Circuit and method providing wide dynamic-range operation of auto-focus(AF) focus state sensor elements, digital imaging device, and computer system including same

摘要

A method and apparatus performing scene-adaptive auto-focusing for image capture with a variable-focus lens. The array of color pixels includes a array of half-covered light sensors to obtain lens-focus state information. The exposure time of the plurality of partially-covered light sensors is dynamically selected as long-exposure or short-exposure, based upon a current measurement of a property (e.g., brightness, or color-specific brightness) of a selected region of interest within a scene to be captured by the array. Then, focus state information corresponding to the selected region of interest is obtained by capturing light from the selected region of interest with first and second partially-covered light sensors. The exposure time of the partially-covered light sensors can be changed based on whether the brightness is greater than a predetermined threshold value.

主权项

1. A method of adaptive auto-focusing of an image capture device, having a lens and an array of light sensors including plurality of pixels and a plurality of focus state detecting elements (FDels) to obtain lens focus state information, the method comprising:
selecting one of a first and second modes of the image capture device based on a measurement of a currently-detected property of a selected region of interest within a scene to be captured by the array of light sensors, wherein in the first mode the FDels in the array of light sensors are exposed for a loner exposure time than the plurality of pixels, wherein in the second mode the FDels in the array of light sensors are exposed for a shorter exposure time than the plurality of pixels; and obtaining lens focus state information corresponding to the selected region of interest by capturing light from the selected region of interest in a first and second FDels among the plurality of FDels, operated with the selected mode.