concept
The function is: The traditional CCD has the limitation of the dynamic range. In the process of collecting an image, only the entire image is sampled once, and it will inevitably appear overexposed to the bright area in the whole image, or to the underexposed phenomenon in the dark area. The function of strong light suppression is to use DSP technology. The simple meaning is to weaken the strong light part and brighten the dark part to achieve light balance.
The principle is: In the image, the video information of the strong light part is processed by the DSP, and the brightness of the video signal is adjusted to the normal range, so as to prevent the front and back contrast in the same image from being too large.
Strong light suppression technology can effectively suppress the halo caused by direct irradiation of strong light spots, the video image is blurred, can automatically distinguish strong light spots, and compensate areas near strong light spots to obtain clearer images.
The addition of a light suppression filter processing chip network camera can effectively suppress the oncoming strong light, and can more clearly capture the vehicle license plate when monitoring road vehicles at night. Applicable to toll stations, parking lot exits and other areas.
Implementation
1. Backlight compensation method (BLC)
The BLC method is to re-specify the metering area on the screen, and ensure the correct exposure by focusing on the metering to avoid the silhouette phenomenon in the darker parts. Specifically, when this function is introduced, the camera only detects one sub-area of ​​the entire field of view. The average signal level of this area is used to determine the working point of the AGC circuit because the average level of the sub-area is low. , AGC amplifier will have a higher gain, so that the output video signal amplitude increases, so that the main picture on the monitor is bright, the background picture will be more bright at this time, but the subjective brightness difference between the subject picture and will be greatly reduced The visibility of the entire field of view has been improved.
2. HLI method HLI method uses the image processing function of the camera to invert the area with small area and high brightness value to prevent the display from appearing on the monitor, which is convenient for monitoring personnel to monitor. . This method is suitable for discarding the high-brightness part of the screen when shooting dark objects or shooting objects with large differences in brightness.
3. Double-exposure extended dynamic range mode The core of the double-exposure extended dynamic range method is the use of a two-speed CCD image sensor, which can take long and short exposures of the scenes taken at the same time, ie, in one frame. Inside, use a slow shutter speed to shoot images in dark areas. Of course, when the high-brightness area is saturated, the image becomes white. At the same time, use a high-speed shutter to shoot at a high-brightness area. The two images are stored in a memory and synthesized in the DSP to obtain an image that simultaneously captures dark areas and highlight areas. In this way, the speed difference between the low speed and high speed shutter will directly affect the size of the dynamic range.
4. Multi-stage sampling method The multi-stage sampling method is a method of shooting in units of pixels in the best cumulative time, which can effectively solve the problems caused by backlight shooting and achieve a wide dynamic in the true sense.
In addition to the above four main methods, there are some digital image processing algorithms that can also achieve strong light suppression.
The function is: The traditional CCD has the limitation of the dynamic range. In the process of collecting an image, only the entire image is sampled once, and it will inevitably appear overexposed to the bright area in the whole image, or to the underexposed phenomenon in the dark area. The function of strong light suppression is to use DSP technology. The simple meaning is to weaken the strong light part and brighten the dark part to achieve light balance.
The principle is: In the image, the video information of the strong light part is processed by the DSP, and the brightness of the video signal is adjusted to the normal range, so as to prevent the front and back contrast in the same image from being too large.
Strong light suppression technology can effectively suppress the halo caused by direct irradiation of strong light spots, the video image is blurred, can automatically distinguish strong light spots, and compensate areas near strong light spots to obtain clearer images.
The addition of a light suppression filter processing chip network camera can effectively suppress the oncoming strong light, and can more clearly capture the vehicle license plate when monitoring road vehicles at night. Applicable to toll stations, parking lot exits and other areas.
Implementation
1. Backlight compensation method (BLC)
The BLC method is to re-specify the metering area on the screen, and ensure the correct exposure by focusing on the metering to avoid the silhouette phenomenon in the darker parts. Specifically, when this function is introduced, the camera only detects one sub-area of ​​the entire field of view. The average signal level of this area is used to determine the working point of the AGC circuit because the average level of the sub-area is low. , AGC amplifier will have a higher gain, so that the output video signal amplitude increases, so that the main picture on the monitor is bright, the background picture will be more bright at this time, but the subjective brightness difference between the subject picture and will be greatly reduced The visibility of the entire field of view has been improved.
2. HLI method HLI method uses the image processing function of the camera to invert the area with small area and high brightness value to prevent the display from appearing on the monitor, which is convenient for monitoring personnel to monitor. . This method is suitable for discarding the high-brightness part of the screen when shooting dark objects or shooting objects with large differences in brightness.
3. Double-exposure extended dynamic range mode The core of the double-exposure extended dynamic range method is the use of a two-speed CCD image sensor, which can take long and short exposures of the scenes taken at the same time, ie, in one frame. Inside, use a slow shutter speed to shoot images in dark areas. Of course, when the high-brightness area is saturated, the image becomes white. At the same time, use a high-speed shutter to shoot at a high-brightness area. The two images are stored in a memory and synthesized in the DSP to obtain an image that simultaneously captures dark areas and highlight areas. In this way, the speed difference between the low speed and high speed shutter will directly affect the size of the dynamic range.
4. Multi-stage sampling method The multi-stage sampling method is a method of shooting in units of pixels in the best cumulative time, which can effectively solve the problems caused by backlight shooting and achieve a wide dynamic in the true sense.
In addition to the above four main methods, there are some digital image processing algorithms that can also achieve strong light suppression.
Testing Equipment Of Guide Rail
Testing Equipment of Elevator Guide Rail
Inspection Equipment of Elevator Guide Rail
Detection Equipment of Elevator Guide Rail
testing facility of Elevator Guide Rail
measuring equipment of Elevator Guide Rail
We carry high quality Testing Equipment Of Guide Rail for all major elevator and escalator brands
for OTIS Elevators, ThyssenKrupp Elevators, Schindler Elevators, KONE Elevators, Mitsubishi Elevators, Fujitec Elevators, Hitachi Elevators, Toshiba Elevators, Fuji Elevators, Express Elevators, Sigma Elevators, LG Elevators, Hyundai Elevators, BLT Elevators, CANNY Elevators, SJEC Elevators, KOYO Elevators
Testing Equipment of Elevator Guide Rail, Inspection Equipment of Elevator Guide Rail, Detection Equipment of Elevator Guide Rail
CEP Elevator Products ( China ) Co., Ltd. , https://www.zjsmartcommercialescalators.com