allsky image processing changes
We’ve noticed for the last few months that the images coming out of the allsky camera were dimmer and lower contrast than previous images. So after a couple of hours researching and testing I discovered that the netpbm collection of software is under constant modification and upgrade. I suspect along the way that some default settings had changed with our fitstopnm and pnmtojpeg programs.
Our processing scripts look something like this:
old
/usr/bin/fitstopnm $i | pnmtojpeg -quality=95 > 1-$i.jpg
convert -interlace NONE -noise 1 1-$i.jpg 2-$i.jpg
new
/usr/bin/fitstopnm $i | ppmbrighten -v 300 | pnmtojpeg -quality=100 > 1-$i.jpg
convert -interlace NONE -noise 1 1-$i.jpg 2-$i.jpg
basically this takes the fits image and brightens up each pixel 300% and now we save the jpg at 100% and not 95%
We reran the processing scripts on the original .FITs images from the last run and got these results:
old processing
new processingIt makes a real difference. One of the problems is that we would have to reprocess maybe three months of images and just doing the one day took approx 20 minutes on our old amd athon XP 2200+ 1.8GHz 1gb server. That works out to about 90*1/3 or 30 hours.
The whole point behind this camera system is to detect fireballs (very bright meteors), showing local cloud cover and lastly gathering pretty pictures of the night sky.