CN112799087A - Distance measuring method and distance measuring device - Google Patents
Distance measuring method and distance measuring device Download PDFInfo
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- 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
- G01S17/32—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
- G01S17/36—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated with phase comparison between the received signal and the contemporaneously transmitted signal
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Abstract
The application provides a distance measuring method and a distance measuring device. In the application, the distance measuring device comprises a light emitting element and a photosensitive unit, wherein the photosensitive unit comprises N photosensitive elements, and N is greater than 1; the distance measurement method comprises the following steps: controlling the light emitting element to emit L incident light signals; for each photosensitive unit, the photosensitive elements in the photosensitive units respectively sense corresponding reflected light signals to obtain M first electric signals; the reflected light signal is the light signal reflected by the incident light signal after encountering the shot object; the first electrical signal comprises information of the reflected optical signal; m is greater than or equal to N; l is less than M; respectively carrying out phase modulation on the second electric signals by adopting M-1 phases to obtain M-1 modulation signals; m-1 phases are different; the second electrical signal comprises information of the incident optical signal; acquiring phase differences according to the second electric signals, the M-1 modulation signals and the M first electric signals; and acquiring the distance between the shot object and the photosensitive unit according to the phase difference. In the embodiment of the application, the frame rate of the ranging can be improved.
Description
Technical Field
The present disclosure relates to ranging technologies, and in particular, to a ranging method and a ranging device.
Background
In the related art, a TOF (Time of Flight) ranging technique based on phase detection may calculate a distance between a ranging apparatus and an object to be measured by a phase difference between a transmission signal transmitted to the object to be measured and a reflection signal reflected by the object to be measured.
Depth images (depth images), also known as range images, refer to images having as pixel values the distances (depths) from a depth sensor to points in a scene, which directly reflect the geometry of the visible surface of the scene. In the depth image, each pixel represents the distance of the object from the depth sensor at that particular (x, y) coordinate.
When the same pixel value is obtained, the phase modulation is performed on the same pixel (depth sensor) for multiple times, for example, 4 groups of pulse sequences are modulated by phases of 0 degree, 90 degrees, 180 degrees, and 270 degrees, respectively, and one depth information is obtained by calculation according to the final integration result as the pixel value. When a frame of depth image is obtained, each phase modulation needs to perform global exposure once, that is, all depth sensors in the depth sensor array are exposed simultaneously, and if the phases of 0 degree, 90 degrees, 180 degrees and 270 degrees need to be respectively subjected to global exposure, at least 4 times of global exposure are needed to obtain the frame of depth image. However, the modulation and exposure time in this scheme is relatively long and the frame rate is low.
Therefore, how to increase the frame rate of ranging is a technical problem to be solved.
Disclosure of Invention
The embodiment of the application provides a ranging method and a ranging device, which can improve the frame rate of ranging.
The embodiment of the application provides a distance measuring method, which is applied to a distance measuring device, wherein the distance measuring device comprises a light emitting element and at least one photosensitive unit, each photosensitive unit comprises N photosensitive elements, and N is an integer greater than 1; the distance measurement method comprises the following steps:
controlling the light-emitting element to emit L incident light signals; l is a positive integer;
for each photosensitive unit, all the photosensitive elements in the photosensitive unit respectively sense corresponding reflected light signals to obtain M first electric signals; the reflected light signal is a light signal reflected by the incident light signal after encountering a shot object; the first electrical signal comprises information of the reflected light signal; m is an integer greater than or equal to N; l is less than M;
respectively carrying out phase modulation on the second electric signals by adopting M-1 phases to obtain M-1 modulation signals; the M-1 phases are different; the second electrical signal comprises information of the incident optical signal;
acquiring a phase difference according to the second electric signal, the M-1 modulation signals and the M first electric signals;
and acquiring the distance between the shot object and the photosensitive unit according to the phase difference.
In one embodiment, when M is equal to N, L is 1.
In one embodiment, N is 4 and M is 4.
In one embodiment, when M is greater than N and equal to L times of N, for each time the light emitting element emits the incident light signal, all the light sensing elements in the light sensing unit respectively sense a corresponding reflected light signal, resulting in N first electrical signals; l is an integer greater than 1;
after the light emitting elements emit the incident light signals for L times, all the light sensing elements in the light sensing units respectively sense the reflected light signals corresponding to the L times, and M first electric signals are obtained.
