KR102076478B1 - Optical Transceiver Using Movable Mirror, Three Dimensional Distance Measuring Apparatus, and Moving Object - Google Patents

Abstract

The present embodiments include (i) a first mirror having a hole through which light emitted from a light source passes, and a light beam reflected on a reflective surface formed as a curved surface, and (ii) light passing through the hole of the first mirror. By including a second mirror that reflects to the object, receives the light reflected from the object, reflects it to the first mirror, and moves in the vertical direction, minimizes the size and cost of the product without using an array type, and pinpoints with high performance. An optical transceiver capable of being measured, a three-dimensional distance measuring device, and a moving object are provided.

Description

Optical Transceiver Using Mobile Mirror, 3D Distance Measuring Apparatus, and Moving Object {Optical Transceiver Using Movable Mirror, Three Dimensional Distance Measuring Apparatus, and Moving Object}

The technical field to which this embodiment belongs relates to an optical transceiver using a movable mirror, a three-dimensional distance measuring device, and a moving object.

The contents described in this section merely provide background information for this embodiment, and do not constitute a prior art.

The 3D distance measurement system measures the distance of a space using various sensors such as a Charge Coupled Device (CCD) image sensor, a Complementary Metal Oxide Semiconductor (CMOS) image sensor, an ultrasonic sensor, and a laser sensor.

A typical 3D distance measurement system scans a space by rotating a 2D distance sensor that scans a plane including the center of the sensor. Since the apparatus using such a two-dimensional distance sensor does not limit cost, size, and sampling rate, there is a limit to production as a commercial product for research purposes.

A device to which a 2D photodiode array is applied measures a distance using a structure light or a time of flight. Structural light is a method of projecting an intrinsic pattern and detecting a corresponding point to calculate depth, and flight time is a method of measuring time difference or phase difference and converting it to a distance. A device to which a 2D photodiode array is applied has a problem in that it is difficult to widen an angle of view and it is difficult to measure pin points due to the large amount of 3D information per pixel.

The distance measuring device to which the one-dimensional photodiode array is applied includes a photodiode array and a laser diode array (or laser diode and diffuser). The photodiode array has a structure in which hundreds to thousands of photodiodes are arranged in a straight line on silicon crystals. The distance measuring device to which the 1D photodiode array is applied is difficult to widen the field of view, and it is difficult to produce it as a commercial product because modules such as high-efficiency diffusers, sensor arrays, and MEMS mirrors required for implementation are expensive. have.

Embodiments of the present invention include (i) a first mirror having a focus through which a light beam reflected by a reflective surface formed by a curved surface formed by passing a light emitted from a light source and (ii) passing through the hole of the first mirror By including the second mirror that reflects light to the object, receives the light reflected from the object, reflects it to the first mirror, and moves in the vertical direction, minimizes the size and cost of the product without using an array type, and pins with high performance The main purpose of the invention is to measure points.

Still other unspecified objects of the present invention can be further considered within the scope of being easily deduced from the following detailed description and its effects.

According to an aspect of this embodiment, a light source that emits light, a first mirror including a hole through which the emitted light passes, reflects light passing through the hole of the first mirror to an object, and reflects from the object It provides an optical transceiver including a second mirror that receives the reflected light and reflects it to the first mirror, and a photodiode that receives the light reflected from the second mirror and converts it into an electrical signal.

According to another aspect of the present embodiment, an optical transceiver that emits light to an object by a start control signal and receives light reflected by the object and converts it into an electrical signal, converts the electrical signal to generate a stop control signal, and It includes a distance meter for measuring the distance by calculating the flight time based on the time difference between the start control signal and the stop control signal, the optical transceiver includes a light source for emitting light, a hole for passing the emitted light, , A first mirror having a focus where light rays reflected on a reflective surface formed as a curved surface are collected, and reflects light passing through the hole of the first mirror to the object, and receives the reflected light from the object to receive the first mirror A second mirror that reflects to, a reflector positioned at the focal point of the first mirror to receive and reflect light reflected from the first mirror, the And a photodiode for receiving the light reflected from the carcass and converting it into an electrical signal, and a rotating part for rotating the light source, the first mirror, the second mirror, the reflector, and the photodiode about an axis of rotation. It provides a distance measuring device.

