Causes Of Color Cast On Analog CCTV Surveillance Camera

1.Camera Imaging
The spectral power distribution is a central wavelength of 830-950nm and a half-peak bandwidth of about 40nm. It is a narrow-band distribution in the near-infrared spectral band and is a range that can be felt by ordinary CCD and CMOS. In this way, real-time monitoring can be performed during the day or at night.
Since any object above absolute zero (-273 ° C) emits infrared light, during the daytime, the CCD or CMOS senses both visible and infrared light. The longer the wavelength, the smaller the refractive index; the shorter the wavelength, the larger the refractive index.
Therefore, when these rays enter the camera lens at the same time and are refracted by the lens lens, visible light and infrared light will be imaged on different target surfaces, while visible light is imaged as a color image and infrared light is imaged as a grayscale image. The resulting image is well adjusted. At this time, infrared light will form a virtual image on this target surface, which will affect the color and quality of the image.

IP Outdoor PTZ Dome Camera

2.Single filter
The filter filters out infrared rays while trimming the light and restoring the true colors of the image. Therefore, it is impossible to image without visible light at night, that is, there is no night vision function. In order to solve this problem, Ao Shuo developed and applied a single peak filter with a double peak height. This camera has a night vision function.
This single filter is low in cost and can be used in both day and night. Due to the opening of the wavelength frequency, the light in the natural world during the day contains more infrared light, and some of it can also enter the CCD or CMOS and interfere with the color reproduction of the image. For example, green plants become gray and black becomes purple.

36X Zoom High Speed Auto Tracking PTZ Camera

If the effects of day and night are to be considered comprehensively, it is difficult to completely adapt the graph of the filter. In the daytime, some infrared light still interferes with the color reproduction of the image; at night, due to the filtering effect of the double-peak glass sheet, the CCD or CMOS cannot make full use of all the light, resulting in snow spots, and reducing the image clarity and low-light performance of infrared cameras .
Incorrect installation will also cause the camera to be discolored. For example, take two infrared cameras with better infrared shooting, or take four lights to test in a small box. The image will appear light purple. Switching mode is normal. The camera first has a photoresistor to sense the illuminance, first turn on the infrared light, and then switch the IR-CUT. When the small box is tested, the infrared light is on, but the IRCUT is not switched (equivalent to the day mode), the infrared light is reflected, and it may look light purple.

Tag: Analog CCTV Surveillance Camera ; Indoor Simutated Dome Dummy CCTV Camera ; High Speed PTZ Dome Camera