CN112346075B - Collector and light spot position tracking method - Google Patents
Collector and light spot position tracking method Download PDFInfo
- Publication number
- CN112346075B CN112346075B CN202011065186.0A CN202011065186A CN112346075B CN 112346075 B CN112346075 B CN 112346075B CN 202011065186 A CN202011065186 A CN 202011065186A CN 112346075 B CN112346075 B CN 112346075B
- Authority
- CN
- China
- Prior art keywords
- photon detection
- light spot
- sensing area
- pixel
- collector
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/88—Lidar systems specially adapted for specific applications
- G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
- G01S17/894—3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
- G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/484—Transmitters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/486—Receivers
- G01S7/4861—Circuits for detection, sampling, integration or read-out
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/486—Receivers
- G01S7/4861—Circuits for detection, sampling, integration or read-out
- G01S7/4863—Detector arrays, e.g. charge-transfer gates
Abstract
The invention discloses a collector and a light spot position tracking method, comprising a sensing area and a reading circuit; wherein the sensing region comprises at least one pixel responsive to a photon detection event occurring when a reflected light spot is incident on the sensing region and outputting a photon detection signal; the readout circuit comprises a counting circuit and a first processing circuit; wherein the counting circuit is configured to receive the photon detection signal and count the number of photon detection events that each pixel responds to; the first processing circuit is used for calculating the measurement center position of the reflection light spot based on a preset algorithm according to the number of the photon detection events, and further determining the position of the corresponding sensing area based on the measurement center position. The invention determines the position of the sensing area corresponding to the light spot by positioning the position of the light beam incident on the collector in real time, and further activates the corresponding pixel to receive the reflected light spot, thereby improving the accuracy of ranging.
Description
Technical Field
The invention relates to the technical field of distance measurement, in particular to a collector and a light spot position tracking method.
Background
A distance measurement may be performed on a target using a Time of Flight (TOF) principle to obtain a depth image including a depth value of the target, and a distance measurement system based on the Time of Flight principle has been widely used in various fields such as consumer electronics, unmanned driving, AR/VR, and the like. A distance measuring system based on the time-of-flight principle typically comprises an emitter and a collector, with the emitter emitting a pulsed light beam to illuminate the target field of view and the collector collecting the reflected light beam, and the distance of the object is calculated by calculating the time-of-flight of the beam from emission to reflection back to reception.
At present, in the actual distance measurement process, the system is influenced by factors such as mechanical oscillation or thermal effect generated by temperature rise of a sensor, so that the position of a reflected light beam incident into a collector can be easily deviated, the reflected light beam does not enter a pre-calibrated pixel, and the real reflected light beam is not collected, so that an output sampling signal has an error, and finally a distance measurement result has an error.
Therefore, how to position the position of the light beam incident on the collector in real time in the actual distance measurement process is particularly important, and the activation of the corresponding pixel acquisition by positioning the position of the light beam incident on the collector in real time is one of the key problems for improving the distance measurement accuracy.
The above background disclosure is only for the purpose of assisting understanding of the inventive concept and technical solutions of the present invention, and does not necessarily belong to the prior art of the present patent application, and should not be used for evaluating the novelty and inventive step of the present application in the case that there is no clear evidence that the above content is disclosed at the filing date of the present patent application.
Disclosure of Invention
The present invention is directed to a collector and a method for tracking a position of a light spot, so as to solve at least one of the above-mentioned problems in the related art.
In order to achieve the above purpose, the technical solution of the embodiment of the present invention is realized as follows:
a collector comprises a sensing area and a readout circuit; wherein the content of the first and second substances,
the sensing region comprises at least one pixel responsive to a photon detection event occurring when a reflected light spot is incident on the sensing region and outputting a photon detection signal;
the readout circuit comprises a counting circuit and a first processing circuit; wherein the counting circuit is configured to receive the photon detection signal and count the number of photon detection events that each pixel responds to; the first processing circuit is used for calculating the measuring center position of the reflection light spot based on a preset algorithm according to the number of the photon detection events, and further determining the position of the corresponding sensing area based on the measuring center position.
