Image processing apparatus working in response to frequency diffused clock as reference input image signals

An image processing apparatus that works in response to a frequency diffused clock as a reference to process an input image signal, the image processing apparatus comprising:

• a system clock generation module that outputs a system clock, which is a standard of operations;
• a synchronizing signal measurement module that measures a synchronizing signal characteristic value, which includes at least a synchronizing signal period and a synchronizing signal cycle corresponding to the input image signal, relative to a measurement clock generated from the system clock as a reference;
• and
• an image signal analyzing module that analyzes the input image signal based on the observed synchronizing signal characteristic value,
• wherein the system clock generation module outputs a single frequency clock having a substantially fixed oscillation frequency as the system clock during a measurement time period when the synchronizing signal measurement module measures the synchronizing signal characteristic value, while varying an oscillation frequency and outputting a frequency diffused clock as the system clock during a time period other than the measurement time period, and
• the image signal analyzing module determines that specification of the input image signal is changed when the observed synchronizing signal characteristic value is out of a predetermined range, while determining that the specification of the input image signal is unchanged when the observed synchronizing signal characteristic value is in the predetermined range, the image signal analyzing module analyzing the input image signal according to a result of the determination.