JPS62203011A - Wide visual field type distance measuring apparatus - Google Patents

Abstract

PURPOSE:To make it possible to accurately detect the distance information of a peripheral part regardless of the posture of a camera, by correcting the error caused by the shift component of the light from a light projecting means in the base line direction of said light by a distance measuring information calculating means. CONSTITUTION:An operational control circuit 14 outputs a light projecting control signal SiD to a light projection driving control circuit 13 to project signal lights from light projecting elements 2a, 2d or 2b, 2c. The signal lights projected from the light projecting elements are reflected from the surface of an object to be incident to a semiconductive position detector 1, and the center-of-gravity position of the formed secondary image in an X-axis direction and that in a Y-axis direction are respectively detected by operational control circuits 14, 15 to be inputted to a microcomputer 16. The computer 16 sets the value, which is obtained by adding correction to the data D1 inputted from the circuit 14 on the basis of the data D2 and angle corresponding to the secondary brightness difference inputted from the circuit 15, as distance measuring information and the delivery quantity of a lens is calculated on the basis of said information to control the lens.

Description

Detailed Description of the Invention (Field of Application of the Invention) The present invention is an optically active wide-field distance measuring method that obtains ranging information by projecting light toward a distance measuring target and receiving the reflected light. This relates to improvements in equipment.

(Background of the Invention) Conventional devices of this type include -dimensional semiconductor device detectors (P
SD) is used to project light not only at the center but also in a direction orthogonal to the base line length, and by utilizing the characteristics of the semiconductor device detector to detect the center of gravity position of the signal light, the periphery in the horizontal or vertical direction They also measured the distance. This means that when using a -dimensional semiconductor device detector, if the light to be projected onto the peripheral area is shifted from the center in a direction other than perpendicular to the baseline length (for example, if the light from the peripheral area is projected in the direction of the baseline length). This created a problem in that the distance measurement range varied greatly depending on whether the camera was positioned horizontally or vertically when shooting. In other words, the objective that wide-field distance measuring devices were trying to solve, which was to obtain good distance measurement even in shooting scenes where two people are lined up and the background is in the center, was achieved by changing the camera's posture. It made a huge difference in ability.

(Objective of the Invention) An object of the present invention is to solve the above-mentioned problems and provide a wide-field distance measuring device that can more accurately detect distance information in the periphery regardless of the posture of the camera. be.

(Characteristics of the Invention) In order to achieve the above object, the present invention provides a light projecting means for projecting light toward a subject by shifting the light from the center of the photographing screen in a direction having both components in the base line length direction and in a direction perpendicular to the base line length direction. The intersection point of the X-axis and Y-axis corresponds to the center of the photographing screen, and the base line length direction and the X-axis direction are made parallel, and a secondary image of the light projecting means is formed by the light reflected from the subject. a two-dimensional light receiving means; a calculating means for calculating the position of the secondary image in the X-axis direction and the Y-axis direction from the X-axis output and Y-axis output of the two-dimensional light receiving means; The calculated value of the position is corrected by the calculated value of the position of the secondary image in the Y-axis direction, and the angle formed by the direction in which the light of the light projecting means deviates from the center of the photographing screen and the baseline length direction, and the distance measurement information is obtained. The present invention is characterized in that it comprises distance measurement information calculating means for calculating distance information, thereby correcting an error due to a deviation component in the base line length direction of the light of the light projecting means.

(Embodiments of the Invention) Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIGS. 2(a) and 2(b) are plan and side views of a two-dimensional semiconductor device detector l used in the present invention. The position of the center of gravity of the signal light in the X direction is determined by output terminals tc and t.
Photocurrent YA output from ci.

The position of the center of gravity of the signal light in the Y direction can be determined by the ratio of YB.

FIG. 3 is a diagram illustrating a distance measuring optical system using the semiconductor device detector 1. The direction connecting the semiconductor device detector 1 and the four light emitting elements 2a to 2d (light emitting elements 2c and 2d are not shown in FIG. 3) is the base line length direction, and the light emitting element 2a
The signal light having a component shifted with respect to the base line length direction, which is projected from ~2d through the light projection lens 3, is reflected at the object surface and enters the semiconductor device detector l through the light reception lens 4. do.

