Depending of what normalization you need, you may use
1) imgdata.params.no_auto_bright=1 to disable auto brighten
2) params.no_auto_scale=1 to disable data scaling to 65536/camera_data_maximum
3) or just use raw data as is from imgdata.rawdata.raw_image (for bayer data) without calls to LibRaw::dcraw_process()
Depending of what normalization you need, you may use
1) imgdata.params.no_auto_bright=1 to disable auto brighten
2) params.no_auto_scale=1 to disable data scaling to 65536/camera_data_maximum
3) or just use raw data as is from imgdata.rawdata.raw_image (for bayer data) without calls to LibRaw::dcraw_process()