The principle of how to reduce the noise of old cameras

What is the noise reduction of digital cameras?

There are usually two ways to reduce noise.

One is to synthesize photos, which is similar to taking two photos from the same angle and then synthesizing one. Because each photo is randomly generated, the noise is not in the same position. Zhang Hecheng can greatly reduce noise. For example, Patriot T60 and Canon 7D are dual processors, that is, taking a photo, and the two processors are processing at the same time. This is the principle.

The second is software patching, which is a destructive patching, and the noise reduction is very limited. Many cameras come with it, and software such as light and shadow magician also has this automatic noise reduction function.

How is the noise reduction function of SLR camera realized? Is it calculated by the processor or by physical means? Hope to explain in detail!

Generally, small cameras (DC) are all operational, and those advanced than small cameras (not just SLR) are all physical operations, so please operate them a little.

First of all, we should understand the causes of noise: noise comes from the noise in image processing, and if the noise is too large, the noise will be more obvious; At present, the signal level obtained by general digital cameras is not enough to meet the needs of proper exposure, especially the sensitivity is improved, that is, the greater the signal-to-noise ratio, that is, the higher the photo quality. If the signal is not strong enough, the camera needs to amplify the signal to achieve proper exposure, and the noise is also amplified. There are two directions to suppress the influence of noise on the picture: one is to reduce noise, and the other is to improve the signal, that is, to improve the signal-to-noise ratio. Noise reduction can reduce the mutual interference between equipment and lines by improving lines, which is the key to noise generation (of course, there are others); Improving the signal level can be achieved by expanding the photosensitive area, such as Sony's back-illuminated CMOS；; At the same time, the noise is removed by the operation of the processor, so the noise level of the camera is getting lower and lower, and the sensitivity can be higher and higher.

LZ is only 10. It's pathetic to get 10 for such a big question.

What is camera noise reduction technology?

Camera noise reduction technology originally refers to noise suppression circuit and processing circuit. Now the back-illuminated CMOS image sensor can be said to be a very famous noise reduction technology. Digital cameras use pixels to record pictures, but when you press the shutter, sometimes there will be noise in the picture other than standard pixels, usually in long exposure, dark areas and other underexposed image parts. Noise reduction is not to completely eliminate noise, but to reduce noise as much as possible through processing. After the noise reduction function is turned on, a "dark frame" will be taken after the main image (the photo taken when the shutter is closed), and then the noise in the photo will be "subtracted" electronically, because the time from pressing the shutter button to taking an image will be doubled for the second photo, which is simply the case, but noise reduction will also reduce the quality of the film.

This function is most suitable for eliminating the noise of landscape photos taken at night. Try to take pictures in an environment with sufficient pipes during the day, which can also reduce noise. Camera noise reduction technology originally refers to noise suppression circuit and processing circuit. Now the back-illuminated CMOS image sensor can be said to be a very famous noise reduction technology.

Cameras can't reduce noise. The camera has the ability to extract normal photos. The stronger the ability, the less noise. Mainly the quality of photosensitive elements, plus the intelligent induction degree of photo processor.

Later software can also reduce noise, but the effect is not very good, and it is very troublesome to achieve good results.

How to reduce the noise generated when taking pictures .....

It is a random change of brightness or color information in an image, which is usually a manifestation of electronic noise. It is usually produced by sensors and circuits of scanners or digital cameras, and may also be affected by film particles or the inevitable shot noise in ideal photodetectors. Several noise reduction methods are as follows:

1, ISO should not be adjusted too high, and the peak value should be 6400 ISO.

2. You can turn on the automatic noise reduction function of the SLR.

3. Post-adjustment can be made through post-software such as PS or LR.

Extended data

Causes of noise:

Both CCD and CMOS photosensitive elements have thermal pixel problems, which are related to imaging quality and temperature. If the temperature of the machine rises and the noise signal is too strong, it will form mottled spots on the screen where it should not appear. These spots are noise, and the control ability of cameras of various brands and models is different.

References:

Baidu encyclopedia-noise