| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| stoft | "But that was part of my point -- the camera does 'raw-capture' processing on the sensor's 12-14bit detector data before it gives you the 'raw' data..." | Read more » | almost 8 years ago | |||
| cfastie | "I think if you capture camera raw you have a single number (DN) for each pixel and you know what kind of Bayer filter that pixel was under. The DN ..." | Read more » | almost 8 years ago | |||
| stoft | "Hmmm ... remember that the jpeg data is derived from MANY pixels which were run thoguht demosaicing from the RGGB filtered data, so unless you had ..." | Read more » | almost 8 years ago | |||
| warren | "We'd have a lot more to work with if we knew which pixels were originally red vs green vs blue, and we could probably make more intelligent decisio..." | Read more » | almost 8 years ago | |||
| stoft | "Sure. No, it's not a photon count, but it is related -- though the DSLR is attempting to extract data that represents a film negative. To do that, ..." | Read more » | almost 8 years ago | |||
| viechdokter | "Thanx for explaining all this. Uhm, these "raw pixel data" you talked about, is THIS an electron/photon count? And if so, how long does the normal ..." | Read more » | almost 8 years ago | |||
| stoft | "Right, the (R+G+B)/3 average contains all the camera can deliver. [Aside: There are, however, separate 'weighted' formulas for combining RGB to get..." | Read more » | almost 8 years ago | |||
| viechdokter | "Ah, okay, I forgot about the "%" sign. I knew I was missing something. Just didn't know what exactly. Thanx for the quick answers. " | Read more » | almost 8 years ago | |||
| dhaffnersr | "hey viechdokter, the "scratched off" ccd screen, is the color film on the sensor's surface, very tricky and very risky to attempt it, but what hap..." | Read more » | almost 8 years ago | |||
| cfastie | "In Spectral Workbench the Y-axis on the spectrogram is "Intensity (%)." If you took the sum of all three channels and plotted them on the same grap..." | Read more » | almost 8 years ago | |||
| viechdokter | "@warren: I just had a look at an old spectrum CSV file of yours (3 years ago): https://spectralworkbench.org/spectrums/481 There it was unscaled ..." | Read more » | about 8 years ago | |||
| warren | "I went ahead and created a specific issue for native 8-bit storage: https://github.com/publiclab/spectral-workbench.js/issues/18 As well as outlin..." | Read more » | about 8 years ago | |||
| viechdokter | "Talking about hung-up scripts, it often is a pain in the neck to login to SBW. "Do you trust this site with your identity?" "Yes" "You must login t..." | Read more » | about 8 years ago | |||
| stoft | "It's ok to have a 'scaled' data file -- but ONLY if that file is clearly identified as such ... like /SpectrumData-SCALED_20160420.csv or /Spectru..." | Read more » | about 8 years ago | |||
| warren | "Hi, all -- 2.55 is definitely related to the 0-255 value. The code that generates the CSV is here: https://github.com/publiclab/spectral-workbench..." | Read more » | about 8 years ago | |||
| viechdokter | "I could re-scale but ... when everybody here gets the same minimum 2.55 increments here and you want reproducible spectral data then everyone shoul..." | Read more » | about 8 years ago | |||
| stoft | "Hmmm, well the RAW data should have the same scale units which would be unsigned 8-bit integer from 000 to 255 -- so the Y axis should show noise h..." | Read more » | about 8 years ago | |||
| viechdokter | "I took the data from the CSV files that Spectral Workbench provides with my spectra. I had a look at one of dhaffners spectrum CSV files and see th..." | Read more » | about 8 years ago | |||
| stoft | "Well, except there's still a problem with the plot. The smallest increment looks to be '4 steps' per scale units of '10'. Either there was some mul..." | Read more » | about 8 years ago | |||
| viechdokter | "Okay, here I combined the 4 channel max/min-difference curves in one diagram so they have the same vertical scale now: And here the combined dat..." | Read more » | about 8 years ago | |||
| viechdokter | "Talking about bits and quantization: I also noticed that certain values (2.55 and multiples thereof like 5.1, 7.65 ...) appear in every spectrum's ..." | Read more » | about 8 years ago | |||
| stoft | "Yes, it's called quantization; the camera only has 8-bits and the scale of the two plots is likely about 3-5x different. Take a look at the 'red' p..." | Read more » | about 8 years ago | |||
| warren | "Hmm, very interesting -- without vertical scale its hard to say though - I believe the "plateaus" on the "average curve" are artifacts of the preci..." | Read more » | about 8 years ago | |||
| viechdokter | "@warren:They would be low-noise green if you average them. ;-) @stoft: BTW, I noticed that curves that were averaged over two or more channels l..." | Read more » | about 8 years ago |