Post Xmas update - making scanners is hard!
The camera is installed, not final but with a cheap rail and 3D printed dovetail. Once everything is working I’ll splurge on a good rail and Y Stage.
Ran into issues with camera smearing, original plan was to keep the light on and don’t bother flashing, but this did not work with my camera - I have a feeling it’s not just my camera, I guess we’ll know when some of you guys start setting up your cameras. I had to synchronize the LED flashes with camera exposures. Purchased a 2 channel oscilloscope, without this tool, I would never have never been able to figure that out.
The pulse system is a retro-reflective sensor(Keyence) sending pulses to TTL line of camera, The camera then sends pulses back via GPIO opto line out to an Arduino Mega who then sends PWM signal to DAC board “DC2197A”
…who then sends analog voltage to Picobuck LED driver. The timing is done using in camera delays and counters (for 4 perfs capture), I also have control over the pulse length in the Arduino code.
With this solved it was time to scan something and I was having a hard time getting started with Spinnaker SDK. It’s not friendly at all, to me at least. And thanks to @matthewepler for helping with Python we almost got it to work.
Until I found this software called “StreamPix 8” from NorPix.
They make this machine vision image / video capture software that is compatible with a LOT of cameras and is packed with features. Some I was dreading having to figure out on my own. Things like video scopes (especially RGB Parade) which are essential when calibrating your LED lights before a scan.
It’s pricy, 1K for the software. I’m a 2 weeks trial and using it for capture and debayering. So far so good and honestly I might buy it to save me some headache and get a headstart on scanning. I really would like to get back to shooting and forget about making scanners for a bit…
Here’s a first scan (done last night) of random shots from an old S35mm negative test roll.
You can watch in 4K if you click the vimeo icon… i think in browser you can’t even go full screen…
Also made a 16mm gate and platter risers (“a la Northlight”)
16mm scans are also going good.
NEXT STEPS ARE:
- MORE LIGHT. I need more light, pulsing really lowered the intensity so now have to figure out how to “overdrive” the LEDs. The pico buck is not going to cut it, it’s limited to 36V and 1A per channel. I had to replace 2 tiny resistors per channel to get to 1A per channel… they are TINY. I got 3 new drivers from TI.
Now the issue with these drivers is that I can’t turn them off! At 0 (LOW DUTY) the DAC outputs 002.5mV which I guess is enough for the LED DRIVER to turn on the LED, albeit at very low intensity… this was fine with Picobuck since the range is 25%-100% or something… but these drivers are full range. Need help with that.
Need faster debayer. Streampix is nice but post debayering is around 1.5 ~2 fps when saving a sequence to DPX 10bit. It defeats the purpose of real-time scanning if you have to wait that much time to save a sequence. Will be talking to them to see if it can be faster.
Perf stabilization. Right now I load DPXs in Resolve and do the stabilization there as well as the negative inversion and grading. (I also use Photoline for creating base inversion luts - the level tools are the best I found in image editing software)
So when points 1,2,3 are solved I will consider this a working machine and start design on final frame.
Right now it works, and pretty well for what it is, I really like the camera / resolution - with more light it will be so much better! I currently have to gain the camera to around 11db which I don’t like. Can’t wait to be able to blast those LED flashes at high intensity.