FIGS. 4(a) and 4(b) are plan and front views showing the arrangement of the light projecting elements 2a to 2d, and the light projecting elements 2a and 2d and the light projecting element 2b are symmetrically arranged with respect to the center of the photographing screen. and 20 are placed.

FIG. 5 shows an example of a drive system for driving the light projecting elements 2a to 2d, in which the drive circuit 5 drives the light projecting elements 2a,
2d or light projecting element 2b.

Drives 2C. The dual switch 6 is switched by a control circuit (not shown) according to the camera's posture and manual input, and determines which of the light emitting elements 2a, 2d or the light emitting elements 2c, 2b is to be driven, and at the same time, which pair is selected. outputs a pair selection signal SMD indicating whether the selected pair has been selected.

FIG. 6 shows, for example, the semiconductor device detector l when the light projected from the light projecting elements 2a and 2d is reflected by a large planar object located at a certain distance and enters the semiconductor device detector 1. It is a figure which shows the state of the secondary image P,, P4 above.

FIG. 1 is a block diagram showing an example of a signal processing system of a wide-field distance measuring device equipped with the above-mentioned distance measuring optical system. 7 is a contact that is switched to the contact 7a side by inputting 1 to a high level calculation mode switching signal from an arithmetic processing circuit to be described later, and to the contact 7b side by inputting a low level calculation mode switching signal. The arithmetic mode switch 8 is switched to the contact 8a side when 2 is input to a high level arithmetic mode switching signal from an arithmetic processing circuit to be described later, and to the contact 8b side when 2 is input to a low level arithmetic mode switching signal. A calculation mode switch 9 whose contactor switches is a signal voltage VX & or (
The sensor amplifier outputs Vxa')-Vxb), and a constant voltage Vr is applied to its non-inverting input terminal.

lO is the photocurrent YA or (YA+YB) input from the semiconductor device detector l, and the signal voltage vya or (Vya+Vyb
), and a constant voltage vr2 is applied to its non-inverting input terminal. 11.12 is a feedback circuit that determines the conversion constant when converting the photocurrent from the semiconductor device detector 1 into voltage; 13 is the drive circuit 5 and the double sweeper 2,66 shown in FIG. A light projection drive control circuit 14 outputs a light projection ffJVB signal SiD to the drive 1lIiII control circuit 13 in accordance with an instruction signal SS from a microcomputer to be described later, and outputs a light projection ffJVB signal SiD to the semiconductor device detector l in the X-axis direction. If the detected data D1 is valid in the arithmetic control circuit that detects the position of the center of gravity of the secondary image, a data status signal El indicating that the detected data D1 is valid.
and output the data. 15 is an arithmetic control circuit that detects the center of gravity position of a secondary image in the Y-axis direction on the semiconductor device detector 1 according to an instruction signal SS from a microcomputer, which will be described later. The data is output together with a data status signal E2 indicating that the data is present. Reference numeral 16 denotes a microcomputer that calculates the distance to the object based on the data D, .

Next, the operation will be explained. The power (not shown) is turned on, and
When a PUC signal is generated in a PUC circuit (not shown), the arithmetic control circuit 14 first outputs a light projection control signal SiD to the drive control circuit 13 in order to start operation according to the instruction signal SS from the microcomputer 16. For example, light emitting element 2
At the same time, a signal light is projected from a and 2d, and an operation start signal is output to the arithmetic control circuit 15.Next, 1 is output as the arithmetic mode switching signal to the arithmetic mode switch 7 to control switching of the switch. The position of the center of gravity in the X-axis direction of the secondary image formed when the signal light projected from the light projecting elements 2a and 2d is reflected from the object surface and is incident on the semiconductor device detector 1 is detected in time series by the sensor amplifier 9. Signal voltage Vx input to
a and the signal voltage (Vxa+Vxb). That is, the signal voltage Vxa inputted from the sensor amplifier 9 is integrated for a certain period of time, and then inversely integrated until the integrated value of the signal voltage Vxa reaches the initial level by the signal voltage (Vxa+Vxb) inputted with a time delay. The ratio of the time required for Vxa/(Vx
a+Vxb). If the data D1 detected in this way is valid,
The data is output to the microcomputer 16 together with a data status signal E indicating that it is valid.

