Patent ID: 8760580

Claim:
An image sharpness device, a composite video signal of a field of a frame having a luminance signal, the image sharpness device comprising: a DC removal unit, receiving the luminance signal and removing a DC component of the luminance signal; at least one filter, passing a component of an output of the DC removal unit within a predetermined frequency band while filtering out the other components of the output of the DC removal unit; at least one noise estimation unit, estimating a noise value of the field of the frame; at least one soft threshold processing unit, forming a sharpness signal by subtracting the noise value from a positive component of the output of the filter and adding the noise value to a negative component of the output of the filter when an absolute value of an output of the filter is greater than the noise value, or forming the sharpness signal by setting the output of the filter to be zero when the absolute value of the output of the filter is smaller than the noise value; and a summing unit, summing the luminance signal and the sharpness signal to output a resultant luminance signal, wherein the noise estimation unit comprises: a noise estimation DC removal unit, receiving a signal in at least one blank line of the field and removing a DC component of the signal, wherein the blank line of the field is a scan line without the luminance signal; a noise estimation filter, passing a component of an output of the noise estimation DC removal unit within the predetermined frequency band while filtering out the other components of the output of the noise estimation DC removal unit; and a noise estimation processing unit, estimating a noise of an output of the noise estimation filter to generate the noise value.