Scanning with digital camera and stitching

[Adrian Bacon]

As I look at the data on their web page and also reading the paper they reference ("https://nae-lab.org/~rei/research/cs/zhao/files/MIRU09.pdf") As I look closer at their web page I believe you are right. I don't think they are reporting the data directly. I don't know about the curve normalization issue you raise when you mentioned multipliers, but it looks like they might be fitting their data to basis sets derived from singular value decompositions. There is not enough information to state this for sure, but if it is true then their data might have some errors relative to the data acquired directly from the cameras. For example, their reported curves are might be a little smoother than the underlying data and may miss some of the small features in the data, e.g. they might not correctly represent the data in the tails of the curves or some small bumps and wiggles in the curves.

It’s not so much about the normalization, but about not applying a multiplier as that will distort the height of the peak and the toe of the peak. It won’t affect where the peak is in terms of placement on the spectrum, just the shape of the response.

 

[alanrockwood]

It’s not so much about the normalization, but about not applying a multiplier as that will distort the height of the peak and the toe of the peak. It won’t affect where the peak is in terms of placement on the spectrum, just the shape of the response.

I don't think a simple multiplier will distort the spectral response. (In fact it won't.) However, if there is some nonlinear function applied somewhere in the processing of the image, then it could result in an effective distortion. I think that most demosaicing algorithms include non-linear processing (for example, bicubic interpolation), so in that sense a multiplier could result in an effective distortion. Also, if the sensor response of the sensor is non-linear, then a multiplier could effect the shape of the spectrum.