Image processing apparatus, image processing method, and storage medium for inspecting print product

1. An image processing apparatus comprising:

one or more processors that are configured to:

set, as a reference position shift amount, a first position shift amount between a reference image serving as a reference for inspection and a first read image obtained by reading a first print product;

calculate a second position shift amount between the reference image and a second read image obtained by reading a second print product which is different from the first print product;

determine presence/absence of a position shift in the second read image based on the reference position shift amount and the second position shift amount; and

determine presence/absence of a position shift in the first read image by comparing the first position shift amount with a value obtained by adding a maximum printing position shift amount to a threshold value.

2. The image processing apparatus according to claim 1 , wherein the first read image is a read image on a first page set in a print job.

3. The image processing apparatus according to claim 1 , wherein the one or more processors are further configured to determine the presence/absence of the position shift from a statistical value of position shift amounts from a first page to n-th page set in a print job, where n is a natural number.

4. The image processing apparatus according to claim 1 , wherein the first read image is an image having feature points the number of which is greater than a threshold, as a result of calculation of the feature points of the first read image.

5. The image processing apparatus according to claim 1 , wherein, among a plurality of the first read images, an image having a large number of feature points is notified to a user as a candidate image for the first read image.

6. The image processing apparatus according to claim 1 , wherein the first read image is an image set based on an instruction from a user.

7. The image processing apparatus according to claim 1 , wherein the one or more processors are further configured to determine presence/absence of a position shift in the second read image by subtracting the reference position shift amount from the second position shift amount.

8. An image processing method comprising:

setting, as a reference position shift amount, a first position shift amount between a reference image serving as a reference for inspection and a first read image obtained by reading a first print product;

calculating a second position shift amount between the reference image and a second read image obtained by reading a second print product which is different from the first print product;

determining presence/absence of a position shift in the second read image based on the reference position shift amount and the second position shift amount; and

determining presence/absence of a position shift in the first read image by comparing the first position shift amount with a value obtained by adding a maximum printing position shift amount to a threshold value.

9. A non-transitory computer-readable storage medium storing instructions that, when executed by a computer, cause the computer to perform an image processing method, the method comprising:

setting, as a reference position shift amount, a first position shift amount between a reference image serving as a reference for inspection and a first read image obtained by reading a first print product;

calculating a second position shift amount between the reference image and a second read image obtained by reading a second print product which is different from the first print product;

determining presence/absence of a position shift in the second read image based on the reference position shift amount and the second position shift amount; and

determining presence/absence of a position shift in the first read image by comparing the first position shift amount with a value obtained by adding a maximum printing position shift amount to a threshold value.