In some embodiments, the counting circuit comprises a plurality of counters, the number of counters is the same as the number of pixels in the sensing region and the counters are connected in a one-to-one correspondence.
In some embodiments, the readout circuit further comprises a TDC circuit and a histogram memory; wherein the TDC circuit is to receive the photon detection signal and form a photon detection event signal, the photon detection event signal to address a location of a histogram memory, and form a histogram based on the location of the histogram memory as a temporal histogram.
In some embodiments, the photon detection event signal includes time data of the occurrence of the respective photon detection event.
In some embodiments, the optical system further comprises a receiving optical element for guiding the reflected pulse beam formed by the reflection of the measured object to the corresponding pixel to form an imaging spot.
In some embodiments, the collector is connected with a processing circuit, and an editable algorithm program is arranged in the processing circuit and used for identifying a problematic depth image and correcting the sensing area incident to the reflection light spot again aiming at the problematic depth image.
The other technical scheme of the embodiment of the invention is as follows:
a spot position tracking method comprises the following steps:
s10, emitting pulse beams to a target through an emitter, wherein at least part of the pulse beams are reflected by the target and enter a sensing area of a collector to form a light spot, and the sensing area collects photons in the light spot and outputs photon detection signals; wherein the sensing region comprises at least one pixel, an event of the pixel acquiring a photon is considered to be a photon detection event occurrence; the central position of the sensing area is a reference central position;
s20: counting the number of the photon detection events and calculating the measurement center position of the light spot based on the counted number;
s30: judging whether the offset of the measuring center position and the reference center position of the sensing area meets a preset threshold value or not; if not, executing step S40;
s40: and determining the position of the measurement sensing area corresponding to the light spot according to the measurement center position.
In some embodiments, in step S20, a counting circuit is used to receive the photon detection signal and count the number of photon detection events to which each pixel responds; the counting circuit comprises a plurality of counters, and the number of the counters is the same as the number of the pixels in the sensing region and the counters are connected in a one-to-one correspondence mode.
In some embodiments, in step S20, the measurement center position (m, n) of the spot is calculated according to the following formula:
wherein, A i Representing the number of photon detection events counted by the ith counter, and j represents the number of pixels in the sensing region.
In some embodiments, the method further comprises the steps of:
s30: judging whether the offset of the measuring center position and the reference center position of the sensing area meets a preset threshold value or not; if not, executing step S40;
s40: and determining the position of the measurement sensing area corresponding to the light spot according to the measurement center position.
The technical scheme of the invention has the beneficial effects that:
compared with the prior art, the method and the device have the advantages that the position of the light beam incident on the collector is positioned in real time, the position of the sensing area corresponding to the light spot is determined, and the corresponding pixel is activated to receive the reflected light spot, so that the accuracy of distance measurement is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic block diagram of a distance measurement system according to one embodiment of the present invention.
Fig. 2 is a structural diagram of a pixel unit of a distance measurement system according to an embodiment of the present invention.
Fig. 3 is a functional block diagram of a collector according to another embodiment of the invention.
FIG. 4 is a diagram of a pixel activation control circuit of a collector according to the embodiment of the figure.
Fig. 5 is a flowchart illustration of a distance measurement method according to another embodiment of the present invention.
Fig. 6 is a flowchart illustrating a spot position tracking method according to another embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the embodiments of the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element. The connection may be for fixing or for circuit connection.
It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the embodiments of the present invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be in any way limiting of the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.
Fig. 1 is a schematic diagram of a distance measuring system according to an embodiment of the present invention. Distance measurement system 10 includes a transmitter 11, a collector 12, and a processing circuit 13. Wherein, the transmitter 11 comprises a light source 111 composed of one or more lasers for emitting a pulse beam 30 to the target 20, at least a part of the pulse beam is reflected by the target to form a reflected beam 40 to return to the collector 12; collector 12 includes a pixel unit 121 composed of a plurality of pixels for collecting photons in reflected light beam 40 and outputting photon signals; processing circuitry 13 synchronizes the trigger signals of emitter 11 and collector 12 to calculate the time of flight required for a photon in the beam to be received from emission to reflection.
