Imaging device and method to correct the focus detection pixels using peripheral standard pixels and correcting defective peripheral standard pixels as well if found

摘要

Pixel values of focus detection pixels are suitably corrected according to reducing occurrence of a residual error of correction. A digital camera ii includes a CCD, an AF detection circuit, a specific pixel correction unit and the like. The CCD has standard pixels and phase difference pixels arranged in a predetermined pattern on an imaging surface, and outputs an image signal of one frame. The AF detection circuit evaluates an in-focus state by referring to a pixel value of the phase difference pixels from the image signal. The specific pixel correction unit determines a first correction value by multiplying the pixel value of the phase difference pixels by a predetermined gain, and compares the first correction value with the pixel value of the standard pixels around the phase difference pixels. If the first correction value is equal to or less than the maximum of those pixel values and equal to or more than their minimum, the pixel values of the phase difference pixels are replaced with the first correction value. Otherwise, the pixel values of the phase difference pixels are replaced with a second correction value obtained by averaging the pixel values of peripheral pixels.

主权项

1. An imaging device comprising:
an image sensor, having standard pixels and focus detection pixels in a predetermined pattern on an imaging surface, for outputting an image signal of one frame from said pixels; a focus evaluation unit for evaluating an in-focus state by referring to brightness of said focus detection pixels from said image signal of said one frame; a first correction value determination unit for arithmetically determining a first correction value by multiplying said brightness of said focus detection pixels by a predetermined gain; a focus detection pixel correction unit for comparing brightness of said standard pixels of a predetermined number disposed around said focus detection pixels with said first correction value, and if said first correction value is in a normal value range equal to or less than a maximum of said brightness of said standard pixels of said predetermined number and equal to or more than a minimum of said brightness of said standard pixels of said predetermined number, replacing said brightness of said focus detection pixels with said first correction value, and if said first correction value is in a value range outside said normal value range, averaging said brightness of said standard pixels of said predetermined number to determine a second correction value, for replacing said brightness of said focus detection pixels with said second correction value to correct said brightness of said focus detection pixels.