Greg, Following up your suggestions...
I was able to run your scripts, but now I have more questions on what's behind them. 1. I assume after combining raw images into one, I can analyze obtained hdr image in Photosphere. >> –r *cam.rsp* Use the given file for the camera’s response curves. If this file exists, it must contain the coefficients of three polynomials, one for each color primary. If the file does not exist, hdrgen will use its principal algorithm to derive these coefficients and write them out to this file for later use. 2. So, if I will combine my images for the calibration scene, hdrgen will derive the coefficients to the file. Is there a way to see those coefficients and to know what the response curve looks like? >>The -C option is to provide a linear factor to correct the overall exposure based on previous calibrations. 3. How do I make the absolute calibration? Usually it is a luminance value of a reflectance standard measured with luminance meter applied in Photosphere. But how do I do it with the given script? >>The -c option is to specify an output color space. The default is "sRGB" which is actually linear CCIR-709 primaries. The only other output color space I would recommend is AdobeRGB. There is a CIE XYZ space supported by dcraw, but I have found it to be somewhat unreliable, and I don't know where the fault lies in this. 4. In order to have luminance values Photosphere has an algorithm that does color calculations from sRGB to CIE XYZ (standard illuminant D65), where Y is the luminance value. Here I can specify an output color space, let's say sRGB, but how would I get luminance values? >>–s *stonits* * * 5.What is this option about? * * *Thank you!* 5. 5. -- Thank you, *Yulia Tyukhova* * * Fulbright Scholar, "Intern LC" Architectural Engineering Graduate Student, UNL-Omaha, NE, USA B.E. and M.E. in Lighting Engineering (MPEI), Moscow, Russia [email protected] [email protected] +1 (402) 996 0910 PKI 247
_______________________________________________ HDRI mailing list [email protected] http://www.radiance-online.org/mailman/listinfo/hdri