The transmitter 11 includes a light source 111, a transmitting optical element 112, a driver 113, and the like. In one embodiment, light source 111 is a VCSEL array light source chip that produces multiple VCSEL (vertical cavity surface emitting laser) light sources on a monolithic semiconductor substrate to form. The light source 111 can emit a pulse light beam outwards under the control of the processing circuit 13 at a certain frequency (pulse period), and the pulse light beam is projected onto the target scene through the emission optical element 112 to form an illumination spot, wherein the frequency is set according to the measured distance.
The processing circuit 13 synchronizes the trigger signals of the emitter 11 and the collector 12, and is used for processing the photon detection signal output by the pixel collecting photon, calculating the flight time of the photon from emission to reflection and further calculating the distance information of the target. In some embodiments, the processing circuit 13 may be a stand-alone dedicated circuit, such as a dedicated SOC chip, an FPGA chip, an ASIC chip, or the like, or may comprise a general purpose processing circuit.
Fig. 2 is a schematic structural diagram of a pixel unit according to an embodiment of the invention. The pixel unit 121 comprises a two-dimensional pixel array of a plurality of pixels for collecting photons in at least part of the light beam reflected back by the object (referred to as photon detection events) and generating corresponding photon detection signals.
In one embodiment, the pixel unit is composed of a plurality of SPADs 205, when the emitter 11 emits a pulse beam to the object to be measured, the pulse beam is reflected by the object to be measured to form a reflected pulse beam, and the receiving optical element 123 in the collector 12 directs the reflected pulse beam to the corresponding pixel to form an imaging spot (shown as a circle in fig. 2, also called a spot), and each pixel is regarded as a sensing area. Generally, in order to receive as many photon signals as possible in the reflected pulsed light beam, a single spot is typically sized to correspond to a plurality of pixels (here corresponding may be understood as imaging, the receiving optical element 123 generally comprising an imaging lens); as shown in fig. 2, a single blob corresponds to 2 × 2=4 pixels, namely: it can be considered that a sensing area is composed of 4 pixels, that is, photons reflected from the reflected pulse beam at the spot are received by the corresponding 4 pixels with a certain probability, and the shaded boxes in fig. 2 indicate the possible case that the reflected light spot is incident on the corresponding pixels.
In general, the distance measuring system can be divided into two cases of on-axis and off-axis according to the arrangement between the emitter 11 and the collector 12. For the coaxial case, the light beam emitted from the emitter 11 is reflected by the object to be measured and then collected by the corresponding pixel in the collector 12, the position of the pixel is not affected by the distance of the object to be measured, i.e. the sensing area corresponding to the reflected light spot after each light beam is reflected can be calibrated in advance. However, in the case of off-axis, due to the existence of parallax, when the distance of the measured object is different, the position of the reflected light spot on the pixel unit changes; in general, the reflected light spots will be shifted along the direction of the baseline (the line between the emitter and the collector, in the embodiment of the present invention, the direction of the baseline is denoted by the horizontal line), so that for each reflected light spot, at least two sensing areas need to be activated synchronously for receiving. In the embodiment shown in fig. 2, three sensing regions 201, 202, 203 are activated simultaneously to form a sampling region 204 for collecting a beam of reflected light spots reflected from the target field of view. Specifically, at the beginning of measurement, the reflection spot is calibrated to be incident on a corresponding sensing region 203 in the sampling region 204 through measurement for a period of time, and the subsequent sampling process only needs to activate the sensing region 203.
In the continuous sampling process, due to the influence of factors such as a thermal effect generated by mechanical oscillation or a temperature rise of the sensor, the imaging light spot of the reflection light spot may shift, as shown by a dotted circle in fig. 2, the reflection light spot is no longer incident into the sensing region 203, but is incident into the sensing region 202 in an inactive state, and then a pixel in the sensing region 203 cannot collect photons in the light spot reflected from the field of view and outputs an invalid interference signal, so that a distance value of the point in the target field of view corresponding to the sensing region 203, which is finally calculated by the processing circuit, may deviate. Therefore, it is necessary to re-correct the sensing region on which the reflected light spot is incident when a sampling abnormality occurs. It will be appreciated that the sampling anomaly may be detected by providing an RGB sensor to capture RGB images of the target field of view to assist in determining the problematic depth image, or by providing an editable algorithm in the processing circuitry to identify the problematic depth image.