According to another aspect of the present embodiment, in a moving object, a distance measuring device for calculating a flight time between the moving object and the object to measure the distance to the object, and implemented to move the moving object based on the distance to the object It includes a mobile device, the distance measuring device, the optical transceiver for emitting light to the object by the start control signal and receiving the light reflected by the object to convert to an electrical signal, converting the electrical signal to a stop control signal And a distance meter that measures a distance by calculating a flight time based on a time difference between the start control signal and the stop control signal, and the optical transceiver passes through a light source emitting light and the emitted light A first mirror including a hole, and having a focus where light rays reflected on a reflective surface formed as a curved surface gather, A second mirror that reflects light passing through the hole of the first mirror to the object, receives the light reflected from the object, and reflects the light to the first mirror, is positioned at the focal point of the first mirror, and the first A reflector that receives and reflects the light reflected from the mirror, a photodiode that receives the light reflected from the reflector and converts it into an electrical signal, and the light source, the first mirror, the second mirror, the reflector, and the photodiode It provides a moving body characterized in that it comprises a rotating portion for rotating relative to the rotation axis.

As described above, according to embodiments of the present invention, (i) a first mirror including a hole through which light emitted from a light source passes, and a focal point where light rays reflected on a reflective surface formed as a curved surface gather, and (ii) By including the second mirror moving in the vertical direction by reflecting the light passing through the hole of the first mirror to the object, receiving the light reflected from the object, and reflecting the first mirror, the size of the product without using an array type and It has the effect of minimizing cost and measuring pin points with high performance.

Even if the effects are not explicitly mentioned here, the effects described in the following specification expected by the technical features of the present invention and the potential effects thereof are treated as described in the specification of the present invention.

1 is a block diagram illustrating a moving object according to an embodiment of the present invention.
2 is a view illustrating a moving body according to an embodiment of the present invention.
3 is a block diagram illustrating a distance measuring device according to another embodiment of the present invention.
4 and 5 are block diagrams illustrating an optical transceiver according to other embodiments of the present invention.
6 is a diagram illustrating a structure of an optical transceiver and a path of movement of light according to another embodiment of the present invention.
7 and 8 are diagrams illustrating a method of moving a movable mirror of an optical transceiver according to another embodiment of the present invention.
9 and 10 are views illustrating three-dimensional information acquired by a distance measuring device according to embodiments of the present invention.

Hereinafter, when it is determined that the subject matter of the present invention may be unnecessarily obscured by those skilled in the art with respect to known functions related to the present invention, the detailed description will be omitted, and some embodiments of the present invention will be omitted. It will be described in detail through exemplary drawings.

1 is a block diagram illustrating a moving object according to an embodiment of the present invention.

As shown in FIG. 1, the moving object 1 includes a distance measuring device 10 and a moving device 20. The movable body 1 may omit some components from among various components illustrated in FIG. 1 or additionally include other components. For example, the moving body may further include a cleaning part.

The moving body 1 means a device designed to be moved from a specific location to another location according to a predefined method, and can be moved from a specific location to another location by using moving means such as wheels, rails, and walking legs. . The moving object 1 may collect external information using a sensor or the like and then move according to the collected information, or may be moved by a user using a separate manipulation means.

Examples of the mobile body 1 may include a robot cleaner, a toy car, a mobile robot that can be used for industrial or military purposes, etc., and the mobile body 1 travels using wheels or walks using one or more legs, or the like. , Combinations of these, and the like.

The robot cleaner is a device that automatically cleans the cleaning space by driving foreign matter such as dust accumulated on the floor while driving in the cleaning space. Unlike a general vacuum cleaner that is moved by an external force by a user, the robot vacuum cleaner cleans the cleaning space while moving using external information or a predefined movement pattern.

The robot cleaner may move automatically using a predefined pattern, or after detecting an external obstacle by a detection sensor, move according to the sensed signal, or according to a signal transmitted from a remote control device operated by a user. It is movable.

The sensing sensor can be implemented with LIDAR. A lidar is a device that shoots a laser signal, measures the time it returns after being reflected, and measures the distance of the reflector using the speed of light. The laser signal is converted into an electrical signal through a photodiode. The laser signal may have a preset wavelength band.

2 is a view illustrating a moving body according to an embodiment of the present invention.

Referring to FIG. 2, a distance measuring device 10 for calculating a flight time between a moving object and an object and measuring a distance to the object is located at the upper end of the main body, but this is only an example and is not limited thereto. Therefore, it can be implemented in one or more at a suitable location.

The distance measuring device 10 transmits and receives light using a pair of light sources and a photodiode, and scans the surroundings in three dimensions using a movable mirror and a rotating body.

The distance measuring device 10 may operate in a time of flight (TOF) method. The time-of-flight method measures the distance between a measurement target and a distance measuring device by measuring the time at which the laser pulses or square wave signals from objects within a measurement range arrive at the receiver by emitting a pulse or square wave signal.

