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The Lenscal DLL provides functions to quickly find lens correction register settings that will best correct the image brightness and color shading distortion caused by the camera's optical system.
The library supports all Bayer sensors with built-in lens correction, and most SOC sensors. Sensors
SOCs not supported are: MT9V125 (SOC0354), MT9V111 (SOC0360), MT9V112 (SOC0366), MT9M111 (SOC1310) and MT9M112 (SOC1320).
Sensors not supported are: MT9P001 (A-5100) and MT9P006 (A-51HD-plus).
The input to the calibration is an image of a flat, gray field. The output is a list of the lens correction registers and their values. To get a good calibration requires careful setup of the camera system under test and correct use of the Lenscal functions and their parameters. Contact your Aptina field application engineer for assistance.
Two kinds of lens correction circuits are in use on Aptina sensors, what I'll call the orthogonal type and the polynomial type. The orthogonal type uses sets of horizontal and vertical gain curves added together to create a two-dimensional gain. The polynomial type uses a two-dimensional polynomial function. The calibration algorithms and parameters are different for each. The orthogonal type sensors are MT9D111 (SOC2010), MT9D112 (SOC2020), MT9D012 (A-2020), MT9T012 (A-3120), and MT9P001 (A-5100). All others are polynomial type.
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