US-12620082-B2 - Inspection apparatus and method for calibrating inspection apparatus

US12620082B2US 12620082 B2US12620082 B2US 12620082B2US-12620082-B2

Abstract

An inspection apparatus includes a support, an image capturing unit, and a controller. The support supports a workpiece. The image capturing unit generates captured image data including an image of the workpiece. The controller executes image processing on the captured image data to evaluate the workpiece. The support includes an engraved portion, including a groove and serving as a reference for inspection, on a surface of the support in a non-contact region that is free from contact with the workpiece. The engraved portion is included in an image capturing range of the image capturing unit. The controller evaluates the workpiece using a dimension of the engraved portion that is stored in the controller in advance and a reference image that is an image of the engraved portion.

Inventors

Masakazu Umehara
Shingo Mori
Naoya Kishimoto

Assignees

Toyota Battery Co., Ltd.
TOYOTA JIDOSHA KABUSHIKI KAISHA
Prime Planet Energy & Solutions, Inc.

Dates

Publication Date: 20260505
Application Date: 20230718
Priority Date: 20220722

Claims (8)

1 . An inspection apparatus, comprising: a support that supports a workpiece; an image capturing unit that generates captured image data including an image of the workpiece; and a controller that executes image processing on the captured image data to evaluate the workpiece; wherein the support includes an engraved portion, including a groove and serving as a reference for inspection of the workpiece, on a surface of the support in a non-contact region that is free from contact with the workpiece, wherein the groove of the engraved portion includes grooves shaped to form a pattern of regular polygons, the regular polygons are identical in shape, and the regular polygons are arranged next to one another in a first direction and a second direction orthogonal to the first direction, the engraved portion is included in an image capturing range of the image capturing unit, and the controller evaluates the workpiece using a dimension of the engraved portion that is stored in the controller in advance and a reference image that is an image of the engraved portion.
2 . The inspection apparatus according to claim 1 , wherein the support is a conveyor roller, and the engraved portion is formed at an end, in an axial direction, of the conveyor roller.
3 . The inspection apparatus according to claim 1 , wherein the groove of the engraved portion includes grooves extending diagonally to a first direction and a second direction orthogonal to the first direction.
4 . The inspection apparatus according to claim 1 , wherein the support is a conveyor roller, and the engraved portion extends continuously over the conveyor roller in a circumferential direction of the conveyor roller.
5 . The inspection apparatus according to claim 1 , wherein the support is a conveyor roller, and the engraved portion is formed in a number of positions in a circumferential direction of the conveyor roller.
6 . The inspection apparatus according to claim 1 , further comprising a lighting device that emits inspection light toward the workpiece and the support from a plurality of directions, wherein the engraved portion diffuses the inspection light emitted from the plurality of directions, and the controller detects, using the captured image data, the reference image that has a region with a lower tone than other regions.
7 . A method for calibrating an inspection apparatus, wherein: the inspection apparatus includes a support that supports a workpiece, an image capturing unit that generates captured image data including an image of the workpiece, and a controller that executes image processing on the captured image data to evaluate the workpiece, the method comprising: providing an engraved portion, including a groove and serving as a reference for inspection of the workpiece, on a surface of the support in a non-contact region that is free from contact with the workpiece, wherein the groove of the engraved portion includes grooves shaped to form a pattern of regular polygons, the regular polygons are identical in shape, the regular polygons are arranged next to one another in a first direction and a second direction orthogonal to the first direction, and the engraved portion is included in an image capturing range of the image capturing unit; and evaluating, by the controller, the workpiece using a dimension of the engraved portion and a reference image that is an image of the engraved portion.
8 . A method for calibrating an inspection apparatus, wherein: the inspection apparatus includes a support that supports a workpiece, an image capturing unit that generates captured image data including an image of the workpiece, and a controller that executes image processing on the captured image data to evaluate the workpiece; and the support includes an engraved portion, including a groove and serving as a reference for inspection of the workpiece, on a surface of the support in a non-contact region that is free from contact with the workpiece, and the engraved portion is included in an image capturing range of the image capturing unit; the method comprising: detecting, by the controller, a reference image that is an image of the engraved portion; identifying, by the controller, a dimension corresponding to one pixel in the captured image using a number of pixels in the reference image and an actual dimension of the engraved portion stored in the controller in advance; and evaluating, by the controller, the workpiece using the identified dimension.