In one embodiment, N is 2, M is 4, and L is 2.
In one embodiment, M is 4, and the M-1 phases are 90 °, 180 °, and 270 °, respectively; the photosensitive element is a photodiode; the M-1 modulation signals comprise a first modulation signal, a second modulation signal and a third modulation signal; the first modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 90 degrees, the second modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 180 degrees, and the third modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 270 degrees;
the obtaining a phase difference according to the second electrical signal, the M-1 modulation signals, and the M first electrical signals includes:
taking the M first electrical signals and the second electrical signal, the first modulation signal, the second modulation signal, and the third modulation signal, respectively, and accumulating charges;
reading the accumulated charge amount to obtain a first charge amount, a second charge amount, a third charge amount and a fourth charge amount; the first charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the second electrical signal, the second charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the first modulation signal, the third charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the second modulation signal, and the fourth charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the third modulation signal;
calculating the phase difference from the first, second, third, and fourth charge amounts and the following calculation:
wherein the content of the first and second substances,
for the phase difference, Q1 is a first charge amount, Q2 is a second charge amount, Q3 is a third charge amount, and Q4 is a fourth charge amount.
Some embodiments of this application still provide a range unit, include: the device comprises a light-emitting element, a control unit, a processing unit and at least one photosensitive unit, wherein each photosensitive unit comprises N photosensitive elements, and N is an integer greater than 1;
the control unit is electrically connected with the light-emitting element and is used for controlling the light-emitting element to emit L incident light signals; l is a positive integer;
for each photosensitive unit, all the photosensitive elements in the photosensitive unit respectively sense corresponding reflected light signals to obtain M first electric signals; the reflected light signal is a light signal reflected by the incident light signal after encountering a shot object; the first electrical signal comprises information of the reflected light signal; m is an integer greater than or equal to N; l is less than M;
the processing unit is electrically connected with the photosensitive unit and is used for performing phase modulation on the second electric signals by adopting M-1 phases to obtain M-1 modulation signals, acquiring phase differences according to the second electric signals, the M-1 modulation signals and the M first electric signals and acquiring the distance between the object to be shot and the photosensitive unit according to the phase differences; the M-1 phases are different; the second electrical signal includes information of the incident optical signal.
In one embodiment, when M is equal to N, L is 1;
n is 4 and M is 4.
In one embodiment, when M is greater than N and equal to L times of N, for each time the light emitting element emits the incident light signal, all the light sensing elements in the light sensing unit respectively sense a corresponding reflected light signal, resulting in N first electrical signals; l is an integer greater than 1;
after the light emitting element emits the incident light signals for L times, all the light sensing elements in the light sensing units respectively sense the reflected light signals corresponding to the L times to obtain M first electric signals;
n is 2, M is 4, and L is 2.
In one embodiment, M is 4, and the M-1 phases are 90 °, 180 °, and 270 °, respectively; the photosensitive element is a photodiode; the M-1 modulation signals comprise a first modulation signal, a second modulation signal and a third modulation signal; the first modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 90 degrees, the second modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 180 degrees, and the third modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 270 degrees;
the processing unit is further configured to sum and accumulate charges by taking the M first electrical signals and the second electrical signal, the first modulation signal, the second modulation signal, and the third modulation signal, respectively, read an accumulated charge amount to obtain a first charge amount, a second charge amount, a third charge amount, and a fourth charge amount, and calculate the phase difference according to the first charge amount, the second charge amount, the third charge amount, and the fourth charge amount, and the following calculation formula:
wherein the content of the first and second substances,
for the phase difference, Q1 is a first charge amount, Q2 is a second charge amount, Q3 is a third charge amount, and Q4 is a fourth charge amount;
the first charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the second electrical signal, the second charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the first modulation signal, the third charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the second modulation signal, and the fourth charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the third modulation signal.
In the embodiment of the present application, in the process of obtaining the distance between the object to be photographed and the light sensing unit, the light emitting element emits L times of incident light signals, all light sensing elements in the light sensing unit respectively sense corresponding reflected light signals, and obtain M first electrical signals, where L is smaller than M, that is, the number of times that the light emitting element emits the incident light signals when obtaining the M first electrical signals is not M but smaller than M, that is, the number of times that the light emitting element emits the incident light signals is smaller than the number of sensed reflected light signals, or the number of times that the light sensing element exposes is smaller than the number of sensed reflected light signals, so that the number of times that the light sensing element exposes can be reduced, and further the frame rate of distance measurement can be improved.
