The Principle Of Moiré In Videoconferencing Cameras
May 24, 2018
The principle of moiré in videoconferencing cameras
The video conference camera may produce something called Moorish in the process of shooting. It will have a certain impact on the shooting. Below, Dai Pu introduces Moore to our customers and avoids them.
In simple terms, Moire is a manifestation of the beat principle. Mathematically speaking, two equal-amplitude sine waves with similar frequencies are superimposed, and the resultant signal's amplitude will change according to the difference between the two frequencies. The beat principle is widely used in broadcasting, television, and communications for frequency conversion and modulation.
Similarly, the beat principle also applies to spatial frequencies. Strains with slightly different spatial frequencies are superimposed. Because of the differences in the spacing of the fringes, the coincident positions gradually shift, and beats are also formed.
If the spatial frequency of the CCD (CMOS) pixels of the light sensor is close to the spatial frequency of the fringes in the image, moiré will occur. To eliminate moire, the resolution of the lens should be much smaller than the spatial frequency of the sensor. When this condition is satisfied, no streaks similar to the photosensitive element appear in the image, and no moiré is produced. In some digital cameras, in order to reduce the moire, a low-pass filter is installed to filter out the higher spatial frequencies in the image, which of course reduces the sharpness of the image. Future digital cameras will not exhibit moiré if the pixel density can be greatly increased and far exceeds the resolution of the lens.
Relieve and eliminate Moiré effects in photography
1, change the camera angle. Since the angle between the camera and the object can cause moire, changing the angle of the camera slightly (by rotating the camera) can eliminate or change any moiré that is present.
2, change the camera position. In addition, moiré can be reduced by changing the angle relationship by moving left or right or up and down.
3, change the focus. A too sharp focus and a high degree of detail on a detailed pattern can cause Moire ripples. Changing the focus slightly can change the sharpness, which in turn helps to eliminate Moire ripples.
4, change the lens focal length. Different lens or focal length settings can be used to change or eliminate Moire ripples.
Video conference camera current application range
With the continuous progress and development of the times, video conferencing cameras and video conferencing systems are becoming more and more common in people's daily lives. They have been widely used both in life and in work.