The moving device 20 calculates a driving route based on the distance to the object or detects an obstacle to move the moving object. The moving device 20 may move the moving object based on the relative position of the artificial marker. The moving device 20 may be implemented as a moving means such as wheels, rails, and walking legs.

Hereinafter, with reference to Figure 3 will be described a distance measuring device that is implemented in the mobile body or operates independently.

3 is a block diagram illustrating a distance measuring device. As shown in FIG. 3, the distance measuring device 10 includes an optical transceiver 100 and a distance meter 200. The distance measuring device 10 may omit some components from among various components illustrated in FIG. 3 or additionally include other components. For example, the distance measuring device 10 may further include an interface.

The optical transceiver 100 transmits a laser signal and receives a reflected signal. The optical transceiver 100 emits light to the object by the start control signal, receives the light reflected by the object, and converts it into an electrical signal. The optical transceiver 100 outputs an electrical signal for a preset detection time.

The optical transceiver 100 converts light into current or voltage, and requires a circuit for buffering and scaling the output of the photodiode. For example, a Trans Impedance Amplifier (TIA) may be connected to the photodiode. The transimpedance amplifier amplifies the current of the photodiode, converts it into a voltage, and outputs it. Transimpedance amplifiers can be divided into R-TIA (Resistive Feedback TIA) and C-TIA (Capacitive Feedback TIA).

The optical transceiver 100 may include a signal converter. A signal converter may be connected to the photodiode of the optical transceiver 100, and a transimpedance amplifier may be connected to the signal converter.

The light source emits light to the object based on a preset sampling period. The sampling period may be set by the control unit of the distance measuring device 10. The sampling period is a time until the optical transceiver 100 emits light according to the start control signal, receives the reflected light, and converts the light into an electrical signal. The optical transceiver 100 may repeat these operations in the next sampling period.

The photodiode receives the light reflected by the object and converts it into an electrical signal. The photodiode may be implemented as a PN junction photodiode, a PIN photodiode, an avalanche photo diode (APD), or the like. The photodiode outputs an electrical signal until the photocarrier disappears. Moreover, as the size of the output signal increases, the time required for the signal to disappear is increased.

The signal converting unit outputs the electrical signal during the detection time during the sampling period so as not to be limited to the extinction time of the output signal. The signal conversion unit may include a resistor, a switch, and a capacitor.

The resistor is connected to the photodiode. One end of the resistor is connected to the photodiode and the other end of the resistor is connected to ground. The resistor can be connected to the anode or cathode of the photodiode.

When the resistance value is small, the waveform has a non-zero value for a time similar to the time when the light passes through the photodiode, but there is a problem in that the output signal is small in size. Therefore, it is necessary to amplify the magnitude of the electrical signal using a resistor having a value greater than a preset value for the resistor. In this case, a signal lag occurs.

In order to solve the signal distortion, the transmission path of the electrical signal is changed through a switch. The optical transceiver 100 may output a signal in which a part of an area in which the size of the electrical signal is reduced is removed. Even if the rear end of the electrical signal is removed, the distance measuring device 10 can measure the distance. This is because the signal discriminator does not detect the end point of the electrical signal, but detects the start point and the maximum size point of the electrical signal and outputs a rising edge and a falling edge.

The switch is connected in parallel to the resistor to change the transmission path of the electrical signal. For example, the switch can be implemented with a transistor or the like.

Switch the electrical signal during the off time (T _c) in (i) the sampling period (T _s) detected time (T _d) passing an electrical signal into a first path and, (ii) the sampling period (T _s) while in 2 Pass by route. The first path is the path through which the signal is passed through the capacitor, and the second path is the path through which the signal is passed through the switch to ground.

The distance measuring device 10 is in the sampling cycle without having to wait for the signal to disappear even if the signal extinction time (T1, T2, T3) is required due to the phenomenon that the electrical signal output from the photodiode 140 is twisted. Therefore, the signal can be processed.

The distance measuring device 10 adjusts the sampling period, calculates and sets an appropriate detection time according to the sampling period, and controls the on-off operation of the switch 152. The control unit of the distance measuring device 10 includes sampling period, detection time, cutoff time, waveform of emitted light, on / off time interval of light source, pulse width of start control signal, pulse width of stop control signal, rotation speed of optical transceiver, The on / off operation of the switch can be controlled by referring to signal processing and waiting time of the signal discriminator and the time calculator.

