Color Temperature

Most light sources are not 100% pure white but have a certain "color temperature", expressed in Kelvin. For instance, the midday sunlight will be much closer to white than the more yellow early morning or late afternoon sunlight. This diagram gives rough averages of some typical light sources.


Normally our eyes compensate for lighting conditions with different color temperatures. A security camera needs to find a reference point which represents white. It will then calculate all the other colors based on this white point. For instance, if a halogen light illuminates a white wall, the wall will have a yellow cast, while in fact it should be white. So if the camera knows the wall is supposed to be white, it will then compensate all the other colors in the scene accordingly.  

Most cameras feature automatic white balance circuits whereby the camera looks at the overall color of the image and calculates the best-fit white balance. However these systems are often fooled especially if the scene is dominated by one color, say red, or if there is little natural white surfaces present in the scene as show in the example below.

A normal camera without “Area White Balance” with a strong red present in the picture will produce a background that looks blue on the white wall shown in this picture.


JVCs “Area White Balance” Feature

The “Area White Balance” feature has been developed by JVC to ignore areas with strong reflections of non-white colors and re-direct the auto white balance circuits to focus on the areas that are white in the picture. The JVC “Area White balance” function can be easily applied to a designated area with more white area and avoid strong color casts in the picture. 

This feature is yet another innovation designed by the experts at JVC to provide users and integrators with tools to allow them to achieve excellent results easily.

To see more of these innovative features please visit us at http://pro.jvc.com