corrections will not work).

I would advise to not use the 'flip' options of the camera SDKs any more now that the 'Flip after dark/flat' is available - I have only left them there because there will be a small number of people who will have a valid use for them and would miss them if I took them away. If I added a new brand of camera now, I would not add a way to control the flip option on the camera if it had one.

cheers,

Robin

[AMIF]

Understood, Robin, thank you!

Camera flip may be useful for asteroid occultations video, when calibration is not needed.
On the other hand, I often use camera flip for calibrated images stacking with uncooled camera, which unstable sensor temperature not infrequently requires getting fresh darks just before long seria.
So this option helps sometimes.