Jump to content

Perry Paolantonio

Basic Member
  • Posts

    665
  • Joined

  • Last visited

Profile Information

  • Occupation
    Other
  • Location
    Boston, MA
  • My Gear
    Eclair ACL II, Pro8mm modded Max8 Beaulieu 4008
  • Specialties
    14k/70mm, 6.5k, 4k, UHD, 2k 8mm-35mm Film Scanning, Film Restoration

Contact Methods

  • Website URL
    http://www.gammaraydigital.com

Recent Profile Visitors

14216 profile views
  1. There are optical readers for the old 35mm/16mm fullcoat mag dubbers. I'd be happy to sell you an MTE dual-head dubber if you're interested, crazy cheap but you'd have to arrange for shipping out of Boston (freight, and it's bulky). But, needs a lot of work because we disassembled it, when we were planning to make it into a film scanner. You'd need to source an optical reader for it though, as we only have mag heads for that unit.
  2. we are doing the perf detection in CPU. On a 14k image detecting the perfs and calculating the offset takes us less than 20ms. Granted we’re not scanning at 30fps. For that you’d need GPU almost certainly. Or you’d do it on the frame grabbers FPGA. Digital registration should improve with resolution. We’ve done some tests with the northlight (mech pin) and scanstation and found the scanstation was more stable. With faster scans they may have to simplify the file more than with a slower scanner, and that might lead to less accuracy. I’ll post some tests done on our scanner in a few weeks using opencv.
  3. Lasergraphics (as far as I know) has never used a laser perf detector. The original director was mechanically pin registered but the current one is sprocketless. The scanstation has been sprocketless and has done optical perfection detection from the beginning. Which I know because we have the first scanstation they shipped. Open CV is what you’re looking for. It’s free, fast and designed specifically to do things like object detection. Lasergraphics software is custom. I don’t know what they use under the hood for perf detection but that kind of thing is available in APIs from frame grabbers, could be implemented in an fpga or could be done in software in their app.
  4. No. it uses the perfs in the captured image for registration, though it doesn't require the *entire* perf. For formats like 35mm only the inside edges of the perfs are visible. See: https://www.gammaraydigital.com/blog/lasergraphics-scanstation-65k-maximum-resolutions for examples of what the scanner "sees" in full overscan with all the common gauges, on the 6.5k sensor. It's all done on the image. frame registration is a trivially easy process using machine vision when you have something like perforations, which are well defined, to use as reference points. They might do this on the frame grabber in an FPGA, or they might do it in CPU or GPU, I have no idea. Even on 14k images like we're working with now, the time it takes to convert a full res image to greyscale, find the perfs, align the perfs to a fixed location on the X/Y axis with rotation, and then apply that translation to the actual image, is just a few milliseconds on a decent CPU. They might be doing this on the GPU, if the image is already there (that would just make sense), but I think they're mostly using the GPU to accelerate scaling, and applying color corrections, because that's faster than CPU, usually.
  5. This is not entirely correct. The second flash isn't for the "darks" it's or the densest area of the film, which for negative means the highlights. You get much more to work with in the highlights with HDR, with a gentler roll-off on the high end, in our experience. We recommend HDR regardless of the film - camera original pos or neg, or even print. We've seen benefits to HDR with all of these formats, despite the accepted "common knowledge" that it's not a benefit with print. (for example: if you have a faded color print that's gone magenta, and you do a single and two-flash scan of it, then bring those files into Resolve and line the frames up, switching between them you'll see more color is there (you can see the trace on a vectorscope get bigger in the HDR scan), which aids in recovering the fade. It's not perfect, but it's a better starting point than single flash scans. Arriscan is 2-flash. The original scanner took two images of each frame, the XT uses the Alexa sensor's dual-gain feature, which acts like a two-flash HDR scan in one image. As far as I'm aware the only widely used commercially made scanner that does 3-flash is the Director. Xena might do this too, but I'm not sure. Rob will tell us. Registration isn't really a huge concern. If you can see the perfs, you can register two frames to a very high degree of accuracy, probably more accurate than mechanical pins, which is what the ScanStation does. As a continuous motion scanner, it takes two images of each frame while the frame is in the gate, but the frame is never at the same position for those two. They are aligned after the images are scanned, and that's how they're able to do 2-flash HDR. As you might imagine, it halves the running speed of an SDR scan because the frame can only be in the gate for so long.
  6. Nothing about this will be fast. Big, yes. Fast? nope.
  7. We're implementing it on our 70mm scanner, kind of just because we get it for free with some of the libraries we're coding with, so why not? But if we add HDR to the scanner (which will likely happen in a few months), it'll be nice to have a 32bit container to put it in . I can't even comprehend what working with 14k files like that is going to entail, but we'll cross that bridge when we get there!
  8. Thanks, feel free to link to it! We posted this originally because there are some ScanStation services that are (or maybe were, not sure) offering 6.5k scans of the film frame, which means they're scaling up. We had to explain to several customers that those other services weren't able to do something we couldn't do (we certainly could, but won't), they were just doing something you shouldn't do! Make sure the Aspect Ratio pulldown is set to Unlocked manually enter the desired output file size (say, 4096x3112) Change the Aspect Ratio pulldown to "Locked to Image Size" Drag a corner of the marquee around the image to the crop you want This will automatically scale the image to the output file size you manually entered, maintaining that aspect ratio. There is a trick, too - the default editing tool for the scanner will scale things to fit based on Lasergraphics best guess at what you want. For more control, and to see the actual resolution, hold down the Ctrl key when you click the Edit button. This enables a hidden checkbox (which long ago was there by default but it was deemed too confusing by lasergraphics) called "Track film/file size". If you check this box and follow the steps above, when you get to the last step (dragging the size of the marquee), the image size fields will change with the scale of the marquee. So if you want to maintain the max resolution of the file but add some overscan, for example, you'd do this: Load the film in 6.5k mode (assuming 16mm) Hold down Ctrl while clicking the Edit button under the Output Presets Make sure the Aspect Ratio is set to Unlocked Change the preset to Full Aperture Change the Aspect Ratio to "Locked to Image Size" Now when you drag the marquee around, the full aperture of the frame will be the max supported for the mode you're loaded into (4.8k for 6.5k mode) and going larger on the marquee means you're just adding some stuff to the outside of that.
