View Full Version : Question & possible answer re DBK21....?

Kokatha man
April 28, 2009, 13:04:22
Further to receiving my DBK21AUO4.AS after asking questions without any experimentation I have been playing with the camera in a scope inside my studio.....and also trawling the net for any/every tip of hint I can!

Using the settings etc suggested to capture I have found that after adjusting all the various controls/sliders etc with the "debayering enabled" so that I had a colour liveview onscreen to do my adjustments with, I discovered that I then had to switch off "debayering enabled" for capture which turned the liveview image into a mono image.....if I didn't the subsequent avi couldn't be converted to a colour one.

Then, when opening the avi I captured (the one which appeared as mono in liveview capture) in Registax5 I had to check the "Use debayer method" box and also the radio button for GB which was what I had enabled with the "bayer pattern" button.....this allowed R5 to create a colour image in processing.....


Finally, on either side of the image after final processing stages in R5 there appeared a "glazed margin" over the image boarders' side edges - which I think I have encountered before - I could easily crop this out but wonder as to why it appeared....?

Stefan Geissler
April 28, 2009, 16:12:42

your procedure is right: Using Y800 video format and disable debayering. What the glazed margins are, I have no idea.

Kokatha man
April 29, 2009, 01:54:30
Thanks for that Stefan.....:good:the "glazing" may be something to do with the alignment process as I think I've seen similar before.....

Am doing a "crash-course" in bayer matrixes et al to see if I can inject a little technical comprehension into my practical acquisitions.....I set the colour combo to "GB" from the various options - I was testing/focussing on a known-colours object and "GB" gave the most realistic appearance.....but can you tell me briefly how selecting the various options therein actually influences the output of the sensor's colour output (ie by what means?):-)

Stefan Geissler
April 29, 2009, 09:52:22

the start pattern setting does not influence the CCD output, but the calculation of colors. If the start pattern is wrong, then you will recieve images with wrong colors. For more details, you may look here:

This document is from the webpage:http://www.theimagingsource.com/en_US/publications/whitepapers/

More information about debayering are available from Prof. Ting Chen : http://scien.stanford.edu/class/psych221/projects/99/tingchen/main.htm .
This is the best document about debayering I found.

Kokatha man
April 30, 2009, 03:53:26
Hi again Stefan.....thanks for that info: some interesting reading coming up for me!:good:

Another point I noticed with my Titan shadow transit of Saturn imaging last night is that varying the brightness level right across the range of the slider and shown values seemed neither to affect the liveview image appearance nor the histograms.....as seemed to be the case also with the "hue" and "saturation" sliders.....is this "normal"....?

Also, the greyed-out "contrast" slider.....is that similar in that it is non-functional.....or are there "tools" I am missing seeing and not enabling here....?

Thanks for the info/advice you've sent and I appreciate any comments you're able to make on the above.:good::good::-)

Regards, K-m.

Stefan Geissler
April 30, 2009, 10:24:31

Well, the brightness is doing some electrical thing on the CCD directly. Its effect is not as big.

If BY8 or Y800 video format is in use, then the Hue and Saturation properties have no effect. This is normal for this camera model. These properties only have an effect on the YUV video formats.

If a slider is grayed-out, then the property is not available by the camera. The slider is not removed, because we do not wanted the toolbar-controls-layout to be destroyed. DCAM cameras have no contrast properties.

Kokatha man
April 30, 2009, 13:46:22
Thanks for that Stefan:good:.....one thing that has me very pleased is the colour rendition of the DBK21, especially in comparison to the old Philips 840k Toucam where the chromatic aberration produced very hard to correct colour-rendition.....principally because I am using a 6" achromatic refractor at the moment til my large newtonian is back together.:-)

The "white balance" setting is producing much closer-to-accurate colours in the planetary images.....I suppose this is a property of the camera's quality....?

Much more an astronomy question but with the new Registax 5 software if I "create a reference frame" from (say) 50 of the better images for some reason the colour is lost in this stage of the processing, and it becomes a monochrome image which will not respond properly to further processing in that particular version of the software.....but if I use Registax4 and utilize the same functions in the process I don't have the problem.....in both versions I have the "use debayer method" etc enabled....?

One for the Registax people perhaps....!

Stefan Geissler
April 30, 2009, 13:49:05

Yes, the last question is a registax poeple question.