Patent ID: 8363151

Claim:
An imaging apparatus comprising: a video signal generator configured to take an image of an object and generate a video signal carrying the image; a filter configured to extract a high frequency component at a specific frequency or higher from a luminance signal of the video signal; a comparator configured to compare an absolute value of the high-frequency component with a specific reference value, to output a first detection signal when the absolute value is equal to or larger than the reference value whereas a second detection signal when the absolute value is smaller than the reference value; a selector configured to select a first chrominance difference signal indicating a specific color in response to the first detection signal whereas a second chrominance difference signal indicating an achromatic color in response to the second detection signal, the first or the second chrominance difference signal being output as a focus-adjustment signal; a down converter configured to down-convert the focus-adjustment signal by decreasing at least either the number of lines in a vertical direction or the number of pixels in a horizontal direction of the focus-adjustment signal; a display configured to display an image of the object with the specific color at an edge portion of the image; a peak detector configured to detect a peak level of the luminance signal; a block-average calculator configured to calculate an average of the peak level in blocks of the image; and an arithmetic unit configured to perform a specific operation to the peak level and the average to obtain the reference value.