Impacts: measurements of distances and speeds. Spherical distortions - wide angle and ultra wide angle lenses (No USB camera currently does this to my knowledge).
#Kinovea video analysis full#
The issue is that bandwidth is limited, so it is not always possible to transmit full color frames at the full framerate.Ī camera should allow us to control the JPEG compression levels. The best solution is a camera that can provide the raw images to the computer, and to perform the color grading there. Component: Image processing chip on the camera or recording software. Resolving power - image processing and JPEG compression A good introductory resource on lens quality measurement methodology is at Cambridge in Colour. (ex: A 3MP rated lens for 1920x1080 images). The lens fitted on the camera should have a megapixel rating at least as high as the pixel count of the sensor. A recent evolution is the use of Megapixel ratings. Lenses quality is measured in various metrics like lp/ph or MTF curves. For a given sensor size, more pixels means smaller ones, which makes it more difficult for the lens to match resolution. More pixels is better but only if the lens is adequate. Some devices are actually limited by their lens, when the lens itself is not able to project an image sharp enough to distinguish details that are two pixels apart. Resolving power - pixel count and lens resolution For laboratory setups artificial lights may be needed. Compromise: low exposure means less light collected at the pixel sites. The most versatile solution is a camera for which exposure duration can be changed manually and is capable of short exposures (Exact requirement to be assessed). It lower reproducibility and the final exposure choosen may not be adequate (long exposure increases motion blur). Some cameras have auto-exposure, they will adjust exposure to measured light levels. Relevance to sport analysis: very high. Impacts: the sharpness of details on moving subjects. Some devices have auto-focus capabilities, in this case care should be taken as to where in the image the focus has been locked. Some lenses have variable focal length, in this case focusing sould usually be redone after changing the focal length. Note that even with motorized focus some webcams can't focus to infinity and anything farther than a few meters, will not be optimally focused. The most efficient solution may be a motorized focus that we can control in software.
#Kinovea video analysis manual#
The most versatile solution is a manual focus that can be adjusted with a ring or lever. A camera with fixed focus should hopefully be focused at infinity in factory. If the subject is always distant, a fixed focus camera may be sufficient. Limited temporal sampling granularity - low framerate. Spherical distortions - wide and ultra wide angle lenses. Limited resolving power - image processing and JPEG compression. Limited resolving power - pixel count and lens resolution. Here are some topics that could be covered: It should be useful for evaluating new hardware on the market and as a buyers guide.
#Kinovea video analysis pdf#
Maybe at some point we can create a PDF or something. Please add your input, illustrative images, comments, remarks, additional degrading factors, formatting suggestions, etc. We are now very near a day where little USB cameras can be considered serious imaging devices. The trigger for this topic though, is the advent of high-quality, interchangeable, small lenses for surveillance-type cameras. This list should be general and relevant to anything that can provide a stream of image and store it on-device or transmit it to a computer (DSLR, Industrial camera, USB camera, IP camera, Smartphone, etc.). I would like to use this thread to compile a list of quality-degrading factors in video, how much they are relevant to sport analysis, which component are involved, and how we may improve upon them.