Description

BACKGROUND 1. Field The following description relates to an inspection apparatus and a method for calibrating an inspection apparatus. 2. Description of Related Art An optical apparatus is used to, for example, find defects in a mixture layer formed from an electrode paste, find wrinkles formed in a current collector, measure the width of the mixture layer, and the like (for example, refer to WO2010/082335). An example of such an inspection apparatus captures an image of an electrode sheet and processes the captured image. This type of inspection apparatus may include a reference mark on a roller that conveys a workpiece. The inspection apparatus uses the reference mark to perform calibration of the inspection apparatus. The actual size of the reference mark is stored in the inspection apparatus in advance. The inspection apparatus captures an image of the reference mark and performs image processing on the captured image data to determine the number of pixels that corresponds to the image of the reference mark. Then, the inspection apparatus compares the number of pixels corresponding to the image of the reference mark with the actual size of the reference mark to determine the size of one pixel. Subsequently, the pixel size is applied to the image of the mixture layer or the workpiece, captured by the image capturing unit, to measure the width of the mixture layer, find defects in the mixture layer, and other evaluations. A sticker is used as the reference mark of the roller. SUMMARY When a sticker is applied to the roller, a step forms between the sticker and the roller surface. The step may cast a shadow. To avoid the formation of such a shadow, the sticker needs to be positioned immediately below a lighting device. However, the region immediately below the lighting device is used to convey a workpiece. Thus, the workpiece will have to be removed from this region before capturing an image of the sticker with the image capturing unit. Further, if the sticker, which has a thickness, is left on the roller during inspection, the sticker will come into contact with the workpiece. Thus, the sticker may form a scratch or impression in the workpiece. In particular, when the workpiece is an electrode sheet of which the base material is a metal foil, the sticker may contact the metal foil and forms an impression in the metal foil. Thus, the sticker cannot be left on the roller when performing inspection, and the sticker will need to be removed from the roller after an image of the sticker is captured. As described above, the generation of an image of the reference mark is troublesome. This decreases the frequency for calibrating the inspection apparatus with an image of the reference. This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. In one general aspect, an inspection apparatus includes a support, an image capturing unit, and a controller. The support supports a workpiece. The image capturing unit generates captured image data including an image of the workpiece. The controller executes image processing on the captured image data to evaluate the workpiece. The support includes an engraved portion, including a groove and serving as a reference for inspection, on a surface of the support in a non-contact region that is free from contact with the workpiece. The engraved portion is included in an image capturing range of the image capturing unit. The controller evaluates the workpiece using a dimension of the engraved portion stored in the controller in advance and a reference image that is an image of the engraved portion. In another general aspect, in a method for calibrating an inspection apparatus, the inspection apparatus includes a support, an image capturing unit, and a controller. The support supports a workpiece. The image capturing unit generates captured image data including an image of the workpiece. The controller executes image processing on the captured image data to evaluate the workpiece. The support includes an engraved portion, including a groove and serving as a reference for inspection, on a surface of the support in a non-contact region that is free from contact with the workpiece. The method includes capturing an image of the engraved portion with the image capturing unit to generate a reference image, and evaluating the workpiece using a dimension of the engraved portion and the reference image that is an image of the engraved portion. In the above inspection apparatus, the support may be a conveyor roller. The engraved portion may be formed at an end, in an axial direction, of the conveyor roller. In the above inspection apparatus, the groove of the engraved portion may include grooves arranged nex