Drawings
Fig. 1 is a schematic structural diagram of a distance measuring device according to an embodiment of the present application.
Fig. 2 is a schematic structural diagram of another distance measuring device according to an embodiment of the present application.
Fig. 3 is a flow chart of a ranging method according to an embodiment of the present application.
Fig. 4 is a schematic structural diagram of another distance measuring device according to an embodiment of the present application.
Fig. 5 is a flow chart of another ranging method according to an embodiment of the present application.
Fig. 6 is a schematic structural diagram of another distance measuring device according to an embodiment of the present application.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.
It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present application. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.
Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments described below and the features of the embodiments can be combined with each other without conflict.
The embodiment of the application provides a distance measuring method. The ranging method indirectly measures the time of flight of light by measuring a phase shift, and then calculates the depth of an object according to the time of flight. The ranging method is applied to a ranging apparatus as shown in fig. 1. As shown in fig. 1, the ranging apparatus 1 includes a transmitting end 2 and a receiving end 3. The transmitting terminal 1 is used for transmitting the modulated incident optical signal O1, and the incident optical signal O1 may be a square wave, but is not limited thereto. After the incident light signal O1 is reflected by the object 4 to form the reflected light signal O2 and the reflected light signal O2 is received by the receiving terminal 3, the distance measuring apparatus 1 can obtain the distance D between the object 4 and the distance measuring apparatus 1 based on the phase difference between the incident light signal O1 and the reflected light signal O2.
In the present embodiment, the emission end 2 includes one light emitting element. As shown in fig. 2, the receiving end 3 includes at least one photosensitive unit 31, and each photosensitive unit 31 includes N photosensitive elements 311, where N is an integer greater than 1. In this example, N is 4. The light sensing element 311 is a photodiode. The photodiode may be a CMOS photodiode, but is not limited thereto. The number of the photosensitive units 31 may be 4, or may be 1, 2, 3, or other numbers.
In the present embodiment, as shown in fig. 3, the ranging method includes the following steps 301 to 305:
in step 301, the light emitting element is controlled to emit an incident light signal L times; l is a positive integer.
In this embodiment, L is 1. That is, the light emitting element is controlled to emit the primary incident light signal O1; l is a positive integer.
In step 302, for each photosensitive unit, all photosensitive elements in the photosensitive unit respectively sense corresponding reflected light signals to obtain M first electrical signals; the reflected light signal is the light signal reflected by the incident light signal after encountering the shot object; the first electrical signal comprises information of the reflected optical signal; m is an integer greater than or equal to N; l is less than M.
In this embodiment, M is 4. I.e. emitting the incident optical signal once, 4 first electrical signals comprising information of the reflected optical signal can be obtained.
In this embodiment, the light sensing element may convert the sensed reflected light signal into a first electrical signal, and the first electrical signal may include, but is not limited to, amplitude information, frequency information, and phase information of the reflected light signal.
In the present embodiment, the reflected light signal O2 can be sensed by all the light sensing units 31 in the receiving end 3. For each light sensing unit 31, each light sensing element 311 in the light sensing unit 31 can sense the reflected light signal O2 reflected to the light sensing element 311, and convert the sensed reflected light signal into a corresponding first electrical signal. Therefore, 4 first electrical signals can be obtained when the light sensing unit 31 senses the reflected light signal O2.
As shown in fig. 2, each of the photosensitive units 31 may include a first photosensitive element a, a second photosensitive element B, a third photosensitive element C, and a fourth photosensitive element D. For convenience of description, the first optical sensing element a converts the sensed reflected optical signal O2 into a first electrical signal designated Oa, the second optical sensing element B converts the sensed reflected optical signal O2 into a first electrical signal designated Ob, the third optical sensing element C converts the sensed reflected optical signal O2 into a first electrical signal designated Oc, and the fourth optical sensing element D converts the sensed reflected optical signal O2 into a first electrical signal designated Od. Therefore, the light sensing unit 31 can obtain 4 first electrical signals Oa, Ob, Oc and Od when sensing the reflected light signal O2.
