Patent ID: 8212927

Claim:
An image signal processing apparatus comprising: an input section supplied with an image signal whose pixel size is converted at a predetermined magnification scale; a sampling frequency calculation section that uses the input image signal after pixel size conversion and calculates sampling frequencies for the image signal before and after pixel size conversion; and a magnification scale determination section that determines a magnification scale using a ratio of sampling frequencies calculated by the sampling frequency calculation section for the image signal before and after pixel size conversion, wherein: the sampling frequency calculation section calculates a sampling frequency for an image signal before pixel size conversion, the sampling frequency causing a signal intensity of an aliasing component contained in the input image signal to be equal to a signal intensity of a component before being the aliasing component, the sampling frequency calculation section extracts a first phase component signal from the input image signal; the sampling frequency calculation section generates a second phase component signal whose phase is orthogonal to the first phase component signal; the sampling frequency calculation section acts on the first and second phase component signals to calculate a coefficient indicative of correlation between the first and second phase component signals at a plurality of different frequencies; and the sampling frequency calculation section acts on the coefficient to calculate a sampling frequency for an image signal before pixel size conversion, the sampling frequency being double a frequency that causes a signal intensity of an aliasing component contained in the input image signal to be equal to a signal intensity of a component before being the aliasing component.