JP2000002521A - Three dimensional input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten necessary time for scanning objects and raise resolution in both directions of main scanning and subsidiary scanning. SOLUTION: A three dimensional input device casts reference light toward a hypothetical plane so as to scan it and outputs data according to the incidence angle of the reference light reflected at an input object. In this case, provided are (n), which is 2 or more, light sources 111 to 11n emitting intensity modulation lights L1 to Ln with different modulation frequencies f1 to fn as reference lights, bias means 15 and 16 guiding the intensity modulation lights emitted by each light source to different sampling areas sp, a photoelectric conversion device 25 of two dimensional position detector placed so that whole area of the hypothetical plane becomes the detection range, and a signal processing means 50 separating the obtained photoelectric conversion signal into components of each modulation frequency and outputting received information according to the incident angle of each intensity modulation light as data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional input device for projecting light onto an object to acquire and output object shape information in a non-contact manner.

[0002]

2. Description of the Related Art A non-contact type three-dimensional measuring device (three-dimensional camera) called a range finder can perform higher-speed measurement than a contact-type three-dimensional measuring device.
It is used for data input to the D system, body measurement, visual recognition of robots, and the like.

An optical projection method is used as a measurement method suitable for a range finder. This method is a method of optically scanning an object to obtain a distance image (three-dimensional image) based on the principle of triangulation, and is a type of an active measurement method of projecting a reference beam and scanning the object. . The reference light reflected by the object passes through the light receiving lens and enters the light receiving surface of the photoelectric conversion element. Since the incident position corresponds to the incident angle, the distance to the object can be calculated by detecting the incident position. When projecting a slit light having a linear beam cross section as reference light, beam deflection in the sub-scanning direction is performed. When projecting a spot-like spot light, beam deflection in the main scanning direction and the sub-scanning direction is performed. . In the projection of the spot light, the scanning mechanism is complicated as compared with the projection of the slit light, but the power required for the light source is small.

Conventionally, there has been known a method in which a plurality of slit lights are deflected by one rotating mirror and projected, and a plurality of ranges obtained by dividing a measurement target range are simultaneously scanned (Japanese Patent Application Laid-Open No. 62-63804). . A television camera is used for light reception, and an object is photographed for a certain period at each sampling point during scanning. By blinking each slit light in a different pattern and discriminating the blinking pattern from the photographing information for a certain period, it is possible to know at which position on the light receiving surface each slit light has entered at each sampling time. According to this method, it is possible to reduce the measurement time as compared with the case where one slit light scans the entire measurement range.

Conventionally, instead of a general CCD area sensor, a large number (for example, 128) of one-dimensional PDSs (position detection type photodetectors) are arranged side by side in the main scanning direction, and are used in a pseudo manner. A technique for forming a two-dimensional light receiving surface has been proposed. Each PSD outputs an analog signal corresponding to the light receiving position of the light incident on the band light receiving surface. According to the PSD, unlike the CCD, no charge accumulation is required, so that high-speed scanning is possible, and the resolution (resolution) in the sub-scanning direction, which is the deflection direction of the slit light, is improved.

[0006]

In the above-described method of projecting a plurality of slit lights, a plurality of frames must be photographed at each scanning position in order to determine a blinking pattern of the slit light. Is lower than when scanning with one slit light. That is, the measurement time is not reduced unless the number of slit lights is large to some extent.
Although the light projection system becomes complicated due to the increase in the number of light sources and blinking circuits, the effect of time reduction is small.

In the method of receiving light with a PSD array,
The resolution in the main scanning direction is determined by the number of arrangements of the PSDs. Since a head amplifier is required for each PSD, it is difficult to increase the number of arrays due to restrictions on the circuit scale.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the time required for scanning an object and to increase the resolution in both main scanning and sub-scanning directions.

[0009]

An apparatus according to the present invention projects a reference beam so as to scan the virtual plane toward a virtual plane, and at the time of passing through each sampling section obtained by subdividing the virtual plane. A three-dimensional input device that outputs data according to an incident angle of the reference light reflected by the input target object, wherein two or more n light sources that emit intensity-modulated lights having different modulation frequencies from each other as the reference light And deflecting means for guiding the intensity-modulated light emitted from each of the light sources to different sampling sections so as to scan the virtual plane while dividing the virtual plane into n, and provided so that the entire area of the virtual plane becomes a detection range. A two-dimensional position detection type photoelectric conversion device, and a photoelectric conversion signal obtained by the photoelectric conversion device, separated into the components of the respective modulation frequencies, and received light information corresponding to the incident angle of the respective intensity modulated lights. The and a signal processing means for outputting as said data.