In step 303, performing phase modulation on the second electrical signals by using M-1 phases respectively to obtain M-1 modulation signals; m-1 phases are different; the second electrical signal includes information of the incident optical signal.
In this embodiment, 3 phases are adopted to perform phase modulation on the second electrical signals, respectively, so as to obtain 3 modulation signals. The second electrical signal includes information of the incident optical signal. For example, the second electrical signal includes amplitude information, frequency information, and phase information of the incident optical signal.
In the present embodiment, the 3 phases are 90 °, 180 °, and 270 °, respectively. The 3 modulation signals are respectively a first modulation signal, a second modulation signal and a third modulation signal. The first modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 90 °, the second modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 180 °, and the third modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 270 °. The frequency of the first modulation signal and the frequency of the second modulation signal are the same as the frequency of the third modulation signal and the frequency of the second electrical signal.
In step 304, a phase difference is obtained from the second electrical signal, the M-1 modulated signals, and the M first electrical signals.
In this embodiment, the M first electrical signals may be first summed with the second electrical signal, the first modulation signal, the second modulation signal, and the third modulation signal, respectively, to accumulate charges, and the stage of accumulating charges may also be referred to as an exposure integration stage. Then, the accumulated charge amount is read to obtain a first charge amount, a second charge amount, a third charge amount and a fourth charge amount, wherein the first charge amount is an accumulated charge amount after the corresponding phase of the first electric signal and the second electric signal, the second charge amount is an accumulated charge amount after the corresponding phase of the first electric signal and the first modulation signal, the third charge amount is an accumulated charge amount after the corresponding phase of the first electric signal and the second modulation signal, and the fourth charge amount is an accumulated charge amount after the corresponding phase of the first electric signal and the third modulation signal. Then, the phase difference is calculated from the first charge amount, the second charge amount, the third charge amount, the fourth charge amount, and the following calculation equation:
wherein the content of the first and second substances,
for the phase difference, Q1 is the first charge amount, Q2 is the second charge amount, Q3 is the third charge amount, and Q4 is the fourth charge amount.
In the present embodiment, 4 charge amounts for calculating the phase difference using the above calculation formula can be obtained by only one exposure without exposing 4 times: the first charge amount, the second charge amount, the third charge amount, and the fourth charge amount, and thus, the time for calculating the phase difference can be reduced, and the frame rate of ranging can be improved.
In step 305, the distance between the subject and the photosensitive unit is acquired from the phase difference.
In the present embodiment, the distance between the subject and the photosensitive unit can be calculated from the phase difference using the following calculation formula:
where D is a distance between the subject and the photosensitive unit, c is a speed of light, and f is a frequency of the first modulation signal.
Note that the distance between the subject and the photosensitive unit may be a distance between the center position of the photosensitive unit and the subject, that is, a distance between the center positions of the 4 photosensitive elements in the photosensitive unit and the subject.
In this embodiment, in the process of acquiring the distance between the object to be photographed and the photosensitive unit, the light emitting element emits 1 time of incident light signal, and all the photosensitive elements in the photosensitive unit respectively sense the corresponding reflected light signals to obtain 4 first electrical signals, that is, the number of times of emitting the incident light signal by the light emitting element when acquiring the 4 first electrical signals is not 4 but less than 4, that is, the number of times of emitting the incident light signal by the light emitting element is less than the number of the sensed reflected light signals, or the number of times of exposing the photosensitive element is less than the number of the sensed reflected light signals, so that the number of times of exposing the photosensitive element can be reduced, and the frame rate of ranging can be improved.
In addition, in the embodiment of the application, the exposure times of the photosensitive element are reduced, so that the power consumption can be reduced. And because the number of times of exposure of the photosensitive element is reduced, the exposure time in the distance measurement process is reduced, and the problems of image distortion and the like caused by overlong exposure time can be further reduced.
The embodiment of the application also provides a distance measuring method. In this embodiment, M is greater than N and equal to L times N. Wherein N is 2, M is 4, and L is 2.
