In order to better "understand" the specification parameters, we need to understand the "mystery" under the parameter indicators that have a great impact on product performance. Taking a surveillance camera as an example, we briefly analyze the two key indicators of high clarity and minimum illumination.
How to recognize a security product? It is believed that in most cases, the user understands through its parameter indicators. Users rarely have the opportunity, or can invest time and labor costs to test the selected products. Therefore, to understand a product, we must start with specifications. Still taking the camera as an example, the parameters examined include: CCD size, horizontal resolution, minimum illumination value, signal-to-noise ratio, shutter speed and other basic parameters, automatic white balance, automatic gain power supply, installation methods, communication interfaces, and other hardware support condition. If it is an integrated camera, it is necessary to examine the indicators such as lens performance. The list of these parameters and indicators is enough to make users dazzled, and how to “get rid of the truthâ€, we must first clear the product selection needs, corresponding to the needs of inspection key indicators.
Clarity indicator: This is the first parameter that will be watched when looking at the color page of the camera. In a sense, the camera's sharpness index determines its grade. Most analog products on the market now have a sharpness level of 500 lines or more, and some 960H solutions have reached 700 lines. Digital cameras, on the other hand, represent the level of sharpness they can achieve at the pixel level, such as 1.3 million pixels and 2 million pixels, which roughly correspond to 700TVL and 1000TVL, respectively. However, individual businesses may also have false or partial conditions. If there is an analog camera monogram horizontal resolution of 540TVL, a little attention will be found behind the small print "central resolution". what does this mean? Limited by the camera with its own lens, CCDDSP program and other factors, some cameras can only show the highest sharpness near the center of the image, but can not achieve this clarity at the edge, the overall average resolution may be only 520TVL, or even more low. So you need to pay extra attention to your choice.
Minimum Illumination Indicator: This is an important parameter of the analog camera, but this parameter can be said to be the most intriguing camera indicator (no one). The camera's minimum illumination is also called the camera's sensitivity. There are many factors that affect the camera's minimum illuminance value, which mainly include the light quantity parameter (F-number) of the camera lens, the light source color temperature parameter, the video level amplitude IRE level, and the camera's several function parameter settings. First, it is the light quantity parameter. A lens with a f-stop of F1.4 has twice the throughput of the F1.2 lens, while the F1.0 lens has 100 times the light throughput of the F10 lens.
Therefore, using lenses with different F values ​​will have a decisive influence on the determination of the camera's minimum illuminance value. Second, the light source color temperature. Color temperature is an indicator of the wavelength of light in a light source. A 3200K light source has most wavelengths between 600 nm and 900 nm. A 9300K light source has wavelengths between 300 and 500 nm. Therefore, different color temperatures will completely change. Test Results. On a typical CCD sensor, a light source with a wavelength of 600 nanometers will produce 10 times more electrons than a light source with a wavelength of 900 nanometers. This is why the color temperature is particularly marked as the meaning of the minimum illuminance measurement result.
IRE grade: The maximum amplitude of the video output of the CCD camera is generally set at 100 IRE (or 700 mV). A 100 IRE video representation can completely drive a monitor displaying the best brightness and contrast quality images. The 50 IRE video represents only half the contrast, 30 IRE (or 210 mV) represents only 30% of the original amplitude, and typically 30 IRE is the lowest value of the available image. Therefore, there is no actual comparability of the minimum illuminance measurement results without the IRE rating. Finally, it is the camera's special function settings.
Some cameras have a frame accumulation (also known as sensitivity boost) function. This function allows the CCD to accumulate more electrons per frame of the image in a way that reduces the scanning speed, thereby presenting a bright picture in a low illumination environment. Turning on this function can increase the minimum illuminance measurement by a geometric multiple. For example, a camera with a 512x increase in sensitivity can easily achieve a level of 0.0001 Lux, but at the expense of image coherence, the imagery is full of animation. To sum up, a meaningful minimum illuminance index should be annotated with its F value, color temperature, IRE level, and whether the frame accumulation setting is turned on, such as 0.5 Lux (F1.45600K30IRE, sensitivity increase OFF). Security community reminds that people who have never failed may not have succeeded.
