Inspection apparatus

• US 20070265743A1
• Filed: 05/09/2007
• Published: 11/15/2007
• Est. Priority Date: 05/09/2006
• Status: Active Grant

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: Kojitani, Kazuto, Tasaki, Hiroshi, Nakajima, Hiroshi, Ito, Seiko
• Granted Patent: US 7,860,620 B2
• Time in Patent Office: Days
• US Class Current: 701/29
• CPC Class Codes: G06F 18/241 relating to the classification model, e.g. parametric or non-parametric approaches
• CPC Class Codes: G06F 18/2433 Single-class perspective, e.g. one-against-all classification; Novelty detection; Outlier detection
• CPC Class Codes: G06T 2207/30108 Industrial image inspection
• CPC Class Codes: G06T 7/0004 Industrial image inspection

Abstract

An inspection apparatus includes a discrimination function determination unit which determines whether or not a discrimination function forms an area including a discrimination sample. The discrimination function is used in non-parametric one-class discrimination. The discrimination sample is discriminated into a class as a single area in an input space where learning samples are plotted.

Claims

1. An inspection apparatus comprising:

a discrimination function determination unit that determines in an input space where learning samples are plotted, whether or not a discrimination function forms a single area,

wherein the area includes a discrimination sample discriminated into a class, and

wherein the discrimination function is used in non-parametric one-class discrimination.

2. An inspection apparatus according to claim 1, further comprising:

a parameter setting unit that sets an area parameter such that the discrimination function forms the single area, in the input space where learning samples are plotted, when the discrimination function determination unit determines that the discrimination function does not form the single area,

wherein the area parameter regulates a size of an area of a basis function,

wherein the basis function regulates the discrimination function, and

wherein the basis function becomes a basis of a density function.

3. An inspection apparatus according to claim 1, wherein a discrimination algorithm of the non-parametric one-class discrimination stores the discrimination sample on a discrimination plane in a model.

4. An inspection apparatus according to claim 1, wherein, when it is determined that discrimination samples are included in the single area, the discrimination function determination unit determines whether or not a line segment deviates from the single area,

wherein the line segment connects the discrimination samples.

5. An inspection apparatus according to claim 1, wherein, when it is determined that the discrimination sample is included in the single area with learning samples, the discrimination function determination unit determines whether or not a line segment deviates from the single area,

wherein the line segment connects a center of the learning samples and the discrimination sample.

6. An inspection apparatus according to claim 3, wherein, when discrimination samples are stored in the model, the discrimination function determination unit determines whether or not a line segment deviates from the single area, and

wherein the line segment connects the discrimination samples on a discrimination plane.

7. An inspection apparatus according to claim 3, wherein, when the discrimination sample and learning samples are stored in the model, the discrimination function determination unit determines whether or not a line segment deviates from the single area, and

wherein the line segment connects a center of the learning samples and the discrimination sample on the discrimination plane.

8. An inspection apparatus according to claim 4, wherein the discrimination function determination unit extracts one or a plurality of points from the line segment to apply the points to the discrimination function, and

wherein the discrimination function determination unit determines whether or not all the points are included in the single area.

9. An inspection apparatus according to claim 4, wherein the discrimination function determination unit obtains a minimum value of the discrimination function on the line segment to determine whether or not the minimum value is not lower than a predetermined threshold.

10. An inspection method performed by an inspection apparatus that decides a discrimination function used to discriminate a state of an inspection target, the inspection method comprising:

a step in which discrimination function determination unit determines in an input space where learning samples are plotted, whether or not a discrimination function forms a single area,

wherein the area includes a discrimination sample discriminated into a class, and

wherein the discrimination function is used in non-parametric one-class discrimination.

11. An inspection method according to claim 10, further comprising

a step in which a parameter setting unit included in the inspection apparatus sets an area parameter such that the discrimination function forms the single area, in the input space where learning samples are plotted, when the discrimination function determination unit determines that the discrimination function does not form the single area,

wherein the area parameter regulates a size of an area of a basis function,

wherein the basis function regulates the discrimination function to be used in the non-parametric one-class discrimination, and

wherein the basis function becomes a basis of a density function.

12. An inspection program which causes a computer to function as an inspection apparatus that decides a discrimination function used to discriminate a state of an inspection target,

wherein the inspection program causes the computer to execute a process to determine in an input space where learning samples are plotted, whether or not a discrimination function used in non-parameteric one-class discrimination forms a single area,

wherein the area includes a discrimination sample discriminated into a class.