WO2017219472A1 - 无人船监控区域相控阵超声波低频成像装置 - Google Patents

无人船监控区域相控阵超声波低频成像装置 Download PDF

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WO2017219472A1
WO2017219472A1 PCT/CN2016/095099 CN2016095099W WO2017219472A1 WO 2017219472 A1 WO2017219472 A1 WO 2017219472A1 CN 2016095099 W CN2016095099 W CN 2016095099W WO 2017219472 A1 WO2017219472 A1 WO 2017219472A1
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receiver
transmitter
phased array
ultrasonic
sensor
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PCT/CN2016/095099
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English (en)
French (fr)
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杨越
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杨越
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    • 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
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging

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  • the invention relates to an unmanned ship monitoring area imaging method and device, in particular to a phased array ultrasonic low frequency imaging method and device in an unmanned ship monitoring area.
  • Drones and driverless cars are in the tech world, and the limelight is exhausted. In contrast, low-profile unmanned ships are less well-known. In the novel, the unmanned ship has always shrouded a mysterious atmosphere.
  • the famous "ghost ship” is the classic material of the writer's fictional nautical story. In reality, the unmanned ship is the treasure of the military field of all countries and is the important competition of science and technology. technology. At present, the unmanned ship is in a period of rapid development. However, the unmanned ship still faces many technical bottlenecks before the launch of the launch and the operation on the water.
  • Unmanned ships do not require human pilots to manipulate them. Whether the concept of "zero crew" is appropriate is appropriate. At present, there are many opinions in the industry. The journalist of "Safety” has proposed the distance between the ideal of "unmanned ship” and reality. It is suggested that if a ship suddenly fires and its position is unknown, according to the existing technology level, the unmanned ship's control will definitely make two kinds of instructions. One is the best method, that is, send the fire extinguishing robot to find the exact fire point and put out the fire. The second is that if the robot can not complete the fire-fighting task, the ship will open the high-pressure water mist fire extinguishing system to complete the fire-fighting mission.
  • the present invention combines phased array ultrasonic waves. Imaging characteristics, a method of indirect sampling of multi-channel Fourier coefficients is proposed. The delay introduced in each channel can be divided into two components, one component refers to beam deflection time delay and the other component is beam focusing time delay. Sub-Nyquist sampling for ultrasonic imaging.
  • the multi-channel Fourier coefficient indirect sampling method is modified to obtain a B-type phased array ultrasonic low-frequency imaging method and device based on multi-channel Fourier coefficient indirect sampling method. Not only saves storage space, but also reduces power consumption, and can clearly image all blind areas of the hull.
  • an object of the present invention is to provide a phased array ultrasonic low frequency imaging device for an unmanned ship monitoring area, comprising: a sensor array, the sensor array is composed of a plurality of independent sensor units, and the transmitter and the sensor unit can receive the transmitter.
  • the generated pulse generates a burst of ultrasonic energy when excited; the receiver; the transmitting/receiving switch, the ultrasonic energy reflected from the unmanned vessel hull back to the sensor array is converted into an electrical signal by the sensor unit and applied to the receiver separately through the transmit/receive switch
  • the digital controller, transmitter, receiver and transmit/receive switch operate under the control of an operator-operated digital controller; and the display system performs a complete scan each time by acquiring a series of echoes, the transmitter gating temporarily opening , Each sensor unit is activated, and then the transmit/receive switch is gated open to receive the echo signals generated by each of the subsequent sensor units. These separate echo signals are combined in the receiver to produce a separate echo signal for displaying the image on the display.
  • the transmitter drives the sensor array
  • the generated ultrasonic energy is directed or deflected by the beam
  • the B-scan can be performed by moving the beam from point to point instead of physically moving the sensor array.
  • the transmitter applies a time delay Ti corresponding to the pulse sent by the subsequent sensor unit, and the time delay is 0 or increment.
  • the transmitter comprises a set of channel pulse code memories.
  • the channel pulse code memory has 128 independent sensor units, and each pulse code memory is preferably a 1-byte by 512-byte memory, and stores a byte sample that determines the ultrasonic pulse to be generated.
  • each pulse is delayed by an appropriate amount, the delay being provided by the transmitting controller by receiving from the digital controller, the master clock, RT and ⁇ four control signals.
