JPH0255732B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] This is a mirror position control device in a lens projection characteristic measuring device, in which the mirror position is detected by a light receiver provided in a projector, and the color distribution of a band-shaped member provided near the lens is detected. The device was made simple and accurate by controlling the position of the mirror.

[Industrial Field of Application] This invention relates to a lens projection characteristic measuring device for measuring the light emitting characteristics of a lens, particularly a lens projection characteristic measuring device of a type in which light from a projector is reflected by a mirror and then incident on the lens. Regarding a control device.

[Prior Art] In recent years, a technology has been used in which a camera device including a lens and an image sensor performs environment recognition using an image input means. As described above, in the technical field, it is not possible to accurately recognize the environment unless the lens projection characteristics are known.

This method determines where on the imaging surface the lens forms an image of light incident on the lens from a certain direction, and based on this result, the direction of incidence of the light is recognized based on the point where the image is formed. be.

As shown in FIG. 5, the lens projection characteristic measuring device for measuring the lens projection characteristics is a television camera 2 equipped with a lens mounted on a rotary table 3 so as to be able to rotate around the optical axis A. , the collimator 4 is used as a projector that emits parallel light, and the lens 1
is fixed obliquely with respect to the optical axis A, and irradiates on an extension of the optical axis A, while a moving axis 6 is provided above this parallel light parallel to the irradiation direction, and this moving axis 6 In this example, a mirror 5 is mounted so as to be positioned in the parallel light via a moving member 7 that moves along this moving axis 6, and this mirror 5 is mounted perpendicularly to the optical axis with respect to the moving member 7. It can be tilted with the direction as the tilt axis. and lens 1
The position on the imaging surface of the television camera 2 on which the incident light is imaged is measured, and the correspondence between the incident direction of the light and the position of the light imaging surface can be known.

Here, in order to automatically measure the projection characteristics of this lens, as shown in FIG. 22, I asked my husband to measure the mirror's inclination angle, mirror position, and camera rotation angle with measuring device 2.
3, 24, and 25, and each motor is controlled by a control device 27 based on the measured values and the value measured by a measuring device 26 of the imaging position of the light on the imaging surface of the television camera 2. I try to do that.

When automatically measuring the projection characteristics of this lens, the inclination angle of the mirror 5 is first set. If the inclination angle of the mirror 5 is determined, the movement of the mirror 5 in the direction of the movement axis 6 is parallel to the parallel light, so the extra latitude θ of the light incident on the lens 1 is uniquely determined,
Further, the azimuth angle of the incident light can be uniquely determined by the rotation of the television camera 2. however,
Even if the co-latitude and azimuth of the incident light are fixed,
If this incident light is not properly incident on the surface of the lens 1 (for example, the state shown in Fig. 5), the incident light will not form an image on the imaging surface, or the amount of light will be insufficient, making it impossible to accurately measure the lens projection characteristics. Can not. Therefore, it is necessary to control the position of the mirror 5 in the direction of the movement axis 6.

Conventionally, as a control device for the direction of the movement axis 6 of the mirror 5, for example, the position of a predetermined mirror 5 on the movement axis 6 at the inclination angle of the mirror 5 is calculated in advance, and this value is input into the control device 27. On the other hand, as shown in FIG. 5, a measuring rail 8 is provided parallel to the moving axis 6, and is fixed to the moving member 7 so that it moves as one and slides on the measuring rail 8 to detect the position of the mirror 5. Some devices are equipped with a position sensor 9 to control the position of the mirror 5.

Other devices for controlling the position of the mirror 5 include:
As shown in FIG. 6, there is a system that directly detects whether light is focused on the imaging surface using an image of the imaging surface of the television camera 2.

In FIG. 6, ψ indicates the field of view of the lens 1, and schematically shows the image of the imaging surface in the case shown in FIG. In the figure, the light 10 from the collimator 4 is insufficiently focused on the imaging surface via the mirror 5. This light is detected by the measuring device, and the mirror 4 is moved in the optical axis direction ( (Indicated by a in the figure)
The mirror 5 is moved so that the light 10 is controlled to be centered on the mirror 5.

[Problems to be Solved by the Invention] By the way, in the first mirror control device described above, the position corresponding to the angle of the mirror 5 must be calculated in advance, which is complicated, and it is also difficult to move the mirror. A position sensor must be provided on the member, which complicates the device.

In addition, in the second device described above, if the measurement lens has a wide field of view, the size of the image on the imaging surface of the mirror, light, etc. will be extremely small, making it difficult to perform the above-mentioned control accurately. It will be difficult to do.

[Means for Solving the Problems] The present invention solves the above-mentioned problems, simplifies the structure of a mirror position control device in a lens projection characteristic measuring device, and accurately controls the mirror position control device. In order to make this possible, we developed a projector that is tilted with respect to the optical axis of the lens and emits light toward a point on an upward extension of the optical axis, and a projector that is movable along the direction of the light and whose mounting angle is variable. A lens projective characteristic measuring device consisting of a mirror that reflects the light toward the lens and a rotary table that rotates the lens is provided with a band-shaped member whose color distribution changes continuously near the lens to be measured, The projector is provided with a light receiver that measures the color distribution of the strip member through the mirror and measures the position of the mirror.

[Operation] As shown in FIGS. 1 and 2, the light L emitted by the collimator 4, which is a projector, is reflected by the mirror 5, and is emitted to the lens 1 with a co-latitude θ. In this case, when irradiating a predetermined lens position 1, the light receiver 10 attached to the side of the collimator 4 is a strip member 1 whose color distribution changes continuously.
1 predetermined color is detected through mirror 5. Also mirror 5
If the position along the axis of movement is incorrect, then
The light from the collimator 4 is irradiated onto a position on the lens 1 that is outside the predetermined position (indicated by a chain line in FIG. 1), and the light receiver 10 detects a color other than the predetermined color of the strip member 11.

