In recent years, LED screens have become more and more widely used. LED screens can be seen in studios, surveillance centers and even environmental surveillance equipment. With othersto showCompared to screens, LED screens have great advantages in brightness, size, etc.
However, during long -term use, we will see that when the mobile phone or other shooting equipment is addressed to the LED screen, it will sometimes appear inexplicable as strange scratches and colors and strange defects. The same goes for the photos taken. Many people think that the current is unstable, but it is not caused by this reason. Today, the publisher will explain in detail why the LED screen photos taken with your mobile phone are not clearly displayed.
Some people call scratches like waves of water “water waves”, but in fact, they have a “moiréffect” scientific name. The explanation is that if there are dense textures in a scene with a digital camera, splines of inexplicable water waves often appear. In simple terms, Moiré is a manifestation of the principle of bad rhythms. Mathematically speaking, if two sinusoidal waves of amplitude equal with close frequencies are superimposed, the amplitude of the synthetic signal will change according to the difference between the two frequencies.
The reason for the flow of molar patterns is that the LED screen used is an insufficient cooling rate. The lines on certain LED screens are not illuminated when taking photos and imaging, which leads to a series of molar patterns. The refresh frequency is the commonly known screen Hertz (Hz).
Most of the time useLCD screenMost default devices at 60 Hz. Because the screen does not always shine, it will refresh itself from time to time. For example, that 60 Hz means refreshing 60 times per second, but there is a visual delay in the naked eye, so that the naked eye cannot completely detect the lightning of the screen.
When a mobile phone pulls a screen, most of them have faster shutter speed. When the shutter speed is faster than the refresh frequency, it can capture the process of refreshing the screen that we cannot see with our naked eyes, which will create “stripes”.
Scan with 1/4, equipped withCross flow drivingCI, a screen with a refresh rate of 1000 Hz as an example, define the exposure time of the camera over 1/1000 seconds, 1/500 seconds, 1/800 seconds and 1/2000 seconds, and the following situations will occur.
Only at the shutter speed of 1/500 second, all the lines are lit twice and the brightness is consistent. At the shutter speeds of 1/800 and 1/1000 seconds, certain lines light up once again, resulting in different degrees of molar patterns. At the shutter speed of 1/2000 seconds, half of the rows were not on, you can therefore imagine the number of molar models.
It is only when the refresh frequency is greater than twice the shutter speed of the camera, the LED screen will avoid molar patterns.
At the generally shutter speed of the 1/2000 seconds camera, the refresh rate of almost 1000 of the ordinary cross driver IC and the refresh rate of 1920 Hz of the Dual Latch Condu Condute is not enough to avoid molar models. Only the high definition PWM driver with high definition with a refresh rate of more than 3840 Hz can guarantee that there is no molar pattern when taking photos on LED screens.
So are there shooting skills that can reduce or eliminate such interference?
(1) Change the angle of the phone’s camera. Since the angle between the phone and the LED screen can cause the moiré, the slightly modification of the camera angle of the phone (by running the phone) can reduce or eliminate Moiré.
(2) Modify the camera’s camera position. The molar models can be reduced by modifying the angle relationship by moving left and right or from top to bottom.
(3) Change orientation. Too clear concentration and details on detailed models can cause molar models, and a slightly changing focus can change clarity, which in turn helps to eliminate molar models.
(4) Modify the focal distance of the lens. Use different lens or focal parameters to modify or eliminate molar models.
(5) Use software to process, use the Photoshop plug-in, etc. To eliminate all molar models appearing on the final image.
(6) Use the front filter to install it directly in front of the CCD so that its exposure conditions meet the spatial frequency, carefully filter the high spatial frequency parts of the image and reduce the chances of molar patterns, but this will also simultaneously reduce the clarity of the image
