Print inspection apparatus, printing system, method of inspecting print data and program
View Patent ↗A sharpness conversion part is provided in a print inspection apparatus and performs an average-masking operation to weaken a sharpness of object image data to be inspected and that of reference image data. After that, a differential value between these data is acquired. With this operation, an inspection for printing is performed by using image data of which the difference is distinguishable by human's visual property, not considering an invisible differential value which is caused by pixel displacement in subpixel order, and it is therefore possible to efficiently obtain a print inspection result with an accuracy almost as high as that by visual inspection. Thus, a print inspection apparatus can be provided, which is capable of correctly extracting difference to be detected by visual check.
1. A print inspection apparatus, comprising:
an image sharpness conversion element for weakening an image sharpness of inspection object data which is acquired in a processing on print image data and that of reference data which represents an image condition as a reference for comparison with said inspection object data by performing an average-masking operation on pixels constituting said inspection object data and pixels constituting said reference data on the basis of a predetermined mask size, respectively;
a comparison element for comparing said inspection object data and said reference data with each other after weakening their respective image sharpnesses, thereby generating comparison result data which describes a difference between a tone value of the said object image data and that of said reference image data by pixel; and
a judgment element for judging whether said difference is significant or not in accordance with a predetermined judgment parameter, thereby generating inspection result data which represents a result of judgment.
2. A method of performing an inspection for printing, comprising the steps of:
(a) weakening an image sharpness of inspection object data which is acquired in a processing on print image data and that of reference data which represents an image condition as a reference for comparison with said inspection object data by performing an average-masking operation on pixels constituting said inspection object data and pixels constituting said reference data on the basis of a predetermined mask size, respectively;
(b) comparing said inspection object data and said reference data with each other after weakening their respective image sharpnesses, thereby generating comparison result data which describes a difference between a tone value of the said object image data and that of said reference image data by pixel; and
(c) judging whether said difference is significant or not in accordance with a predetermined judgment parameter, thereby generating inspection result data which represents a result of judgment.
3. A printing system which generates print image data and performs at least one of plate making and output on the basis of said print image data, comprising:
(a) a print inspection apparatus for performing an inspection of said print image data, which comprises
(a-1) an image sharpness conversion element for weakening an image sharpness of inspection object data which is acquired in a processing on said print image data and that of reference data which represents an image condition as a reference for comparison with said inspection object data by performing an average-masking operation on pixels constituting said inspection object data and pixels constituting said reference data on the basis of a predetermined mask size, respectively;
(a-2) a comparison element for comparing said inspection object data and said reference data with each other after converting their respective image sharpnesses, thereby generating comparison result data which describes a difference between a tone value of the said object image data and that of said reference image data by pixel, and
(a-3) a judgment element for judging whether said difference is significant or not in accordance with a predetermined judgment parameter, thereby generating inspection result data which represents a result of judgment.
4. The printing system according to claim 3 , further comprising:
(b) an image reader capable of reading at least one of images for a printing plate, a plate-making making film and a printed matter,
wherein image data acquired by said image reader becomes at least one of said inspection object data and said reference data.
5. A program stored in and executed by a computer to cause said computer to function as a print inspection apparatus comprising:
an image sharpness conversion element for weakening an image sharpness of inspection object data which is acquired in a processing on print image data and that of reference data which represents an image condition as a reference for comparison with said inspection object data by performing an average-masking operation on pixels constituting said inspection object data and pixels constituting said reference data on the basis of a predetermined mask size, respectively;
a comparison element for comparing said inspection object data and said reference data with each other after weakening their respective image sharpnesses, thereby generating comparison result data which describes a difference between a tone value of the said object image data and that of said reference image data by pixel; and
a judgment element for judging whether said difference is significant or not in accordance with a predetermined judgment parameter, thereby generating inspection result data which represents a result of judgment.