Hello,
I am looking for a tool that can take a photo (street light halo as an example) as an input and give me the different parameters (such as scattered light intensity vs scattering angle plot) as as output.
Please let me know. I am attaching the photo of a halo.
Thanks.
Such tool is an image processing software. There are several ones, for example, Matlab or ImageJ (it is free). These packages transfer image into matrix with 3 Red, Green, Blue matrix components. Than you could draw cross-section of each matrix to have dependence of corresponding intensity from distance from lamp center. If you will measure in such a way lamp intensity, you can normalize on it light distribution, so you will have dependence of scattered intensity on distance from lamp. If you know distance from camera to lamp, you can calculate angular dependence of scattered intensity.
About lamp intensity, for above shot there is obvious saturation of your camera sensor, so to have correct normalization of scattered intensity you must take another shot with shorter exposition, to put lamp intensity into linear camera range.
Sometimes if the range of the image intensity is wider that that linear range of your camera, you need to combine, overlap two or several shots into one, changing their expositions to cover whole object scattering range.
By the way, *.JPG image format is not the best format for such treatment. PNG, TIF, RAW are more precise due to lossless image compression and wider dynamic registration range for the case of RAW format.
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