Fig. 3 is a schematic structural diagram of a collector according to an embodiment of the present invention. The collector includes a pixel unit 31 and a readout circuit 32; the pixel unit 31 is a two-dimensional pixel array composed of a plurality of pixels, wherein each pixel is configured as a sensing region or a sensing region composed of at least two pixels, a photon detection event occurs when the reflection light spot is incident on the sensing region, and the pixels in the sensing region output photon detection signals in response to the photon detection event.
In one embodiment, readout circuitry 32 includes counting circuitry 321 and first processing circuitry 322. Wherein the counting circuit 321 is configured to receive the photon detection signal and count the number of photon detection events for each pixel response. In one embodiment, the counting circuit 321 includes a plurality of counters, the number of counters is the same as the number of pixels in the sensing region and connected in a one-to-one correspondence, for counting the number of photon detection events that each pixel responds to.
The first processing circuit 322 calculates the measurement center position of the light spot based on a preset algorithm according to the counted number of photon detection events, and further determines the position of the corresponding sensing region according to the measurement center position of the light spot. In some embodiments, the pre-set algorithm includes, but is not limited to, a centroid method, a weighted centroid method, a least squares method, a maximum likelihood method, and the like. The method comprises the steps of determining the central position of an initial sensing area to be calibrated as a reference central position, calculating the measuring central position of a light spot according to the number of photon detection events responded by the sensing area, determining the position of the measuring sensing area corresponding to the light spot according to the measuring central position if the offset between the measuring central position and the reference central position does not meet a preset threshold, and further activating the corresponding measuring sensing area to collect photons and output photon detection signals.
In one embodiment, readout circuitry 32 also includes a TDC circuit 323 and a histogram memory 324. Where the TDC circuitry is configured to receive the photon detection signal and form a photon detection event signal including time data of the occurrence of the respective photon detection event, i.e., the time of flight of the photon from emission to collection, in some embodiments the photon detection event signal may be in the form of timestamp data, a digital timing signal, time code data, or other representation. Further, the photon detection event signal is used to address a histogram memory location, forming a histogram based on the histogram memory location as a temporal bin (bin). Wherein the histogram abscissa represents time, the ordinate represents count values of photon detection events, photon detection event signals generated in response to all photon detection events within the sensing region are assigned within time bins of the histogram, and count values of photon detection events are obtained within each time bin.
In the distance measuring system comprising the collector in any embodiment of the foregoing embodiments, the pulse light beam emitted by the emitter to the target area is reflected and then incident on the sensing area of the collector to form a light spot, and the sensing area is a pre-calibrated initial sensing area and comprises at least one pixel. The reading circuit judges whether the central position of the light spot is the same as the position of the initial sensing area; if the light spots are different, determining the corresponding position of the measurement sensing area according to the central position of the light spot; adjusting bias voltages of pixels in the measurement sensing region by a processing circuit to activate the measurement sensing region for collecting photons in the light spot and outputting a photon detection signal; further receiving the photon detection signal and forming a photon detection event signal, forming a histogram based on the photon detection event signal, and further calculating distance information from the histogram. Therefore, the position of the light spot is tracked, and the corresponding sensing area is activated to collect photons in the light spot, so that the ranging accuracy of the distance measuring system can be improved.
In an embodiment, the processing circuitry further comprises second processing circuitry for adjusting bias voltages of pixels in the measurement sensing regions to activate each sensing region for collecting photons in the light spot and outputting photon detection signals. Wherein the activated state is available for receiving photons in the reflected beam when the bias voltage across the SPAD pixel is greater than the avalanche voltage. The second processing circuit is associated with the sensing regions, specifically, each sensing region may be connected to one second processing circuit, or each pixel in each sensing region may be connected to one second processing circuit, which is not limited in this embodiment of the present invention.
