[Digikam-devel] dcraw -h (was Re: extragear/graphics/digikam/utilities/imageeditor/editor)

[Thorsten Schnebeck]

> I'm almost sure that the frog file is corrupted, has nothing to do with
> dcraw. I observe this on about 5% of my images after download from camera.
> When I download them a second time the files are OK.

Yep, looks brocken. Its not good to have such an image in the raw data base. 
Do you have a better one?


> Very strange, as one 
> had to rub-in the bits. Maybe it is a flash card issue since it is the same
> problem with card reader or camera USB download.
>
> The quad size problem of dcraw pertains to any format needing filter as
> Dave pointed out. There may be more formats than cr2 using filters.

Should be every cam with a RGB or CYMG bayer sensor.
I think I do understand what -h does and that this the wrong way using dcraw 
in digikam. For our example 

dcraw -i -v CANON-EOS350D.CR2
Filename: CANON-EOS350D.CR2
Timestamp: Thu Sep 29 13:34:40 2005
Camera: Canon EOS 350D DIGITAL
ISO speed: 400
Shutter: 1/320.0 sec
Aperture: f/11.0
Focal Length: 72 mm
Raw colors: 3
Filter pattern: RGGBRGGBRGGBRGGB
Daylight multipliers: 2.467797 0.917149 1.164814
Camera multipliers: 2269.000000 1018.000000 1652.000000
Raw size: 3516 x 2328
Image size: 3474 x 2314
Output size: 3474 x 2314

a high quality standard should use something like:

dcraw -c -w -n -m -q 3 -4 CANON-EOS350D.CR2 > eos350.pnm
Not sure about the "-m" option cause AFAIK raw images dont use colorprofiles 
only JPEGs use CMS but as dcraw also uses lcms maybe its better to apply one 
profile to the output.

But -q 3 (== ADH interpolation) was a great step in interpolation quality. 
Using -h (== -q 1) and a quite simple linear interpolation is for sure speedy 
but raw should be about quality and than about speed. 

BTW, this is dcraw 7.93

Bye

  Thorsten