  • the receiver is composed of three segments: a time gain control segment, a beamforming segment and an intermediate processor, and the time gain control segment includes an amplifier for each receiver channel and a time gain control circuit, and the input coupling of each amplifier
  • the corresponding sensor unit is received and amplified to receive the echo signal, and the amplification factor provided by the amplifier is controlled by a control line driven by the time gain control circuit.
  • the beamforming segment of the receiver consists of a set of receiver channels, one for each sensor unit.
  • the relationship of the time delay increment Ti of every ith signal is given by the following relationship:
  • T i -(i-(n-1)/2)dsin ⁇ /c+(i-(n-1)/2) 2 d 2 cos 2 ⁇ /2RTc+T 0 (1)
  • d is the equal distance between the centers of adjacent sensor units 12,
  • c is the speed of the sound wave in the research object
  • RT is the area where the transmit beam is focused
  • T 0 is a delay offset that guarantees that all calculated values (T i ) are positive values
  • the introduced delay can be divided into two components, one component is the beam deflection time delay, the other component is the beam focus time delay, and the focus time delay component introduced for each receiver channel continuously changes during the reception echo to provide the reception echo.
  • the dynamic focus delay component is as follows:
  • T k (k-(n-1)/2) 2 d 2 cos 2 ⁇ /2RC (2)
  • R distance from the center of the array 11 to the focus point P;
  • T k time delay associated with the echo signal from the kth unit
  • the receiver (14) Under the guidance of the digital controller (16), the receiver (14) provides a delay in the scan to move Stately focusing on point P along the beam, the occurrence of each ultrasonic pulse producing a series of data points representing the amount of reflected sound waves located at point P of a corresponding sequence of ultrasonic beams;
  • the display system (17) receives a series of data points generated by the receiver (14) and converts the data to a form that produces the desired image.
  • the amount of series data points is only plotted as a function of time. If a B-scan is required, each data point in the series is used to control the brightness of one pixel in the image, and the data necessary to provide a display by scanning a series of measurements of the continuous deflection angle ( ⁇ ).
  • the resulting image data is written into a memory 155 storing a two-dimensional array of converted scan data
  • the memory control provides dual port access to the memory
  • the digital scan converter can read the updated data on the display processor While continuously updating the values continuously with new data, the display processor responds to the operator command received from the control panel and performs a conventional image processing function on the converted scan data in the memory.
  • FIG. 1 is a block diagram of an ultrasonic imaging system embodying the present invention
  • Figure 2 is a block diagram of the transmitter portion of the transmitter of Figure 1 and a graphical representation of the signals in any of the transmitter channels;
  • Figure 3 is a circuit block diagram of a preferred embodiment of the time frequency control filter of the present invention.
  • FIG. 4 is a plan view of a band pass filter constituting the time frequency control filter of FIG. 3;
  • an ultrasonic imaging system includes a sensor array 11 that is comprised of a plurality of individual sensor units 12 that can generate a burst of ultrasonic energy upon receipt of a pulse generated by the transmitter 13.
  • the ultrasonic energy reflected from the unmanned vessel hull back to the sensor array 11 is converted by each sensor unit 12 into an electrical signal and applied separately to the receiver 14 through a set of switches 15.
  • Transmitter 13, receiver 14 and switch 15 operate under the control of operator-operated digital controller 16.
  • the transmitter 13 is gated temporarily to activate each sensor unit 12, and then the switch 15 is gated open to receive the echo signals generated by each of the subsequent sensor units 12, these separate echoes
  • the signals are combined in receiver 14 to produce a single echo signal for producing a pixel or a line of the image on display 17.
  • the transmitter 13 drives the sensor array 11 and the generated ultrasonic energy is directed or deflected by the light beam.
  • a B-scan can be performed by moving the beam from point to point instead of physically moving the sensor array 11.
  • T i -(i-(n-1)/2)dsin ⁇ /c+(i-(n-1)/2) 2 d 2 cos 2 ⁇ /2RTc+T 0 (1)
  • d is the equal distance between the centers of adjacent sensor units 12,
  • c is the speed of the sound wave in the research object
  • RT is the area where the transmit beam is focused
  • T 0 is a delay offset that guarantees that all calculated values (T i ) are positive.
  • the first term of this expression deflects the beam by a set angle ⁇ and uses the second term when the transmitted beam needs to be focused to a fixed area.
  • the segment scan is performed by progressively changing the time delay Ti of the continuous excitation.
  • the angle ⁇ can be changed in small increments to deflect the transmit beam in a continuous direction.