Since the color distribution of the strip member 11 is known, the position of the mirror is detected and controlled based on the color detected by the light receiver.

[Example] Hereinafter, an example of a mirror position control device in a lens projection characteristic measuring device according to the present invention will be described. FIG. 3 shows an embodiment of a mirror position control device in a lens projection characteristic measuring device according to the present invention. In this embodiment, the collimator 4, which is a light projector, is fixed to a base 12 using a stand 13 so as to emit parallel light upward to the lens 1 using, for example, a reference crosshair. Further, a television camera 2 with a lens 1 attached thereto is attached to a base 12 via a rotary table 3. A moving shaft 6 on which the mirror 5 is movably attached via a moving member 7 is fixed on a base 12 using two stands 14. Note that the positional relationship between these can be changed depending on the size of the lens 1, television camera 2, etc.

Two stands 14 supporting the moving shaft 6
A band member 11 having a colored portion 11a whose color brightness changes continuously is spanned between the two. The strip-like member 11 is attached to the height of the first principal surface of the lens 1 using a mounting material, and is cut at a point ( (hereinafter referred to as the optical axis position), the brightness of the colored portion 11a is set to be 1/2 of the brightest portion and the darkest portion. The collimator 4 is provided with a light receiver 10 parallel to the optical axis of the collimator 4 on the opposite side across the light from the strip member 4, which detects the brightness of the coloring of the strip member 11 through the mirror 4. It is being The light receiver 10 is connected to a differential amplifier 16, and the differential amplifier 16 receives a signal identical to the signal when the light receiver 10 detects the brightness at the optical axis position of the strip member 11. A reference signal generator 17 that generates a signal is connected. The output terminal of the differential amplifier 16 is connected to a control device 27 to control the mirror moving motor 21. Note that in this embodiment as well, the control device 27
Similar to the case shown in FIG. 7, the mirror tilt mode 20,
Controls the television camera rotation motor 22.

Therefore, the procedure for measuring the projection characteristics of a lens according to this embodiment is as follows: First, in order to determine the extra latitude θ of the incident light from the collimator 4 to the lens 1, the mirror 5 is moved to a predetermined angle by operating the mirror tilt motor 20. Tilt. At this time, the extra latitude θ is uniquely determined by the inclination of the mirror 4, but the irradiation light is not necessarily irradiated onto a predetermined position of the lens 1. Therefore, adjustment is performed by moving the mirror 4 along the movement axis 6. That is, the light receiver 10
The brightness of the color of the strip member 11 at a location corresponding to the position currently irradiated with the light of the collimator 4 is detected, and this value is compared with the value of the reference signal generator 17 using the differential amplifier 16. , the motor control device 27 drives the mirror moving motor 21 in a direction in which the detected value approaches the reference signal, and moves the mirror 5 when the reference signal and the detected value match.
to stop. The light from the collimator 4 is now incident on the predetermined position of the lens at the extra latitude θ. In this state, the control device 27 controls the television camera rotation motor 25.
is driven to rotate the television camera 2, and the light is incident on the lens 1 over all incident azimuth angles. This means that the extra latitude θ and the azimuth angle 0 to 2π have been measured.

By performing this procedure for the necessary extra latitude values, it is possible to measure the projection characteristics of the lens with respect to the necessary extra latitudes and azimuths.

Therefore, according to this embodiment, there is no need to provide a position measuring device or the like to the movable part of the mirror position control device in the lens irradiation specific measurement device, and the structure can be simplified, and the mirror position can be measured accurately. can be done.

In this example, the change in the color of the strip member was a change in the brightness of the color, but other changes, such as the fourth
As shown in the figure, two different colors may be applied in different proportions depending on the location.
Further, although the light receiver and the strip member are positioned to sandwich the lens, it goes without saying that they may be provided in the same direction.

[Effects of the Invention] As explained above, according to the present invention, since the mirror position control device in the lens projection characteristic measuring device is configured as described above, there is no need to provide a measuring device etc. on the movable member, and the detection Since this is performed optically, the structure of the control device can be simplified, and the mirror can be controlled with high precision.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a mirror position control device in a lens projection characteristic measuring device according to the present invention, FIG. 2 is a front view of the measuring device shown in FIG. 1, and FIG. 3 is a side view showing an embodiment of the present invention. FIG. 4 is a diagram showing another example of the belt-shaped member used in the present invention, FIG. 5 is a side view showing an example of a conventional control device, and FIG. 6 is a diagram showing another example of a conventional control device. FIG. 7 is a block diagram showing the control system of the conventional control device and the present invention. 1...Lens, 2...TV camera, 3...Rotating table, 4...Collimator (projector), 5...Mirror,
6...Movement axis, 10... Light receiver, 11... Band-shaped member.

Claims (1)

[Claims] 1. A projector that is tilted with respect to the optical axis of the lens and emits light toward a point on an upward extension of the optical axis of the lens; In a lens projective characteristic measurement device that consists of a mirror that reflects the direction and a rotary table that rotates the lens, a band-shaped member whose color distribution changes continuously is placed near the lens to be measured, and the projector is equipped with this 1. A mirror position control device in a lens projection characteristic measuring device, characterized in that a light receiver is provided for measuring the color distribution of the band-shaped member through the mirror and measuring the position of the mirror.