On the other hand, since the arithmetic control circuit 15 starts operating according to the instruction signal SS from the microcomputer 16 at the same time as the operation start signal is input from the arithmetic control circuit 14,
A calculation mode switching signal of 2 is output to the calculation mode switch 8 to control switching of the switch, and the light emitting element 2
The position of the center of gravity in the Y-axis direction of the secondary image formed when the signal light projected from a and 2d is reflected on the object surface and is incident on the semiconductor device detector 1 is input in time series from the sensor amplifier 10. Detection is performed using the signal voltage Vya and the signal voltage (Vya+vyb). That is, the signal voltage Vya inputted from the sensor amplifier 10 is integrated for a certain period of time, and then inversely integrated until the integrated value of the signal voltage Vya reaches the initial level by the signal voltage (Vya+Vyb) inputted with a time delay. The ratio of the time required to the -0 constant time,
That is, it is determined by performing the calculation Vy a/(Vya+Vy b)A''. Then, similarly to the calculation control circuit 14, if the data D2 detected in this way is valid, the data state indicating that it is valid is determined. The data is output to the microcomputer 16 along with the signal E2. Next, the operation of the microcomputer 16 will be explained using FIG. If there is a sufficiently large flat object with
The center of the secondary image P1 of a is a, and the secondary image P4 of the light projecting element 2d
The center of is d, and its center of gravity is O (intersection of x-axis and y-axis)
Assuming that the object was moved and the distance changed, the center of the secondary image P1, which was at a, became a', and the center of the secondary image P4, which was also d, became d'. If each of them moves, the center of gravity in this case becomes e, and since the center of gravity itself changes only by the component in the X-axis direction, if only the X-axis component of the center of gravity is known, that is, the data D1 input from the arithmetic control circuit 14 It becomes possible to use the information as it is as the distance measurement information at this time. However, generally speaking, assuming only objects with uniform reflectance, the distance measuring device is not practical, so let us consider a case where the reflectances of the secondary images P and P4 are different.

In such a case, it moves on the line segment a-d including the above-mentioned center of gravity e due to one change in the center of gravity-reflectance. Due to this movement, both the X-axis direction component and the Y-axis direction component of the center of gravity change, but if the angle formed by the line segment a - d and the X-axis is θ, and the position of the center of gravity is (Xg, Yg), then the center of gravity e position (Xe,
O), then Xe = Xg - Y g/'t a nθ
Since the following relational expression holds true and θ is a constant determined by design, accurate distance measurement is possible regardless of the reflectance if xg and Yg can be detected.
From the above, the microcomputer 16 performs calculations based on the above formula to calculate distance measurement information. That is, as described above, for the data D1 input from the arithmetic control circuit 14, the secondary images P and P input from the arithmetic control circuit 15 are
A value corrected by data D2 corresponding to the brightness difference of 2 and the angle θ is used as distance measurement information, and based on this information, the amount of lens extension is determined and the lens is controlled by means not shown. Furthermore, even if the distances to the objects corresponding to the secondary images Pl and P4 are different, the weighted average distance based on the luminance is calculated using the above formula.

Depending on the posture of the camera, the light emitting element 2 may be used as a light emitting means.
b, '2c may be used, so the microcomputer 16 determines which pair has been selected from the pair selection signal SMD, and when it is determined that the light projecting elements 2b and 2c have been used, calculates the center of gravity Xe (distance measurement information) using the angle θ' formed by the X-axis and the line segment b-c connecting the centers of the secondary images P2 and P3 that have been set in advance. do.

(Correspondence between the invention and the embodiments) In this embodiment, the light projecting elements 2a to 2d serve as the light projecting means of the present invention, the semiconductor device detector 1 serves as the two-dimensional light receiving means, and the calculation control circuits 14 and 15 serve as the calculation means. , and the microcomputer 16 respectively correspond to distance measurement information calculation means.

