Analysis Causes The Camera To Stroboscopic Flash
Apr 17, 2018
Analysis causes the camera to stroboscopic flash
First of all, when explaining the shooting time of the conference camera, before outputting the display screen, there will be some strobe causes. First, explain the normal display principle.
The computer's monitor can display more than 60 images in a second (this capability is called the refresh rate). It is assumed here to be 70, and the selected conference camera is generally 24 frames per second. That is, the computer has completed several frames of display while the camera is shooting an image. Assume that the camera starts shooting the first image when the computer starts a new frame, then after 1/24 seconds, the computer shows 70/24=3-2/24 frames, which is a little worse than the three frames.
According to the above introduction, we can know that the computer monitor still has the following few lines that are not fired, that is, the following lines are still ambiguous, and the above light is shining, so the top light is emitted three times, and the bottom is only lighted twice. This causes display. The image above is bright and dark, with a boundary line. The upper part is bright and the lower part is dark. It is at 22/24. In 22/24 seconds, the line will go up another 2/22 to the top, then to the top and then from the bottom. This endless indefiniteness gives us the impression that the image is flickering.
As mentioned earlier, dynamic pictures consist of a series of slightly different frames. When displaying a post, instead of displaying the entire image at once, the electron gun sweeps the screen points one by one according to a certain path. It is usually swept down line by line. The display process is as follows. First, it is all black for a short period of time. It is fired one line at a time until all the lines are struck. One frame of image display is completed. Then it is all black and ready for the next image display. So at some point, it may be that one frame of the image has just ended or it may have just begun. It may also be half displayed, and it may be completely black. The camera is also shot with a still image, with little difference between frames. (So the change in a very short period of time may not be able to take down), you can think of it as a high-speed camera.
If the computer's monitor refresh rate is 71, then the computer can display 71/24=3-1/24 frames after 1/24th of a second, that is, only 1/24 frames are not displayed, that is, only the 1/24th boundary line goes up. Changed 1/24, compared to the refresh rate of 70, the speed of transition slowed down, giving us the impression that the flickering of the image is not so serious. It can be inferred that when the refresh rate is 69 or even 68 miles, the flicker can become serious.
