Hi Michael, A short update on a couple of settings (mode normal/quality, auto-exposure, auto-gamma, and ICE). For details see: http://www.stadspartijeindhoven.nl/jv/SettingsAnalysis.ods I'm not completely ready with all settings yet, but If you have suggestions for additional tests, let me know.
Setting mode to "quality" results in a recalibration before each scan, whereas in "normal" mode the scanner only calibrates when the scanner is switched on. Apart from that, a bit is set in MODE SELECT byte 7. I do not notice other settings changes. Setting auto-exposure results in a double scan when asking a preview. The first scan probably assesses the appropriate exposure settings, and the second is the actual preview. The effect is noticable in the preview. Perhaps if I wouldn't have asked a preview, this additional scan would have happened before the actual scan, but I didn't check. Remarkably, the SCSI 0A command for SET EXPOSURE TIME does not change. The only output command with new data in between the exposure scan and the preview scan is a SCSI D7. Apparently exposure related settings are part of what's being sent here. Setting auto-gamma does not lead to any changes at all. Does that make any sense? When setting ICE, in MODE SELECT byte 4 an additional bit is set, which results in sending RGBI-data to Cyberview instead of just RGB. The infrared-channnel can be converted into a monochrome picture which shows the dust and scratches, and some vague contours of the original slide. I did not yet check if the RGB-data is original or has the scratches removed. The settings do not appear to influence these SCSI-commands: - SCSI 08 (READ CALIBRATION INFORMATION) - SCSI 0A (WRITE - SET SCAN FRAME) - SCSI 0A (WRITE - SET EXPOSURE TIME) - SCSI 0A (WRITE - SET HIGHLIGHT SHADOW) - SCSI 0A (WRITE 17, function unknown) - SCSI 0A (WRITE - REQUEST CALIBRATION INFORMATION) - SCSI 18 (COPY) - SCSI 1B (SCAN) - SCSI D2 (? RELEASE) The remaining commands are infuenced: - SCSI 15 (MODE SELECT) - SCSI 0F (READ SCAN PARAMETERS) - SCSI D7 (? READ CUSTOM DATA) - SCSI DC (? WRITE CUSTOM DATA) About the interpretation of DC and D7 (and probably bytes 12 and 13 of SCSI 0F as well): No, I did not see any larger amounts of data written to the scanner. I suppose only very basic calibration parameters are being sent, nothing else. Is it possible that the calibration scan data (1+13+31 lines) are used by Cyberview to do shading correction? Why do you think the first six DC-bytes are 12-bit RGB-values? The most-significant 4 bits are used sometimes, and apart from that there is some unbalance I cannot explain. If interpreted as 2-byte integers, most of the time the three values are around 3000. But sometimes they double or even triple, and in a couple of cases the first value is the only one that deviates. I don't see any logical reasons for that. Might these 2-byte values represent floating point numbers? They are not IEEE half-precision values, I checked that. Would there be any use for floats? The D7-data returned by the scanner show something similar in bytes 6-11. If they refer to RGB respectively, what could be the reason that the first value is 1.5 times the 2nd and 3rd? When interpreted as 2-byte integers, bytes 0-5 have three values which resemble numbers I found in discussions about 16-bit CCD saturation. These values are updated after the scanner has sent out calibration data (1+13+31 lines). I can imagine the scanner presents this information for calibration purposes, right? To be continued, I suppose. Jan
