Digital Photography

I like to experiment. I'll try to keep notes about the tools (software) I use…

I bought (sept 2009) a Canon SX110IS as a replacement for my Canon A710IS (which has a nasty scratch on the lens). I know the XS120 is out, but it is not supported by CHDK yet. Besides, the 110 has a larger CCD, which might result in less image noise… I'll hang the old A710IS under my new kite The A710IS was replaced by a 2nd hand A720IS after a dive in the Maas.

On Linux, it can be done with gphoto2 (tested gphoto 2.4.7 with my Canon SX110IS)

• power on camera
• unmount camera 'disk'

5 frames, one every 10 seconds

• gphoto2 -F 5 -I10 –capture-image-and-download
• gphoto2 -F 5 -I10 –capture-image (faster, photo's stay on camera)

• I use Gimp (the GNU Image Manipulation Program, a free Photoshop like program) to improve and manipulate the pictures I take.

“With Hugin you can assemble a mosaic of photographs into a complete immersive panorama, stitch any series of overlapping pictures and much more”. Amazing stuff!!!

align_image_stack -m -a FS_ *.JPG
enfuse -o result.tif --wExposure=0 --wSaturation=0 --wContrast=1 --HardMask FS_*

I just started experimenting with HDR…

• A script for Gimp that can combine 3 exposures to a single image. The script and a nice tutorial can be found at: http://tir.astro.utoledo.edu/jdsmith/code/exposure_blend.php

• Hugin is able to 'do' HDR. It can create a HDR panorama (openexr file). It also does 'exposure blending'…

• Interesting tutorial: http://photoblog.edu-perez.com/2009/02/hdr-and-linux.html

• “The pfstools package is a set of command line programs for reading, writing and manipulating high-dynamic range (HDR)” Quite good (realistic) result:

align_image_stack -a A_ *.JPG -o out         # gives aligned tifs, and out.hdr
pfsin out.hdr | pfstmo_mantiuk06 |pfsout out0.tif
pfsin out.hdr | pfstmo_mantiuk06 -f 0.5 -s 1 -v |pfsout out1.tif
pfsin out.hdr | pfstmo_drago03 -b 0.8 | pfsgamma -g 1.7 |pfsout out2.tif
pfsin out.hdr | pfstmo_reinhard02 -s |pfsout out3.tif

CHDK is software that you can install on the memory of most (compact) Canon cameras. It allows you to program it (Basic and Lua), and use new or enhanced features. Great stuff! I'll keep notes...

First experiments, has to be tuned…

# list is an ascii file that lists the images
mencoder mf://@list -mf fps=1 -vf scale=640:480 -ovc lavc -lavcopts vcodec=mpeg4 -oac copy -o movie.avi
mencoder "mf://@lost" -mf fps=1 -vf scale=640:480 -o test.avi -ovc lavc -lavcopts vcodec=msmpeg4v2:vbitrate=10

Movie with embedded subtitles:

mencoder "mf://@clouds.lst" -ovc lavc -lavcopts vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=2000:keyint=15:vstrict=0:acodec=ac3 -o clouds.avi -sub "clouds.srt" -subfont-text-scale 3

capture a video from screen (add –full-shots for opengl stuff). xvidcap also works…

recordmydesktop  -windowid $(xwininfo |grep "Window id:"|sed -e "s/xwininfo\:\ Window id:\ // ;s/\ .*//" )

Convert video to mpg for wmp (dos)

export opt="vbitrate=2160000:mbd=2:keyint=132:vqblur=1.0:cmp=2:subcmp=2:dia=2:mv0:last_pred=3"
mencoder -ovc lavc -lavcopts vcodec=msmpeg4v2:vpass=1:$opt  -nosound -o /dev/null in.ogg 
mencoder -ovc lavc -lavcopts vcodec=msmpeg4v2:vpass=2:$opt  -nosound -o out.mpg in.ogg