SEPARATION FILTER SELECTION DEVICE AND TIRE INSPECTION DEVICE

• US 20100026799A1
• Filed: 10/19/2007
• Published: 02/04/2010
• Est. Priority Date: 10/27/2006
• Status: Active Grant

• Current Assignee: Bridgestone Corporation
• Original Assignee: Bridgestone Corporation
• Inventors: Mizuno, Tomohiro, Iino, Hirotaka, Togii, Akira, Fujisawa, Yoshitaka, Mizutani, Akinobu
• Granted Patent: US 8,305,436 B2
• Time in Patent Office: Days
• US Class Current: 348/92
• CPC Class Codes: G01M 17/027 using light, e.g. infrared, ultraviolet or holographic techniques
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: G06T 7/001 using an image reference approach

Abstract

A separation filter selection device provided with an image input unit, a memory unit, a setting unit, an evaluation unit and a separation filter selection unit is disclosed. The image input unit inputs a captured image capturing a tire surface including a characteristic portion thereof. The memory unit stores plural filters for performing image processing of the captured image, stores a training image in which the characteristic portion is separated from the captured image, and a weighted image in which a weighting is set to a predetermined region of the captured image. The setting unit combines two or more filters out of the plural filters and sets a separation filter. The evaluation unit derives an evaluation value of the separation filter on the basis of an image in which a differential between the processed image that has been processed by each of the filters of the separation filter, and the training image, and to which a weighting based on the weighted image is applied. The separation filter selection unit repeats the setting of the setting unit and the evaluation value computation of the evaluation unit until the evaluation value is within a specific range, and selects the separation filter corresponding to the evaluation value resulting from the repeated processing as a separation filter for separating the characteristic portion from the captured image.

Claims

1. A separation filter selection device comprising:

an image input unit for inputting a captured image of a tire surface, the image including a characteristic portion;

a memory unit for storing a plurality of filters for performing image processing of the captured image, storing a predetermined training image that corresponds to an image in which the characteristic portion has been separated from the captured image and that corresponds to an image resulting from image processing of the captured image using the plurality of filters, and storing a weighted image in which a weighting is set to a predetermined region of the captured image;

a setting unit for setting as a separation filter a filter group combining two or more filters from the plurality of filters stored in the memory unit;

an evaluation unit for performing image processing of the captured image with each of the two or more filters of the separation filter, and calculating an evaluation value of the separation filter on the basis of an image that is a differential image between a processed image after image processing and the training image and to which a weighting based on the weighted image is applied; and

a separation filter selection unit for repeating the setting of the setting unit and the evaluation value calculation of the evaluation unit until the evaluation value is within a predetermined specific range, and selecting a separation filter corresponding to the evaluation value resulting from the repeated calculation as a separation filter for separating the characteristic portion from the captured image.

2. The separation filter selection device of claim 1, wherein:

the memory unit also stores a predetermined weighting coefficient that corresponds to the number of filters in the separation filter; and

the evaluation unit derives the evaluation value of the filter group on the basis of the differential image to which the weighting according to the weighted image is applied and of the weighting coefficient corresponding to the number of filters in the set separation filter.

3. The separation filter selection device of claim 1, wherein the separation filter selection unit treats the evaluation value as being within a specific range after a specific number of repetitions have been carried out, and ends the repetition.

4. The separation filter selection device of claim 2, wherein the separation filter selection unit treats the evaluation value as being within a specific range after a specific number of repetitions have been carried out and ends the repetition

5. The separation filter selection device of claim 1, wherein:

the setting unit sets a filter group including an array of filters as the separation filter; and

the evaluation unit performs image processing of the captured image in accordance with the filter array sequence of the set separation filter.

6. The separation filter selection device of claim 2, wherein:

the setting unit sets a filter group including an array of filters as the separation filter; and

the evaluation unit performs image processing of the captured image in accordance with the filter array sequence of the set separation filter.

7. The separation filter selection device of claim 3, wherein:

the setting unit sets a filter group including an array of filters as the separation filter; and

the evaluation unit performs image processing of the captured image in accordance with the filter array sequence of the set separation filter.

