Patent ID: 6829007
Filing Date: 2004-12-07
Classification: H04N

Abstract:
An image processing apparatus having offset and optical black correction circuit coupled to receive an optical black signal from a charge coupled device, comprising:a sampling circuit for sampling the optical black signal at a predetermined reference voltage; an analog-to-digital converter coupled to the sampling circuit for converting the sampled signal into a digital signal; a detector circuit to detect the optical black level of the digital signal; a digital averager coupled to the detector circuit to average the optical black pixels at the beginning of each line of the optical black signal; a line noise filter coupled to the digital averager to remove line noise from the optical black signal; a digital comparator, having a predetermined reference, coupled to the line noise filter to compare the optical black signal from the line noise filter to the reference and generate a difference; and a correction circuit for correcting the optical black level by feeding back the difference obtained by the digital comparator such that the difference is added and subtracted to the analog optical black signal.