P-Iris is an automatic, precise iris control first developed by Axis Communications of Sweden and Kowa Company of Japan. It involves a P-Iris lens and specialized software that optimize image quality. The system is designed to address the shortcomings of an auto-iris lens. P-Iris provides improvements in contrast, clarity, resolution and depth of field.
Having good depth of field—where objects at different distances from the camera are in focus simultaneously—is important in the video monitoring of, for example, a long corridor or parking lot.
In bright situations, P-Iris limits the closing of the iris to avoid blurring (diffraction) caused when the iris opening becomes too small. This can typically happen in cameras that use DC-iris lenses in combination with megapixel sensors that have small pixels. Being able to avoid diffraction and at the same time benefit from an automatically controlled iris is highly valued in outdoor video surveillance applications. A P-Iris lens uses a motor that allows the position of the iris opening to be precisely controlled. Together with software that is configured to optimize the performance of the lens and image sensor, P-Iris automatically provides the best iris position for optimal image quality in all lighting conditions.
In Axis network cameras with P-Iris, the user interface provides a scale of f-numbers that ranges between the widest and smallest iris opening. This feature enables the user to adjust the preferred iris position, which is the iris position used by the automatic control for most lighting conditions.
P-Iris allows fixed network cameras to reach a new level of performance in image quality. The advanced iris control will be especially beneficial for megapixel/HDTV cameras and demanding video surveillance applications. P-Iris is expected to replace DC iris as the standard iris control for fixed network cameras.