The capacitor is connected to the point where the photodiode and resistor are connected to output an electrical signal. The capacitor serves to remove the DC component of the electrical signal. A non-inverting amplifier circuit may be connected to the rear end of the capacitor.

The distance meter 200 may include one or more signal discriminators that convert electrical signals to measure an accurate time point and output a stop control signal.

The distance meter 200 converts the electrical signal to a signal point having the maximum signal size to have a predetermined size by using a signal discriminator, adjusts the size of the converted electrical signal, and detects a time point having a predetermined size. . The signal discriminator converts the electrical signal to generate a stop control signal.

The signal discriminator receives an electrical signal from a photodiode or transimpedance amplifier. The received electrical signal, that is, the input signal has a form of rising and falling by the reflected light. The signal discriminator accurately measures a desired time point for the input signal and outputs an electrical signal.

Depending on the type of the input signal, the input signal has a front time point (T _front ), a target time point (T ₁ , T ₂ ) that meets a set threshold, and a peak time point (T _max ). The signal discriminator performs a two-step conversion process to detect a time point closest to the _front end point (T _front ) and the peak point (T _max ). The converted signal has a front end (T _front ), a rising point (T _rising1 , T _rising2 ) meeting a set threshold, a falling time (T _falling1 , T _falling2 ), and a rear end point (T _end ) meeting the set threshold. The rear end time point T _end is the same time point as the peak time point T _max of the signal before conversion.

The signal discriminator converts the input signal or converts the input signal using a constant fractionation discriminator (CFD). Determining a certain fraction is a method of finding a point in time at which the point at which the original signal is delayed and the signal adjusted by a predetermined size ratio become the same as the predetermined ratio of the maximum size.

The signal discriminator measures an accurate time point from the rising and falling electric signal and outputs the signal. The signal discriminator converts the electrical signal and detects a time point having a preset reference size to generate a stop control signal. If the slope of the input signal is converted so that the signal point having the maximum signal size has a predetermined size, the rising point (T _rising1 , T _rising2 ) is closer to the _front point (T _front ) and the falling point (T _falling1 , T _falling2 ) is It becomes closer to the T _end .

The signal discriminator adjusts the magnitude of the converted input signal. The signal discriminator amplifies the magnitude of the converted input signal by N (where N is a natural number). The signal discriminator converts the signal to have a slope close to vertical through a plurality of amplification processes. Since the slope is large, it is possible to obtain an accurate point of view even if the circuit is simply implemented with a comparator.

The signal discriminator converts an input signal such that a signal point having a maximum signal size in the input signal has a predetermined size. For example, the signal is converted to zero. The distance measurer 200 may detect a point in time close to the point in time with the maximum size by converting the point in time with the maximum size to zero to compare the threshold.

The signal discriminator detects at least one viewpoint having a preset reference size from the input signal whose size is adjusted, and outputs a signal. Here, the output signal may be of two types. For example, the range finder 200 may output rising and falling edges.

The distance meter 200 measures time and distance in a time-of-flight manner. The distance measurer 200 measures the distance by calculating the flight time based on the time difference between the start control signal and the stop control signal. The distance meter 200 calculates a distance from time using the speed of light.

The distance meter 200 may include one or more time digital converters that convert the difference between the two times into digital values. The input signal of the time-to-digital converter may be in the form of a pulse of the same signal source or an edge of another signal source. For example, the distance measuring device 10 may calculate a time difference based on the rising edge or falling edge of the start control signal and the rising edge or falling edge of the stop control signal.

The time digital converter may be composed of a time delay element and a flip-flop. The time delay device may be implemented as a digital device using an inverter or an analog device using a current source. Various methods such as a phase deviation method, a method using a high resolution clock, and an equivalent time sampling method can be applied to the time digital converter.

The time digital converter uses (i) the number counted by the coarse counter and the fine counter (N ₁ , N ₂ ) and (ii) the time by using the large clock of the normal counter and the small clock of the precision counter. Measure. The time difference between the large clock of the counter and the small clock of the precision counter usually determines the resolution of the time digital converter.

The time-to-digital converter includes a slow oscillator that generates a large clock and a fast oscillator that generates a small clock. A phase detector detects when a large clock and a small clock are synchronized.

In conventional time digital converters, slow oscillators and fast oscillators adjust the number of buffers to adjust the clock width. The conventional time-to-digital converter has a resolution of 80 picoseconds (ps) due to the signal delay time of the buffer itself.