(Modification) In this example, a pair of light projecting elements arranged symmetrically with respect to the center of the screen has been considered, but even if one light projecting element is arranged around the screen, the direction perpendicular to the baseline length direction The present invention can be applied if both components of
It is assumed that the reflectance of the secondary image P4 is O (zero). However, in such a configuration, differences in object reflectance cannot be taken into account. Further, since only one of the two pairs of light emitting elements is selected, each pair can be selected in a time-sharing manner for distance measurement, or the four light emitting elements 2a
~2d can be selected independently and time-divisionally for distance measurement.

Of course, it is also possible to perform the scanning on four or more points one by one, on any pair symmetrical to the center of the screen, or even on a combination thereof. Furthermore, it is also possible to further arrange a light emitting element for distance measuring the center part of the screen, and in this case, just by setting Yg=O, distance can be measured by the circuit shown in FIG.

In addition, although the two-dimensional information (data DI, D2) is processed simultaneously by the arithmetic and control circuits 14 and 15, the outputs of the sensor amplifiers 9 and 10 are selected by switches and sent to the arithmetic and control circuit 14 in a time-sharing manner. If the configuration is such that each signal voltage is inputted, the arithmetic control circuit 15 can be omitted.

(Effects of the Invention) As explained above, according to the present invention, the light projecting means projects light toward the subject while being shifted from the center of the photographic screen in a direction having both components in the base line length direction and in a direction perpendicular to the base line length direction. The intersection point of the X-axis and Y-axis corresponds to the center of the photographing screen, and the base line length direction and the X-axis direction are made parallel, and a secondary image of the light projecting means is formed by the light reflected from the subject. a two-dimensional light receiving means; a calculating means for calculating the position of the secondary image in the X-axis direction and the Y-axis direction from the X-axis output and Y-axis output of the two-dimensional light receiving means; The calculated value of the position is corrected by the calculated value of the position of the secondary image in the Y-axis direction, and the angle formed by the direction in which the light of the light projecting means deviates from the center of the photographing screen and the baseline length direction, and the distance measurement information is obtained. Since the present invention is equipped with distance measurement information calculation means to calculate distance information, and thereby corrects the error caused by the deviation component in the base line length direction of the light of the light projecting means, it is possible to obtain more distance information in the peripheral area regardless of the camera posture. It can be detected accurately.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a plan and side view of a two-dimensional semiconductor device detector used in the present invention, and FIG. 3 is the semiconductor device detector of FIG. 2. A fourth diagram illustrating a distance measuring optical system which is an embodiment of the present invention using
The figure also shows a plan view and a front view showing the arrangement of a light projecting optical system, FIG. 5 shows a drive system for driving a light projecting element, and FIG. 6 shows a secondary image on a semiconductor device detector. The explanatory diagram, FIG. 7, is a diagram similarly explanatory of the case where the secondary image on the semiconductor device detector moves. l...Semiconductor device detector, 2...Light emitter, 7.8...Calculation mode changeover switch, 9
, 10...Sensor amplifier, 14.15 Old...
Arithmetic control circuit, 16... Microcomputer, SMD... pair selection signal, D, , D2...
Data signal, P1 to P4...Reflection image. Patent Applicant Canon Co., Ltd. Agent Minoru Nakamura Figure 1

Claims (1)

[Claims] 1. A light projection means that projects light toward the subject in a direction that is shifted from the center of the photographic screen in a direction that has both components in the base line length direction and a direction perpendicular thereto, and a light projection means that projects light toward the subject in a direction that has both components in the base line length direction and a direction perpendicular to the base line length direction, and a point of intersection of the X and Y axes at the center of the photographic screen. a two-dimensional light receiving means that forms a secondary image of the light projecting means by light reflected from the subject with the base line length direction and the X-axis direction parallel to each other; and an X-axis output of the two-dimensional light receiving means. and a calculation means for calculating the position of the secondary image in the X-axis direction and the Y-axis direction from the Y-axis output; A wide field of view type measurement device comprising a distance measurement information calculation means for calculating distance measurement information by correcting the calculated value of the position and the angle formed by the direction in which the light of the light projecting means deviates from the center of the photographing screen and the base line length direction. range device.