In the present embodiment, as shown in fig. 4, two photosensitive elements are included in each photosensitive unit. The light emitting element emits an incident light signal twice. For each time the light emitting element emits an incident light signal, all the light sensing elements in the light sensing unit respectively sense the corresponding reflected light signal, and 2 first electrical signals are obtained. After the light emitting element emits the incident light signal twice, all the light sensing elements in the light sensing unit respectively sense the reflected light signal corresponding to 2 times, and 4 first electric signals are obtained in total.
In this embodiment, as shown in fig. 5, the ranging method may include the following steps 501 to 510:
in step 501, a light emitting element is controlled to emit an incident light signal.
In step 502, for each light sensing unit, all light sensing elements in the light sensing unit respectively sense corresponding reflected light signals, and two first electrical signals are obtained.
In this embodiment, as shown in fig. 4, each of the light sensing units includes two light sensing elements, and the two light sensing elements respectively sense corresponding reflected light signals to obtain two first electrical signals.
In step 503, the second electrical signal is phase modulated with a 90 ° phase to obtain a first modulated signal.
In step 504, the two obtained first electrical signals are respectively and respectively anded with the second electrical signal and the first modulation signal to accumulate charges, and the accumulated charge amount is read to obtain a first charge amount and a second charge amount.
The present step is similar to the method for obtaining the first charge amount and the second charge amount in the above embodiments, and is not repeated herein.
In step 505, the light emitting elements are controlled to emit an incident light signal.
In the present embodiment, after obtaining the first charge amount and the second charge amount, the incident light signal is emitted again to obtain the third charge amount and the fourth charge amount.
In step 506, for each light sensing unit, all light sensing elements in the light sensing unit respectively sense corresponding reflected light signals, and two first electrical signals are obtained.
This step is similar to step 502 and will not be described herein again.
In step 507, the second electrical signal is phase-modulated with a 180 ° phase and a 270 ° phase, respectively, to obtain a second modulation signal and a third modulation signal.
This step is similar to step 503 and will not be described herein again.
In step 508, the two obtained first electrical signals are respectively and respectively anded with the second modulation signal and the third modulation signal to accumulate charges, and the accumulated charge amount is read to obtain a third charge amount and a fourth charge amount.
This step is similar to step 504 and will not be described herein.
In step 509, a phase difference is calculated from the first charge amount, the second charge amount, the third charge amount, and the fourth charge amount.
The method for calculating the phase difference in this step is similar to that in the above embodiments, and is not described herein again.
In step 510, the distance between the subject and the photosensitive unit is acquired from the phase difference.
This step is similar to step 305 and will not be described herein again.
In this embodiment, in the process of acquiring the distance between the object to be photographed and the photosensitive unit, the light emitting element emits the incident light signal twice, and all the photosensitive elements in the photosensitive unit respectively sense the corresponding reflected light signals to obtain 4 first electrical signals, that is, the number of times that the light emitting element emits the incident light signal when acquiring the 4 first electrical signals is not 4 but less than 4, that is, the number of times that the light emitting element emits the incident light signal is less than the number of the sensed reflected light signals, or the number of times that the photosensitive element is exposed is less than the number of the sensed reflected light signals, so that the number of times that the photosensitive element is exposed can be reduced, and the frame rate of ranging can be improved.
It can be understood by those skilled in the art that in the embodiment of the present application, the photosensitive element can be exposed once every time an incident light signal is emitted, and the charge amount can be read once, except that L is 1, the charge amount accumulated after the photosensitive element is exposed L times after L incident light signals are emitted is not read once.
An embodiment of the present application further provides a ranging apparatus, as shown in fig. 6, the ranging apparatus including: a light emitting element 61, a control unit 62, a processing unit 63, and at least one photosensitive unit 311, each photosensitive unit 31 including N photosensitive elements 311, N being an integer greater than 1;
the control unit is electrically connected with the light-emitting element and is used for controlling the light-emitting element to emit L incident light signals; l is a positive integer.
For each photosensitive unit, all photosensitive elements in the photosensitive unit respectively sense corresponding reflected light signals to obtain M first electric signals; the reflected light signal is the light signal reflected by the incident light signal after encountering the shot object; the first electrical signal comprises information of the reflected optical signal; m is an integer greater than or equal to N; l is less than M.
The processing unit is electrically connected with the photosensitive unit and is used for respectively carrying out phase modulation on the second electric signals by adopting M-1 phases to obtain M-1 modulation signals, acquiring phase differences according to the second electric signals, the M-1 modulation signals and the M first electric signals and acquiring the distance between a shot object and the photosensitive unit according to the phase differences; m-1 phases are different; the second electrical signal includes information of the incident optical signal.