The time-to-digital converter adjusts the clock width by changing the position and signal path of the gates on the circuit to the slow and fast oscillators. For example, a slow oscillator and a fast oscillator can be combined into the same gate. The slow and fast oscillators of the time-to-digital converter according to this embodiment change the position and signal path of the gates, so that the time-to-digital converter has a resolution of about 10 picoseconds (ps).

The time-to-digital converter handles the rising and falling edges together, so you can design by sharing a slow or fast oscillator.

The interface is a communication path that transmits and receives information to and from other devices (or hosts). Other devices may connect to the distance measuring device 10 through an interface to set parameters. The distance measuring device 10 may transmit the time and distance measured through the interface to another device.

When the distance measuring device 10 applies the differential method implemented by the RC circuit in the process of converting the slope of the signal, the frequency characteristic of the signal changes according to the distance change to generate a time error. If a certain fractional discrimination method is applied in the process of converting the slope of the signal, the slope of the signal is different, so the charging time of the capacitor of the comparator is different and the response time of the comparator is different to generate a time error. Therefore, the distance measuring device 10 performs a process of correcting the time error.

The distance meter 200 corrects the flight time using the pulse width of the stop control signal. Since the pulse width of the output signal of a general photodiode is severely changed, there is a problem in that it is difficult to use the pulse width to work error when it is not in a close region by matching 1 to N. Since this embodiment has undergone a process of converting a signal, it is possible to simply model the relationship between the pulse width and the work error.

The distance meter 200 models the function between the work error and the pulse width, and measures the correction factor in advance. The distance meter 200 corrects the flight time by applying a correction factor inversely proportional to the pulse width. Since the intensity of the reflected signal is weak and the pulse width is narrow, the work error increases, so the distance meter 200 sets a large correction factor. Since the intensity of the reflected signal is strong and the pulse width is wide, the work error is small, so the distance meter 200 sets the correction factor to be small.

The distance meter 200 calculates the pulse width based on the rising edge or falling edge of the stop control signal, and adds the factor value applied to the function of the pulse width vs. work error to the flight time before correction. The distance measuring device 10 may calculate an accurate flight time by correcting the flight time using the pulse width of the reflected signal.

Hereinafter, a structure of an optical transceiver capable of 3D scanning will be described with reference to FIGS. 4 to 8.

Referring to FIG. 4, the optical transceiver 100 includes a light source 110, a first mirror 120, a second mirror 130, and a photodiode 140. The optical transceiver 100 may omit some of the various components exemplarily illustrated in FIG. 4 or additionally include other components. Referring to FIG. 5, the optical transceiver 100 includes a reflector 150, a rotating unit 160, a point adjusting unit 112, a reference angle adjusting unit 132, a moving angle adjusting unit 134, and a vertical frequency adjusting unit ( 136), the horizontal frequency control unit 162, or a combination thereof.

The light source 110 is a device that emits light, and may be implemented as a laser diode (LD). The light source may generate a nanosecond laser pulse signal. The laser signal may have a preset wavelength band. The light source 110 may be connected to a point control unit 112 for controlling the number of point group data acquired per unit time by adjusting a speed at which the light source emits based on a preset sampling period. For example, the point adjusting unit 112 may set the emission speed of the light source 110 to obtain 10K points per second.

The first mirror 120 includes a hole through which the emitted light passes. That is, a hole is formed through the reflective surface. The optical transceiver 100 forms a movement path of light to pass through the first mirror 120, thereby minimizing the size of the optical transceiver 100 while maintaining a straight path of light from the light source 110 to the second mirror 130. You can. The reflective surface of the first mirror 120 does not employ optical components such as a two-way mirror or a half mirror that transmits a portion of light, and thus is not employed because it generally reduces sensitivity, and is holed in the center of the mirror And a few mm of light passes therethrough to form a path for the light to travel to the second mirror 130.

The first mirror 120 is formed as a curved surface and has a focus where light rays reflected on the reflective surface of the first mirror 120 are collected. The size of the reflective surface of the first mirror 120 has an appropriate size based on the distribution of light reflecting according to the angle of the moving second mirror 130. The first mirror 120 performs a condensing and reflection function using a parabolic reflective mirror (a lens and a mirror). That is, the light reflected back through the second mirror 130 is collected and sent to the reflector 150.

The reflector 150 is positioned at the focal point of the first mirror 120 by the curved surface. The reflector 150 receives light reflected from the first mirror 120 and reflects the light to the photodiode 140. Although the photodiode 140 may directly receive the reflected rays due to the curved surface of the first mirror 120, the reflected rays due to the curved surface of the first mirror 120 may pass through the reflector 150 to the photodiode 140. It can move in the vertical direction. That is, the reflected rays may form a parallel straight path or a straight path before entering the photodiode 140. The photodiode 140 is positioned on a virtual straight path passing through the focal point of the first mirror 120.

