Popular post: IPC common image question answer

Infrared is not confocal

Description of the phenomenon: Due to the difference in the wavelength of infrared light and visible light, the refractive index is different when passing through the same glass, so the imaging focus is also different, resulting in different infrared and visible light and clear focus. This is a common issue in the industry. It exists in the vast majority of shots, and some day and night confocal lenses are effective in improving this phenomenon.

Problem positioning: Lens day and night results in confocal performance.

Solution/Avoidance Method: Avoid large areas of infrared visible light overlapping scenes.

Laser fog

Phenomenon: When the laser ball has more atmospheric particles, such as foggy weather and dusty weather, it is prone to fogging at telephoto. This is due to the fact that the power of the laser is more concentrated than that of the infrared light in the case of a long-focus laser, and this phenomenon is inevitable when the atmospheric particles reflect the laser light.

Problem positioning: caused by reflection of atmospheric particles.

Solution/circumvention method: Test under conditions with better atmospheric conditions.

Hemispherical Fog

Phenomenon: Due to the built-in infrared light of the device reflecting light on buildings and external scenes, it causes fog on the image screen.

Problem Location: Check whether there are objects that may cause infrared reflection, such as ceilings, measurements, walls, wires, branches, etc.

Solution/Avoidance Method: Adjust the direction of the infrared/device to avoid reflective structures and objects.

Stay up and down repeatedly

Phenomenon: Due to the reflection of external objects, etc., the device repeatedly switches between day and night, the picture is very dark for a while, and the picture is very bright for a while.

The cause of the problem: In the color mode, as the environment becomes dark, the threshold for switching between black and white is reached; after the black and white is switched on, the infrared is automatically turned on. Since the infrared reflection is serious, the screen is bright, the color threshold is reached, the color is switched and the infrared is turned off; Switch;

Solution/circumvention method: Avoid the infrared light from excessively approaching the wall and other external reflective objects, so as to avoid external reflection caused by repeated switching; Do not test infrared in the carton, carton test will inevitably cause repeated switching.

Flashlight effect

Phenomenon: When the infrared light angle is smaller than the viewing angle of the device, a flashlight effect will appear. The screen looks bright in the middle and dark in all directions.

Problem location: The infrared fill light angle is smaller than the field of view angle.

Solution/circumvention method: adjust the angle of the fill light to adjust the angle of view (infrared manual mode); adjust the angle of view to adjust the fill angle (adjust the focal length).

Wide dynamic dark area noise

Phenomenon: When the wide dynamic level is turned on, it may cause a lot of noise in wide dynamic dark areas. Decreasing the exposure compensation and adjusting the wide dynamic level can improve the phenomenon.

Problem Location: The wide dynamic level is not suitable; after the wide dynamic is turned on, the exposure compensation is increased.

Solution: Adjust the wide dynamic level appropriately; reduce exposure compensation; reduce sharpness.

License Plate Smear

Phenomenon: There is trailing in the evening / night license plate.

Problem Location: 3D noise reduction will produce trailing objects; slow shutter will produce trailing objects.

Solution: Generally, the shutter speed needs to reach 1/100-1/200 at night to meet the requirement of no smear; reducing 3D noise reduction can improve the license plate tailing situation.

Horizontal stripes

Phenomenon: In the case of street lights at night, bright and dark stripes appear on the screen.

Problem location: The result of the periodic variation of the brightness in the different areas of the screen with the frequency of the power supply caused by the mismatch between the shutter speed and the power supply frequency of the street lamp; the frame rate is matched with the power frequency section of the lamp, and the horizontal stripes move.

Solution: Do not set the shutter speed more than 1/100; increase the DC fill light, and press down the brightness of the 50HZ streetlight; the 50Hz power supply lighting, the frame rate is adjusted to 25 frames.

White balance color cast

Phenomenon: There are differences between the basic tone of the picture and the human eye.

Problem positioning: The same color in large areas of the screen, such as lawns, trees, etc.; mixed color temperature environment: There are multiple light sources with large differences in color temperature.

Solution: The degree of color cast can be reduced by adjusting the saturation; the PK test can be adjusted to deliver manual white balance.