Patent ID: 6940548

Claim:
An image processing apparatus having offset and optical black correction circuit coupled to receive a control signal having a first and second phase and an optical black signal from a charge coupled device, comprising: a. a first circuit to sample the optical black signal at a predetermined reference voltage, the first circuit comprises i. a correlated double sampler, ii. a first and second programmable gain amplifier, the first programmable gain amplifier coupled to the correlated double sampler, iii. an adder coupled between the first and second programmable gain amplifiers, and iv. an analog-to-digital converter coupled to the second programmable gain amplifier for converting the sampled signal into a digital signal; b. a second circuit to correct the optical black offset coupled to the first circuit, wherein the second circuit couples between the adder and the second programmable gain amplifier to add the positive and negative differnce to the optical black signal, the second circuit comprises i. a reverse programmable gain amplifier coupled to the analogto-digital converter to amplify the optical black level of the digital signal; and ii. an integrator coupled to the reverse programmable gain amplifier to detect the optical black level of the digital signal; wherein the integrator couples to the adder.