Patent ID: 8446531

Claim:
A method using image processing hardware for processing image frames of an analog input signal for displaying images, the method comprising: sampling the analog image signal at a sampling frequency provided by a reference clock signal to produce samples; computing values of an autocorrelation function using the samples and a delayed version of the samples for a range of delays; computing a sampling frequency offset from the values of the autocorrelation function; and adjusting the sampling frequency using the sampling frequency offset; wherein there are M samples, where M is an integer number, and wherein computing the values comprises computing values for a delay τ, of an autocorrelation function expressible as: autocorrelation_function ⁢ ⁢ ( τ ) = ∑ i = 0 M ⁢  difference_function ⁢ ⁢ ( sample ⁡ ( i + τ ) , sample ⁢ ⁢ ( i ) )  , where difference_function (x, y) computes a difference between x and y, and sample(i) is an i-th buffered sample.