How to recognize a security product? It is believed that in most cases, the user understands through its parameter indicators. Users rarely have the opportunity, or can invest time and labor costs to test the selected products. Therefore, to understand a product, we must start with specifications. Still taking the camera as an example, the parameters examined include: CCD size, horizontal resolution, minimum illumination value, signal-to-noise ratio, shutter speed and other basic parameters, automatic white balance, automatic gain power supply, installation methods, communication interfaces, and other hardware support condition. If it is an integrated camera, it is necessary to examine the indicators such as lens performance. The list of these parameters and indicators is enough to make users dazzled, and how to “get rid of the truthâ€, we must first clear the product selection needs, corresponding to the needs of inspection key indicators.
Clarity indicator: This is the first parameter that will be watched when looking at the color page of the camera. In a sense, the camera's sharpness index determines its grade. Most analog products on the market now have a sharpness level of 500 lines or more, and some 960H solutions have reached 700 lines. Digital cameras, on the other hand, represent the level of sharpness they can achieve at the pixel level, such as 1.3 million pixels and 2 million pixels, which roughly correspond to 700TVL and 1000TVL, respectively. However, individual businesses may also have false or partial conditions. If there is an analog camera monogram horizontal resolution of 540TVL, a little attention will be found behind the small print "central resolution". what does this mean? Limited by the camera with its own lens, CCDDSP program and other factors, some cameras can only show the highest sharpness near the center of the image, but can not achieve this clarity at the edge, the overall average resolution may be only 520TVL, or even more low. So you need to pay extra attention to your choice.
Minimum Illumination Indicator: This is an important parameter of the analog camera, but this parameter can be said to be the most intriguing camera indicator (no one). The camera's minimum illumination is also called the camera's sensitivity. There are many factors that affect the camera's minimum illuminance value, which mainly include the light quantity parameter (F-number) of the camera lens, the light source color temperature parameter, the video level amplitude IRE level, and the camera's several function parameter settings. First, it is the light quantity parameter. A lens with a f-stop of F1.4 has twice the throughput of the F1.2 lens, while the F1.0 lens has 100 times the light throughput of the F10 lens.
Therefore, using lenses with different F values ​​will have a decisive influence on the determination of the camera's minimum illuminance value. Second, the light source color temperature. Color temperature is an indicator of the wavelength of light in a light source. A 3200K light source has most wavelengths between 600 nm and 900 nm. A 9300K light source has wavelengths between 300 and 500 nm. Therefore, different color temperatures will completely change. Test Results. On a typical CCD sensor, a light source with a wavelength of 600 nanometers will produce 10 times more electrons than a light source with a wavelength of 900 nanometers. This is why the color temperature is particularly marked as the meaning of the minimum illuminance measurement result.
IRE grade: The maximum amplitude of the video output of the CCD camera is generally set at 100 IRE (or 700 mV). A 100 IRE video representation can completely drive a monitor displaying the best brightness and contrast quality images. The 50 IRE video represents only half the contrast, 30 IRE (or 210 mV) represents only 30% of the original amplitude, and typically 30 IRE is the lowest value of the available image. Therefore, there is no actual comparability of the minimum illuminance measurement results without the IRE rating. Finally, it is the camera's special function settings.
Some cameras have a frame accumulation (also known as sensitivity boost) function. This function allows the CCD to accumulate more electrons per frame of the image in a way that reduces the scanning speed, thereby presenting a bright picture in a low illumination environment. Turning on this function can increase the minimum illuminance measurement by a geometric multiple. For example, a camera with a 512x increase in sensitivity can easily achieve a level of 0.0001 Lux, but at the expense of image coherence, the imagery is full of animation. To sum up, a meaningful minimum illuminance index should be annotated with its F value, color temperature, IRE level, and whether the frame accumulation setting is turned on, such as 0.5 Lux (F1.45600K30IRE, sensitivity increase OFF). Security community reminds that people who have never failed may not have succeeded.
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