  • the timing of the pulse 20 is reversed, but the equation of equation (1) still applies.
  • an echo signal generated by ultrasonic energy is emitted from a reflective object located at a continuous position along the ultrasonic beam.
  • These signals are sensed by each sensor unit of the sensor array 11, and the sample of the echo semaphore in time from a particular point represents the amount of reflection in a particular area (R). Due to the difference in the distance traveled between the focus point P and each of the sensor units 12, these echo signals do not occur at the same time, and their amplitudes are not equal.
  • the function of the receiver 14 is to amplify and modulate these individual echo signals, for each The appropriate time delays are given and added together to provide a separate echo signal that accurately shows that the ultrasonic energy is reflected from the focus point P located at a distance R along the ultrasonic beam determined to be the angle ⁇ .
  • a time delay is introduced for each sensor unit channel of each receiver.
  • the delay introduced at each channel can be divided into two components, one component being the beam deflection time delay and the other component being the beam focus time delay.
  • the received beam deflection and focus time delay are the same delay (Ti) as the transmission delay described above.
  • the focus time delay component introduced for each receiver channel continuously changes during the reception of the echo to provide dynamic focus of the receive beam at the region R from which the echo signal is received.
  • the dynamic focus delay component is as follows:
  • T k (k-(n-1)/2) 2 d 2 cos 2 ⁇ /2RC (2)
  • R distance from the center of the array 11 to the focus point P;
  • T k time delay associated with the echo signal from the kth unit, used to continuously add to other echo signals
  • the receiver 14 Under the direction of the digital controller 16, the receiver 14 provides a delay in the scan so that the deflection of the receiver 14 tracks the direction of beam deflection of the transmitter 13 and it samples the echo signal in a continuous region and provides a suitable delay to dynamically Focus on the point P along the beam.
  • the occurrence of each ultrasonic pulse produces a series of data points representing the amount of reflected acoustic waves located at point P along a corresponding sequence of ultrasonic beams.
  • Display system 17 receives a series of data points generated by receiver 14 and converts the data to a form that produces the desired image. For example, if an A-scan is required, the amount of series data points is only plotted as a function of time. If a B-scan is required, each data point in the series is used to control the brightness of one pixel in the image, and the data necessary to provide a display by scanning a series of measurements of the continuous deflection angle ( ⁇ ).
  • the transmitter 13 includes a set of channel pulse code memory sets labeled as memory 50.
  • memory 50 there are 128 independent sensor units 12 and, therefore, there are 128 independent channel pulse code memories 50.
  • Each pulse code memory 50 is typically a 1-byte by 512-byte memory that stores a byte sample 51 that determines the ultrasonic pulse 52 to be generated.
  • byte samples 51 are read from each of the pulse code memory 50 by a 40 MHz master clock and applied to a driver 53 that is placed at a signal level suitable for driving the sensor 11.
  • the byte sample is a sequence of four 1 byte and four 0 byte alternating to produce a 5 MHz ultrasonic pulse 52.
  • ultrasonic pulses 52 are applied to the sensor unit 12 and produce an ultrasonic energy response. If all 512 bytes are used, a pulse centered at the carrier frequency (eg, 5 MHz in this example) with a bandwidth as narrow as 40 kHz will be transmitted.
  • the carrier frequency e.g, 5 MHz in this example
  • the pulse 52 for each of the N channels must be delayed by an appropriate amount.
  • These delays are provided by a transmit controller 54 that receives four control signals (start, master clock, RT, and ⁇ ) from digital controller 16 (FIG. 1).
  • the transmission focus RT and the above equation (1) are fixed by the input control signal ⁇ , and the transmission controller 54 calculates the continuous transmission channel.
  • the required delay increment Ti Upon receiving the initial control signal, the transmit control 54 gates one of the four possible phases of the 40 MHz master clock signal to the first transmit channel 50.
  • a complete B-scan consists of a delta ⁇ increment of 128 ultrasonic pulses of 0.7 through a 90 degree segment centered on the central axis 21 (Fig. 1).
  • Receiver 14 is comprised of three segments: a time gain control segment 100, a beamforming segment 101, and an intermediate processor 102.
  • the time gain control terminal 100 includes an amplifier 105 for each receiver channel and a time gain control circuit 106.
  • the input of each amplifier 105 is coupled to a corresponding sensor unit 12 to receive and amplify the echo signals it receives.