Referring to fig. 4, in one embodiment, the second processing circuit may be configured as an over bias control circuit. First, a global bias voltage V is applied to all pixels in the pixel array HV A second processing circuit for applying an excess bias voltage V to each pixel q Then the bias voltage applied to the pixel at this time is V q -V HV . According to the position of the measurement sensing area determined by the first processing circuit, the second processing circuit regulates and controls the excessive bias voltage Vq of the pixels in the measurement sensing area to be larger than zero until the bias voltage is larger than the avalanche voltage, so that the pixels in the measurement sensing area are in an activated state, the pixels are used for collecting photons in the light spot and outputting photon detection signals, and the photon detection signals are accurate numerical values.
In one embodiment, special pixel structures may also be provided for controlling the activation and deactivation of each pixel, such as: and the processing circuit regulates and controls the execution of the control logic in the storage unit on the corresponding pixel according to the position of the measurement sensing area determined by the first processing circuit so as to adjust the bias voltage applied to the pixel.
Referring to fig. 5, a distance measuring method according to another embodiment of the present invention includes the steps of:
s1, controlling an emitter to emit a pulse beam towards a target area; the pulse light beam is reflected and then enters the sensing area of the collector to form a light spot.
S2, controlling a sensing area in the collector to collect photons in the light spots and outputting photon detection signals; wherein the sensing region is a pre-calibrated initial sensing region.
In particular, the sensing region comprises at least one pixel, and an event that the pixel acquires a photon is considered to be a photon detection event.
S3, judging whether the central position of the light spot is the same as the position of the initial sensing area or not; and if not, determining the position of the corresponding measurement sensing area according to the central position of the light spot, and activating the measurement sensing area to collect photons in the light spot so as to output a photon detection signal.
Specifically, step S3 further includes: the number of photon detection events is counted and the center position of the spot is calculated based on the counted number. In some embodiments, a counting circuit is utilized to receive the photon detection signals and count the number of photon detection events to which each pixel responds; the counting circuit comprises a plurality of counters, the number of the counters is the same as the number of the pixels in the sensing region, and the counters are connected in a one-to-one correspondence mode so as to count the number of photon detection events responded by each pixel.
And S4, receiving the photon detection signal and forming a photon detection event signal, forming a histogram based on the photon detection event signal, and further calculating distance information according to the histogram.
The distance measuring method of the embodiment of the invention determines the position of the corresponding measuring sensing area by tracking the central position of the light spot in real time, so that the corresponding sensing area is activated to collect photons in the light spot, the light spot is ensured to fall into the activated sensing area, and the accuracy of distance measurement is improved.
It should be noted that the distance measuring method of the present invention is implemented by using the distance measuring system described in the foregoing embodiment, and specific reference is made to the description in the embodiment of the distance measuring system, which is not described herein again.
With reference to the embodiments shown in fig. 2 and fig. 3, the present invention further provides a light spot position tracking method, which is applied in the foregoing distance measurement system, wherein a reflected light spot is incident into a sensing region of an acquirer and generates a photon detection event, and pixels in the sensing region output photon detection signals in response to the photon detection event, and referring to fig. 6, the light spot position tracking method includes the following steps:
s10: emitting a pulse beam to a target through an emitter, reflecting at least part of the pulse beam by the target to be incident into a sensing area of a collector to form a light spot, collecting photons in the light spot by the sensing area and outputting a photon detection signal; the sensing region comprises at least one pixel, an event that the pixel collects photons is regarded as a photon detection event, and the central position of the sensing region is a reference central position;
s20: counting the number of photon detection events and calculating the measurement center position of the light spot based on the counted number;
specifically, a counting circuit is utilized to receive the photon detection signals and count the number of photon detection events to which each pixel responds. In one embodiment, the counting circuit comprises a plurality of counters, and the number of the counters is the same as the number of pixels in the sensing region and is connected in a one-to-one correspondence for counting the number of photon detection events responded by each pixel.
