# US 11,445,087 B2 · Skew compensation based on scale factor

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- Number: US 11,445,087 B2
- Document ID: US11445087B2
- Status: Granted
- Kind: B2
- Application number: 17/278,375
- Filed: 2019-07-24
- Published: 2021-11-18
- Granted: 2022-09-13
- Earliest claimed: 2019-01-24
- Assignees: Hewlett-Packard Development Company, L.P.
- Applicants: Hewlett-Packard Development Company, L.P.
- Inventors: Eul Hwan Lee
- Web page: https://patentgrep.com/patent/US11445087B2

## CPC

- H04N 1/3877: {Image rotation}
- H04N 1/3878: {Skew detection or correction}
- G06T 3/40: Scaling of whole images or parts thereof, e.g. expanding or contracting
- H04N 1/00718: {Skew}
- H04N 1/393: Enlarging or reducing
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

An example image scanning device includes an image sensor to scan a manuscript, a memory, and a processor to generate a scan image corresponding to the manuscript, perform rotation processing for the generated scan image using a scale factor, perform scaling processing for the rotated scan image, and store the scale-processed scan image in the memory.

## Claims

### Claim 1

An image scanning device, comprising:
an image sensor to scan a manuscript;
a memory; and
a processor to:
generate a scan image corresponding to the manuscript,
perform rotation processing for the generated scan image using a scale factor,
perform scaling processing for the rotated scan image, and
store the scale-processed scan image in the memory.

### Claim 2 (depends on 1)

The image scanning device of claim 1, wherein the processor is to:
control the image sensor to scan the manuscript based on at least one of a scanning speed or an input scan resolution, and
perform the rotation processing for the scan image using the scale factor corresponding to the at least one of the scanning speed or the input scan resolution.

### Claim 3 (depends on 1)

The image scanning device of claim 1, wherein the processor is to:
calculate a second rotation angle using the generated scan image,
calculate a first rotation angle by taking into account the scale factor to the calculated second rotation angle, and
perform rotation processing for the scan image using the calculated first rotation angle and the scale factor.

### Claim 4 (depends on 3)

The image scanning device of claim 3, wherein the processor is to:
detect an upper line of the manuscript in the generated scan image, and
calculate the first rotation angle using an angle of the detected upper line.

### Claim 5 (depends on 1)

The image scanning device of claim 1, wherein the processor is to:
perform additional image processing for the rotated scan image, and
perform scaling processing for the scan image for which additional image processing is performed.

### Claim 6 (depends on 5)

The image scanning device of claim 5, wherein the additional image processing includes at least one of segmentation to distinguish attributes by pixels, color correction, smoothing, or sharpening.

### Claim 7 (depends on 1)

The image scanning device of claim 1, wherein the generated scan image has a resolution in a main scanning direction which is different from a resolution in a sub-scanning direction.

### Claim 8

A skew compensation method of an image scanning device, the method comprising:
generating a scan image;
performing rotation processing for the generated scan image using a scale factor;
performing scaling processing for the rotated scan image; and
storing the scale-processed scan image.

### Claim 9 (depends on 8)

The skew compensation method of claim 8,
wherein the generating comprises scanning a manuscript based on at least one of a scanning speed or an input scan resolution and generating the scan image, and
wherein the performing of the rotation processing comprises performing rotation processing for the scan image using the scale factor corresponding to the at least one of the scanning speed or the input scan resolution.

### Claim 10 (depends on 8)

The skew compensation method of claim 8, wherein the performing of the rotation processing comprises:
calculating a second rotation angle using the generated scan image;
calculating a first rotation angle in consideration of the scale factor to the calculated second rotation angle; and
performing rotation processing for the scan image using the calculated first rotation angle and the scale factor.

### Claim 11 (depends on 10)

The skew compensation method of claim 10, wherein the calculating of the first rotation angle comprises:
detecting an upper line of a manuscript in the generated scan image and calculating the first rotation angle using an angle of the detected upper line.

### Claim 12 (depends on 8)

The skew compensation method of claim 8, further comprising:
performing additional image processing for the rotated scan image,
wherein the performing of the scaling processing comprises performing a scaling operation for the scan image for which additional image processing is performed.

### Claim 13 (depends on 12)

The skew compensation method of claim 12, wherein the additional image processing includes at least one of segmentation to distinguish attributes by pixels, color correction, smoothing, or sharpening.

### Claim 14 (depends on 8)

The skew compensation method of claim 8, wherein the generated scan image has a resolution in a main scanning direction which is different from a resolution in a sub-scanning direction.

### Claim 15

A non-transitory computer-readable recording medium including a program for executing a skew compensation method, the non-transitory computer-readable recording medium comprising:
instructions to perform rotation processing for a scan image using a scale factor;
instructions to perform scaling processing for the rotated scan image; and
instructions to store the scale-processed scan image.