Lidar device and method of operating the same

Abstract

To provide: a LiDAR device which enables acquisition of additional intensity data from wasted pixels in a receiver by utilizing a circuit (counter) used in a TDC (time-to-digital converter); and a method of operating the same.SOLUTION: A LiDAR device according to an embodiment of the present invention includes: a transmitter for transmitting laser light towards a target; and a receiver for receiving a reflected laser light signal reflected by the target. The receiver includes a plurality of column circuits connected to sensors in the receiver through N (N is a natural number equal to or greater than 2) independent channels for each column of a pixel array corresponding to the sensors in the receiver.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] Embodiments of the present invention relate to a rider device and an operation method thereof.

Background Art

[0002] In recent years, with the increasing interest in self-driving cars and driverless cars, LiDAR (Light Detection and Ranging) has attracted attention. A LiDAR is a device that uses a laser to obtain distance information about the surroundings. Thanks to its excellent accuracy and resolution and the advantage of being able to grasp objects in three dimensions, it tends to be applied not only to automobiles but also to various fields such as drones and airplanes.

[0003] Conventionally, the entire array of the LiDAR transceiver operates according to a pre-designed operation algorithm. At this time, the histogram method is used as the noise processing method. The histogram method is a method of accumulating a large number of measurement values (Interframe) to obtain one TOF (Time Of Flight) result (1Frame). The FPS (Frame Per Sec), which is the Frame update speed per second, is one of the main performance indicators of the LiDAR.

[0004] According to such a conventional technology, as the resolution (number of Pixels) of the receiving unit increases, the area of the receiving unit that one pixel of the transmitting unit has to cover increases. Due to the limitation of the number of ROICs including TDC (counter) (one per column), there is a problem that the area of the receiving unit required during operation is generated.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] One embodiment of the present invention provides a lidar device and an operation method thereof that utilize a circuit (counter) used in a TDC to additionally acquire intensity data from wasted pixels in a receiving unit.

[0007] The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

Means for Solving the Problems

[0008] A lidar device according to an embodiment of the present invention includes a transmitting unit that transmits a laser to a target, and a receiving unit that receives a reflected signal of the laser reflected back from the target. The receiving unit includes a plurality of column circuits connected to sensors of the receiving unit via N (N is a natural number of 2 or more) independent channels for each column of a pixel array corresponding to the sensors of the receiving unit.

[0009] The receiving unit may further include a sensor array module in which sensors of the receiving unit are configured such that, for each column of the pixel array, the number of sensors of the receiving unit per row is N times that of the sensors of the transmitting unit.

[0010] Based on a control signal transmitted via a column scanner, the column circuit can alternately operate sensors of the receiving unit for each row of the pixel array and process a sensor reaction of the receiving unit to the reflected signal.

[0011] The column circuit is connected to the sensors of the receiving unit via a first channel and a second channel, which are two independent channels. The column circuit can generate TOF (Time Of Flight) histogram data via the first channel and acquire intensity data indicating the number of times the pixel has reacted via the second channel.

[0012] The column circuit can acquire the intensity data through a circuit configuration based on a single slope analog digital converter (Single Slope ADC).

[0013] The column circuit includes a switch and can operate such that the sensor of the receiving unit and the first and second channels are alternately connected in frame units via the switch.

[0014] The column circuit further includes a multiplexer (MUX) and a counter, and the first and second channels can share the counter via the multiplexer.

[0015] A method for operating a lidar device according to an embodiment of the present invention includes: a step in which a transmitting unit transmits a laser to a target; a step in which a receiving unit receives a reflected signal of the laser reflected from the target; and a step in which the receiving unit performs signal processing on a sensor reaction of the receiving unit to the reflected signal via a plurality of column circuits connected to a sensor of the receiving unit, and the column circuit is connected to the sensor of the receiving unit via N (N is a natural number of 2 or more) independent channels for each column of a pixel array corresponding to the sensor of the receiving unit.

[0016] The receiving unit can include a sensor array module in which the sensor of the receiving unit is configured to be N times the sensor comparison of the transmitting unit per row for each column of the pixel array (Column).

[0017] The column circuit is connected by a first channel and a second channel, which are two independent channels, to the sensor of the receiving unit, generates TOF histogram data via the first channel, and can acquire intensity data indicating the number of times the pixel has reacted via the second channel.

[0018] Specific details of other embodiments are included in the detailed description and the accompanying drawings.

Advantages of the Invention

[0019] According to one embodiment of the present invention, additional Intensity Data can be acquired from the pixels of the receiving unit by utilizing the circuit (counter) used in the TDC, thereby enabling output acquisition using all the pixels of the receiving unit without waste.

[0020] According to one embodiment of the present invention, the FPS can be improved by nearly up to twice without reducing the lidar performance.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0022] FIG. 1 is a block diagram showing a lidar device according to one embodiment of the present invention.

[0023] Referring to FIG. 1, a lidar device 100 according to one embodiment of the present invention includes a transmission unit 110, a reception unit 120, a signal processing unit 130, a control unit 140, and a drive unit 150.

