Issue link: https://digital.copcomm.com/i/1081203
59 Q1 2019 / CINEMONTAGE 59 Q1 2019 / CINEMONTAGE DEPTH SENSORS OR VIDEO CAMERAS iPi Soft Motion Capture allows you to use multiple depth sensors or video cameras (or both). For depth sensors, iPi Soft supports such products as the Microsoft Kinect, Orbbec3D and Intel RealSense. It will also support the new Project Kinect for Azure (also known as Kinect 4) when it is released. For video cameras, iPi Soft Motion Capture supports web cameras such as the Sony PlayStation3 Eye or action cameras such as GoPro. Which one should you choose when motion capturing with iPi Soft — depth sensors, web cameras or action cameras? The truth is, depending on your needs, each setup has its advantages and disadvantages. There is no "one size fits all" answer. The benefit to using depth sensors is that they are easier to set up and calibrate and require less space due to their wider angle of view. The minimum required space is 7x4 feet. That means you can set up a few depth sensors in a confined space such as a small office, or even your living room for that matter. Perhaps one of the greatest benefits to using depth sensors is that the new real-time tracking for live preview in version 4.1 works with them (see Figure 3). It also doesn't matter what color your clothes are. While they can work in small spaces, a limitation to using depth sensors is that their capture area is limited to 7x7 feet. Thus, they are not your best choice if your MoCap performance requires sweeping movements over large areas. Depth sensors are also limited to a frame rate of 30 fps. While that's fine in many cases, video cameras allow for faster frame rates, which can be useful when tracking extremely fast motions. Also, they cannot be used outdoors. In the case of web cameras, such as the Sony PlayStation3 Eye and the Logitech C922, iPi Soft Motion Capture supports three to 16 cameras (see Figures 4 and 5). Compared to depth sensors, they allow for somewhat better tracking and their ability to record at 60 fps may avoid errors during very fast motions. Web cameras also allow for a much larger capture area, up to 20x20 feet (perfect for martial arts maneuvers or acrobatic dancers) and, importantly, allow you to track three actors at the same time. In addition, motion tracking with web cameras can have less problems with bodily occlusion than depth sensors, especially if you use more than six cameras. They also allow you to do your motion capturing outdoors (but you should try to avoid direct sunlight). Web cameras are also inexpensive. A single Sony PlayStation3 Eye is a scant few bucks, so buying anywhere from three to 16 of them won't cost much. Setup and calibration, however, does take more time than with depth sensors, and you must have a computer with enough USB ports available — although you'll only need half the number of ports as cameras (for example, three ports for six cameras and four for eight). You'll also need a fast hard drive, such as an SSD. In addition, while web cameras offer more space for motion capture, they also need it. They require a minimum of 13x13 feet. Like web cameras, you can use between three and 16 action cameras such as GoPro (see Figure 6). The benefit to using action cameras is that you don't need external power when recording — only the camera's built-in batteries. That means you can capture your motion in places where an electric outlet is nowhere to be found. In fact, you don't even need a computer. Action cameras also have higher frame rates, such as 90 and even 120 fps, which is useful when doing very fast motion. For action cameras, in version 4.1 there is a new feature that lets you automatically synchronize videos recorded based on flash detection. The new algorithm detects flashes between separate videos and synchronizes them automatically, greatly speeding TECH TIPS Figure 3: The Microsoft Kinect 2 depth sensor. Figure 4: The Sony PlayStation3 Eye camera.