The second mirror 130 reflects the light passing through the hole of the first mirror to the object, and receives the reflected light from the object and reflects the light to the first mirror. The second mirror 130 moves at a predetermined period to change the slope of the normal of the second mirror. The second mirror 130 is a movable mirror, and can move in a bending motion, a shaking motion, a reciprocating motion, a seesaw motion, a rotation motion, or a combination thereof. For example, it can be implemented as a swing mirror.

A reference angle adjusting unit 132 for adjusting the angle at which the second mirror 130 is installed may be connected to the second mirror 130. For example, the reference angle adjusting unit 132 may set the normal of the second mirror 130 to -55 degrees based on the horizontal surface of the ground, and set the second mirror 130 to be inclined at 45 degrees.

The second mirror 130 may be connected to a movement angle adjusting unit 134 for changing the angle at which the second mirror 130 moves. For example, the movement angle adjusting unit 134 may set the second mirror 130 to swing +/- 10 degrees.

The second mirror 130 may be connected to a vertical frequency adjusting unit 136 that changes a period in which the second mirror 130 moves in the vertical direction. For example, the vertical frequency control unit 136 may set the second mirror 130 to oscillate at 200 Hz.

The photodiode 140 is a device that receives light reflected from the second mirror 130 or a reflector and converts it into an electrical signal. In the photodiode 140, when light of photon energy strikes the diode, a principle in which electrons are active because mobile electrons and positive charge holes are generated may be applied. The photodiode 140 may be implemented as a PN junction photodiode, a PIN photodiode, an avalanche photodiode (APD), or the like.

The optical transceiver 100 adjusts a moving path and angle of light using a moving second mirror 130 to secure a vertical field of view, thereby converting it into a conventional single lens and photodiode array. Unlike the implemented device, pin point measurement is possible.

The optical transceiver 100 may include a transmitting optical unit and a receiving optical unit. The transmitting optical section and the receiving optical section are paths of the laser signal, and may be formed in a barrel structure. The optical transceiver 100 may set the angles of the plurality of mirrors differently to simultaneously detect obstacles in the horizontal direction and the ground direction. Obstacles can be detected in all directions by connecting mirrors to the transmitting and receiving optics and rotating the transmitting and receiving optics, respectively. For example, the scan lines may be set at 45 degrees and 60 degrees, respectively, or may be composed of two or more.

The optical transceiver 100 may include a rotating unit 160. The optical transceiver 100 performs horizontal scanning through the rotating unit 160. The rotating unit 160 rotates the light source 110, the first mirror 120, the second mirror 130, and the photodiode 140 based on the rotation axis. The light source 110 and the photodiode 140 are installed on a support and operate a driving device such as a motor connected to the support.

A horizontal frequency adjusting unit 162 for adjusting the rotation speed of the rotating unit 160 may be connected to the rotating unit 160. For example, the horizontal frequency adjusting unit 162 may be set to rotate the rotating unit 160 at 5 Hz.

Referring to FIG. 6, light emitted from the light source 110 may form a movement path from ① to ⑥.

① Light emitted from the light source 110 passes through the hole of the first mirror 120 and moves in a straight path to the second mirror 130. The light emitted from the light source 110 may be collimated through a collimator. The collimator makes the incident beam parallel.

② The light reflected from the moving second mirror 130 moves to the object 2 according to the angle of the second mirror 130.

③ The light reflected from the object 2 moves to the second mirror 130 in a straight path.

④ Light reflected from the moving second mirror 130 moves to the first mirror 120.

⑤ Light collected from the first mirror 120 moves to the reflector 150.

⑥ The light reflected from the reflector 150 moves in a straight path to the photodiode 140.

As illustrated in FIG. 6, by arranging the holes of the first mirror, the second mirror, the reflector, and the photodiode to adjust the movement path of the light, the light source and the photodiode are positioned adjacent to each other, so that the light transceiver 100 and the rotating body To minimize the size of, it is possible to minimize the radius of rotation of the rotating body (160).

7 and 8 are diagrams illustrating a method of moving the movable mirror of the optical transceiver.

