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First video image performance standard hits the road

First video image performance standard hits the road

In September 2013, after 18 months of preparation, Underwriters Laboratories (UL), a US-based independent safety science company, published the US security industry's first video image performance standard, UL2802. UL aspired to provide end users and systems integrators (SI) with a tool that not only effectively informs them of a camera's performance when faced with price versus performance decisions, but also helps them clearly identify if the device is as good as it is advertised, according to Neil Lakomiak, Business Development Manager of Built Environment at Underwriters Laboratories.

“We've been approached by various groups of people in the last several years, asking us if we're willing to develop standards around video. I think one of the major issues is that they've wanted to be able to compare the performance between different cameras for their given applications,” Lakomiak said. “I would say this idea was primarily coming out from the end-users community and some of the manufacturers. It was developed to differentiate each camera's capabilities while facing numerous cameras coming with similar functions in the marketplace.

As a result, the development team has built up a set of 9 requirements based on a camera's specifications.” The 9 attributes, which include image resolution/sharpness, TV distortion, relative illumination, dynamic range, maximum frame rate, gray level, sensitivity, bad pixel, and veiling glare, are believed to be the most crucial characteristics of image quality, according to Lakomiak.

Testing Procedures
The standard is designed to assess the image quality of individual cameras based on a set of 9 criteria. For example, UL2802 tests gray level by using an emissive test target made up of 12 lamps with uniform emissive surfaces at different luminosities. The difference between adjacent luminosity levels is half an optical stop. The picture taken of the test target is analyzed based on the signal levels and signal-to-noise ratio from the image of each lamp in the picture. The final gray-level score will depend on the signal levels and signal-to-noise ratio retrieved from the image of the 12 lamps.

The test for veiling glare is conducted under an ambient light source to generate consistent light around the camera. One picture is then taken with the light turned off and another one with the light on. The score is determined by comparing the gray-level degradation and color shift when the light source is on and off.

Definition of Score Range
To certify a camera, a manufacturer must send in their product for the 9-step test. The camera will then be given scores, from zero to 100, for each test.

For dynamic range, cameras that receive a score between zero to 20 are suitable for indoor applications; 20 to 40 are ideal for outdoor applications on a cloudy day or in the shade; 40 to 60 are good for applications with partial sunlight; 60 to 80 are capable of being applied under strong sunlight; and 80 to 100 are applicable to any lighting condition.

In regard to sensitivity, cameras that score between zero to 20 may work well under the lighting conditions in a bar; 20 to 40 could be used in twilight; 40 to 60 are suitable for full-moon lighting conditions; 60 to 80 are good for partial-moon lighting; and 80 to 100 are good for nightglow illumination (see more details in Chart 1).

According to Lakomiak, getting low scores only suggests that the camera does not perform well under those conditions — it does not exclude them from other areas. This ratings system aims to show how well a product performs in these nine aspects individually. Lakomiak explained, “This is only to provide end users a tool on how to choose the best camera for their application. Therefore, just because one camera scored low on one of the atrributes, does not mean that it is a bad camera. It always depends on the specific application for which the camera is being used.”

Open Resources for Integrators
Most manufacturers do not disclose certain information about the attributes of their cameras. As a result, end users are not fully informed before they make a decision. However, if a manufacturer wants a certain product certified, the results of the testing for this certification will be published on UL's online directory, allowing the public to take the results into consideration when purchasing video camera devices. That is to say, this standard will be instrumental to end users and SIs as an additional decision-making tool.

Impact on Verticals
The three verticals with the largest growth — healthcare, government, and education — are going to be the dominant verticals for this performance standard, said Lakomiak. Some government entities with an urgent need for video surveillance products have been paying close attention to the development of this standard. Several US law enforcement agencies have been asking UL to develop additional video standards for specific applications, like wearable video devices, according to Lakomiak.

Next Steps
It is still too early to evaluate the impact of this standard on the security industry since UL2802 is still in its fledgling stage. To market this standard to different channels in the global security industry, UL still needs to overcome many obstacles. Reaching a consensus amongst manufacturers still remains a major challenge for this standard. Another long-term obstacle for UL will be seeing how well the standard evolves alongside the advancement of technology.

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