In one embodiment, M is equal to N, L is 1, N is 4, and M is 4.
In another embodiment, M is greater than N and equal to L times N, N is 2, M is 4, and L is 2. Aiming at each time that the light-emitting element emits an incident light signal, all the light-sensing elements in the light-sensing units respectively sense corresponding reflected light signals to obtain N first electric signals; l is an integer greater than 1. After the light emitting element emits L incident light signals, all the light sensing elements in the light sensing unit respectively sense the L corresponding reflected light signals, and M first electrical signals are obtained.
In one embodiment, M is 4, and M-1 phases are 90, 180, and 270, respectively; the photosensitive element is a photodiode; the M-1 modulation signals comprise a first modulation signal, a second modulation signal and a third modulation signal; the first modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 90 °, the second modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 180 °, and the third modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 270 °. The processing unit is further configured to sum and accumulate the M first electrical signals with the second electrical signal, the first modulation signal, the second modulation signal, and the third modulation signal, respectively, read an accumulated charge amount to obtain a first charge amount, a second charge amount, a third charge amount, and a fourth charge amount, and calculate a phase difference according to the first charge amount, the second charge amount, the third charge amount, the fourth charge amount, and the following calculation formula:
wherein the content of the first and second substances,
for the phase difference, Q1 is the first charge amount, Q2 is the second charge amount, Q3 is the third charge amount, and Q4 is the fourth charge amount. The first charge amount is an accumulated charge amount after the phase of the corresponding first electric signal and the second electric signal, the second charge amount is an accumulated charge amount after the phase of the corresponding first electric signal and the first modulation signal, the third charge amount is an accumulated charge amount after the phase of the corresponding first electric signal and the second modulation signal, and the fourth charge amount is an accumulated charge amount after the phase of the corresponding first electric signal and the third modulation signal.
In the embodiment of the present application, in the process of obtaining the distance between the object to be photographed and the light sensing unit, the light emitting element emits L times of incident light signals, all light sensing elements in the light sensing unit respectively sense corresponding reflected light signals, and obtain M first electrical signals, where L is smaller than M, that is, the number of times that the light emitting element emits the incident light signals when obtaining the M first electrical signals is not M but smaller than M, that is, the number of times that the light emitting element emits the incident light signals is smaller than the number of sensed reflected light signals, or the number of times that the light sensing element exposes is smaller than the number of sensed reflected light signals, so that the number of times that the light sensing element exposes can be reduced, and further the frame rate of distance measurement can be improved.
In the present application, the apparatus embodiments and the method embodiments may complement each other without conflict. The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of the application. One of ordinary skill in the art can understand and implement it without inventive effort.
The present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features herein disclosed.
Claims (10)
1. A distance measuring method is characterized by being applied to a distance measuring device, wherein the distance measuring device comprises a light-emitting element and at least one photosensitive unit, each photosensitive unit comprises N photosensitive elements, and N is an integer greater than 1; the distance measurement method comprises the following steps:
controlling the light-emitting element to emit L incident light signals; l is a positive integer;
for each photosensitive unit, all the photosensitive elements in the photosensitive unit respectively sense corresponding reflected light signals to obtain M first electric signals; the reflected light signal is a light signal reflected by the incident light signal after encountering a shot object; the first electrical signal comprises information of the reflected light signal; m is an integer greater than or equal to N; l is less than M;
respectively carrying out phase modulation on the second electric signals by adopting M-1 phases to obtain M-1 modulation signals; the M-1 phases are different; the second electrical signal comprises information of the incident optical signal;
acquiring a phase difference according to the second electric signal, the M-1 modulation signals and the M first electric signals;
and acquiring the distance between the shot object and the photosensitive unit according to the phase difference.
2. The ranging method of claim 1, wherein when M is equal to N, L is 1.
3. The method of claim 2, wherein N is 4 and M is 4.
4. The distance measuring method according to claim 1, wherein when M is greater than N and equal to L times of N, for each time the light emitting element emits the incident light signal, all the light sensing elements in the light sensing unit respectively sense a corresponding reflected light signal, resulting in N first electrical signals; l is an integer greater than 1;
after the light emitting elements emit the incident light signals for L times, all the light sensing elements in the light sensing units respectively sense the reflected light signals corresponding to the L times, and M first electric signals are obtained.
