CRAcorrectionOmniVision CRA Correction
Matching Sensors to Lenses for Better Imaging Systems
June 2009
Security B: Highly Confidential 1
Agenda
What is CRA? How CRA affects light collection efficiency of the sensor How to make your selection Summary
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What is CRA?
CRA is an acronym for Chief Ray Angle The angle of the incident rays passing through the center of the lens aperture Measured at the image sensor Center of the sensor CRA=0° CRA typically increases for pixels furthest away from the center of the sensor
Chief Ray 1 Lens Aperture Image Sensor
Chief Ray 2
CRA 1 Optical axis
Half Field of View CRA 2
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Light collection efficiency reduction
On-Axis Pixel
CRA=0°
Off-Axis Pixel
CRA=25°
Common CMOS pixels behave l……