  9. Ok, should be up and running now. Sorry about that - looks like the permissions on the site got all messed up but I've given it a swift kick and now it's back.
  10. hmm. we've had some really weird issues with our server the past few days. Let me look into it. It should be there, but I'm not sure why it's getting that error.
  11. If I had to hazard a guess - I'm thinking they scanned the film as 16mm, then used software to separate the two halves, then the two stacked images that resulted from that. You could do this in something like AVISynth, or Open CV or something like that. But the way to do this correctly if you're going to go that route, is to make your intermediate files into an image sequence. Then you can bring that into Resolve or some other NLE and define the frame rate that it would be output to. That's kind of the only way I could see winding up with really weird frame rates. The more convoluted the process the more likely you wind up with a wacky result!
  12. It is not, at least, not on the ScanStation. The ScanStation can scan unslit 8mm - you install the 16mm gate, but you select Double 8mm when loading the film. It repositions the camera accordingly, and only scans down one side of the film. Then you move the film from the takeup side over to the feed side, and run the other half. The frame rate thing is weird. I'm going to go out on a limb here and say that whoever is using this machine has no idea what they're doing, or maybe it's a ScanStation Personal and that machine can't do this and they had to come up with some weird workarounds (I don't know, but it could be the case. We have the full ScanStation and it does do this. It was a request I personally made with Lasergraphics years ago, that they implemented). Setting the frame rate honestly couldn't be simpler - as Rob pointed out, there's a pulldown with all the available frame rates. So unless they're doing something weird like not scanning directly to the format you want and then doing some kind of post-scan frame rate conversion outside the ScanStation, I don't really see why they can't just scan it at 24. Do you mean that your resulting file has both the forward and backward image? If so, unless you asked for that, that's being done wrong. I believe there's also an option to do that (you would use the Ultra Pan 8 setting, which would scan one frame that's the entire width of the 16mm film. In that case you'd see forward and backward frames, but the resolution of each of the frames would be about half of the resolution you'd get if you loaded it as double 8mm (because the camera/lens position is different for D8mm). There is no need. We scan unslit double 8mm and do so all the time. Works great on the ScanStation, and the end result is the same as scanning slit 8mm. Costs the same as scanning regular slit 8mm as well.
  13. I don't think there are very many of these in daily use anymore but I could be wrong. We've got one we haven't turned on in some time - (it's for sale!). Beautiful machine, but slow beyond belief. A modern scanner doesn't need to be real time, but it's a big difference between 4fps and 4spf (seconds per frame)...
  14. Ain't that the truth. You need to figure out a mechanism to move the film through the machine (motors, rollers, sensors, hardware to mount it on, controllers to orchestrate everything) You need to come up with a stable light source, Ideally one that's matched to the type of film you're scanning (pos or neg) and a way to trigger that light source at the right time and intensity. You need to select the correct camera and optics to ensure you're getting a good match for the resolution of the film at the distance your camera is from the gate. Yes, you can get cheap 4k cameras. They're cheap for a reason. Lenses really matter here too. You need to write software to interface with items 1, 2, and 3, and also deal with processing the images once they're captured (either exporting to a file that you deal with later, or handling all the color science stuff in the scanner. We've been working for 3 years on a scanner for in-house use that is very near completion. Max res is 14k and it'll do large formats from 35mm through 15p IMAX - 1-3fps at max res, 16bit sequential RGB, faster for smaller gauges down to about 8k. Building this was not a simple process, even though all the parts are available off the shelf. I am currently neck deep in the software side of this machine, and while it's coming along, every day brings up something we hadn't considered, or that we didn't quite anticipate. Yes, building one is an order of magnitude easier than it was 20 years ago. But building it right is hard.
  15. A while back, we ended up doing a blog post on this, in part because of the issue you raise, but also because some other ScanStation 6.5k owners were saying they'd do 6.5k of the *frame* -- that'd mean they're scaling up from the native 4.8k (for the full aperture of the frame) for 16mm. And that would be dishonest. Also, all kids of wrong if you're doing archival scans. https://www.gammaraydigital.com/blog/lasergraphics-scanstation-65k-maximum-resolutions @Daniel D. Teoli Jr. - what Frank is saying here is that some people think they're getting a 4k scan of the image when they order a 4k scan with full overscan. The resulting file is 4k, but because of the stuff outside the (film) frame, the frame is actually much smaller. In the case of the link above, with the ScanStation 6.5k and standard 16mm film, you get 4.8k for the film frame, within a 6.5k file. That means about 74% of the width of the file is the film frame, the rest is the stuff outside the frame. If you were to do a 4k scan (a 4k *file* that is), the full aperture area would be about 3k.
×
×
  • Create New...