Optical: systems and elements – Lens – With variable magnification
Reexamination Certificate
2000-06-28
2001-09-18
Mack, Ricky (Department: 2873)
Optical: systems and elements
Lens
With variable magnification
Reexamination Certificate
active
06292307
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to automatically focusing an optical Instrument having a lens with only two focus positions. The invention is particularly useful for, but not necessarily limited to, a digital still or video image camera applications.
BACKGROUND OF THE INVENTION
A number of cameras, both for taking video and/or still digital images have photo sensors located at the focal plane of the camera to acquire an image focused onto the focal plane by a lens. In some cameras an electric motor moves the lens relative to the focal plane of the camera in order to adjust the focus of the image at the focal plane. In cheaper cameras, the lens is designed to function over a wide range of object distances so that the objects are reasonably focused on the focal plane without requiring the lens to be moved at all, although this necessarily reduces the actual sharpness of the image and is therefore not suitable for higher quality cameras.
For digital still and video cameras, autofocusing is a known technique which can be achieved by analysing the sharpness of captured images. By comparing edge and/or high frequency signals in the images captured at different lens positions, the best lens position with a peak of image sharpness can be determined.
As portable communicators become more complex and may have video capabilities, an attached digital camera with autofocus functionality would be very useful. However, for portable devices, power consumption needs to be as low as possible, whereas both the electric motor for driving a lens and the computation required to determine autofocus using known techniques consumes significant power. Furthermore, the current autofocus detection techniques involve quite complex calculations requiring many images to be captured and analysed at different lens positions in order to find the peak of sharpness.
REFERENCES:
patent: 5570433 (1996-10-01), Nagamine et al.
patent: 5835641 (1998-11-01), Sotoda et al.
patent: 6002706 (1999-12-01), Staver et al.
patent: 6014455 (2000-01-01), Sumiyoshi et al.
Kharitonenko Igor
Wu Jing
Zhang Xing
Fekete Douglas D.
Mack Ricky
Motorola Inc.
LandOfFree
Automatically focusing an optical instrument having a lens... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Automatically focusing an optical instrument having a lens..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Automatically focusing an optical instrument having a lens... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2514108