  • the amplification provided by amplifier 105 is controlled by a control line 107 driven by time gain control circuit 106.
  • As is known in the art as the range of the echo signal increases, its amplitude decreases. As a result, unless the echo signal transmitted from the more distant reflector is more amplified than from the near reflector, the brightness of the image is rapidly reduced as a function of distance (R).
  • This amplification is controlled by the operator who manually sets 8 (typical) TGC linear potentiometers to provide a value for relatively uniform brightness over the entire scan segment area.
  • the time interval in which the echo signal is acquired determines the range from which it is transmitted, and this time interval is divided into eight segments by the TGC control circuit 106.
  • the settings of the eight potentiometers are used to set the gain of the amplifier 105 in each of the eight corresponding time intervals, so that the echo signal is amplified by an increasing amount during the acquisition time interval.
  • the present invention employs the same digital form as the TGC control signal 107 used to set the gain of the amplifier 105.
  • This digital TGC gain control signal is provided on the bus 109 to the intermediate processor.
  • each receiver channel 110 receives an analog echo signal from one of the TGC amplifiers 105 at input 111 and produces a series of digitized output values on I bus 112 and Q bus 113.
  • Each of these I and Q values represents a sample of the echo signal for each signal envelope at a particular distance (R).
  • R the distance
  • These samples have been delayed as described above so that when they are added at each of the I and Q sample samples from the other receiver channels 110 at the addition points 114 and 115, they represent the point from the deflected beam ( ⁇ ) at a distance R.
  • the amount and phase of the echo signal reflected by P In the preferred embodiment, each echo signal is sampled at equal intervals of about 150 [mu]m over the entire scan line (typically 40 to 200 mm).
  • the intermediate processor segment 102 receives beam samples from the addition points 114 and 115.
  • the I and Q values of each beam sample are 16-byte numbers representing the in-phase and quadratic components of the magnitude of the acoustic wave reflected from one point (R, ⁇ ).
  • the intermediate processor 102 can perform a variety of calculations on these beam samples, depending on the type of image to be reconstructed. For example, if a conventional volume image is to be generated, the detection process shown at 120 is implemented by computing each digital quantity M with the output of each beam sample and 121, and the intermediate processor 102 can also include a correction processor 122.
  • This correction processor 122 examines the received beam samples and calculates the correction values that the transmitter 13 and receiver 14 can use in subsequent tests to improve beam focus and deflection. This correction is necessary, for example, to take into account the non-uniformity of the medium of the sound waves emanating from each sensor unit in the scan.
  • the present invention also employs a correction processor 123 as shown by a TFC (Time Frequency Control) filter.
  • TFC filter 123 receives the I and Q signals from summing points 114 and 115 at its inputs 124 and 125, and generates corresponding I" and Q" signal streams at its corresponding outputs 126 and 127.
  • the outputs 126 and 127 of the TFC filter 123 will be directly trained to the input of the detection processor 120 to generate beam value samples at the processor output 121.
  • receiver 14 produces a series of 8-byte digitized digits at its output 121 that are applied to the input of display system 17.
  • the "scan data" is stored in the memory 150 in a matrix, the rows of the scan data array 150 are coincident with the acquired corresponding beam angles ( ⁇ ), and the columns of the scan data array 150 and corresponding samples are acquired along each beam.
  • the distance (R) is consistent.
  • the R and ⁇ control signals 151 and 152 from the receiver 14 display the position at which each input value is to be stored in the array 150, and a memory control circuit 153 writes that value to the appropriate memory address in the array 150.
  • the scanning can be repeated continuously, and the data stream from the receiver 14 will continuously update the scan data array 150.
  • the scan data in array 150 is read by a digital scan converter 154 and converted to a form that produces the desired image. If a conventional B-scan image is to be generated, for example, the magnitude M(R, ⁇ ) stored in the scan data array 150 is converted into a magnitude M (x, y) of the amount of position (x, y) pixels in the display image. ). The conversion of such an ultrasonic image data from polar coordinates to Cartesian coordinates is described.
  • the resulting image data is written into memory 155 that stores a two-dimensional array of converted scan data.
  • a memory control 156 provides dual port access to memory 155 so digital scan converter 154 can continuously update values continuously with new data while display processor 157 reads the updated data.
  • the display processor 157 performs a conventional image processing function on the converted scan data in the memory 155 in response to an operator command received from the control panel 158.