[0024] The transmitting unit 110 can transmit a laser to a Target. For this purpose, the control unit 140 can transmit a control command to the transmitting unit 110 via the driving unit 150. At this time, the transmitting unit 110 can transmit a Start signal indicating the time point when it starts to transmit the laser to the target to the signal processing unit 130.

[0025] The receiving unit 120 can receive the reflected signal of the laser reflected back from the target. At this time, the receiving unit 120 can transmit a Stop signal indicating the time point when the reception of the reflected signal is completed to the signal processing unit 130.

[0026] The signal processing unit 130 can perform signal processing according to the control command of the control unit 140. That is, the signal processing unit 130 uses the Start signal and the Stop signal to calculate the time from when the laser light transmitted through the transmitting unit 110 hits the target until it is received by the receiving unit 120, and based on the calculated time, it can measure the distance of the target.

[0027] For this purpose, conventionally, the transmitting unit 110 and the receiving unit 120 operate as a whole according to an operation algorithm designed in advance by the command of the control unit 140. At this time, the histogram method was used as the noise processing method.

[0028] The histogram method is a method of accumulating a large number of measurement values (Interframe) to obtain the TOF (Time Of Flight) result of one frame (Frame). For reference, the FPS (Frame Per Sec), which is the frame update speed per second, is one of the main performance indicators of the lidar.

[0029] According to such a prior art, as the resolution (number of pixels) of the receiving unit 120 increases, the area of the receiving unit 120 that one pixel of the transmitting unit 110 has to cover increases. Due to the limitation of the number of ROICs including TDC (counter) (one per column), there is a problem that the area of the receiving unit 120 involved during operation occurs.

[0030] As shown in FIG. 2, the receiving unit 120 can include a plurality of column circuits 220 connected to the sensor 230 of the receiving unit 120 via N (N is a natural number of 2 or more) independent channels 240, 250 for each column of the pixel array corresponding to the sensor 230 of the receiving unit 120 so that output can be obtained without wasted pixels.

[0031] The receiving unit 120 can further include a sensor array module 210 in which the sensor 230 of the receiving unit 120 is configured with N times the number of sensors of the transmitting unit 110 per row for each column of the pixel array.

[0032] Based on a control signal transmitted via a column scanner (see 301 in FIG. 3), the column circuit 220 can alternately operate the sensors 230 of the receiving unit 120 for each row of the pixel array constituting the sensor array module 210 to signal-process the reaction of the sensor 230 of the receiving unit 120 to the reflected signal.

[0033] For reference, in FIG. 2, the column scanner and the row scanner refer to circuits for changing channels and enabling them according to the module operation algorithm.

[0034] Hereinafter, the description will be limited to the case where the number of channels connected to each of the column circuits 220 is 2. This is merely for the convenience of explanation and easy understanding, and it is obvious that it is not for limiting the scope of the rights of the present invention.

[0035] The sensor 230 of the receiving unit 120 can be connected to each column circuit 220 via a first channel 240 and a second channel 250. That is, the sensor 230 of the receiving unit 120 can be connected to each column circuit 220 via the first channel 240 and the second channel 250, which are two independent channels.

[0036] The column circuit 220 can generate TOF (Time Of Flight) histogram data via the first channel 240 and obtain intensity data via the second channel 250. Here, the intensity data is the number of the total data sum accumulated in the histogram and can indicate the number of times the pixel has responded.

[0037] For this purpose, as shown in FIG. 3, the column circuit 220 includes a switch 310, a charge pump 320, a sample and hold amplifier (S / H) 330, a comparator 340, a multiplexer (MUX) 350, and a counter 360.

[0038] The column circuit 220 can operate such that the sensor 230 of the receiving unit 120 and the first and second channels 240, 250 are alternately connected in frame units via the switch 310.

[0039] When the first channel 240 is selected via the switch 310, the column circuit 220 can generate TOF histogram data for the pixel via the first channel 240.

[0040] That is, as shown in FIG. 4, on the first channel 240, the column circuit 220 can start counting with a start signal and stop counting with a stop signal via a counter 360 that takes the start signal and the stop signal as inputs.

[0041] As a result, the column circuit 220 can output a TOF indicating the time measurement value between start and stop, and can accumulate the output TOF in a histogram to generate the TOF histogram data.

[0042] On the other hand, when the second channel 250 is selected via the switch 310, the column circuit 220 can generate intensity data for the pixel via the second channel 250. That is, as shown in FIG. 5, the column circuit 220 can acquire intensity data based on a circuit configuration based on a single slope analog digital converter (Single Slope ADC) 510 on the second channel 250.

[0043] On the second channel, the charge pump 320 receives a stop signal from the sensor 230 corresponding to the pixel, and accumulates the number of stop signals to output V cp . At this time, since the measurement period of the stop signal requires accumulation of the number of times, it can be realized in a row unit. V cp can indicate a value obtained by combining several interframes.

