![]() ![]() Not only does it compare the images captured by each of the Pro’s six lenses for any given frame of a video, but it also compares an image captured by a single lens to images captured by that same lens in adjacent frames of the video. In the case of video capture, the Insta360 Pro’s optical flow stitching algorithm works on an even more sophisticated principle. By letting a computer actually “see” what’s happening in an image, optical-flow-based stitching avoids this type of problem. The problem is obvious to any human, but how do you explain it to an algorithm? If the stitching algorithm had been able to notice the stark shift in the arrangement of pixels at the seam where the tower is cut in half – a sudden jump from gray concrete to blue sky – it wouldn’t have made this mistake. In practice, this means that the Insta360 Pro can avoid taking shots like the one of Toronto’s CN tower above, where a key object has fallen victim to an indiscriminate stitching algorithm. An optical-flow-based stitching algorithm allows for a granular comparison of the six images captured by the Pro’s lenses, so that the images can be stitched together intelligently, according to their actual subjects. Take the Insta360 Pro, with its six independent lenses, as an example. Instead of stitching together images according to a one-size-fits-all rule – essentially programming a computer to match dotted line A with dotted line B – the optical flow approach lets a computer keep track of the actual content of an image, down to the level of individual pixels. Optical flow is a subject worthy of an army of PhD’s, but the basic idea is simple enough. The Insta360 Pro solves this problem with a cutting-edge stitching technology that’s based on the science of optical flow. And it’s the reason you’ve probably seen shots that turn out like this: It’s a little like trying to solve a jigsaw puzzle where the image on every piece is changing in real time. ![]() but this was shot on the FS700 at 240 fps.The Insta360 Pro ensures a seamless stitch using the science of optical flow.ģ60-degree cameras face a thorny problem: How do you take visual data captured by multiple lenses, facing multiple directions, and then produce a final image that blends all of this information into one seamless whole?Īdd on the fact that the various subjects of these lenses may be moving unpredictably - crossing from the field of view of one lens to another and then back again, hovering about the zone where two lenses overlap, or shifting between the foreground and background of a scene at different rates- and the problem gets a whole lot thornier. just shot 4 spots for a motorcycle shop in Brooklyn sledge-hammering helmets and igniting jackets. This one comes from a friend that works at Adobe, and made sense when he told me - basically the algorithm is using "anchor" frames to base the new frames on, and if it has an even number of frames between the two anchors you increase the possibility of a good slow down.Īgain, great job. Use evenly divisible numbers when slowing down your footage. Again, any unwanted movement will cause strain on the algorithm. Motion blur will definitely screw with the optical flow algorithm, and you can always add motion blur back if you need it to look more "cinematic" 30fps with a high shutter-speed will eliminate motion blur. If you are planning slow motion on a conventional camera, shoot at the highest frame rate possible, with the highest shutter speed possible. If smooth slow motion is a crucial plot element to your film, maybe wait to make that film until you have access to the tools necessary. If you have a slow motion shot in mind, and you can't record in higher framerates, and interpolating between frames in After Effects or Premiere doesn't look good, then don't use it. The best thing to do is not work outside of your limitations. Optical Flow or other interpolation also has its limitations, but can achieve decent results sometimes. I think the step-printing like effect of essentially playing 24fps back at 12fps is just fine if all you have is a 24fps camera. That's great for dreamlike effect, but it's not quite the smooth slow motion solution people would usually want. It's effectively playing a slower framerate, so by definition the motion won't be as smooth. "Non-jittery" is subjective, but while step printing or its digital equivalent don't introduce artifacts, I still think it looks jittery. Instead of frames playing in their normal sequence (1, 2, 3) they play as (1, 1, 2, 2, 3, 3). Each frame is essentially repeated once, as described in the video. That is essentially what the editing software is doing when you adjust the speed of a video to 50%. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |