Patent ID: 7688356

Claim:
A clamp level adjusting apparatus comprising: an image pickup device that includes an effective pixel area producing an image signal and a lightproof area formed around said effective pixel area to produce a black level standard signal; an integrating section that adds said black level standard signal of a plurality of horizontal rows in said lightproof area until a number of rows to be integrated reaches the number of rows of an extracting range to output an integrated value, and when said black level standard signal is supplied exceeding the number of rows of said extracting range, said integrating section sequentially updates said integrated value for output by subtracting the output value of the top row in said extracting range therefrom; a dividing section that divides said integrated value by a predetermined value to produce a vertical moving average value of black level standard signals in said extracting range; a clamp level calculating section that produces a clamp level value corresponding to each horizontal row in said effective pixel area based on the vertical moving average value; and a clamp section that corrects a black level of said image signal in accordance with said clamp level value.