JP2015075583A - Subject imaging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow focusing on a surface of a subject when imaging a product having a curved surface shape by use of a line scan camera in a subject imaging system.SOLUTION: An imaging system 10 includes: a line scan camera 14 that scans a product 12 having a curved surface shape to image a surface of the product 12; and a movement mechanism 16 that moves the line scan camera 14 to the product 12 to set a focal position of the line scan camera 14 on the surface of the product 12.

Description

  The present invention relates to an imaging system for a subject, and relates to an imaging system that scans a subject having a curved surface and images the surface of the subject.

  Some products produced on a production line have a curved shape. An image of such a product may be imaged, and it may be determined whether or not the product that is the subject is a non-defective product using the image data acquired thereby.

  As a technique related to the present invention, for example, in Patent Document 1, light is obliquely applied to an inspection surface, specular reflection light from the inspection surface is picked up and picked up. A surface curved surface inspection method for inspecting a surface curved surface by comparing a lightness value with a previously stored lightness value is disclosed.

Japanese Patent Laid-Open No. 2000-9492

  When imaging a product having a curved surface shape using a line scan camera, the line scan camera is scanned to image the entire product. In this case, the distance between the line scan camera and the surface of the product may change during scanning, resulting in out of focus.

  An object of the present invention is to provide a subject imaging system that can focus on the surface of a product when imaging a product having a curved shape using a line scan camera.

  An object imaging system according to the present invention includes a line scan unit that scans a subject having a curved surface to image the surface of the subject, and moves the line scan unit relative to the subject to move the line scan unit to the surface of the subject. And a moving mechanism for adjusting the focal position of the line scan unit.

  Further, in the subject imaging system according to the present invention, the subject is disposed on a reference plane parallel to a scanning plane defined by a longitudinal direction of the line scanning unit and a scanning direction orthogonal to the longitudinal direction, and the reference plane When the height of the line scanning unit is constant along the longitudinal direction of the line scanning unit and has the curved surface shape that varies along the scanning direction, the line scanning unit moves on the subject along the scanning direction. Scanning is preferred.

  In the subject imaging system according to the present invention, it is preferable that the line scan unit forms a two-dimensional image of the surface of the subject using scanned data.

  According to the present invention, the line scanning unit is moved with respect to the subject by the moving mechanism, and the focal position of the line scanning unit is adjusted to the surface of the subject. Thereby, it is possible to always focus when imaging the entire subject.

It is a figure showing an imaging system of an embodiment concerning the present invention. In embodiment which concerns on this invention, it is a figure which shows the positional relationship of a product and a line scan camera.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. Also, in the following, corresponding elements in all drawings are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a diagram illustrating an imaging system 10. 2 is a side view showing the positional relationship between the product 12 and the line scan camera 14. The lower view of FIG. 2 is a plan view of the upper view of FIG. The imaging system 10 scans a product 12 having a curved shape and images the surface of the product 12, and moves the line scan camera 14 relative to the product 12 to scan the surface of the product 12. And a moving mechanism 16 for adjusting the focal position of the camera 14.

  The product 12 is carried in a state where it is placed on the upper surface 20 of the belt conveyor 18. The belt conveyor 18 is a device that moves an endless wide belt that is spanned by two rotation driving units 19 that are driven by the control of the control unit 22. The upper surface 20 of the belt conveyor 18 is a reference surface parallel to a scanning surface determined by a longitudinal direction of the line scan camera 14 and a scanning direction orthogonal to the longitudinal direction. As shown in FIG. 1, the product 12 has a curved surface shape in which the height from the reference surface 20 is constant along the longitudinal direction of the line scan camera 14 and changes along the scanning direction. The moving direction of the belt conveyor 18 and the scanning direction of the line scan camera 14 are opposite to each other as shown in FIGS.

  The line scan camera 14 has an image pickup unit in which a plurality of image pickup devices are arranged in a line along the longitudinal direction, and the image data obtained by scanning the image pickup unit is used to detect two images on the surface of the product 12. An imaging apparatus for forming a dimensional image. The line scan camera 14 scans along the scanning direction shown in FIG. Image data captured by the line scan camera 14 is stored in a storage device (not shown). In the line scan camera 14, the direction of the imaging direction V is set so that the product 12 is imaged by a desired display method based on the relationship with the reflected light irradiated from the illuminator 17 and reflected by the product 12. The The two-dimensional image formed by the line scan camera 14 can be displayed on the liquid crystal monitor 23 or the like as needed after being transmitted to the control unit 22.

  The distance measuring device 15 is a device that measures the distance between the line scan camera 14 and the product 12. The distance measuring device 15 is controlled by the control unit 22 from the time when the light is irradiated from the light source inside the sensor toward the surface of the product 12 to the time when the light is reflected by the surface of the product 12 and received by the light receiving element of the sensor. Is converted into a distance between the line scan camera 14 and the product 12 based on an angle θ formed by the light irradiation direction L of the distance measuring device 15 and the imaging direction V of the line scan camera 14. The converted distance information is transmitted to the control unit 22.

