Shift and average multiple images (JPEG, PNG, or TIFF), mainly for astrophotos
Function: Read specified images, determine image shifts, average them, and write into a new PNG file.
New Feature: Comet tracking is now capable. Use -C option to measure the motion, and then -X -Y options to track the comet motion.
Requirements: R with libraries of jpeg, png, and tiff
Usage: in command line, type Rscript imageSynth.R [-Xxtr] [-Yytr] [-C] [file names of images] e.g. (1) Rscript imageSynth.R *.jpg This is a standard use to stack all jpg files in the working directory.
(2) Rscript imageSynth.R -C FirstFrame.jpg LastFrame.jpg
To measure the motion of a comet between the first and the last frame. The first and last frame images are registered in blue and red colors, respectively. Measure the positional difference in the registered image and put in the -X and -Y options as described in (3).
(3) Rscript imageSynth.R -X-45 -Y29 *.jpg
To track comet motion. The pixel values should be specified with the -X and -Y options (without space).
Options
-F : focal length to apply cos^4-law correction for optical vignetting (e.g. -F50 for a (cos θ/50º)^4 correction).
-T : switch to apply transfer function to enhance contrast
-D : specify dark frames (e.g. -L1,2 to use the 1st and 2nd image files as dark frames)
-L : specify Red-filtered frames to apply LRGB composite (e.g. -L3,4,5 to use the 3rd, 4th, 5th image files as L-channel)
-C : switch to position calibration mode for comet tracking
-X, -Y : apply comet tracking
Limitations
- Pixel sizes of image files must be the same.
- For the comet tracking, the motion is presumed to be straight at a constant speed. Time intervals of multiple frames should be constant.
See also: Usage in Japanese: http://d.hatena.ne.jp/kamenoseiji/20140609/1402309169 GitHub repository: https://github.com/kamenoseiji/imageSynth