CN-121994454-A - Position shift/focus shift detection system

Abstract

The invention aims to accurately detect the position deviation and focus deviation of a camera. The positional deviation/focus deviation detection system includes a detection unit that detects whether or not there is a positional deviation of the camera in a captured image captured by the camera with a mark having a circular outline shape, and a focus deviation determination unit that calculates a shade ratio of a focus confirmation target included in the captured image of the camera when the detection unit detects that there is no positional deviation of the camera, and determines a focus deviation based on the shade ratio.

Inventors

• Liu Laidajiang

Assignees

• 丰田自动车株式会社

Dates

Publication Date

20260508

Application Date

20251016

Priority Date

20241101

Claims (4)

1. 1. A positional deviation/focus deviation detection system that detects a focus deviation of a camera, the positional deviation/focus deviation detection system characterized by comprising: A detection part for detecting whether the camera has position deviation, and And a focus offset determination unit that calculates a shade ratio of a focus checking target included in a captured image of the camera when the detection unit detects that there is no positional offset of the camera, and determines a focus offset based on the shade ratio.
2. 2. The positional deviation/focal deviation detecting system according to claim 1, further comprising: a judging unit that judges whether the outline shape of the mark image is a circle or an ellipse in the photographed image of the mark whose outline shape is a circle, The detection unit uses the positions of 2 focuses of the ellipse for matrix calculation when the outline shape of the marker image is an ellipse, and detects whether the camera is shifted or not when the outline shape of the marker image is a circle.
3. 3. The positional deviation/focal deviation detecting system according to claim 2, characterized by having: A correction unit that corrects distortion of the photographed image, The determination unit determines whether the outline shape of the marked image of the mark is a circle or an ellipse in the photographed image corrected for distortion by the correction unit.
4. 4. The positional deviation/focal deviation detecting system according to claim 3, wherein, The correction unit acquires the photographed image again when the detection unit detects that there is no positional deviation of the camera, and calculates the shade ratio of the focus checking optotype after correction by the correction unit.

Description

Position shift/focus shift detection system Technical Field The present invention relates to a positional shift/focus shift detection system that detects positional shift/focus shift of a camera. Background An inspection apparatus for inspecting a subject, for example, a defect inspection apparatus for inspecting a defect of an object (for example, a casting) is mounted with a camera for capturing an image (for example, refer to patent document 1). Patent document 1 Japanese patent application laid-open No. 2011-119930 Disclosure of Invention The camera mounted on the defect inspection apparatus needs to be accurately aligned with respect to the subject and accurately focused on the object. If the camera is displaced, the object cannot be accurately measured, and even when the inspection result is learned by machine learning, there is a problem that the number of learning sheets increases. If there is a focus shift, fine defects of the object cannot be clearly imaged, and the determination accuracy is deteriorated. The present invention aims to provide a positional shift/focus shift detection system capable of accurately detecting positional shift/focus shift of a camera. A positional deviation/focus deviation detection system includes a detection unit that detects whether or not a positional deviation of a camera is detected in a captured image captured by the camera of a mark having a circular outline, and a focus deviation determination unit that calculates a gradation ratio of a focus confirmation target included in the captured image of the camera when the detection unit detects that there is no positional deviation of the camera, and determines a focus deviation from the gradation ratio. According to this system, since the shift of the focal point is determined after it is determined that there is no positional shift of the camera, the shift of the focal point can be accurately determined, and the positional shift and the focal point shift of the camera can be reduced, thereby performing the measurement of the object with high accuracy. Drawings Fig. 1 is a schematic diagram showing an example of the configuration of a misalignment detection system according to an embodiment. Fig. 2 is a schematic diagram illustrating a method for determining the contour shape of the marker image 30. Fig. 3 is a schematic diagram illustrating a method of determining a positional shift of a camera based on a marker image. Fig. 4 is a schematic diagram illustrating correction of distortion. Fig. 5 is a schematic diagram for explaining a focus offset determination method. Fig. 6 is a flowchart showing an example of processing by the positional deviation detection system according to the embodiment. Detailed Description Hereinafter, this embodiment will be described with reference to the drawings. In the drawings, elements having the same function may be denoted by the same reference numerals. In addition, the drawings illustrate embodiments and examples in accordance with the principles of the present invention, but these are used in order to understand the invention and are not intended to limit the invention in any way. The description of the present invention is merely exemplary in nature and is in no way intended to limit the scope or applicability of the invention in any way as claimed. While the embodiment of the present invention has been described in detail in this embodiment, other embodiments are possible, and it is to be understood that the present invention can be modified in structure or replaced with various elements without departing from the scope and spirit of the technical idea of the present invention. Accordingly, the following description should not be construed as limiting the scope of the invention. Fig. 1 is a schematic diagram showing an example of the configuration of a positional deviation/focal point deviation detection system 1 according to an embodiment. In the lower part of fig. 1, an example of the observation field of view on the arrangement surface 5 of the object W as the determination target of the positional shift/focal shift is also shown. The positional deviation/focal point deviation detection system 1 is a system for detecting positional deviation/focal point deviation of a camera 2 mounted on an industrial robot or the like, for example. The positional deviation/focus deviation detection system 1 may be a computer provided with a central processing unit (Central Processing Unit: CPU), a field programmable gate array (Field Programmable GATE ARRAY: FPGA), an Application Specific Integrated Circuit (ASIC), or the like that analyzes the photographic image data Im captured by the camera 2. The camera 2 is mounted on a housing of an industrial robot, for example, and moves in a three-dimensional space with 6 degrees of freedom. The 6 degrees of freedom include 3 degrees of freedom in which the camera 2 rotates with each of the X axis, the Y axis, and the Z axis as a rotation center, i