Patent ID: 8306351

Claim:
An apparatus for filtering noise in an image signal, comprising: an analog-to-digital converter (ADC), for receiving the image signal and converting the image signal into a digital signal; a first filter, for receiving the digital signal and filtering a first noise portion of the digital signal to generate a first signal, inspecting the digital signal to generate a first inspection result, generating a compensation signal according to the digital signal, and determining the first signal to be the compensation signal or the digital signal according to the first inspection result, wherein the first filter comprises: a first delay unit, for receiving and delaying the digital signal to generate a second signal; a first noise inspector, coupled to the first delay unit, for receiving and inspecting the digital signal and the second signal to generate a first control signal; a first calculation unit, coupled to the first noise inspector, for receiving the first control signal and a second control signal and performing a calculation on the first control signal and the second control signal to generate a third control signal; a selection unit, coupled to the first calculation unit, for determining whether to assert the second control signal according to a state of the third control signal; a compensation unit, coupled to the first delay unit, for compensating the second signal to generate the compensation signal; and a first multiplexer, coupled to the compensation unit and the first calculation unit, for selecting one of the digital signal and the compensation signal as the first signal according to the state of the third control signal, wherein the third control signal is corresponding to the first inspection result; and a second filter, coupled to the first filter, for receiving the first signal and filtering a second noise portion of the first signal; wherein the first noise portion is a sample-based impulse noise, and the second noise portion is a line-based impulse noise.