In the three-dimensional input apparatus according to the second aspect of the present invention, the signal processing means may determine a position where the intensity-modulated light is reflected on the input target object from the respective components and the corresponding deflection angle information of the intensity-modulated light. Is calculated as the data.

[0011]

FIG. 1 is a diagram showing an outline of a three-dimensional input device 1 according to the present invention, and FIG. 2 is a block diagram of a signal processing circuit 50.

The three-dimensional measuring apparatus 1 includes a light projecting system 10 for projecting light beams L _{1 to} L _n so as to perform raster scanning toward a virtual plane VS, and light beams L ₁ to L ₁ reflected from an object Q to be measured. and a signal processing circuit 50 for outputting the distance data DP ₁ to DP _n corresponding to the incident angle of the light receiving system 20, and the light-receiving receiving L _n.

The light projecting system 10 includes n light sources 11 ₁ to 11.
1 _n, from the galvanometer mirror 16 is the light source 11 ₁ to 11 one by one to _n provided modulation circuit 12 ₁ to 12 _n, the galvanometer mirror 15, and the sub-scanning direction of the deflecting means is a main scanning direction of the deflecting means It is configured. Light source 11 ₁ to 11
_{As n} , a semiconductor laser (LD) is preferable, but a light emitting diode and a discharge lamp can also be used. Each of the galvanometer mirrors 15 and 16 is composed of a mirror for reflecting a light beam and an electromagnetic mechanism for rotating the mirror, and deflects a total of n light beams L _{1 to} L _n and guides them to the virtual plane VS.
The virtual plane VS is divided into n parts in the main scanning direction, and the n divided areas are scanned in parallel. Each light source 11 ₁ to 1
1 _n is used as a light source dedicated to one divided area.
A drive voltage is applied to the electromagnetic mechanisms of the galvanomirrors 15 and 16 from a control system (not shown). The main scanning is of a reciprocating type in which the direction of beam deflection is reversed every line.

The light receiving system 20 includes an imaging lens 21 and a light receiving device 25 for detecting the incident angles of the light beams L _{1 to} L _n . The light receiving device 25 is a two-dimensional position detection type photo detector (PSD) that outputs photoelectric conversion signals X1 and X2 according to the spot position of the light incident on the light receiving surface.
By using the PSD, scanning can be speeded up as much as charge accumulation is not required, as compared with the case of using a CCD imaging device.

The light receiving system 20 and the light projecting system 10 are arranged at a fixed distance from each other, and the positional relationship between them is known. Therefore, the light beams L ₁ to L
_If the incident angle of L _n is known, the light beam L _{1 on the} object Q
~L _n can be determined by applying triangulation to the distance between the reference position in the apparatus and the portion P ₁ to P _n which has been irradiated.
The incident angles of the light beams L _{1 to} L _n correspond to the distance between the center and the spot on the light receiving surface of the light receiving device 25. If the output of the light receiving device 25 is periodically sampled in the scanning period, each sampling section (in principle, a point) obtained by subdividing the virtual plane VS in the main scanning direction and the sub-scanning direction.
The depth of the object Q (the position in the direction orthogonal to the virtual plane VS) can be measured for each sp. That is, a distance image having the sampling section sp as a pixel can be obtained. However, the light receiving device 25 enters a plurality of light beams L ₁ ~L _n reflected by the object Q, the photoelectric conversion signals indicating the position of the irradiation range in which they overlap is output. Therefore, it is necessary to determine the spot position of the light beam L ₁ ~L _n on the light receiving surface.

The intensity-modulated by the modulation circuit 12 ₁ to 12 _n to the light source 11 ₁ to 11 _n in order to enable the determination of the spot position is performed, to a different value their modulation frequency f ₁ ~f _n mutually Is set. That is, each light beam L
₁ ~L _n are different intensity-modulated light having modulation frequencies. The signal processing circuit 50 has a filter circuit 53 composed of a total of 2n bandpass filters with each of the modulation frequencies f _{1 to} f _n as the center frequency of the transmission band, and converts each of the photoelectric conversion signals X1 and X2 to the frequency f. Separate into components of _{1 to} f _n .
The photoelectric conversion signals X1 and X2 amplified to appropriate levels by the amplifiers 51 and 52 are input to the filter circuit 53. The separated components of the frequencies f _{1 to} f _n are detected by the detection circuit 5.
4, the signals S1 _i and S2 _i (i = 1 to n) having a predetermined polarity.
And input to the distance calculation circuit 55 as incident angle information of each of the light beams L _{1 to} L _n . The distance calculation circuit 55 is composed of n circuit blocks having the same configuration, and the signals S1 _i , S2
_i generates and outputs a distance data DP ₁ to DP _n from.

