Method for inspecting image

Claim 2

A printed image inspection method of the type in which image data derived from a sample print are compared with image data derived from a reference print and stored in a memory means, characterized by: preparing a plurality of data by shifting by one picture element unit within a tolerable range either of sample row data derived from each row of said sample print or reference row data stored in said memory means; comparing said sample row data and said reference row data by means of said plurality of data; and determining whether said sample print is acceptable or not depending upon whether or not the minimum value of a level difference between said sample row data and said reference row data.

Claim 3

A printed image inspection method as set forth in Claim 1 wherein a special level tolerance or allowance is set for the edges of said sample print.

Claim 4

A printed image inspection method as set forth in Claim 1 wherein said sample row data and said reference row data are shifted by one picture element in the widthwise direction and compared with each other; in response to the positional deviation between said two data when said two data are most closely coincident with each other, said sample row data or said reference row data are compensated for the positional deviation in the widthwise direction of said print; and said reference row data is compared with the other one of said sample row data and said reference row data.

Claim 5

A printed image inspection mehtod as set forth in Claim 1 wherein a plurality of data are prepared by shifting by a picture element unit either said sample row data derived from each line of said sample print or said sample row data stored in said memory means; said sample row data and said reference row data are compared in level with each other by using said plurality of data; the deviation between said two data is obtained when the difference in level between said two data becomes minimum; and in response to said deviation thus obtained, the address of either of said sample row data or said reference row data is corrected.

Claim 6

A printed image inspection method as set forth in Claim 1 wherein either of said sample row data derived from each row of said sample print or said reference row data is shifted by one picture element unit with respect to each other, whereby a plurality of data are prepared; said sample row data and said reference row data are compared in level with each other by using said plurality of data; whether said sample print is acceptable or not is determined depending on the relationship of the difference in level between said sample row data and said reference row data with a fixed value, a value obtained by multiplying said reference row data by a predetermined constant or a difference in level of density at a portion where the density abruptly changes; the deviation between said two data is obtained in response to the positional relationship between said two data when said difference in level becomes minimum; and in response to said deviation thus obtained, the address of either of said two data is corrected.

Claim 7

A printed image inspection method of the type in which the image of a sample print is divided into a plurality of picture elements in the form of a matrix and the density of each picture element of said sample print is compared with the density of each picture element of a reference print, whereby defective picture elements of said sample print are detected, characterized by: setting a plurality of combinations each consisting of a tolerance for graduation difference between a reference picture element and a sample picture element and a tolerance for defective picture elements which exceed said first mentioned tolerance; and determining that said sample print has defects or is unacceptable if one or more of said plurality of combinations are found.

Claim 8

A printed image inspection method of the type in which the image of a sample print is divided into a plurality of picture elements in the form of a matrix and the density of each picture element of said sample print is compared with the density of each picture element of a reference print, whereby defective picture elements of said sample print are detected, characterized by: setting a plurality of combinations each consisting of a tolerance for graduation difference between a reference picture element and a sample picture element and a tolerance for defective picture elements which exceed said first mentioned tolerance; and determining that said sample print has defects or is unacceptable if one or more of said plurality of combinations are found.

Claim 9

A printed image inspection device comprising: a sync signal generating means for generating sync signals in response to the transport of a print; a camera for scanning the image on said print in response to said sync signals derived from said sync signal generating means, thereby obtaining the image information; a reference row data memory means in which is stored the image information derived from a reference print by means of said camera; and a decision circuit for preparing a plurality of data each representing an expected deviation of said print by shifting by one or more picture elements either sample row data derived from said camera or the data derived from said reference row data memory means and for comparing said reference row data with said sample row data by using said plurality of data.

Claim 10

A printed image inspection device comprising: a sync signal generating means for generating sync signals in response to the transport of a print; a camera for scanning the image on said print in response to said sync signals derived from said sync signal generating means, thereby obtaining the image information; a reference row data memory means in which is stored the image information derived from a reference print by means of said camera; and a decision circuit for preparing a plurality of data each representing an expected deviation of said print by shifting by one or more picture elements either sample row data derived from said camera or the data derived from said reference row data memory means and for comparing said reference row data with said sample row data by using said plurality of data.

