Comments

Author Comment Last activity Moderation
stoft " Yes, once the camera exposure is under control (and fixed value) then the linearity can be measured -- IF you have controlled means of adjusting t..." | Read more » about 5 years ago
stoft "From that link, I found a 'settings' file here: https://gitlab.com/bath_open_instrumentation_group/picamera_cra_compensation/blob/fdb98308149e686a..." | Read more » about 5 years ago
stoft " Right, the camera's do automate as much as possible, which works against the needs of spectrometers. If the AGC cannot be shut off, then it become..." | Read more » about 5 years ago
stoft " Good work and observations. Yes, I think HDR techniques can help extract additional dynamic range from these simple cameras. In reading through yo..." | Read more » about 5 years ago
stoft "Progress. Right, the likely alignment issue is grating to camera which is notoriously hard to do without having much mechanical control beyond tape..." | Read more » about 5 years ago
stoft " Right ... the optical distances are very small ;-) which is why mechanical rigidity is so important ... (think of the 'optical bench' which is mad..." | Read more » about 5 years ago
stoft " A while back I experimented with some 35mm 'slide-mount' holographic grating film (I believe it was 1200) vs the DVD (which is 740). The diffracti..." | Read more » about 5 years ago
stoft " Looks like a nice clean construction. The glue should help mechanical stability. I did notice the swap from DVD to what appears to be a film holog..." | Read more » about 5 years ago
stoft "Observation of some basic system parameters will help define the limits. 1) A single stable source (Solux and CFL) plus the PLab-class spectromete..." | Read more » about 5 years ago
stoft "With non steady-state sources, measurement error results from asynchronous data sampling. The 'fix' is either long integration time (assuming the s..." | Read more » about 5 years ago
stoft "Ok, the project concepts are taking shape which always prompts more thoughts. 1) By 2D mapping the light spectrum and relative intensity, you will..." | Read more » about 5 years ago
stoft "A few more thoughts... On absolute 'average' intensity - You could use a Solux source (at fixed distance and known orientation) as a transfer stan..." | Read more » about 5 years ago
stoft " Ah, I've seen the curve on the web but it was not attributed to the specific sensor. It's helpful to now have that information. It looks like the ..." | Read more » about 5 years ago
stoft " Jasmin, glad my previous notes were helpful. I did find one plot for the IMX219, but it was not from Sony and only covered to 700nm. The IMX265 c..." | Read more » about 5 years ago
stoft "Interesting project. I did not readily find spectral response curves from Sony on the IMX219 sensor though others in that family of devices appear..." | Read more » about 5 years ago
stoft "The spectrum of most common halogen lamps is neither smooth nor flat and generally do not have published spectral data. You might consider the Solu..." | Read more » almost 6 years ago
stoft "Pollution comes in many forms and many of the worst contaminants will not alter the appearance so visible light spectrometers (i.e. PLab types) wil..." | Read more » about 6 years ago
stoft "Depending on what information is needed from the spectrum (i.e. like the entire available spectrum, using a CLF will not be useful. A broadband sou..." | Read more » about 6 years ago
stoft "Since H2O is a colorless fluid, 'color' appears not to be the correct intent of the question. The author would need to clarify the objective. " | Read more » about 6 years ago
stoft "@Ag8n true, calibrating before a measurement (or series of) helps assure the measurement data is referenced. As per wavelength references, while t..." | Read more » over 6 years ago
stoft "I suspect there are two issues here: 1) the software interface and 2) mechanical instability. On #1, I believe the web-based software always needs ..." | Read more » over 6 years ago
stoft "Questions are good ;-) Reading between the lines of your description, the "blank" is the Transmission Reference (i.e. the clear container with onl..." | Read more » over 6 years ago
stoft "Great! 1) I'd also suggest using stiff cardboard, Exacto knife, hot-melt glue (or fast-set 'yellow' wood glue 2) use double-stick for the DVD att..." | Read more » over 6 years ago
stoft "You could buy a webcam from Amazon, use a spare DVD some razor blades, black paper, double-stick tape and build one for about $50 (most of the expe..." | Read more » over 6 years ago