FIG. 3 is a block diagram of the distance calculation circuit 55. In the drawing, only one of a total of n circuit blocks corresponding to each of the light beams L _{1 to} L _n is shown. The distance calculation circuit 55 includes a subtractor 551 and an adder 55
2, a divider 553, an A / D converter 554, and a look-up table (LUT) 555. By performing the calculation of the following expression for the signal S1 _i, S2 _i of the frequency f _i that is input from the detection circuit 54, obtained is incident position x of the light beam L _i on the light receiving surface.

X = (S1 _i −S2 _i ) / (S1 _i + S2 _i ) The received light data DX obtained by A / D converting the output of the divider 553 indicating the incident position x is used as LUT 555 as incident angle information.
Is input to The LUT 555 includes deflection angle data D as projection angle information from the drive system of the galvanometer mirror 16.
Y is input. LUT555 outputs a value which is previously stored in the address designated by the received data DX and the deflection angle data DY as the distance data DP _i.

FIG. 4 shows a galvanomirror 15 for main scanning.
FIG. 5 is a diagram showing an arrangement relationship between a light source and a light source, and FIG.
FIG. 4 is a schematic diagram of directional deflection. Light source 11₁~ 11_nIs the light
The axes pass through the central part of the reflecting surface of the galvanometer mirror 15 and
Are arranged so as to form an angle θ. Light source 11₁~ 11_nOr
The light beam emitted from the collimator lens 13₁~ 13
_nAnd is incident on the galvanometer mirror 15. Galva
The no-mirror 15 rotates within a range of the angle θ / 2. Each light source
11₁~ 11 _nThe light beam from
The light enters the different ranges of the vano mirror 16 and is collectively polarized.
Turned As shown in FIG.₁~ 11_nAnd garba
The central part of the reflection surface of the mirror 15 is on the same plane.
The axis of rotation of the Levano mirror 15 is orthogonal to the plane.

[0020]

According to the first or second aspect of the present invention,
The time required for scanning the object can be reduced, and the resolution in both the main scanning and sub-scanning directions can be increased.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a three-dimensional input device according to the present invention.

FIG. 2 is a block diagram of a signal processing circuit.

FIG. 3 is a block diagram of a distance calculation circuit.

FIG. 4 is a diagram showing an arrangement relationship between a galvanomirror and a light source for main scanning.

FIG. 5 is a schematic diagram of deflection of a light beam in a main scanning direction.

[Explanation of symbols]

1 three-dimensional input device VS virtual plane L ₁ ~L _n light beam (intensity modulation light) 15,16 galvanometer mirror (deflecting means) Q input object DP ₁ to DP _n distance data (data) 11 ₁ to 11 _n light sources 25 Light receiving device (photoelectric conversion device) 50 Signal processing means

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiichi Ide 2-3-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka International Building Minolta Co., Ltd. 2F065 AA04 AA06 AA19 AA53 DD03 DD06 FF01 FF09 FF44 GG06 GG07 GG23 JJ16 JJ26 LL13 LL62 MM16 NN06 NN08 QQ01 QQ03 QQ25 QQ26 QQ27 QQ33

Claims (2)

[Claims] 1. An incident angle of said reference light reflected from an input target object at a point in time when the reference light is projected so as to scan the virtual plane toward the virtual plane and passes through each sampling section obtained by subdividing the virtual plane. A three-dimensional input device that outputs data according to the following two or more n light sources that emit intensity-modulated lights having different modulation frequencies from each other as the reference light, and scans the virtual plane by dividing the virtual plane into n light sources. Deflecting means for guiding the intensity-modulated light emitted from each of the light sources to a different sampling section; a two-dimensional position detection-type photoelectric conversion device provided so that the entire area of the virtual plane is a detection range; A signal processing unit that separates the photoelectric conversion signal obtained by the conversion device into the components of the respective modulation frequencies, and outputs light reception information corresponding to the incident angle of the respective intensity modulated lights as the data. A three-dimensional input device comprising: a step; 2. The signal processing means includes arithmetic means for calculating a position of the input target object where the intensity-modulated light is reflected from the respective components and the corresponding deflection angle information of the intensity-modulated light as the data. The three-dimensional input device according to claim 1, wherein