Monday, July 23, 2007

Debayering in TIS DBK/DFK cameras

DBK/DFK allows us to reconstruct color information (debayer) in different places, but it is not well documented (** see below), I spent a whole afternoon to figure them out how it works and I hope it will be useful to you. Here're the three possibilities:

1. On camera: it's done on the hardware, I call it the "device codec" which one can set in the device property.

By setting to Y800/BY8, the Debayering is switched off and you can do 60fps, you can store the data in Y800 and the file size will be smallest. By doing that, Registax can handle more frames with its ~2G limit. With this consideration, even if you are not doing 60fps, you still benefit from this approach for you can capture a longer AVI and can still be processed by Registax in one shot without cutting the AVI into several 2G pieces.

By setting to UYVY, the Debayering is switched on hardware level, and you can do 30fps at most. Data size is 3 times as in Y800/BY8.

2. In IC Capture: if you choose to switch off Debayering in hardware by setting Y800/BY8 in device codec, you can do it by the image capturing software. IC Capture allows you to Debayer with different algorithms on the fly.

For slower machines, Debayering by IC Capture might lead to lower frame rate, since CPU cycles are used for Debayering. Debayering in IC Capture will generate the same file size as in UYVY device codec and RGB24 file codec.

Debayering by IC Capture enables one to generate color AVIs in RGB24 but still enjoy the power of 60fps.

3. In Registax: it's done by Registax during image processing. Debayering are disabled in the camera and also in IC Capture, and this job can be left for Registax.

In this situation, you can get the smallest file size by saving in Y800 file codec, and it saves CPU cycles for Debayering during image capture, too.

Due to the smallest file size generated, one can have the most number of frames in a single AVI file and still within the ~2G file limit of Registax.

** I was wrong, it's well documented now, check below:

http://www.astronomycamerasblog.com/wp-content/uploads-extra/astronomycapture.pdf

1 comment:

Unknown said...

Useful information !
In fact there no documentation at all about the subject.
(please note that the link that you´ve mentioned does not work )
I´m trying to find out more info about the DBK31 color, I´m beggining to use it but with no techical support... hard task.