In one embodiment, the first processing circuitry calculates the measured center position (m, n) of the light spot based on a barycentric method. Specifically, the coordinate calculation formula of the measurement center position of the light spot is as follows:
wherein A is i Represents the number of photon detection events counted by the ith counter, j represents the number of pixels in the sensing region; in this embodiment, it can be assumed that j is 4,x i 、y i And coordinate values of the ith pixel in the x direction and the y direction are respectively represented, and the measurement center position (m, n) of the incident light spot is calculated by substituting the number of photon detection events counted by each counter into a calculation formula. It is understood that, in the embodiment shown in fig. 2, the vertex of the upper left corner of the pixel unit is assumed as the coordinate origin, the directions of the x axis and the y axis are as shown in fig. 2, the horizontal and vertical coordinates of each pixel in the pixel unit and the center position of each sensing area are determined values, and the reference center position coordinate of the sensing area is assumed to be (x, y).
S30: judging whether the offset of the measurement center position and the reference center position of the sensing area meets a preset threshold value or not; if not, executing step S40;
whether an offset error occurs is judged according to the calculated measurement center position (m, n) and the reference center position (x, y) of the sensing area. In one embodiment of the present invention, the preset threshold is set according to the size of the sensing region, for example, the preset threshold of the offset is set to the size of one pixel. If each pixel is square, the size of each pixel is 1 × 1mm, the reference center coordinate of the sensing region is (3,1), the measurement center position coordinate is (2.8,1), and the offset of the measurement center position from the reference center position of the sensing region satisfies a preset threshold, the measurement center position and the sensing center position are considered to be approximately the same. Similarly, if the measurement center position coordinate is (1,1), the offset between the measurement center position and the reference center position at this time does not satisfy the preset threshold, and step S40 needs to be executed.
S40: and determining the position of the measurement sensing area corresponding to the light spot according to the measurement center position.
If it is determined that an offset error occurs according to the offset between the measurement center position and the reference center position, the position of the sensing region at this time is already inaccurate, for example, if it is determined that the measurement center position is offset leftward by more than one pixel from the reference center position according to the offset, the sensing region where the light spot is incident is no longer the initial sensing region 203, and if it is determined that the light spot incident position at this time corresponds to the sensing region 202 according to the offset, the sensing region 202 corresponding to the light spot incident position is readjusted according to the measurement center position to activate to collect the reflected light spot.
Further, the steps S20 to S40 are repeated until the offset amount of the measurement center position from the reference center position of the sensing region satisfies the preset threshold.
Specifically, after the position of the sensing area is adjusted according to the position of the measuring center, the emitter is controlled to emit a pulse beam towards the target area, the sensing area 202 is controlled to activate and receive the reflected light spot within a certain time to generate a photon detection event, a photon detection signal is generated in response to the photon detection event, the counting circuit records the number of the photon detection events within the certain time, and whether the offset between the position of the measuring center and the sensing position meets a preset threshold value is calculated according to the counted number to determine the position of the sensing area corresponding to the light spot. By performing iterative operations on the steps, the accuracy of spot position tracking can be increased.
The invention further provides a computer-readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the spot position tracking method of the above embodiment. The storage medium may be implemented by any type of volatile or non-volatile storage device, or combination thereof.
Embodiments of the present invention may comprise or utilize a special purpose or general-purpose computer including computer hardware, as discussed in greater detail below. Embodiments within the scope of the present invention also include physical and other computer-readable media for carrying or storing computer-executable instructions and/or data structures. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer system. The computer-readable medium storing the computer-executable instructions is a physical storage medium. Computer-readable media carrying computer-executable instructions are transmission media. Thus, by way of example, and not limitation, embodiments of the invention can include at least two distinct computer-readable media: physical computer readable storage media and transmission computer readable media.
The embodiment of the present application further provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement at least the spot position tracking method in the foregoing embodiment.
It is to be understood that the foregoing is a more detailed description of the invention, and that specific embodiments are not to be considered as limiting the invention. It will be apparent to those skilled in the art that numerous alterations and modifications can be made to the described embodiments without departing from the inventive concepts herein, and such alterations and modifications are to be considered as within the scope of the invention. In the description herein, references to the description of the term "one embodiment," "some embodiments," "preferred embodiments," "an example," "a specific example," or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention.
