# US 7,609,892 B2 · Image processing method, image processing system, and image processing program

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- Number: US 7,609,892 B2
- Document ID: US7609892B2
- Status: Granted
- Kind: B2
- Application number: 11/922,013
- Filed: 2006-07-12
- Published: 2009-01-29
- Granted: 2009-10-27
- Earliest claimed: 2005-08-19
- Assignees: Panasonic Corporation
- Inventors: Satoshi Sato; Kunio Nobori; Katsuhiro Kanamori
- Web page: https://patentgrep.com/patent/US7609892B2

## CPC

- H04N 23/70: Circuitry for compensating brightness variation in the scene
- G01B 11/2433: {for measuring outlines by shadow casting}
- G06T 5/90: Dynamic range modification of images or parts thereof
- G06T 7/11: Region-based segmentation
- G06T 7/174: involving the use of two or more images
- G06T 7/42: using transform domain methods
- G06T 2207/10152: Varying illumination
- G06T 2207/20056: Discrete and fast Fourier transform, [DFT, FFT]
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

The process captures a plurality of images under a light source whose luminance varies over time, such as a fluorescent lamp, under such an imaging condition that a plurality of images that are different from one another in terms of light source conditions can be captured (S11). The process detects a temporal luminance variation from the plurality of captured images (S12), estimates a shadow area by using the temporal luminance variation (S13), and performs an image process such as a process of synthesizing a linearized image or an image segmentation based on optical characteristics (S14).

## Claims

### Claim 1

An image processing method performed by a processor, comprising:
an imaging step of imaging a same object a plurality of times by means of an imaging device under a light source whose luminance varies over time under such an imaging condition that a plurality of images that are different from one another in terms of light source conditions can be imaged; and
an image processing step of performing an image process by using a plurality of images imaged in the imaging step,
wherein the image processing step includes:
a step of detecting a temporal luminance variation from the plurality of images;
a step of estimating a shadow area in the plurality of images by using the detected temporal luminance variation; and
a step of performing an image segmentation based on optical characteristics by using information of the estimated shadow area and the plurality of images.

### Claim 2 (depends on 1)

The image processing method of claim 1, wherein:
the light source is a light source whose luminance varies periodically; and
an exposure time that is sufficiently short with respect to a luminance variation cycle of the light source is set as the imaging condition.

### Claim 3 (depends on 1)

The image processing method of claim 1, wherein the light source is a fluorescent lamp, an LED or a display.

### Claim 4 (depends on 1)

The image processing method of claim 1, wherein the imaging condition is at least one of an exposure time, an imaging timing and an imaging cycle.

### Claim 5 (depends on 1)

The image processing method of claim 1, comprising:
a step of obtaining light source information of the light source; and
a step of determining the imaging condition based on the obtained light source information.

### Claim 6 (depends on 5)

The image processing method of claim 5, wherein the light source information is at least one of a luminance variation cycle, a luminance variation range and position information of the light source.

### Claim 7

An image processing program residing on computer-readable memory being a program for instructing a computer to perform an image process, wherein the program instructs the computer to perform:
an imaging step of imaging a same object a plurality of times by means of an imaging device under a light source whose luminance varies over time under such an imaging condition that a plurality of images that are different from one another in terms of light source conditions can be imaged; and
an image processing step of performing an image process by using a plurality of images imaged in the imaging step,
wherein the image processing step includes:
a step of detecting a temporal luminance variation from the plurality of images;
a step of estimating a shadow area in the plurality of images by using the detected temporal luminance variation; and
a step of performing an image segmentation based on optical characteristics by using information of the estimated shadow area and the plurality of images.