  • the converted luminance data displayed in the memory 155 may have a brightness level region that is much larger than the luminance region of the display device 160.
  • the display processor reads the converted scan data from memory 155, provides the desired image optimization and writes the optimized luminance values into a display memory 161.
  • the memory 161 is shared by the display control circuit 162 through the memory control circuit 163, where the luminance value It is mapped to control the brightness of corresponding pixels on display 160.
  • Display controller 162 is a commercially available integration circuit designed to operate on a particular model of display 160.
  • display 160 can be a CRT where display controller 162 is a CRT control chip that provides the desired horizontal and vertical scanning circuitry and maps the display data to the CRT at the appropriate time during the scan.
  • display system 17 can take a variety of forms depending on the capacity and flexibility of the particular ultrasound system.
  • the use of a programmed microprocessor to implement digital scan converter and display functions results in a display system that is therefore flexible and powerful.
  • the beamforming section 101 of the receiver 14 is comprised of a set of receiver channels 110, each pair of units 11 of the sensor 11 (Fig. 1).
  • Each receiver channel pair implements a digital beamforming function in response to a command from digital controller 16 (FIG. 1), 40 MHz on the master clock, distance signal (R) and beam angle signal ( ⁇ ).
  • These include: sampling the analog input signal at analog to digital converter 200, modulating the sampled signal at demodulator 201; filtering the high frequency and signal produced by demodulator 201 with low pass filter 202; at decimator 203
  • the data rate is reduced; the digital data streams generated in the delay FIFO (e.g., advanced/first-out memory) 204 and phase rotator 205 are time delayed and phase adjusted. All of these units are controlled by a receive channel control 206 which produces the desired clock and control signals in response to commands from digital controller 16 (FIG. 1). In the preferred embodiment, all of these units are contained on a single integrating circuit.
  • Analog to digital converter 200 samples the analog input signal imaged by waveform 210 to a regular interval determined from the rising edge of the delayed sampling clock of receive channel control 206.
  • the sampling clock signal is a 40 MHz clock signal enabling the use of ultrasonic frequencies up to 20 MHz without violating the Nyquist sampling criteria.
  • a 5MHz ultrasonic carrier frequency for example, 8 samples per carrier cycle
  • a 10-byte number is generated at the output of the analog-to-digital converter at 40MHz. signal.
  • the SINE (sinusoidal) value is digitally multiplied by the sampled input signal to produce a demodulated, common phase value (I) supplied to the low pass filter 202, and the COSINE (cosine) value is multiplied by the same input signal digitally.
  • the demodulated secondary phase value (Q) supplied to the individual low pass filter 202 is generated.
  • the low pass filter 202 is a finite impulse response filter debugged to different frequencies provided by the demodulator 201, but intercepts the higher sum frequency, the input signal of each low pass filter, thus displaying each echo signal packet A 40 MHz digital value stream of the amount of I or Q components of the network.
  • decimator 203 The rate at which the demodulated I and Q component samples of the echo signal are reduced by the decimator 203.
  • the 12-byte digital signal is supplied to the decimator at a rate of 40 MHz, which is not high enough from a precise point of view, but the data rate that is difficult to maintain throughout the system.
  • decimator 203 selects every 8 digital samples to reduce the data rate to 5 MHz. This corresponds to the frequency of the baseband clock signal generated by the receive channel controller 206 and is used to operate the remaining units of the receiver channel.
  • the I and Q output signals of decimator 203 are thus digitized samples 219 of the echo signal envelope.
  • the decimation ratio and baseband clock frequency can be changed to values other than 8:1 and 5MHz.
  • the echo signal envelope climate represented by the demodulated and extracted digital samples is delayed by delay FIFO 204 and phase rotator 205 to provide the desired beam deflection and beam focus. These delays are added to the coarse delay provided by the delayed sample clock signal applied to analog to digital converter 200 described above. That is, the total delay provided by receiver channel 110 is the sum of the delays provided by the delayed sampling clock signal supplied to analog to digital converter 200, delay FIFO 204 and phase rotator 205.
  • the delay FIFO 204 is a memory device in which consecutive digital sample values are written while being generated by the decimator 203 at 5 MHz. These stored values are written to successive memory addresses and then read from the memory device and provided to phase rotator 205.
  • the amount of delay the difference between the memory address being provided by the digital sample and the memory address being stored by the digital sample being received Decide.