Referring to FIG. 7, the second mirror 130, which is a movable mirror, may move using electromagnetic force by a magnet and a coil. The center of the mirror has a soft hinge and permanent magnets at both ends. The coil is placed at the end (or close to the end) of the back side of the reflective surface. The second mirror is shaken when a current is flowed by periodically changing the direction of the coil. Here, since the force generated by the magnet and the coil is small, in order for the second mirror 130 or the normal 135 of the second mirror 130 to move at a high frequency, it is necessary to use a material capable of smoothly moving the hinge. . As the tension of the hinge is stronger, the second mirror 130 may move even with less force, but it is difficult to make high-frequency movement.

The movable mirror may use MEMS technology or use an ultrasonic motor (Piezo Motor), and it is preferable to operate in a structure as shown in FIG. 7 in consideration of the cost ratio.

7, the vertical scanning speed may be low, and a method of rotating the polyhedron by connecting the motor may be applied. In FIG. 8, the second mirror 130, which is a movable mirror, is formed of a polygonal column, and a structure capable of rotating and rotating the rotation axis is illustrated. The optical transceiver may adjust the relationship between the rotational speed of the second mirror 130 and the emission speed of the light source to differently adjust the inclination of the normal of the reflective surface at periodic viewpoints.

The distance measuring device 10 adjusts the vertical scanning movement of the second mirror through a control unit implemented by an FPGA or the like. The control unit periodically sends a +/- signal to swing the second mirror. If the signal is a periodic waveform, the angle of the mirror is constant according to the periodic viewpoint. If necessary, the PSD sensor can be mounted on the back of the mirror to measure the angle.

The distance measuring device 10 controls horizontal rotational movement through a control unit implemented by an FPGA or the like. The control unit controls the rotation speed of the rotating unit and measures the rotation angle through an encoder inside or outside the rotating body.

The control unit for adjusting the vertical scanning movement of the second mirror and the control unit for adjusting the horizontal rotation movement may be implemented as independent modules.

The distance meter 200 receives the vertical angle from the control unit that controls the vertical scanning movement of the second mirror, receives the horizontal angle from the control unit that controls the horizontal rotational movement, and stores the vertical angle and the horizontal angle.

The distance measuring device 10 receives the light emitted from the light source from the photodiode, and calculates the inter-plane (ToF). The distance measuring device 10 transmits a vertical angle, a horizontal angle, and a flight time to the host through the interface. Inter-aircraft can be calibrated or calibrated. The distance measuring device 10 may transmit data to the host after performing filtering to remove noise for at least one of vertical angle, horizontal angle, and flight time.

9 and 10 are diagrams illustrating 3D information acquired by a distance measuring device. The location unit of the point cloud data shown in FIGS. 9 and 10 is a meter.

The point group data obtained using the optical transceiver having the structure shown in FIG. 6 is illustrated in FIG. 9. (i) the normal of the movable mirror is set to -55 degrees relative to the horizontal plane of the ground, the movable mirror is set to be inclined at 45 degrees, (ii) the rotating part is set to rotate at 5 Hz, and (iii) the movable mirror is + / -When swinging at an angle of 10 degrees and setting to vibrate at 200 Hz, (iv) setting the emission rate of the light source or the sampling rate of the distance measuring device to obtain 10K points per second, the distance measuring device is three-dimensional as shown in FIG. Can acquire point cloud data of.

An application that must measure the bottom surface together can acquire point cloud data as shown in FIG. 10. (i) set the normal of the movable mirror to -55 degrees relative to the horizontal plane of the ground, (ii) set the rotating part to rotate at 10 Hz, (iii) swing the movable mirror at an angle of +/- 10 degrees and swing at 800 Hz Set to vibrate to, (iv) set the light emission rate or the sampling rate of the distance measuring device to obtain 10K points per second, and (v) set the height of the optical transceiver to 0.1 meters, the distance measuring device 3D point cloud data shown in FIG.

The numerical values set by the point adjusting unit 112, the reference angle adjusting unit 132, the moving angle adjusting unit 134, the vertical frequency adjusting unit 136, and the horizontal frequency adjusting unit 162 are suitable according to the design to be implemented. Values can be used.

Although the components included in the distance measuring device and the optical transceiver are shown separately in FIGS. 3 to 5, a plurality of components may be combined with each other and implemented as at least one module. The components are connected to a communication path connecting a software module or hardware module inside the device to operate organically with each other. These components communicate using one or more communication buses or signal lines.

The distance measuring device and the distance measuring device may be implemented in a logic circuit by hardware, firmware, software, or a combination thereof, or may be implemented using a general purpose or special purpose computer. The device may be implemented using a fixed-wired device, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or the like. In addition, the device may be implemented as a System on Chip (SoC) including one or more processors and controllers.

