[ Huaqiang Security Network News ] When people choose infrared light, they must consider it comprehensively. We have six factors to choose infrared light. You may wish to take a look.
1. The minimum illumination given by the camera. What is the minimum illumination concept here? The video signal produced by the camera is nominally 1V, the standard value is 0.7V, and the video signal value at the lowest illumination is 1/3-1/2 standard. Therefore, the image of the camera at the lowest illumination will never be "like a white."
2. The image clarity produced by the camera at the minimum illumination is measured by a TV signal test card. The black and white stripes require a black reflectance of approximately 0% and a white reflectance of greater than 89.9%. However, we sometimes do not have such conditions when we observe it on the spot. For example, the reflectivity of leaves and grass is very low, and the contrast is small, so it is not easy to obtain clear images.
3. While giving the minimum illumination of the camera, the required value of the aperture F is also given, and the zoom lens generally only gives the maximum value of 1:F, that is, the minimum value of the aperture F (the maximum size of the aperture), F= f/D, then D is a fixed value, and when the focal length of f is increased by 10 times, F becomes large (that is, the actual size of the aperture becomes small). Luminous flux will be greatly affected.
4. When using an auto iris lens, automatic gain control or automatic electronic shutter camera, the lens aperture F value will also change. For example, if there is a scene near the camera, it will reflect back to the camera, or there will be a light-illuminating camera nearby. At this time, the sensitivity of the camera will be reduced, the size of the auto-iris will be turned off, and the luminous flux will be greatly affected.
5. The protective cover also has an effect on the effect of the infrared light. In the transmission process, the transmittance and reflectivity of the infrared light are different through different media. Different window glass, especially automatic defrost coated glass, has different attenuation of infrared light.
6. Some equipment manufacturers or distributors do not give the irradiation distance of infrared lamps, only the number of powers, which may be less troublesome for production and sales, but this is a very vague concept because of power consumption. In addition to conversion to infrared light energy, there are power supply heat loss, circuit heat loss, light source heat loss, filter glass infrared light efficiency and so on. For infrared lamps of the same power, the irradiation distance may be very different.
With the rapid development of infrared night vision systems, the supply of infrared lamps will also increase, but the red light products are not as easy as some people think, and the conditions in technology, testing equipment and so on are different. I hope users can compare and compare them more. , choose carefully.
1. The minimum illumination given by the camera. What is the minimum illumination concept here? The video signal produced by the camera is nominally 1V, the standard value is 0.7V, and the video signal value at the lowest illumination is 1/3-1/2 standard. Therefore, the image of the camera at the lowest illumination will never be "like a white."
3. While giving the minimum illumination of the camera, the required value of the aperture F is also given, and the zoom lens generally only gives the maximum value of 1:F, that is, the minimum value of the aperture F (the maximum size of the aperture), F= f/D, then D is a fixed value, and when the focal length of f is increased by 10 times, F becomes large (that is, the actual size of the aperture becomes small). Luminous flux will be greatly affected.
4. When using an auto iris lens, automatic gain control or automatic electronic shutter camera, the lens aperture F value will also change. For example, if there is a scene near the camera, it will reflect back to the camera, or there will be a light-illuminating camera nearby. At this time, the sensitivity of the camera will be reduced, the size of the auto-iris will be turned off, and the luminous flux will be greatly affected.
5. The protective cover also has an effect on the effect of the infrared light. In the transmission process, the transmittance and reflectivity of the infrared light are different through different media. Different window glass, especially automatic defrost coated glass, has different attenuation of infrared light.
6. Some equipment manufacturers or distributors do not give the irradiation distance of infrared lamps, only the number of powers, which may be less troublesome for production and sales, but this is a very vague concept because of power consumption. In addition to conversion to infrared light energy, there are power supply heat loss, circuit heat loss, light source heat loss, filter glass infrared light efficiency and so on. For infrared lamps of the same power, the irradiation distance may be very different.
With the rapid development of infrared night vision systems, the supply of infrared lamps will also increase, but the red light products are not as easy as some people think, and the conditions in technology, testing equipment and so on are different. I hope users can compare and compare them more. , choose carefully.
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