  • the 5MHz baseband clock signal establishes an interval of 200 nanoseconds between stored digital samples, so the FIFO 204 can provide a maximum time delay of 25.6 microseconds in 200 nanosecond increments.
  • Phase rotator 205 causes the digital reproduction of the echo signal to be delayed by an amount that delays the resolution of FIFO 204 by less than 200 nanoseconds.
  • the I and Q digital samples supplied to phase rotator 205 may pass through a phase vector 221 and the resulting rotated I and Q digital samples may be reproduced with phase vector 222.
  • phase vectors (such as the vector sum of each of the I and Q components) is invariant, but the values of I and Q are changed relative to each other such that the output phase vector 222 is rotated by the amount ⁇ from the input phase vector 221.
  • the phase may be advanced by + ⁇ or delayed (- ⁇ ) as a response to the phase control signal received from the bus of the receive channel controller 206.
  • receiver channel 110 The general description of the receiver channel 110 and the detailed description of the I and Q output signals of each receiver channel 110 are added together to form a beam signal.
  • a TFC filter 123 embodying the present invention is shown to include an input 124 and 125 coupled to a rotator circuit 250 that receives corresponding I and Q beam samples.
  • the rotator circuit 250 is identical to that disclosed above and in the aforementioned U.S. Patent No. 4,896,287. It receives a digital phase offset command ( ⁇ ) at input 251 as each of the I and Q digital beam samples is received at its inputs 124 and 125.
  • the phase vector represented by the I and Q input components is rotated by an amount ⁇ , the resulting component, and the rotated phase vector is generated as I' and Q' signals on buses 252 and 253.
  • the digital phase cheap command ( ⁇ ) is generated by a ⁇ processor 254.
  • the TGC gain signal on bus 109 is applied to the address starting at processor 254, the data stored in the memory address of the corresponding address is read and used to calculate the phase offset command ⁇ for rotator circuit 250 when reading from the clock (not When the signal of control line 255 is shown to go low.
  • the value of the digitized phase offset command ([Delta][theta] is therefore a function of the TGC gain signal, as explained in more detail below.
  • the TFC filter 123 also includes a relative value that adjusts the frequency components of the I' and Q' signals produced by the rotator circuit 250.
  • the total signal loss is small, With a good signal-to-noise ratio, the I' and Q' signal components after the echo signal is rotated are each filtered high so that the entire bandwidth is used to form the image. This results in an increase in image resolution, especially in landscape sizes.
  • the total signal loss is large at a longer distance, the signal-to-noise ratio is poor, and the I' and Q' signal components after the echo signal is rotated are each low-pass filtered, so the bandwidth of the signal contributing to the image over a long distance is relatively large. It is reduced. This filtering increases the penetration rate due to the noise bandwidth being sacrificed over long distance construction with axial image resolution.
  • a circuit that performs these filtering operations in which the first stage 260 is comprised of a low pass filter and the second stage 261 is comprised of a high pass filter.
  • the block denoted as Z-1 represents the unit delay, and the symbols + and x represent the adder and the multiplier, respectively.
  • Filters 260 and 261 are conventional finite impulse response digitizers in which low pass filter 260 has an impulse response (1, A1, 1) and the high pass filter has an impulse response (-1, A2, -1).
  • a new data value is applied to filter 260.
  • the delay is implemented by a clock-controlled register that transfers data between registers on each clock edge. In one clock cycle, all mathematical operations (such as addition or multiplication) are performed.
  • a low pass filter 260 having an impulse response (1, A1, 1) performs two additions and one multiplication in any given clock cycle.
  • the data entering the filter is added to the data input to the filter before two clock cycles.
  • the output signal generated by this operation is added to the filter input signal one clock cycle before being multiplied by the coefficient A1.
  • All mathematical operations are performed in one clock cycle, so there is one output signal (such as pipeline implementation) for each input signal to the filter.
  • the output signal of low pass filter 260 enters the input of high pass filter 261 along the pipeline to produce a pipelined band pass filter whose characteristics are completely controlled by the selection of coefficients A1 and A2.
  • the coefficient A1 of the low pass filter 260 is substantially increased beyond the coefficient A2 of the high pass filter 261, so the high pass filter 261 will determine the response of the filter in the near field.
  • the coefficient A2 of the high pass filter 261 is substantially increased beyond the coefficient A1 of the low pass filter 260, so the low pass filter 260 determines the response of the filter 258 (Fig. 3).
