JP-2026075503-A - Optical apparatus, calibration apparatus, and calibration method

JP2026075503AJP 2026075503 AJP2026075503 AJP 2026075503AJP-2026075503-A

Abstract

[Problem] To perform calibration simply and accurately. [Solution] The optical device 10 has a first optical system 11 and a second optical system 12. The first optical system 11 images the incident subject light beam onto a first imaging area of the image sensor 13. The second optical system 12 is fixed at a predetermined position relative to the first optical system 11. The second optical system 12 images the incident subject light beam onto a second imaging area of the image sensor 13. The optical device 10 can acquire calibration parameters for the first optical system 11 and the second optical system 12 as a stereo optical system based on constraints. Under the constraints, the first optical system 11 and the second optical system 12 image the subject light beam onto a single image sensor 13. [Selection Diagram] Figure 1

Inventors

西井裕亮
菅原俊
淺谷南己
中村匡芳
小路春樹

Assignees

京セラ株式会社

Dates

Publication Date: 20260508
Application Date: 20241022

Claims (9)

A first optical system that images the incident subject light beam onto a first imaging area of the image sensor, The system comprises a second optical system fixed at a predetermined position relative to the first optical system, which causes the incident subject light beam to form an image on the second imaging area of the image sensor, An optical device capable of obtaining calibration parameters for the first optical system and the second optical system as a stereo optical system, based on the constraint that the first optical system and the second optical system form an image of a subject light beam on a single image sensor.
In the optical apparatus described in claim 1, An optical device further comprising a control unit that obtains the calibration parameters by calculating them.
In the optical apparatus according to claim 1 or 2, The calibration parameters include internal parameters, which include at least a first parameter that specifies the image center in the image sensor of each of the first and second optical systems, and external parameters, which include at least a second parameter that specifies the translational position of the second optical system relative to the first optical system in a plane parallel to the light-receiving surface of the image sensor. The aforementioned external parameters are based on the constraints and internal parameters of the optical device.
In the optical apparatus described in claim 3, The calibration parameters are calculated by feeding back the provisional calibration results of the external parameters, which are calculated using the provisional calibration results of the internal parameters, to the update amount of the internal parameters in an optical device.
In the optical apparatus described in claim 3, An optical device in which the calibration parameters are calculated by calculating the external parameters based on the calibration results obtained by optimizing the internal parameters.
The optical device comprises a first optical system that images an incident subject light beam onto a first imaging area of an image sensor, and a second optical system fixed at a predetermined position relative to the first optical system and images an incident subject light beam onto a second imaging area of the image sensor, and includes a control unit that calculates calibration parameters for the stereo optical system. The control unit, A provisional calibration result of the internal parameters in the calibration parameters is calculated, which includes at least a first parameter that identifies the image center in the image sensor of each of the first and second optical systems. Based on the provisional calibration results of the internal parameters and the constraints that the first optical system and the second optical system form an image beam of the subject on a single image sensor, a provisional calibration result of the external parameters of the calibration parameters is calculated, which includes at least a second parameter that specifies the translational position of the second optical system relative to the first optical system in a plane parallel to the light-receiving surface of the image sensor. A calibration device that calculates the calibration parameters by feeding back the provisional calibration result of the external parameters to the update amount of the internal parameters.
The optical device comprises a first optical system that images an incident subject light beam onto a first imaging area of an image sensor, and a second optical system fixed at a predetermined position relative to the first optical system and images an incident subject light beam onto a second imaging area of the image sensor, and includes a control unit that calculates calibration parameters for the stereo optical system. The control unit, The calibration result is calculated by optimizing the internal parameters of the calibration parameters, which include at least a first parameter that identifies the image center in the image sensor of each of the first and second optical systems. Calibration device for calculating the calibration parameter by calculating an external parameter of the calibration parameter, which includes at least a second parameter that specifies the translational position of the second optical system relative to the first optical system in a plane parallel to the light-receiving surface of the image sensor, based on the calibration result and constraints that the first optical system and the second optical system image the subject light beam onto a single image sensor.
A method for calculating calibration parameters for a stereo optical system having a first optical system that images an incident subject light beam onto a first imaging area of an image sensor, and a second optical system fixed at a predetermined position relative to the first optical system and images an incident subject light beam onto a second imaging area of the image sensor, A provisional calibration result of the internal parameters in the calibration parameters, which include at least a first parameter that identifies the image center in the image sensor of the first optical system and the second optical system, is calculated. Based on the provisional calibration results of the internal parameters and the constraints that the first optical system and the second optical system form an image beam of the subject on a single image sensor, a provisional calibration result of the external parameters of the calibration parameters is calculated, which includes at least a second parameter that specifies the translational position of the second optical system relative to the first optical system in a plane parallel to the light-receiving surface of the image sensor. A calibration method for calculating the calibration parameters by feeding back the provisional calibration result of the external parameters to the update amount of the internal parameters.
A method for calculating calibration parameters for a stereo optical system having a first optical system that images an incident subject light beam onto a first imaging area of an image sensor, and a second optical system fixed at a predetermined position relative to the first optical system and images an incident subject light beam onto a second imaging area of the image sensor, The calibration result is calculated by optimizing the internal parameters of the calibration parameters, which include at least a first parameter that identifies the image center in the image sensor of each of the first and second optical systems. A calibration method for calculating the calibration parameters by calculating external parameters of the calibration parameters, which include at least a second parameter that specifies the translational position of the second optical system relative to the first optical system in a plane parallel to the light-receiving surface of the image sensor, based on the calibration results and constraints that cause the first optical system and the second optical system to image the subject light beam onto a single image sensor.

