Over the last months I posted a lot of material w.r.t. the photon transfer curve, and the impact of various noise sources on the PTC. After several blogs “in dark”, also the situation “with light” was studied. But in principle, the series about the PTC is now finished. Then the question can be asked : “And what’s next ?” In the early days of the blog, I got several comments on the material posted. But over the last couple of months I hardly got any reactions. So I do not know what “my customers” would like to see being discussed on the blog. For that reason I am writing this post. I am searching for subjects to talk about, write about and publish on this blog. I would like to do another series of publications on a particular subject, but what kind of subject ?
A while ago, I got an interesting suggestion : post and discuss design errors ever made in imaging. I would not pretend that I never made any design error, but also for this subject I would like to get input from others. Is anyone willing to share his/her mistakes that others can learn from ? If yes, they are utmost welcome. If you want I can discuss and post them without any reference. So the world-wide imaging community will never know where the errors came from.
I am curious to see whether this request for suggestions, subjects, topics can start a new series of posts on my blog. Looking forward to it !
Albert, 12-12-2010.
dark current spectroscopy
A next step would be to discuss the impact of noise going forward down the image processing chain. For instance, how does temporal noise contribute during color recovery for a Bayer pattern and how does fixed pattern noise manifest itself as a more than “just noticable difference” as artifacts. Why does the importance of noise vary when you are considering a single frame versus a video stream. And what are the options for correcting noise in the imaging chain — dark frame subtraction, et.al.
Posting design errors would be a very interesting thing for me!
I would also appreciate if you you post comments about important papers of the imaging field. Everytime I read something I always wonder if what is proposed there is interesting for the industry or just a pure academic work.
Series about 1/f noise and RTS manifestation would be interesting.
Items about image lag, such as image lag measurement and image lag reduction.
image lag is good item. How about noise source of CIS and how to reduce these noise? Thanks. The blog in harvestimging is perfect.
Thanks for the excellent PTC series.
For next topic suggestion, I might suggest looking at the various types of dark current, how each varies with voltage+ temperature, and how to isolate/reduce each type.
This has already been covered in various books, but bringing your practical approach and semiconductor physics background to the analysis would be interesting I think.
Impact of AGC and A2D quantization.
From a photographer’s perspective, the PTC curves show the “base ISO” setting of a camera. What do the PTC curves look like at 2x, 4x… gain?
Role of the ADC: is it possible to get 14-stops of dynamic range with a 14 bit ADC (see Pentax K-5 @ DxOMark). Etc.
Such (a pair of?) postings might be first steps towards Dan McGraph’s “down the processing chain” or towards-system level suggestion. Additional topics I would enjoy seeing covered:
– how noise scales with pixel pitch (e.g. fill factor, quantum eff, how to compare sensors with different resolutions)
– pixel binning and CCD charge binning
– how far can one increase full-well/saturation capacity?
– impact of CDS
– is the industry near the end of the roadmap already? (“photonics doesn’t scale”?). How does the PTC of a state-of-the-art sensor compare to clearly unavoidable noise sources?