8. The separation filter selection device of claim 5, wherein:

the setting unit sets a selected separation filter group comprising a first separation filter and a second separation filter as the separation filter, and adds, to the selected separation filter group, a new separation filter generated by crossing the first separation filter with the second separation filter at a specific probability, and/or a new separation filter generated by modifying at least one filter of at least one separation filter included in the selected separation filter group as another filter at a specific probability;

the evaluation unit performs image processing of the captured image with each of the separation filters included in the selected separation filter group, and calculates evaluation values for each of the separation filters; and

the separation filter selection unit selects, as a selected separation filter group to be used next time in the setting unit, a first separation filter and a second separation filter based on each of the evaluation values calculated by the evaluation unit, repeats the setting of the setting unit and the evaluation value calculation of the evaluation unit for the next selected separation filter group a prescribed number of times, and selects the separation filter based on the evaluation value resulting from the repeated calculation.

9. The separation filter selection device of claim 8, wherein the separation filter selection unit sets the selected separation filter group to be used next time in the setting unit such that the first separation filter and the second separation filter are selected at a probability corresponding to the size of each of the evaluation values derived by the evaluation unit.

10. The separation filter selection device of claim 8, wherein the separation filter selection unit sets the selected separation filter group to be used next time in the setting unit such that the separation filter with the largest evaluation value derived by the evaluation unit is selected as the first separation filter or as the second separation filter.

11. The separation filter selection device of claim 9, wherein the separation filter selection unit sets the selected separation filter group to be used next time in the setting unit such that the separation filter with the largest evaluation value derived by the evaluation unit is selected as the first separation filter or as the second separation filter.

12. A tire inspection device comprising:

a memory unit for storing an array of the separation filters selected by the separation filter selection device of claim 1 and for storing filters configuring the separation filters;

an imaging unit for imaging the surface of a tire;

an image processing unit for performing image processing of an image captured by the imaging unit in accordance with the separation filters stored in the memory unit; and

a display unit for displaying results of the processing by the image processing unit.

13. A tire inspection device comprising:

a memory unit for storing an array of the separation filters selected by the separation filter selection device of claim 2 and for storing filters configuring the separation filters;

an imaging unit for imaging the surface of a tire;

an image processing unit for performing image processing of an image captured by the imaging unit in accordance with the separation filters stored in the memory unit; and

a display unit for displaying results of the processing by the image processing unit.

14. A tire inspection device comprising:

a memory unit for storing an array of the separation filters selected by the separation filter selection device of claim 3 and for storing filters configuring the separation filters;

an imaging unit for imaging the surface of a tire;

an image processing unit for performing image processing of an image captured by the imaging unit in accordance with the separation filters stored in the memory unit; and

a display unit for displaying results of the processing by the image processing unit.

15. A tire inspection device comprising:

a memory unit for storing an array of the separation filters selected by the separation filter selection device of claim 5 and for storing filters configuring the separation filters;

an imaging unit for imaging the surface of a tire;

an image processing unit for performing image processing of an image captured by the imaging unit in accordance with the separation filters stored in the memory unit; and

a display unit for displaying results of the processing by the image processing unit.

16. A tire inspection device comprising:

a memory unit for storing an array of the separation filters selected by the separation filter selection device of claim 8 and for storing filters configuring the separation filters;

an imaging unit for imaging the surface of a tire;

an image processing unit for performing image processing of an image captured by the imaging unit in accordance with the separation filters stored in the memory unit; and

a display unit for displaying results of the processing by the image processing unit.

17. A tire inspection device comprising:

a memory unit for storing an array of the separation filters selected by the separation filter selection device of claim 9 and for storing filters configuring the separation filters;

an imaging unit for imaging the surface of a tire;

an image processing unit for performing image processing of an image captured by the imaging unit in accordance with the separation filters stored in the memory unit; and

a display unit for displaying results of the processing by the image processing unit.

18. A tire inspection device comprising:

a memory unit for storing an array of the separation filters selected by the separation filter selection device of claim 11 and for storing filters configuring the separation filters;

an imaging unit for imaging the surface of a tire;

an image processing unit for performing image processing of an image captured by the imaging unit in accordance with the separation filters stored in the memory unit; and

a display unit for displaying results of the processing by the image processing unit.