Intro to Image Sensor Capture:...
Intro to Image Sensor Capture: ENLIGHTEN US!
One standard of raw data? Think about the varying grid patterns of image sensors:
Most use 4-pixel blocks with 2 green, 1 red and 1 blue in the form of CCD or CMOS.
Fuji has that plus between each pixel is a smaller, less sensitive pixel with their SuperCCD SR sensor.
Sony's got a funky four color CCD where the second green is "emerald" instead.
Sigma uses something more film-like with the Foveon X3, where the pixels are stacked directly Blue on top of Green on top of Red.
My point being: Don't even RAW images get interpolated when saved in-camera? And if not, could one standard format of raw data be established? And why DNG?
The formats that DNG supports are the same as those of...
The formats that DNG supports are the same as those of Camera Raw, which are at:
http://www.adobe.com/products/photoshop/cameraraw.html
They include cameras from Fujifilm, Sigma, and Sony, as well as the usual suspects. Do these include the ones you mention? DNG has no trouble supporting a variety of sensor formats. And DNG can support de-mosaiced (interpolated) sensor data too.
"Why DNG?".
What is important is that having a controlled documented standard for Raw is part of the solution to the goals of this website. DNG may be that standard, or a step on the way to that standard, or a proof of concept that such a standard can exist.
Raw formats AIUT are a direct lzw compressed data dump of...
Raw formats AIUT are a direct lzw compressed data dump of the CCD, which has to be interpreted back to a DIB for display.
The Raw data is not interpolated until it get to the decoding engine, be that in camera or in the PC/MAC.
There should be an additional header in the Openraw format Specifying the Bit Pack Structure
IE
RGGBA: RED GREEN GREEN BLUE ALPHA
or The specific arrangement, hence making it easy for the developer to interpret the image.