The distance measuring device and the distance measuring device may be mounted on a computing device provided with hardware elements in software, hardware, or a combination thereof. Computing devices include various devices or communication devices such as communication modems for performing communication with wired / wireless communication networks, memory for storing data for executing programs, and microprocessors for executing and calculating and executing programs. It can mean a device.

The operation according to the present embodiments may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. Computer readable media refers to any media that participates in providing instructions to a processor for execution. Computer-readable media may include program instructions, data files, data structures, or combinations thereof. For example, there may be a magnetic medium, an optical recording medium, a memory, and the like. The computer program may be distributed over a networked computer system to store and execute computer readable code in a distributed manner. Functional programs, codes, and code segments for implementing the present embodiment can be easily deduced by programmers in the technical field to which the present embodiment belongs.

The present embodiments are for explaining the technical spirit of the present embodiment, and the scope of the technical spirit of the present embodiment is not limited by these examples. The protection scope of the present embodiment should be interpreted by the claims below, and all technical spirits within the equivalent range should be interpreted as being included in the scope of the present embodiment.

1: moving body 10: distance measuring device
20: mobile device 100: optical transceiver
110: light source 120: first mirror
130: second mirror 140: photodiode
150: reflector 160: rotating part
200: distance meter

Claims (16)

In the distance measuring device,
An optical transceiver that emits light to an object by a start control signal and receives light reflected from the object and converts it into an electrical signal;
Convert the electrical signal to generate a stop control signal, and calculate the flight time using a time digital converter that adjusts the position of the logic element included in the oscillator based on the time difference between the start control signal and the stop control signal. It includes a distance meter for measuring,
The optical transceiver,
A light source that emits light;
A movable mirror that reflects the light to an object and receives and reflects light reflected from the object; And
And a photo diode that receives light reflected from the movable mirror and converts it into the electrical signal.
The time digital converter,
A slow oscillator generating a first clock;
A fast oscillator generating a second clock smaller than the first clock;
A normal counter for counting the first clock of the slow oscillator;
A precision counter counting the second clock of the fast oscillator; And
And a phase detector configured to detect a time point when the first clock and the second clock are synchronized. delete delete According to claim 1,
The movable mirror moves at a predetermined period to change the slope of the normal of the movable mirror. According to claim 4,
The movable mirror is a distance measuring device characterized in that it moves in a bending motion, a tremor motion, a reciprocating motion, a seesaw motion, a rotation motion, or a combination thereof. According to claim 4,
The movable mirror is a distance measuring device characterized in that it moves using electromagnetic force by a magnet and a coil. According to claim 4,
The movable mirror is formed of a polygonal column, and the distance measuring device is characterized in that it rotates and moves. According to claim 4,
Distance measuring device further comprises a reference angle adjusting unit for adjusting the angle at which the movable mirror is installed. According to claim 4,
Distance measuring device further comprises a moving angle adjusting unit for changing the angle at which the movable mirror moves. According to claim 4,
Distance measuring device further comprises a vertical frequency control unit for changing the period in which the movable mirror moves in the vertical direction. According to claim 1,
A distance measuring device further comprising a rotating part that rotates the light source, the movable mirror, and the photodiode about an axis of rotation. The method of claim 11,
Distance measuring device further comprises a horizontal frequency adjusting unit for adjusting the rotation speed of the rotating unit. According to claim 1,
A distance measuring device further comprising a point control unit for controlling the number of point group data acquired per unit time by adjusting the speed at which the light source emits based on a preset sampling period. delete delete In the mobile body,
A distance measuring device that measures a distance to the object by calculating a flight time between the moving object and the object; And
And a moving device implemented to move the moving object based on the distance to the object,
The distance measuring device,
An optical transceiver that emits light to an object by a start control signal and receives light reflected from the object and converts it into an electrical signal;
Convert the electrical signal to generate a stop control signal, and calculate the flight time using a time digital converter that adjusts the position of the logic element included in the oscillator based on the time difference between the start control signal and the stop control signal. It includes a distance meter for measuring,
The optical transceiver,
A light source that emits light;
A movable mirror that reflects the light to the object and receives and reflects light reflected from the object;
A photo diode that receives light reflected from the movable mirror and converts it into the electrical signal; And
And a rotating part rotating the light source, the movable mirror, and the photodiode about an axis of rotation,
The time digital converter,
A slow oscillator generating a first clock;
A fast oscillator generating a second clock smaller than the first clock;
A normal counter for counting the first clock of the slow oscillator;
A precision counter counting the second clock of the fast oscillator; And
And a phase detector configured to detect a point in time at which the first clock and the second clock are synchronized.

Images