Identification and recognition

Testing

To ensure that identification and recognition goals are met, it is essential to test the installed cameras in realistic conditions. Make sure you use varying levels of lighting, and review the recorded footage in order to verify that you get the required image quality.

Typical problems to be aware of:

  • Camera placement or lens selection that distorts facial features

  • Difficult lighting conditions that create shaded areas or whiteout effects

  • Compression settings that cause image blur or pixelation

  • Motion blur caused by slow shutter speeds or low frame rates

  • Excessive noise in low-light situations

  • Overlay text appearing in a crucial part of the scene

The pixel counter feature available in some Axis cameras lets you draw a rectangle in the image around an area of interest. The camera reports the pixel dimensions of the rectangle, making it easy to verify that the camera installation fulfills requirements. 

Figure 5: The pixel counter feature in action.

There are also numerous test targets that can be placed in front of cameras to help determine if resolution requirements are met. One such target is available from the link below:

Figure 6:  An example of a test target.

SKL target

For more advanced calibration, a Rotakin device (rotating man) may be used, which simulates object motion and resulting image blur.

Conclusion