Claim 11

A printed image inspection device comprising: a sync signal generating means for generating sync signals in response to the transport of a print; a camera for scanning the image on said print in response to said sync signals drived from said sync signal generating means, thereby obtaining the image information; a reference data memory means in which is stored the image information derived from a reference print by means of said camera; a first circuit for shifting by one or more picture elements the sample data derived from said camera and the data derived from said reference data memory means with respect to each other in the widthwise direction, whereby a deviation at which said two data most closely coincide with each other is obtained; and a second circuit for compensating for the deviation in response to the output from said first circuit and comparing said two data one picture element by one picture element, thereby determining whether or not the image of a sample print is acceptable.

Claim 12

A printed image inspection device comprising: a sync signal generating means for generating sync signals in response to the transport of a print; a camera for scanning the image on said print in response to said sync signals drived from said sync signal generating means, thereby obtaining the image information; a reference data memory means in which is stored the image information derived from a reference print by means of said camera; a first circuit for shifting by one or more picture elements the sample data derived from said camera and the data derived from said reference data memory means with respect to each other in the widthwise direction, whereby a deviation at which said two data most closely coincide with each other is obtained; and a second circuit for compensating for the deviation in response to the output from said first circuit and comparing said two data one picture element by one picture element, thereby determining whether or not the image of a sample print is acceptable.

Claim 13

A printed image inspection device comprising: a sync signal generating means for generating sync signals in response to the transport of a print; a camera for scanning the image on said print in response to said sync signals derived from said sync signal generating means, thereby obtaining the image information; a reference picture data memory means in which is stored the image information derived from a reference print by means of said camera; a decision-level setting circuit for selecting one of a plurality of predetermined decision levels and setting the level of the image information of each picture element read out from said reference picture element data memory means in response to said selected decision level; a decision circuit for comparing in level between the image information derived from said decision level setting circuit and the image information of a sample print derived by said camera, thereby determining whether the image has defects or not; and an address correction circuit for generating an address signal for reading out the contents in said reference picture element data memory in response to the output from said sync signal generating means and for correcting said address signal in response to the output from said decision circuit.

Claim 14

A printed image inspection device comprising: a sync signal generating means for generating sync signals in response to the transport of a print; a camera for scanning the image on said print in response to said sync signals derived from said sync signal generating means, thereby obtaining the image information; a reference picture data memory means in which is stored the image information derived from a reference print by means of said camera; a decision-level setting circuit for selecting one of a plurality of predetermined decision levels and setting the level of the image information of each picture element read out from said reference picture element data memory means in response to said selected decision level; a decision circuit for comparing in level between the image information derived from said decision level setting circuit and the image information of a sample print derived by said camera, thereby determining whether the image has defects or not; and an address correction circuit for generating an address signal for reading out the contents in said reference picture element data memory in response to the output from said sync signal generating means and for correcting said address signal in response to the output from said decision circuit.

Claim 15

A printed image inspection device comprising: a sync signal generating means for generating sync signals in response to the transport of a print; a camera for scanning the image on said print in response to said sync signals derived from said sync signal generating means, thereby obtaining the image information; a memory means in which is stored the image information derived from a reference print by means of said camera; and a decision circuit which has a plurality of decision elements each of which is set with a first tolerance for graduation difference between a sample picture element and a reference picture element and a second tolerance for defective picture elements in excess of said first tolerance and which delivers a defective signal when one or more of said decision elements-determine that the image information of a sample print derived from said camera has defects.

Claim 16

A printed image inspection device comprising: a sync signal generating means for generating sync signals in response to the transport of a print; a camera for scanning the image on said print in response to said sync signals derived from said sync signal generating means, thereby obtaining the image information; a memory means in which is stored the image information derived from a reference print by means of said camera; and a decision circuit which has a plurality of decision elements each of which is set with a first tolerance for graduation difference between a sample picture element and a reference picture element and a second tolerance for defective picture elements in excess of said first tolerance and which delivers a defective signal when one or more of said decision elements-determine that the image information of a sample print derived from said camera has defects.