In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Moreover, various embodiments or examples and features of various embodiments or examples described in this specification can be combined and combined by one skilled in the art without being mutually inconsistent. Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope of the invention as defined by the appended claims.
Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. One of ordinary skill in the art will readily appreciate that the above-disclosed, presently existing or later to be developed, processes, machines, manufacture, compositions of matter, means, methods, or steps, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
Claims (9)
1. A collector is characterized in that: comprises a sensing area and a readout circuit; wherein the content of the first and second substances,
the sensing region comprises at least one pixel which responds to a photon detection event which occurs when the reflection light spot is incident to the sensing region and outputs a photon detection signal;
the readout circuit comprises a counting circuit and a first processing circuit; wherein the counting circuit is configured to receive the photon detection signal and count the number of photon detection events to which each pixel responds; the first processing circuit is used for calculating the measuring center position of the reflected light spot based on a preset algorithm according to the number of the photon detection events, and if the offset between the measuring center position and the reference center position does not meet a preset threshold value, determining the position of a sensing area corresponding to the light spot based on the measuring center position and activating the corresponding sensing area; and the reference central position is the central position of the pre-calibrated initial sensing area.
2. The collector of claim 1, wherein: the counting circuit comprises a plurality of counters, and the number of the counters is the same as that of the pixels in the sensing area and the counters are connected in a one-to-one correspondence mode.
3. The collector of claim 1, wherein: the readout circuit further comprises a TDC circuit and a histogram memory; wherein the TDC circuit is configured to receive the photon detection signal and form a photon detection event signal, the photon detection event signal is configured to address a location of a histogram memory, and form a histogram based on the location of the histogram memory as a temporal histogram.
4. The collector of claim 3, wherein: the photon detection event signal contains time data of the occurrence of the corresponding photon detection event.
5. The collector of claim 1, wherein: the device also comprises a receiving optical element for guiding a reflected pulse light beam formed by the reflection of the measured object to the corresponding pixel to form an imaging light spot.
6. The collector of claim 1, wherein: the collector is connected with a processing circuit, and an editable algorithm program is arranged in the processing circuit and used for identifying the depth image with the problem and re-correcting the sensing area where the reflection light spot is incident according to the depth image with the problem.
7. A spot position tracking method is characterized by comprising the following steps:
s10: emitting a pulse beam to a target through an emitter, wherein at least part of the pulse beam is reflected by the target and enters a sensing area of a collector to form a light spot, and the sensing area collects photons in the light spot and outputs a photon detection signal; wherein the sensing region comprises at least one pixel, an event of the pixel acquiring a photon is considered to be a photon detection event occurrence; the central position of the sensing area is a reference central position;
s20: counting the number of the photon detection events, calculating the measurement center position of the light spot based on the counted number, determining the position of the sensing area corresponding to the light spot based on the measurement center position if the offset between the measurement center position and the reference center position does not meet a preset threshold, and activating the corresponding sensing area.
8. The spot position tracking method according to claim 7, wherein: in step S20, a counting circuit is used to receive the photon detection signal and count the number of photon detection events responded by each pixel; the counting circuit comprises a plurality of counters, and the number of the counters is the same as the number of the pixels in the sensing area and the counters are connected in a one-to-one correspondence mode.
