Camera shake determination device, printing apparatus and camera shake determination method

A method for determining whether or not blurring in an image has been produced by camera shake, the method comprising:

• referencing image data in which has been recorded, per block unit, coefficients that are obtained when pixel values forming an image in a spatial domain are converted to a frequency domain per block unit composed of a plurality of pixels;
• detecting whether edges are included per block unit using the coefficients, and determining as a blur level the proportion of edges, among the detected edges, in which the edge width is over a certain threshold;
• determining coordinates composed of first coefficient values and second coefficient values per block in a coordinate system in which the coordinate axes are first coefficient values representing frequency components in a first direction in the blocks and second coefficient values representing frequency components in a second direction perpendicular to the first direction in the blocks, and calculating an extent of bias in the distribution of the coordinates as the ellipticity;
• and
• determining whether blurring in the image has been produced by camera shake based on the relationship between the blur level and the ellipticity.

A computer program product for determining whether or not blurring in an image has been produced by camera shake, the computer program product comprising:

• a non-transitory computer readable medium;
• and
• a computer program stored on the non-transitory computer readable medium, the computer program causing a computer to implement the functions of:
• referencing image data in which has been recorded, per block unit, coefficients that are obtained when pixel values forming an image in a spatial domain are converted to a frequency domain per block unit composed of a plurality of pixels;
• detecting whether edges are included per block unit using the coefficients, and determining as a blur level the proportion of edges, among the detected edges, in which the edge width is over a certain threshold;
• determining coordinates composed of first coefficient values and second coefficient values per block in a coordinate system in which the coordinate axes are first coefficient values representing frequency components in a first direction in the blocks and second coefficient values representing frequency components in a second direction perpendicular to the first direction in the blocks, and calculating an extent of bias in the distribution of the coordinates as the ellipticity;
• and
• determining whether blurring in the image has been produced by camera shake based on the relationship between the blur level and the ellipticity.