  The illuminator 17 is an apparatus that emits light so that the product 12 is imaged by a desired display method when the line scan camera 14 images the product 12. The operation of the illuminator 17 is controlled by the control unit 22.

  The line scan camera 14, the distance measuring device 15, and the illuminator 17 are held by a plate-like holding member 24. The plate-like holding member 24 is attached by being joined to the nut portion 28 of the moving mechanism 16.

  The moving mechanism 16 is a device that raises or lowers the holding member 24 under the control of the control unit 22. The moving mechanism 16 is a ball screw actuator including a ball screw configured to include a ball or the like (not shown) between the screw shaft 26 and the nut portion 28, and an electric motor 30 that rotates the screw shaft 26.

  The screw shaft 26 is attached between an upper portion 25 and a lower portion 29 of a support member 27 having a substantially U-shape. The upper end portion of the screw shaft 26 passes through the upper portion 25 of the support member 27 and is connected to the electric motor 30. The nut portion 28 has a through hole at the center, and the screw shaft 26 is inserted into the through hole via a ball or the like.

  The electric motor 30 is attached to the upper portion 25 of the support member 27 and has a rotation drive mechanism that rotates the screw shaft 26 under the control of the control unit 22. The electric motor 30 can be configured using, for example, a stepping motor.

  The controller 22 operates the belt conveyor 18 in response to the external activation signal. The control unit 22 controls the line scan camera 14 and the illuminator 17 so that the line scan camera 14 images the product 12 and the illuminator 17 illuminates the product 12 with the operation of the belt conveyor 18.

  Based on the distance information transmitted from the distance measuring device 15, the control unit 22 calculates the ascending or descending distance of the holding member 24 so that the surface of the product 12 matches the focal position F of the line scan camera 14. Based on the calculated distance, the control unit 22 controls the rotation of the electric motor 30 of the moving mechanism 16 so that the holding member 24 moves up or down.

  Next, the operation of the imaging system 10 having the above configuration will be described. The product 12 is arranged on the reference surface 20 of the belt conveyor 18 with the A direction of the product 12 aligned with the longitudinal direction of the line scan camera 14 and the B direction of the product 12 aligned with the scanning direction of the line scan camera 14. Thereafter, when the belt conveyor 18 operates in accordance with the external activation signal, the line scan camera 14 scans the product 12 along the scanning direction and images the surface of the product 12.

  As shown in the upper diagram of FIG. 2, the surface of the product 12 has a curved surface. However, according to the imaging system 10, the surface of the product 12 is line-scanned based on the distance measured by the distance measuring device 15. The ascending or descending distance of the holding member 24 is calculated so as to match the focal position F of the camera 14. Then, the holding member 24 is raised or lowered by the calculated distance by the moving mechanism 16.

  As a result, even when the distance between the line scan camera 14 and the product 12 changes during the scan of the line scan camera 14, the line scan is performed so that the surface of the product 12 matches the focal position F of the line scan camera 14. Since the camera 14 is raised or lowered, it is possible to always perform imaging with focus.

  In the above description, the curved shape of the product 12 has been described. However, the curved shape referred to here includes, for example, a corrugated shape and a bent shape.

  Further, in the imaging system 10, the line scan camera 14 has been described as scanning by operating the belt conveyor 18 when imaging the product 12. However, the line scan camera 14 itself may be moved for scanning. .

  In the imaging system 10, the holding member 24 that holds the line scan camera 14 is raised or lowered in order to align the surface of the product 12 with the focal position of the line scan camera 14, but the product 12 side is raised or lowered. You may let them.

  DESCRIPTION OF SYMBOLS 10 Imaging system, 12 products, 14 Line scan camera, 15 Distance measuring device, 16 Movement mechanism, 17 Illuminator, 18 Belt conveyor, 19 Rotation drive part, 20 Reference plane, 22 Control part, 23 Liquid crystal monitor, 24 Holding member, 25 Upper part, 26 Screw shaft, 27 Support member, 28 Nut part, 29 Lower part, 30 Electric motor.

Claims (3)

A line scan unit that scans on a subject having a curved surface and images the surface of the subject;
A moving mechanism that moves the line scan unit relative to the subject to adjust the focal position of the line scan unit to the surface of the subject;
An imaging system for a subject characterized by comprising: The subject imaging system according to claim 1,
The subject is disposed on a reference plane parallel to a scanning plane defined by a longitudinal direction of the line scanning unit and a scanning direction orthogonal to the longitudinal direction, and a height from the reference plane is a longitudinal direction of the line scanning unit. Having the curved surface shape that is constant along the scanning direction and varies along the scanning direction,
The line scan unit scans the subject along the scanning direction. In the imaging system of the subject according to claim 1 or 2,
The line scan unit forms a two-dimensional image of the surface of the subject using the scanned data.

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