JPH0255733B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] This is a projective characteristic measuring device for a lens, and by making light incident on the lens by reflection from a mirror, it is possible to simplify the device, improve accuracy, and measure a wide range of lenses. made possible.

[Industrial application field]

The present invention relates to a lens projection characteristic measuring device for measuring the projection characteristics of an imaging lens, and more particularly, it is comprised of an irradiation device that makes light incident on the lens and a measurement device that measures where on the imaging surface the light is coupled. The present invention relates to a lens projection characteristic measuring device.

[Conventional technology]

2. Description of the Related Art In recent years, technology for environmental recognition using a camera device consisting of a lens and an image sensor as an image input means has become important. In such technical fields,
Accurate environmental recognition cannot be performed without knowing the projective characteristics of the lens.

This is because, as shown in Fig. 7, we know where on the imaging surface 3 the light 2 entering the lens 1 from a certain direction will be imaged by the lens 1, and based on this measurement, the image will be formed. This is because the direction of incidence of light is recognized depending on the location. In the example shown in FIG. 7, the light incident from the extra latitude φ and the azimuth θ is crystallized at a point P (X, Y) on the imaging surface 3. These (φ, θ) and (X, Y) are related by the theoretical projection characteristics of the lens, but in reality, it is difficult to measure the projection characteristics of the lens due to the presence of errors. It becomes necessary.

Conventionally, lens aberrations have been widely measured in order to determine lens characteristics, and devices that automatically measure lens aberrations have also been developed. However, there is still no effective device for measuring the projection characteristics of a lens.

[Problem that the invention seeks to solve]

As mentioned above, there is no device that measures the projection characteristics of a lens, but by irradiating the lens with light from each direction and electrically detecting this image formation with the image sensor on the imaging surface, the direction of incidence of the light can be determined. Since the purpose is to measure the relationship between the image position and the imaging position, the following device can be envisaged.

This is a device in which a collimator 4, which serves as a projector and projects a reference pattern as parallel light, is fixed downward and the direction of a television camera 5 is changed. For this reason, in the example shown in FIG. 4, the television camera 5 is placed on a two-axis goniometer stage 6 provided on the X, Y stage 7. Further, in the example shown in FIG. 5, the television camera 5 is supported by a support device 8 that can swing around two axes at the lens portion 5a. Furthermore, in the example shown in FIG. 6, the lens portion of the television camera 5 is supported by a support device 10 placed on a rotary table 9 and swingable in one axis.

However, in such an example, since the heavy television camera is moved, the support device and the like become large-sized, and it is difficult to improve the precision of the angle control of the incident light.

Conversely, it is possible to move the collimator 4, but the collimator 4 is also heavy like a television camera, and has the same problems.

[Means for solving problems]

The present invention solves the above-mentioned problems and provides a compact and highly accurate lens projection characteristic measuring device.The present invention includes an irradiation device that injects light from a predetermined direction toward the lens of an imaging system, and a device to which this light is directed on the imaging surface. In a lens projection characteristic measuring device comprising a measuring device for measuring whether an image is formed at a certain position, the irradiation device is tilted with respect to the optical axis of the lens and irradiates light toward a point on an upward extension of the optical axis. It consists of a projector, a mirror that is movable along the direction of irradiation of the light and whose mounting angle is variable and reflects the light toward the lens, and a rotary table that rotates the lens.

[Effect]

As shown in FIG.
7 and enters the lens 11, but the mirror 17
By changing the position and angle of the lens 11
The extra latitude of the incident light is changed relative to that of the lens 11.
By rotating the lens on a rotary table, light is incident on the lens from any azimuth angle.

〔Example〕

Embodiments of the lens projection characteristic measuring device according to the present invention will be described below.

1 to 3 show a lens projection characteristic measuring device according to the present invention.

In this embodiment, a television camera 12 with a lens 11 attached thereto is attached to a rotary table 13 so that it can rotate around the optical axis A of the lens 11. A collimator 14 as a light projector that irradiates the reference pattern as parallel light is connected to the lens 11.
The lens 11 is installed obliquely in a plane that includes the optical axis of the lens 11, so that the irradiated light is directed to a point on an upward extension of the optical axis of the lens 11. A moving shaft 15 is fixed substantially parallel to the irradiated light, and a mirror 17 is provided on the moving shaft 15 so as to be variable in angle via a mounting member 16 that moves along the moving shaft 15.

The angle of the mirror 17 can be changed by a mirror rotation motor 20 and a speed reduction device with an accuracy smaller than the resolution of the image sensor.
The moving shaft 15 can be moved by the following steps. Furthermore, the television camera 12 is rotatable by a camera rotation motor 22 in a rotary table. These movements such as rotation are controlled by a control section as shown in FIG. That is, the movement of each motor 20, 21, 22 is driven by a control device 27 via a motor driver 28, while the movement of each motor 20, 21, 22 is controlled by rotary engoders 23, 24, 25 and a counter 26. The control device 27 controls each motor based on the motion state of each motor 20 , 21 , 22 and the image signal from the measuring device 28 connected to the television camera 12 . In the figure, reference numeral 18 is a base, and 19 is a stand erected on the base to support each device.

In order to measure the projection characteristics of a lens with the lens projection characteristics measuring device according to this embodiment, light is made to enter a desired measurement position. That is, the extra latitude is determined by changing the position and angle of the mirror 17, and the azimuth is determined by rotating the rotary table 13. In this state, the measurement device 28 may be used to measure where the image is focused on the imaging surface of the television camera. Note that this measurement can also be performed automatically by storing the measurement position in advance in the control device 27.

Therefore, according to this embodiment, since the driving part is the mirror 17 and it is lightweight, the device can be made compact, and the measurement accuracy of lens projection characteristics can be improved simply by improving the angle change of the mirror 17 and the rotational operation of the television camera 12. In addition to being able to obtain good results, since the operation of each motor is automatically controlled, the projection characteristics of the lens can be measured extremely easily and accurately. Furthermore, by changing the position and angle of the mirror, it is possible to measure from 0 degrees extra latitude (indicated by the dashed line in Figure 1) to all latitudes of 90 degrees or more, and it is also easy to measure special lenses such as fisheye lenses. It is possible.

〔Effect of the invention〕

As explained above, according to the present invention, the structure of the lens exit characteristic measuring device is simplified, so the rigidity of the device can be increased, so the measurement accuracy can be increased, and automation is also possible. In addition to being easy, the angle range that can be measured is wide, and the projection characteristics of a wide range of lenses can be measured.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing a lens projection characteristic measuring device according to the present invention, Fig. 2 is a plan view showing an embodiment of the present invention, and Fig. 3 is a control system of the projective characteristic measuring device shown in Fig. 2. 4 to 6 are diagrams showing a conventional lens projection characteristic measuring device, and FIG. 7 is an explanatory diagram showing the lens projection characteristics. 11...Lens, 12...TV camera, 13
... Rotating table, 14 ... Collimator (light emitter), 1
7...Mirror.

Claims (1)

[Claims] 1. In a lens projection characteristic measuring device consisting of an irradiation device that enters light from a predetermined direction toward a lens of an imaging system and a measuring device that measures where on the imaging surface this light is focused, the irradiation device The projector is tilted with respect to the optical axis of the lens and irradiates light toward a point on an upward extension of the optical axis, and the projector is movable along the direction of irradiation of the light and has a variable mounting angle to reflect the light toward the lens. A lens projection characteristic measuring device comprising a mirror and a rotary table for rotating the lens.