I’ve been using a CMOS, board level, USB camera for capturing 10-12, bracketed, 800x600, still images using 4VL2 in Linux. I can control exposures while setting white balance and gain/ISO constant to produce a decent range of LDR images with broad light gradients. I also update each LDR image’s EXIF header with exposure time, ISO, f-stop, and color space using Exiftool. However, using HDRgen I keep getting ‘can’t resolve for response function’. When I try using Photosphere, I get the same error and so use the default camera response function and then calibrate against a measured, point luminance reading taken while capturing the LDR images. When I sample the resultant HDR image pixels, the pixels within the area used for calibration agree with those physically measured, however luminance values measured within much brighter areas in the scene (i.e. out the window) are much lower (by half) than what was physically measured.
Can anyone offer any insights on what the issue might be with not being able to generate the camera response function and also why the luminance values after calibration are off? Could it have something to do with using 4VL2 to capture the images from what’s essentially a web cam?
The camera sensor is a Sony IMX322 and the captured images are in sRGB color space.
As always, thank you,