Cannot get automatic calibration to work
Posted: Sat Aug 20, 2022 5:17 am
Hi,
I have built a UVEX and a Calibrex and have begun “sea trials”.
When I installed Demetra I worked through the sample images, was able to successfully process them, and gained a reasonably clear understanding of what each step is doing.
I have tried many times to get the automatic calibration procedure to work with my own images with no success. I can do a manual calibration and process a spectrum satisfactorily.
I have tried
1) a helium discharge lamp which gives a lovely clean spectrum
2) a neon discharge lamp - much busier spectrum
3) sky calibration
4) Calibrex calibration lamp
When I try to process my object image it immediately fails and turns red
If I first try to process my calibration image when I press run nothing happens
I have opened the calibrate “tab” and have played with parameters in there to no avail.
I find Demetra to otherwise be very logical and easy to use -although I am somewhat baffled by the number of points in a fully processed spectrum - I assume there is some interpolation required to get the same number of points as the reference spectra to determine the response?
Related to that, I have access to a fully calibrated ocean optics spectrometer with which I took a helium spectrum. I measured the peak heights in that spectrum and the UVEX spectrum (I used Gaussian fits) and took the ratios to get a response curve for the UVEX/camera combination I am using. It came out quite nicely and was much as I expected it to be- the far red and blue ends fall of in sensitivy.
Questions
1) any suggestions to try to get the automatic calibration working?
2) is it possible to use the response curve I determined with the ocean optics spectrometer in Demetra?
Appreciate any suggestions you may have.
Sincerely,
Peter
I have built a UVEX and a Calibrex and have begun “sea trials”.
When I installed Demetra I worked through the sample images, was able to successfully process them, and gained a reasonably clear understanding of what each step is doing.
I have tried many times to get the automatic calibration procedure to work with my own images with no success. I can do a manual calibration and process a spectrum satisfactorily.
I have tried
1) a helium discharge lamp which gives a lovely clean spectrum
2) a neon discharge lamp - much busier spectrum
3) sky calibration
4) Calibrex calibration lamp
When I try to process my object image it immediately fails and turns red
If I first try to process my calibration image when I press run nothing happens
I have opened the calibrate “tab” and have played with parameters in there to no avail.
I find Demetra to otherwise be very logical and easy to use -although I am somewhat baffled by the number of points in a fully processed spectrum - I assume there is some interpolation required to get the same number of points as the reference spectra to determine the response?
Related to that, I have access to a fully calibrated ocean optics spectrometer with which I took a helium spectrum. I measured the peak heights in that spectrum and the UVEX spectrum (I used Gaussian fits) and took the ratios to get a response curve for the UVEX/camera combination I am using. It came out quite nicely and was much as I expected it to be- the far red and blue ends fall of in sensitivy.
Questions
1) any suggestions to try to get the automatic calibration working?
2) is it possible to use the response curve I determined with the ocean optics spectrometer in Demetra?
Appreciate any suggestions you may have.
Sincerely,
Peter