5. The method of claim 4, wherein N is 2, M is 4, and L is 2.
6. The method according to claim 1, characterized in that M is 4, said M-1 phases being respectively 90 °, 180 ° and 270 °; the photosensitive element is a photodiode; the M-1 modulation signals comprise a first modulation signal, a second modulation signal and a third modulation signal; the first modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 90 degrees, the second modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 180 degrees, and the third modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 270 degrees;
the obtaining a phase difference according to the second electrical signal, the M-1 modulation signals, and the M first electrical signals includes:
taking the M first electrical signals and the second electrical signal, the first modulation signal, the second modulation signal, and the third modulation signal, respectively, and accumulating charges;
reading the accumulated charge amount to obtain a first charge amount, a second charge amount, a third charge amount and a fourth charge amount; the first charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the second electrical signal, the second charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the first modulation signal, the third charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the second modulation signal, and the fourth charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the third modulation signal;
calculating the phase difference from the first, second, third, and fourth charge amounts and the following calculation:
wherein the content of the first and second substances,
for the phase difference, Q1 is a first charge amount, Q2 is a second charge amount, Q3 is a third charge amount, and Q4 is a fourth charge amount.
7. A ranging apparatus, comprising: the device comprises a light-emitting element, a control unit, a processing unit and at least one photosensitive unit, wherein each photosensitive unit comprises N photosensitive elements, and N is an integer greater than 1;
the control unit is electrically connected with the light-emitting element and is used for controlling the light-emitting element to emit L incident light signals; l is a positive integer;
for each photosensitive unit, all the photosensitive elements in the photosensitive unit respectively sense corresponding reflected light signals to obtain M first electric signals; the reflected light signal is a light signal reflected by the incident light signal after encountering a shot object; the first electrical signal comprises information of the reflected light signal; m is an integer greater than or equal to N; l is less than M;
the processing unit is electrically connected with the photosensitive unit and is used for performing phase modulation on the second electric signals by adopting M-1 phases to obtain M-1 modulation signals, acquiring phase differences according to the second electric signals, the M-1 modulation signals and the M first electric signals and acquiring the distance between the object to be shot and the photosensitive unit according to the phase differences; the M-1 phases are different; the second electrical signal includes information of the incident optical signal.
8. The range finder device of claim 7, wherein when M equals N, L is 1;
n is 4 and M is 4.
9. The distance measuring device of claim 7, wherein when M is greater than N and equal to L times of N, for each time the light emitting element emits the incident light signal, all the light sensing elements in the light sensing unit respectively sense a corresponding reflected light signal, resulting in N first electrical signals; l is an integer greater than 1;
after the light emitting element emits the incident light signals for L times, all the light sensing elements in the light sensing units respectively sense the reflected light signals corresponding to the L times to obtain M first electric signals;
n is 2, M is 4, and L is 2.
10. A ranging device as claimed in claim 7 characterized in that M is 4, said M-1 phases being respectively 90 °, 180 ° and 270 °; the photosensitive element is a photodiode; the M-1 modulation signals comprise a first modulation signal, a second modulation signal and a third modulation signal; the first modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 90 degrees, the second modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 180 degrees, and the third modulation signal is a signal obtained by phase-modulating the second electrical signal with a phase of 270 degrees;
the processing unit is further configured to sum and accumulate charges by taking the M first electrical signals and the second electrical signal, the first modulation signal, the second modulation signal, and the third modulation signal, respectively, read an accumulated charge amount to obtain a first charge amount, a second charge amount, a third charge amount, and a fourth charge amount, and calculate the phase difference according to the first charge amount, the second charge amount, the third charge amount, and the fourth charge amount, and the following calculation formula:
wherein the content of the first and second substances,
for the phase difference, Q1 is a first charge amount, Q2 is a second charge amount, Q3 is a third charge amount, and Q4 is a fourth charge amount;
the first charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the second electrical signal, the second charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the first modulation signal, the third charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the second modulation signal, and the fourth charge amount is an accumulated charge amount after the phase of the corresponding first electrical signal and the third modulation signal.
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