9. The spot position tracking method according to claim 8, wherein: in step S20, the measurement center position (m, n) of the spot is calculated according to the following formula:
wherein A is i Representing the number of photon detection events counted by the ith counter, j representing the number of pixels in the sensing region, x i 、y i And coordinate values of the ith pixel in the x direction and the y direction are respectively represented, and the measurement center position (m, n) of the incident light spot is calculated by substituting the number of photon detection events counted by each counter into a calculation formula.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011065186.0A CN112346075B (en) | 2020-10-01 | 2020-10-01 | Collector and light spot position tracking method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011065186.0A CN112346075B (en) | 2020-10-01 | 2020-10-01 | Collector and light spot position tracking method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112346075A CN112346075A (en) | 2021-02-09 |
| CN112346075B true CN112346075B (en) | 2023-04-11 |
Family
ID=74361503
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011065186.0A Active CN112346075B (en) | 2020-10-01 | 2020-10-01 | Collector and light spot position tracking method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112346075B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113176579A (en) * | 2021-03-01 | 2021-07-27 | 奥比中光科技集团股份有限公司 | Light spot position self-adaptive searching method, time flight ranging system and ranging method |
| CN114114300B (en) * | 2022-01-25 | 2022-05-24 | 深圳市灵明光子科技有限公司 | Scattered point redistribution distance measuring device and laser detection system |
| CN114494407B (en) * | 2022-04-14 | 2022-07-22 | 宜科(天津)电子有限公司 | Image processing method for distance measurement |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007234199A (en) * | 2006-03-03 | 2007-09-13 | Sony Corp | Optical spot position controlling device, optical spot position controlling method, and optical disk recording and reproducing device |
| US10698110B2 (en) * | 2015-03-05 | 2020-06-30 | Teledyne Digital Imaging, Inc. | Laser scanning apparatus and method |
| US9753126B2 (en) * | 2015-12-18 | 2017-09-05 | Gerard Dirk Smits | Real time position sensing of objects |
| WO2017112416A1 (en) * | 2015-12-20 | 2017-06-29 | Apple Inc. | Light detection and ranging sensor |
| CN106911381A (en) * | 2017-01-20 | 2017-06-30 | 西南电子技术研究所（中国电子科技集团公司第十研究所） | Laser link communication measurement hybrid system |
| CN110609293B (en) * | 2019-09-19 | 2022-05-27 | 深圳奥锐达科技有限公司 | Distance detection system and method based on flight time |
| CN110596722B (en) * | 2019-09-19 | 2022-10-04 | 深圳奥锐达科技有限公司 | System and method for measuring flight time distance with adjustable histogram |
| CN110596721B (en) * | 2019-09-19 | 2022-06-14 | 深圳奥锐达科技有限公司 | Flight time distance measuring system and method of double-shared TDC circuit |
| CN111664798B (en) * | 2020-04-29 | 2022-08-02 | 奥比中光科技集团股份有限公司 | Depth imaging method and device and computer readable storage medium |
-
2020
- 2020-10-01 CN CN202011065186.0A patent/CN112346075B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112346075A (en) | 2021-02-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110596722B (en) | System and method for measuring flight time distance with adjustable histogram | |
| CN110596721B (en) | Flight time distance measuring system and method of double-shared TDC circuit | |
| CN112198519A (en) | Distance measuring system and method | |
| CN112346075B (en) | Collector and light spot position tracking method | |
| CN110596725B (en) | Time-of-flight measurement method and system based on interpolation | |
| US11703569B2 (en) | LIDAR data acquisition and control | |
| CN111830530B (en) | Distance measuring method, system and computer readable storage medium | |
| CN110596724B (en) | Method and system for measuring flight time distance during dynamic histogram drawing | |
| CN110596723B (en) | Dynamic histogram drawing flight time distance measuring method and measuring system | |
| WO2022021797A1 (en) | Distance measurement system and distance measurement method | |
| CN110687541A (en) | Distance measuring system and method | |
| WO2022160611A1 (en) | Time fusion-based distance measurement method, system, and device | |
| US20230305150A1 (en) | Adaptive search method for light spot positions, time of flight distance measurement system, and distance measurement method | |
| CN111965658B (en) | Distance measurement system, method and computer readable storage medium | |
| CN111796295B (en) | Collector, manufacturing method of collector and distance measuring system | |
| CN111766596A (en) | Distance measuring method, system and computer readable storage medium | |
| CN112731425A (en) | Histogram processing method, distance measuring system and distance measuring equipment | |
| CN111812661A (en) | Distance measuring method and system | |
| CN110780312A (en) | Adjustable distance measuring system and method | |
| CN213091889U (en) | Distance measuring system | |
| CN111796296A (en) | Distance measuring method, system and computer readable storage medium | |
| US20220364849A1 (en) | Multi-sensor depth mapping | |
| WO2022088492A1 (en) | Collector, distance measurement system, and electronic device | |
| CN213903798U (en) | Distance measuring system with dual light-emitting modes | |
| CN114236504A (en) | dToF-based detection system and light source adjusting method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |