TWI634871B - Ultrasound image detection method - Google Patents

Abstract

The ultrasonic image detecting method includes simultaneously transmitting a plurality of first plane waves; receiving at least one first reflected wave reflected by the object by the first plane wave; simultaneously transmitting a plurality of second plane waves according to the at least one first reflected wave; receiving The at least one second reflected wave reflected by the object by the second plane wave; and the plurality of decision plane waves are used to determine an angle or a position of the object according to the at least one second reflected wave. The two adjacent first plane waves sandwich the first angle, and the two adjacent second plane waves sandwich the second angle, and the first angle is greater than the second angle.

Description

Ultrasonic image detection method

The invention discloses a method for detecting ultrasonic images, in particular to a method for detecting ultrasonic images with high-speed detection function.

With the rapid development of medical technology, the detection technology of ultrasonic waves is becoming more and more mature. In general, the ultrasonic detection method uses a probe that emits an ultrasonic signal to emit an ultrasonic signal below the skin. In addition, the ultrasonic signal probe uses the reflected ultrasonic signal to determine the shape and position of the object that is invisible to the naked eye for various medical purposes.

The traditional ultrasonic probe emits ultrasonic signals by sequentially transmitting ultrasonic signals by using a plurality of piezoelectric devices, and the ultrasonic signals of each angle correspond to the direction of one scanning line. Moreover, the ultrasonic probe performs image recognition and object detection according to the ultrasonic signal corresponding to the direction of the scan line and its reflected signal. However, the detection mechanism of the traditional ultrasonic probe must use multiple angle detection modes to identify the position and angle of the object. Moreover, the ultrasonic probe sends the ultrasonic signal to the object, and then receives the ultrasonic signal reflected by the object (2r/c). Where r is the ultrasonic signal detection depth and c is the speed of sound. Therefore, in the conventional ultrasonic probe, if M detection angles and N scanning lines are considered, a total of M × N × (2r / c) time is required, and when M and N become large, the cost of detecting an object is required. Processing time will be amazing.

An embodiment of the present invention provides a method for detecting an ultrasonic image, comprising simultaneously transmitting a plurality of first plane waves different from an angle of a surface; and receiving at least one first reflected wave reflected by the object by the first plane wave; a first reflected wave simultaneously emitting a plurality of second plane waves different from an angle of the surface; receiving at least one second reflected wave reflected by the object by the second plane wave; and using the complex number according to the at least one second reflected wave Plane plane waves to determine the angle or position of the object. The two adjacent first plane waves sandwich the first angle, and the two adjacent second plane waves sandwich the second angle, and the first angle is greater than the second angle.

1 is an architectural diagram of an embodiment of the ultrasonic sounding system 100 of the present invention. The ultrasonic sounding system 100 includes an ultrasonic probe 10 for contacting the surface 11. Surface 11 can be any plane, such as a skin surface. The ultrasonic sounding detection system 100 can use the ultrasonic probe 10 to detect the position and angle of an object that is invisible to the naked eye below the surface 11. For example, the ultrasonic probe 10 can be used to detect the position and angle of the elongated or needle-like object below the skin. . The ultrasonic probe 10 includes a plurality of transceivers TS1 to TSN, a buffer device 12, and a processor 13. Each of the plurality of transceivers TS1 through TSN may be coupled to the cache device 12. The cache device 12 can be coupled to the processor 13. Each transceiver can simultaneously transmit plane waves in different directions. For example, the transceiver TS1 can transmit a plane wave in the direction S1. The transceiver TS2 can transmit a plane wave in the direction S2. The transceiver TS3 can transmit a plane wave in the direction S3. The transceiver TSN can transmit a plane wave in the direction SN. N is a positive integer. The cache device 12 can be any form of data storage device, such as a memory. The processor 13 can be any device having a signal processing function, such as a central processing unit, a microprocessor, or a programmable logic unit. In the ultrasonic sounding system 100, the processor 13 may be disposed within the ultrasonic probe 10, but the invention is not limited thereto. For example, the processor 13 can be a processing device in the ultrasonic machine, and the ultrasonic probe 10 can be wired or wirelessly connected to the ultrasonic machine, so that the processing device in the ultrasonic machine can be analyzed and The signal detected by the ultrasonic probe 10 is processed. In the present embodiment, the ultrasonic probe 10 simultaneously emits plane waves of different angles. In other words, a plurality of plane waves different in angle from the surface 11 will be simultaneously emitted by the ultrasonic probe 10. Therefore, the ultrasonic probe 10 can simultaneously detect the space under the surface 11 at different angles, so that it has the function of quickly capturing the angle or position of the object. The structure of the transceiver of the ultrasonic probe 10, the principle of transmitting a plane wave of a specific angle, and a method of detecting an object will be described in detail below.

Figure 2 is an architectural diagram of the transceiver TSN in the ultrasonic probe 10. As described herein, the transceivers TS1 to TSN in the ultrasonic probe 10 may be transceivers of the same configuration. For simplification of description, FIG. 2 is only representative of the structure of the transceiver TSN. The transceiver TSN includes a signal generating device 14 and piezoelectric devices ELE1 to ELEM, where M can be a positive integer greater than two. The signal generating device 14 is connectable to the processor 13. Therefore, the processor 13 can control the signal generating device 14 to generate different voltages to drive the piezoelectric devices ELE1 to ELEM. For example, in FIG. 2, the signal generating device 14 can generate a first group of signals, and the first group of signals includes a voltage signal SE1, a voltage signal SE2, a voltage signal SE3, ..., and a voltage signal SEM. The piezoelectric devices ELE1 to ELEM can be driven by the first set of signals to generate a plurality of waves WAV1 to WAVM. For example, the piezoelectric device ELE1 can be driven by the voltage signal SE1 to generate the wave WAV1, the piezoelectric device ELE2 can be driven by the voltage signal SE2 to generate the wave WAV2, and the piezoelectric device ELE3 can be driven by the voltage signal SE3 to generate the wave WAV3, the piezoelectric device The ELEM can be driven by a voltage signal SEM to generate a wave WAVM. Moreover, in the first group of signals, the delay time of the voltage signal SE1 to the voltage signal SEM is different. In the embodiment of FIG. 2, the voltage signal SE2 has a delay time compared to the voltage signal SE1, the voltage signal SE3 has a delay time compared to the voltage signal SE2, and so on. Since the delay time of the voltage signal SE1 to the voltage signal SEM is different, the time for driving the piezoelectric devices ELE1 to ELEM is also different. In Fig. 2, the piezoelectric device ELE1 first generates the wave WAV1, and then the piezoelectric device ELE2 regenerates the wave WAV2, and then the piezoelectric device ELE2 regenerates the wave WAV3, and so on. Since the generation time of the wave WAV1 to the wave WAVM is different, the position of the wave front of the wave WAV1 to the WAVM is different. The first plane wave BFW can be synthesized by the tangential line of the wavefront of these waves WAV1 to WAVM.

Fig. 3 is a schematic diagram showing the synthesis of the first plane wave BFW in the ultrasonic probe 10. As mentioned above, since the wavefront positions of the wave WAV1 to the wave WAVM are different, the tangent of the wavefront of these waves WAV1 to WAVM can synthesize the first plane wave BFW. Also, since the first plane wave BFW of the present invention is linear, the time difference between the wave WAV1 and the wave WAVM is the same. For example, in FIG. 3, the time difference between the tangential time point of the wavefront of the wave WAV1 and the tangential time point of the wavefront of the wave WAV2 is D1. The time difference between the tangential time point of the wavefront of the wave WAV2 and the tangential time point of the wavefront of the wave WAV3 is D2. D1 is equal to D2. Since the time difference between the wave WAV1 and the wave WAVM is the same, in FIG. 2, the time difference between the voltage signal SE1 and the voltage signal SEM driving the two adjacent piezoelectric devices of the piezoelectric devices ELE1 to ELEM is also the same. In other words, the delay time of the voltage signal SE2 compared to the voltage signal SE1 is the same as the delay time of the voltage signal SE3 compared to the voltage signal SE2. Thus, the first plane wave BFW synthesized by the waves WAV1 to WAVM generated by the piezoelectric devices ELE1 to ELEM is linear. Moreover, by changing the delay time of the voltage signal SE1 to the voltage signal SEM, the angle between the synthesized first plane wave BFW and the surface 11 can be controlled.

Figure 4 is a schematic diagram of the ultrasonic probe 10 transmitting a plurality of first plane waves BFW1 to BFWN. A method of how the ultrasonic probe 10 detects the object Obj quickly will be described below. First, the ultrasonic probe 10 simultaneously emits a plurality of first plane waves BFW1 to BFWN different from the angle of the surface 11, wherein two adjacent first plane waves sandwich the first angle. For example, in the first plane waves BFW1 to BFWN simultaneously emitted by the ultrasonic probe 10, the angle between the first plane wave BFW1 and the surface 11 is θ1 (hereinafter referred to as an angle θ1). The angle between the first plane wave BFW2 and BFW1 is θ2 (hereinafter referred to as the angle θ2). The angle between the first plane wave BFW3 and BFW2 is θ3 (hereinafter referred to as the angle θ3), and so on. In Fig. 4, the object Obj may be a long or needle-like object, at an angle to the surface 11. After the ultrasonic probe 10 emits the N first plane waves BFW1 to BFWN, part of the first plane wave will be reflected by the object Obj to generate at least one first reflected wave. After the transceivers TS1 to TSN of the ultrasonic probe 10 receive the at least one first reflected wave, the processor 13 will generate a first detection angle corresponding to the object Obj. However, the first detection angle is only a rough estimated angle because only a small portion of the first plane wave is reflected by the object Obj, so the angle estimation error value is large. In order to further increase the accuracy of the angle estimation, the ultrasonic probe 10 can perform the following steps.

Fig. 5 is a schematic diagram of the ultrasonic probe 10 for transmitting a plurality of second plane waves BFW1' to BFWN'. As described above, after obtaining the first detection angle with a large error value, the ultrasonic probe 10 can simultaneously emit a plurality of second plane waves BFW1' to BFWN' different from the angle of the surface 11, wherein two adjacent The second plane wave clamps the second angle. For example, in the second plane waves BFW1' to BFWN' simultaneously emitted by the ultrasonic probe 10, the angle between the second plane wave BFW1' and the surface 11 is θ1' (hereinafter referred to as an angle θ1'). The angle between the second plane wave BFW2' and BFW1' is θ2' (hereinafter referred to as the angle θ2'). The angle between the second plane wave BFW3' and BFW2' is θ3' (hereinafter referred to as the angle θ3'), and so on. After the ultrasonic probe 10 emits N second plane waves BFW1' to BFWN', a portion of the second plane wave will be reflected by the object Obj to generate at least one second reflected wave. After the transceivers TS1 to TSN of the ultrasonic probe 10 receive the at least one second reflected wave, the processor 13 will generate a second detection angle corresponding to the object Obj. As illustrated herein, the angle of the two adjacent first plane wave clips is greater than the angle of the two adjacent second plane wave clips. In other words, the second plane waves BFW1' to BFWN' emitted by the ultrasonic probe 10 are closer than the first plane waves BFW1 to BFWN. For example, numerically, the angle θ2 of Fig. 4 will be larger than the angle θ2' of Fig. 5, the angle θ3 of Fig. 4 will be larger than the angle θ3' of Fig. 5, and so on. Therefore, the error value of the second detection angle is smaller than the first detection angle because the ultrasonic probe 10 emits a relatively tight second plane wave BFW1' to BFWN', so the second plane wave reflected by the object Obj The number will increase, which will result in the result of the ultrasonic probe 10 determining the position or angle of the object Obj or more accurately. Further, the second plane waves BFW1' to BFWN' are generated in a manner similar to the manner in which the first plane waves BFW1 to BFWN described in Figs. 2 and 3 are generated, and thus will not be described again. A method of judging whether the position or angle of the object Obj is determined by the second plane wave reflected by the object Obj will be described below.

Figure 6 is a schematic diagram of a plurality of decision plane waves P1 to PQ and their included angles in the ultrasonic probe 10. As described above, the ultrasonic probe 10 emits N second plane waves BFW1' to BFWN', and a portion of the second plane wave will be reflected by the object Obj to form at least one second reflected wave. After the transceivers TS1 to TSN of the ultrasonic probe 10 receive the at least one second reflected wave, the at least one second reflected wave can be converted into an electrical signal. The processor 13 can further process the electrical signal corresponding to the at least one second reflected wave and parse the reflection angle of the at least one second reflected wave. The processor 13 can also store the electrical signal corresponding to the at least one second reflected wave and its reflection angle in the buffer device 12 for calculating the optimal angle corresponding to the object Obj. Here, the processor 13 can use the Signal Decision Boundary Algorithm to obtain the optimal angle corresponding to the object Obj. For example, processor 13 may store a number of decision plane waves P1 to PQ angles. The decision plane waves P1 to PQ are illustrated as Figure 6, where Q can be a positive integer greater than two. The angle between the decision plane wave P1 and the surface 11 is Pθ1 (hereinafter referred to as the angle Pθ1). The angle between the decision plane wave P2 and P1 is Pθ2 (hereinafter referred to as the angle Pθ2). The angle between the decision plane wave P3 and P2 is Pθ3 (hereinafter referred to as the angle Pθ3), and so on. It should be understood that the above-mentioned included angle Pθ1, the included angle Pθ2, the included angle Pθ3, and the corresponding decision plane wave number may be stored in the processor 13 by electromagnetic data. In other words, the decision plane waves P1 to PQ are not plane waves transmitted by the transceiver by the entity, but are stored in the processor 13 in the form of virtualized digital electromagnetic data for determining the object Obj according to the at least one second reflected wave. The best angle. The number of decision plane waves P1 to PQ of the present invention may be greater than the number of second plane waves BFW1' to BFWN', in other words, Q may be greater than N. That is, the third angle (for example, the angle Pθ1, the angle Pθ2, and the angle Pθ3) of the two adjacent decision plane waves in the decision plane waves P1 to PQ may be smaller than the second angle sandwiched by the two adjacent second plane waves. In other words, the decision plane waves P1 to PQ can be arranged more closely than the second plane waves BFW1' to BFWN' to accurately determine the optimum angle of the object Obj based on the signal of the at least one second reflected wave. A method of determining the optimum angle of the object Obj based on the second reflected wave is described below.

Fig. 7 is a schematic diagram showing the optimum angle generated by the plurality of decision plane waves P1 to PQ and their included angles in the ultrasonic probe 10 according to the second reflected wave RWAV. As mentioned before, after the second plane waves BFW1' to BFWN' are emitted by the ultrasonic probe 10, some of the second plane waves are reflected by the object Obj to form a second reflected wave. For the sake of simplification, Fig. 7 uses the second reflected wave RWAV to represent the direction in which the second plane wave is reflected by the object Obj. As shown in Fig. 7, the second reflected wave RWAV is received by the ultrasonic probe 10. Next, the ultrasonic probe 10 buffers the reflection angle of the second reflected wave RWAV, and groups the decision plane waves P1 to PQ stored in the processor 13 to generate a complex array of decision plane waves. For example, the decision wave of the first group may be P1, P4, P7, . The decision wave of the second group can be P2, P5, P8.... The decision wave of the third group can be P3, P6, P9.... Then, the processor 13 compares the reflection angles corresponding to the second reflected wave RWAV with the plurality of decision angles corresponding to the decision plane waves of the groups, to select a set of optimal decision plane waves from the decision plane waves of the groups to meet The angle or position of the object Obj. For example, the processor 13 may first compare the angles of the decision wave waves P1, P4, P7, . . . of the first group with the reflection angles corresponding to the second reflected wave RWAV. Then, the angles of the decision plane waves P1, P4, P7, ... of the second group are compared with the reflection angles corresponding to the second reflected wave RWAV. Then, the angles of the decision plane waves P3, P6, P9, ... of the third group are compared with the reflection angles corresponding to the second reflected wave RWAV. In the present embodiment, in the decision wave of the first group, the angle of the decision plane wave P1 is close to the reflection angle corresponding to the second reflected wave RWAV. Therefore, the processor 13 will judge that the optimum angle of the corresponding object Obj is the angle Pθ1 between the decision plane wave P1 and the surface 11. In other words, based on the second reflected wave RWAV, the processor 13 finally determines that the optimum angle of the object Obj is the angle Pθ1. In the preferred embodiment, if the number of decision plane waves used by the processor 13 is large (Q is large), the arrangement of the decision plane waves is very dense. The accuracy of the processor 13 finally determining the optimal angle of the object Obj is further enhanced. In theory, the optimal angle of the object Obj is the angle of the normal vector of the object Obj. Further, the angle at which the object Obj is incident on the surface 11 can be estimated from the optimum angle. For example, when the optimum angle is the angle Pθ1, the angle at which the object Obj is incident on the surface 11 approaches (90 ⁰ - Pθ1). Moreover, in the physical sense, the optimal angle represents the angle of the normal vector of the object Obj, so when the plane wave is emitted at the optimal angle, if the object Obj is within the detection range of the plane wave, the object Obj will approach the vertical direction. It reflects its plane wave with almost no deflection of the refraction.

Fig. 8 is a schematic diagram showing the optimum plane wave OptBFW1 to OptBFWN to the object Obj according to the optimum angle in the ultrasonic probe 10. As mentioned before, the ultrasonic probe 10 will ultimately rely on at least one second reflected wave to determine the optimum angle. Next, the ultrasonic probe 10 transmits the optimal plane waves OptBFW1 to OptBFWN to the object Obj according to the optimum angle. For example, in the present embodiment, the optimum angle is the angle Pθ1. Therefore, the ultrasonic probe 10 simultaneously transmits the optimum plane waves OptBFW1 to OptBFWN. Further, the angle between the optimum plane waves OptBFW1 to OptBFWN and the surface 11 is P?1. Since the forward direction of all the optimal plane waves OptBFW1 to OptBFWN is substantially perpendicular to the object Obj, the optimum plane wave within the reflection range of the object Obj is reflected in a direction close to the vertical direction to form a plurality of optimal reflected waves. After the ultrasonic probe 10 receives a plurality of optimal reflected waves, the image of the object Obj can be enhanced based on the optimal reflected waves. In the end, the ultrasonic probe 10 can not only quickly recognize the position or angle of the object Obj, but also enhance the image of the object Obj, so that the user can see clear and accurate ultrasonic images in a short time.

Compared with the conventional ultrasonic image detecting method, the ultrasonic image detecting method of the present invention has a function of quickly determining the position or angle of the object Obj, and thus can be quickly imaged. The principle is detailed below. In the traditional ultrasonic image detection method, imaging or image enhancement requires M×N×(2r/c) time, where r is the ultrasonic signal detection depth, c is the sound speed, and M is the number of detection angles, N Is the number of scan lines. When M and N get bigger, the time spent will be amazing. In the present invention, the ultrasonic probe 10 first transmits a plurality of first plane waves simultaneously and receives at least one first reflected wave. The time spent in this step is at most (2r/c). Next, the ultrasonic probe 10 simultaneously emits a plurality of second plane waves and receives at least one second reflected wave. The time spent in this step is at most (2r/c). Then, according to the optimal angle, the ultrasonic probe 10 simultaneously emits a plurality of optimal plane waves and receives a plurality of optimal reflected waves. The time spent in this step is at most (2r/c). Therefore, since the time required for the ultrasonic image detecting method of the present invention is at most 3×(2r/c), compared with the conventional ultrasonic image detecting method requiring M×N×(2r/c) time, Significantly reduce the processing time, this effect will also cause the frame rate of the ultrasound image will not be greatly reduced.

Figure 9 is a flow chart of the ultrasonic image detection method. The ultrasonic image detecting method includes steps S901 to S906. However, any reasonable changes or modifications of the steps are within the scope of the invention. Steps S901 to S906 are described as follows.  <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> Step S901: </td><td> Simultaneously emit a complex number that differs from the surface 11 First plane waves BFW1 to BFWN; </td></tr><tr><td> Step S902: </td><td> receiving at least one of the first plane waves BFW1 to BFWN reflected by the object Obj a reflected wave; </td></tr><tr><td> Step S903: </td><td> according to at least one first reflected wave, simultaneously emitting a plurality of seconds different from the angle of the surface 11 Plane waves BFW1' to BFWN'; </td></tr><tr><td> Step S904: </td><td> receiving at least one of the second plane waves BFW1' to BFWN' reflected by the object Obj Second reflected wave RWAV; </td></tr><tr><td> Step S905: </td><td> Depending on the at least one second reflected wave RWAV, a plurality of decision plane waves P1 to PQ are used to determine the object Angle or position of Obj; </td></tr><tr><td> Step S906: </td><td> According to the detection results of the decision plane waves P1 to PQ, the best plane wave OptBFW1 to OptBFWN is transmitted. Go to the object Obj and return to step S903. </td></tr></TBODY></TABLE>

The detailed description of steps S901 to S906 has been described in the foregoing, and thus will not be described again. It should be understood that the object Obj described above may be an object that changes its angle or position over time. Therefore, steps S903 to S906 may constitute an execution loop to cause the ultrasonic probe 10 to continuously detect an object moving over time. Moreover, in the present invention, since the ultrasonic probe 10 can adjust the angle of the plane wave emitted next time with reference to the previously detected angle, it is possible to achieve more accurate angle detection and simultaneously transmit multiple angles of the optimal angle. The best plane wave is used to enhance the image of the object.

In summary, the present invention provides an ultrasonic image detecting method, which has the effect of greatly reducing the processing time of object imaging. The ultrasonic probe simultaneously emits a relatively scattered first plane wave to estimate a rough object angle. The ultrasonic probe adjusts the angle of the second plane wave emitted next time according to the rough object angle detected by the previous reference, so that the distribution of the second plane wave is concentrated. Moreover, the ultrasonic probe further detects the optimal angle by using a plurality of decision plane waves according to the second reflected wave reflected by the relatively concentrated second plane wave. Finally, the ultrasonic probe simultaneously emits multiple optimal plane waves at the optimal angle to enhance the image of the object. Therefore, the processing time required for the ultrasonic image detection method of the present invention is only a fixed short time (M×N×(2r/c)) compared to the conventional ultrasonic image detection method. 3 × (2r / c)) can be. Therefore, the ultrasonic image detecting method of the present invention allows the user to see clear and accurate ultrasonic images in a short time. The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

100‧‧‧Ultonic detection system
10‧‧‧Ultrasonic probe
11‧‧‧ surface
Obj‧‧ objects
BFW, BFW1 to BFWN, BFW1' to BFWN'‧‧‧ plane wave θ1 to θ3, θ1' to θ3'‧‧‧ angle
12‧‧‧ Cache device
13‧‧‧ Processor
TS1 to TSN‧‧‧ transceiver
S1 to SN‧‧ direction
SE1 to SEM‧‧‧ voltage signal
ELE1 to ELEM‧‧‧ piezoelectric devices
14‧‧‧Signal generating device
WAV1 to WAVM‧‧‧ waves
D1 and D2‧‧ ‧ time difference
P1 to PQ‧‧‧ decision plane wave
Pθ1 to Pθ4‧‧‧ angle
RWAV‧‧‧ reflected wave
OptBFW1 to OptBFWN‧‧‧ Best Plane Wave
S901 to S906‧‧‧ steps

Figure 1 is an architectural diagram of an embodiment of the ultrasonic sounding system of the present invention. Figure 2 is a block diagram of the transceiver in the ultrasonic probe of Figure 1. Fig. 3 is a schematic view showing the synthesis of the first plane wave in the ultrasonic probe of Fig. 1. Figure 4 is a schematic diagram of the ultrasonic probe of Figure 1, transmitting a plurality of first plane waves. Figure 5 is a schematic diagram of the ultrasonic probe of Figure 1, transmitting a plurality of second plane waves. Figure 6 is a schematic diagram of a plurality of decision plane waves and their included angles in the ultrasonic probe of Fig. 1. Fig. 7 is a schematic diagram showing the optimum angle generated by a plurality of decision plane waves and their included angles in the ultrasonic probe of Fig. 1 according to the second reflected wave. Figure 8 is a schematic diagram of the ultrasonic wave probe of Fig. 1 for transmitting an optimum plane wave to an object according to an optimum angle. Figure 9 is a flow chart of the ultrasonic image detecting method of the present invention.

Claims (10)

An ultrasonic image detecting method includes: simultaneously transmitting a plurality of first plane waves different from an angle of a surface, wherein two adjacent first plane waves are clamped by a first angle; and receiving the first plane waves is reflected by an object At least one first reflected wave according to the at least one first reflected wave, simultaneously emitting a plurality of second plane waves different from the angle of the surface, wherein two adjacent second plane waves are sandwiched by a second angle; receiving the first And at least one second reflected wave reflected by the object; and determining, according to the at least one second reflected wave, a plurality of decision plane waves to determine an angle or a position of the object; wherein the first angle is greater than the second angle . The method of claim 1, further comprising: transmitting an optimal plane wave to the object according to a detection result of the decision plane waves; wherein a forward direction of the optimal plane wave is substantially perpendicular to the object. The method of claim 1, wherein two of the decision plane waves are sandwiched by a third angle, and the third angle is smaller than the second angle. The method of claim 1, further comprising: buffering a reflection angle corresponding to each of the second reflected waves of the at least one second reflected wave; generating a complex array of decision plane waves, wherein each group of decision plane waves includes a complex number a decision plane wave; and a plurality of decision angles corresponding to the reflection angle corresponding to each of the second reflected waves and the decision plane waves of the groups, to select a set of optimal decisions from the decision plane waves of the groups The plane wave conforms to the angle or the position of the object. The method of claim 1, further comprising: after receiving the at least one first reflected wave corresponding to the first plane waves, generating a first detection angle corresponding to the object; and receiving the second After the at least one second reflected wave corresponding to the plane wave, a second detection angle corresponding to the object is generated; wherein an error value of the second detection angle is smaller than an error value of the first detection angle. The method of claim 1, wherein each of the first plane waves is generated by a plurality of piezoelectric devices, the piezoelectric devices are driven by a first group of signals, and the first group The delay time of the signal is different. The method of claim 6, wherein the first group of signals is generated by a signal generating device, and the first group of signals drives the two adjacent ones of the piezoelectric devices to have the same time difference to transmit the same The piezoelectric devices synthesize each of the first plane waves. The method of claim 1, wherein each of the second planar waves is generated by a plurality of piezoelectric devices, the piezoelectric devices are driven by a second group of signals, and the second group The delay time of the signal is different. The method of claim 8, wherein the second group of signals is generated by a signal generating device, and the second group of signals drives the two adjacent ones of the piezoelectric devices to have the same time difference to transmit the same Some piezoelectric devices to synthesize each of the second plane waves. The method of claim 1, wherein each of the decision plane waves of the plurality of decision plane waves corresponds to a group of different delay time signals used by the plurality of piezoelectric devices.