US 6,646,680 B1 · Focusing method and apparatus for high resolution digital cameras

Abstract

A focusing method and apparatus, for use with digital cameras having an electronic viewfinder with less display resolution than in the image generated by the camera's photocell array, uses a uniformly subsampled representation of the entire image for focusing, rather than displaying a selected portion of the higher resolution image. The focusing is assisted by the exaggerated discontinuities produced by subsampling. Introducing flicker enhances focusing sensitivity by repetitively displaying, on the electronic viewfinder, a prescribed set of different reduced-resolution images obtained by subsampling the same high-resolution image at different sampling locations. Each subsampled image of the set of reduced resolution images uses a different set of substantially uniformly distributed pixels.

Claims15

Dependent claims

A dynamic focusing method for a high-resolution digital camera having an adjustable focusing mechanism and a reduced-resolution electronic viewfinder display, the focusing method comprising:

(a) dividing a high-resolution image generated by a high-resolution image sensor into a plurality of blocks of pixels, each block having a plurality of pixels, selecting one pixel from a pixel position within each block, and displaying a reduced-resolution image, with substantially uniform vertical and horizontal scaling, obtained from the selected pixel within each block for at least one display frame on the reduced-resolution viewfinder display;
(b) repeating (a) for a prescribed number of times using a different pixel position each time, the prescribed number of times being fewer than the number of pixels in at least one block of pixels;
and
(c) repeating (b) to produce a periodic sequence of reduced-resolution images.

1 more element

Dependencies are inferred from the claim text.

Focusing method and apparatus for high resolution digital cameras

Life of this patent

Focusing method and apparatus for high resolution digital cameras

Life of this patent

Abstract

Claims15