[0044] When the single slope ADC 510 receives V cp output via the charge pump 320, it samples this via the sample and hold amplifier 330 to output V cp ' to maintain a constant voltage. The single slope ADC 510 receives V cp ' and V ramp via the comparator (COMP) 340, and when the two values (V cp ', V ramp ) become equal, it outputs V comp , and the counter 360 can receive V comp output from the comparator 340 to acquire intensity data (Intensity Data).

[0045] The column circuit 220 can share the counter 360 between the first channel 240 and the second channel 250 via the multiplexer 350. That is, when the first channel 240 is selected via the switch 310, the column circuit 220 opens the first channel 240 and sends the TOF to the counter 360, and when the second channel 250 is selected via the switch 310, the column circuit 220 opens the second channel 250 and sends the V comp to the counter 360.

[0046] On the other hand, when the number of channels is 3 or more instead of 2 for RX per 1 for TX as described above, the present invention is also applicable. In this case, in another embodiment of the present invention, together with pixel operation switching (one embodiment of the present invention), the FPS can be improved by interpolation.

[0047] FIG. 6 is a flowchart showing a method of operating a lidar device according to an embodiment of the present invention.

[0048] The method of operating the lidar device described here is only one embodiment of the present invention. In addition, various steps can be added as necessary as follows, and the following steps can also be implemented by changing the procedure. Therefore, the present invention is not limited to each step and its procedure described below.

[0049] Referring to FIGS. 1, 2, and 6, in step 610, the transmitter 110 of the lidar device 100 can transmit a laser to the target.

[0050] Next, in step 620, the receiver 120 of the lidar device 100 can receive the reflected signal of the laser reflected from the target.

[0051] Next, in step 630, the receiving unit 120 of the rider device 100 can signal-process the reaction of the sensor 230 of the receiving unit 120 to the reflected signal via a plurality of column circuits 220 connected to the sensor 230 of the receiving unit 120.

[0052] Here, each of the column circuits 220 can be connected to the sensor 230 of the receiving unit 120 via two independent channels 240, 250 for each column of the pixel array corresponding to the sensor 230 of the receiving unit 120, whereby the reaction of the sensor 230 of the receiving unit 120 to the reflected signal can be signal-processed.

Description of Reference Numerals

[0053] 100 Rider device, 110 Transmitting unit, 120 Receiving unit, 130 Signal processing unit, 140 Control unit, 150 Driving unit, 220 Column circuit, 230 Sensor, 240 First channel, 250 Second channel, 310 Switch, 320 Charge pump, 330 Sample-and-hold amplifier, 340 Comparator, 350 Multiplexer, 360 Counter, 510 Single-slope ADC.

Claims

1. A transmitter that sends a laser to a target, and a receiver that receives a reflected signal of the laser reflected back from the target, and the receiver includes a plurality of column circuits connected to the sensors of the receiver via N (N is a natural number of 2 or more) independent channels for each column of a pixel array corresponding to the sensors of the receiver A lidar device characterized by this.

2. The receiver further includes a sensor array module in which the sensors of the receiver are configured such that, for each column of the pixel array, the number of sensors of the transmitter per row is N times that of the sensors of the transmitter The lidar device according to claim 1, characterized by this.

3. Based on a control signal transmitted via a column scanner, the column circuit alternately operates the sensors of the receiver for each row of the pixel array, and signal-processes the sensor reaction of the receiver to the reflected signal The lidar device according to claim 1, characterized by this.

4. The column circuit is connected by a first channel and a second channel which are two independent channels, generates TOF (Time Of Flight) histogram data via the first channel, and acquires intensity data indicating the number of times the pixel has reacted via the second channel The lidar device according to claim 1, characterized by this.

5. The column circuit acquires the intensity data by a circuit configuration based on a single slope ADC (Single Slope Analog Digital Converter) The lidar device according to claim 4, characterized by this.

6. The column circuit includes a switch, and operates such that the sensors of the receiver and the first channel and the second channel are alternately connected in frame units via the switch The lidar device according to claim 4, characterized by this.

7. The column circuit further includes a multiplexer (MUX) and a counter, and the first channel and the second channel share the counter via the multiplexer The lidar device according to claim 6, characterized by this.

8. A step in which the transmitter sends a laser to a target, and a step in which a receiving unit receives a reflected signal of the laser that is reflected back from the target; a step in which the receiving unit performs signal processing on a sensor reaction of the receiving unit with respect to the reflected signal through a plurality of column circuits connected to a sensor of the receiving unit; including; the column circuit is connected to the sensor of the receiving unit via N (N is a natural number of 2 or more) independent channels for each column of a pixel array corresponding to the sensor of the receiving unit; A method for operating a lidar device, characterized by the above.

9. the receiving unit includes a sensor array module in which the sensor of the receiving unit is configured to be N times the sensor comparison of the transmitting unit per row for each column of the pixel array; A method for operating a lidar device according to claim 8, characterized by the above.

10. the column circuit is connected by a first channel and a second channel, which are two independent channels, to the sensor of the receiving unit, generates TOF histogram data through the first channel, and obtains intensity data indicating the number of times the pixel has reacted through the second channel; A method for operating a lidar device according to claim 8, characterized by the above.

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