What does photography crawl mean?

The noise of digital camera, also called noise, mainly refers to the rough part of the image when CCD(CMOS) receives and outputs light as the received signal, and also refers to the foreign pixels that should not appear in the image, usually caused by electronic interference. It looks like the image has been dyed and covered with some tiny rough spots. The digital photos we usually take may not be noticed if we use a personal computer to reduce the high-quality images and then look at them. However, if the original image is enlarged, there will be a color (pseudo-color) that did not exist originally, and this pseudo-color is image noise.

In addition to noise, there is another phenomenon that is easily confused with noise, which is a bad point. Under the same digital camera setting conditions, if the clutter always appears in the same position in the captured image, it shows that this digital camera has bad points. General manufacturers have regulations on the number of bad spots. If the number of bad spots exceeds the specified number, you can replace the camera with dealers and manufacturers. If the noise points do not appear in the same position, it means that these noise points are due to the noise formed during use.

Thermal pixel: both CCD and CMOS photosensitive elements have thermal stability problems, which are related to imaging quality and temperature. If the machine temperature rises and the noise signal is too strong, it will form mottled spots where the picture should not be. These points are what we call dry points. Various brands and models of cameras have different ability to control dry spots. Cameras of the same model also have certain individual differences, and some cameras have the function of reducing dry spots. But the problem of dry spot is a problem that all DC can't completely overcome now (improving the sensitivity (ISO), especially when the exposure time is long or the camera temperature rises).