Description

This invention relates to an optical device, a calibration device, and a calibration method. A stereo camera system is known that uses multiple cameras to photograph a subject and calculate its three-dimensional position (see Patent Document 1). In a stereo camera system, accurate identification of intrinsic and extrinsic parameters is required to accurately calculate the three-dimensional position. In identifying intrinsic and extrinsic parameters, optimization of the intrinsic and extrinsic parameters is performed so that the predicted position, based on hypothetical values of the intrinsic and extrinsic parameters, matches the position in the image based on the actually captured image, for feature points of a target onto which a known pattern has been drawn. International Publication No. 2015/015542 Figure 1 is a block diagram showing a schematic configuration of an imaging device including an optical device according to this embodiment.Figure 1 is an external perspective view showing the structure of the optical device.Figure 1 shows an external view of the checkerboard used for calibrating the optical device.Figure 3 shows an example of a first partial image of the checkerboard, captured from various poses and positions.This is a flowchart illustrating the calibration parameter calculation process by a first method, which may be performed by a control unit provided in the optical device shown in Figure 1.This is a flowchart illustrating the calibration parameter calculation process by a second method, which may be performed by a control unit provided in the optical device shown in Figure 1. The embodiments of optical devices to which this disclosure is applied will be described below with reference to the drawings. As shown in Figure 1, an optical device 10 according to one embodiment of this disclosure comprises a first optical system 11 and a second optical system 12. The optical device 10 may also include an image sensor 13 to constitute a stereo imaging device 14. As shown in Figure 2, the first optical system 11 images the incident subject light beam lx1 onto the first imaging area ia1 of the image sensor 13. The first imaging area ia1 may be less than half of the entire light-receiving surface of the image sensor 13. Specifically, the first imaging area ia1 may be defined as any area within one region divided by a line connecting the midpoints of a pair of sides on the rectangular light-receiving surface of the image sensor 13. The first optical system 11 may include at least one refractive optical element. The refractive optical element is, for example, a lens or mirror that refracts the incident light beam. The second optical system 12 may be fixed in a predetermined position relative to the first optical system 11. Specifically, the second optical system 12 may be fixed so that its optical axis is parallel to that of the first optical system 11. Alternatively, the second optical system 12 may be fixed so that its optical axis is inclined relative to the optical axis of the first optical system 11. Furthermore, the second optical system 12 may be fixed at a position offset from the first optical system 11 when viewed from a direction perpendicular to the light-receiving surface of the image sensor 13. Also, the second optical system 12 may be fixed at a position offset from the first optical system when viewed from a direction parallel to the light-receiving surface of the image sensor 13. The second optical system 12 may be fixed in a position that images the incident subject light beam lx2 onto the second imaging area ia2 of the image sensor 13. The second imaging area ia2 may be less than half of the entire light-receiving surface of the image sensor 13. Specifically, the second imaging area ia2 may be defined as any area within the other region divided by a line connecting the midpoints of a pair of sides on the rectangular light-receiving surface of the image sensor 13. This pair of sides may be parallel to the direction in which the first optical system 11 and the second optical system 12 are aligned, or in other words, in a shifted direction, when viewed from a direction perpendicular to the light-receiving surface. Alternatively, this pair of sides may be inclined with respect to the direction in which the first optical system 11 and the second optical system 12 are aligned. The second optical system 12 may include at least one refractive optical element. The optical device 10 can acquire calibration parameters based on specific constraints. These constraints are that the first optical system 11 and the second optical system 12 each image the subject light beams lx1 and lx2 onto a single image sensor 13. The calibration parameters are those that enable the first optical system 11 and the second optical system 12 to function as a stereo optical system. Calibration parameters may include internal and external parameters. Calibration parameters are actual values that include errors from th