Short status update:
Branch pixelshift3 now allows to access individual frames from Pentax pixelshift and Pentax hdr (bracketing) files.
Combining the individual subframes from pixelshift files into a so called 'super resolution' file follows later.

In next step I will implement the simple combination of 4 shots to a super resolution image.
Then I have to solve some issues with pixelshift images and raw preprocessing in rt. i.e. .badpixels files currently won't work correctly on shot 1, 2 and three if you use the coordinates from shot 0. There will be also some things which can't work at all with pixelshift shots. i.e. raw ca correction can not be applied, because it has to be applied on the raw data before combining the shots, but that would make combining the shots impossible because raw ca corrections moves the pixel values.
When all the issues are solved, I will try the approach from dcrawps to avoid artifacts caused by movements but slightly different. I want to use the green channel variation as a blend mask between the super resolution combined image and an amaze demosaiced image from 1st shot.