  • the ultrasonic sensor 11 generates pulses at a carrier frequency of 5 MHz, a bandwidth of about 2 MHz, and a Gaussian energy distribution over the bandwidth.
  • Filters 260 and 261 are conventional three-point FIR (finite impulse response) filters in which a single coefficient A1 determines the low pass frequency characteristic and a single coefficient A2 determines the high pass frequency characteristic.
  • phase offset command of rotator circuit 250 and the coefficient commands A1 and A2 of filter 258 can be implemented as a function of the TGC gain signal on bus 109.
  • the coefficient commands A1 and A2 are stored in the corresponding memories 265 and 266 and they are read from the memory and directly applied to the filter 258 by the read clock signal of the control line 255.
  • the TGC gain signal bus 109 is coupled to the first address of the memory 265 and 266.
  • the amplitude of the TGC gain signal customizes the coefficient values A1 and A2 stored at a particular address within the contiguous memory address.
  • the time frequency control filter of the present invention is easily implemented in an intermediate processor and applied to the formed receive beam. Its structure is considerably simplified by deriving the control parameters of the filter into a TGC gain signal, a control equation for the existing signal of the ultrasonic imaging system. Numerous modifications and changes may be made by those skilled in the art without departing from the scope of the invention. Therefore, it is to be understood that the appended claims are intended to cover all such modifications and changes in the true spirit of the invention.

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  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Abstract

一种无人船监控区域相控阵超声波低频成像装置和方法，其中，装置包括：由多个独立传感器单元（12）组成的传感器阵列（11），发送器（13），传感器单元（12）可以在收到所述发送器（13）产生的脉冲激发时产生一阵超声波能量；接收器（14）；发送/接收开关（15），从无人船船体反射回所述传感器阵列（11）的超声波能量被传感器单元（12）转换成一个电信号并通过发送/接收开关（15）单独施加到所述接收器（14）上；数字控制器（16），发送器（13），接收器（14）和发送/接收开关（15）在操作员操纵的所述数字控制器（16）的控制下运行；以及显示系统（17），产生一个单独的回音信号用来在显示系统（17）上显示图像的一个像素或一条线。

Description

无人船监控区域相控阵超声波低频成像装置 技术领域
本发明涉及无人船监控区域成像方法及装置，特别是无人船监控区域相控阵超声波低频成像方法及装置。
背景技术
无人机与无人驾驶汽车在科技界呼风唤雨,风头出尽,相较之下,低调的无人船知名度稍逊一筹。在小说中,无人船始终笼罩着一丝神秘气息,著名的"幽灵船"是作家虚构航海故事的经典素材,而在现实中,无人船是各国军事领域的心头宝,是科技竞争的重要技术。目前无人船处于高速发展的时期，然而无人船在下水试航之前以及水上作业的时候，仍然面临很多技术瓶颈没有解决。
无人船，顾名思义，无需人类驾驶员对其进行操控，“零船员”概念的出现到底是否恰当，目前业界众说纷纭，刊物《安全》的记者就曾提出“无人船”理想与现实的距离，其中提出，如果某船突然起火其方位不明，依照现有的科技水平，无人船的操控着肯定会做出两种指令，一种是最优方法，即派灭火机器人寻找准确着火点并进行扑灭，第二种是如果机器人无法完成灭火任务，船舶将开启高压细水雾灭火系统完成灭火任务，两套方案，一套备用，看似没有缺陷，而有一个问题无法回避，就算全船都有监控设备，然而并不能保证监控设备毫无盲区，而此时若恰好在盲区内着火或者为引起火灾的来源，则两套方法都无法实施，我们只能眼睁睁看着船烧尽沉没。
由此看来，对无人船的各个盲区都能进行有效的成像是正待解决的问题，近年来提出的压缩感知理论指出，以低于香农定理规定的最低频率，即2倍频对稀疏信号进行采样，一样能够得到信号的精确的重建，将其应用于超声波成像之中，可以有效减少数据点和降低采样率，也就是超声波低频成像。该技术中的次奈奎斯特采样方法目前存在很多问题，比如不稳定，实现难度大或者先验条件严格，并不能直接有效的应用与超声波低频成像之中，因此本发明结合相控阵超声波成像特点，提出一种融合多通道傅立叶系数间接采样的方法，在每个通道引入的延迟可以分成两个分量，一个分量指的是波束偏转时间延迟，另一个分量是波束聚焦时间延迟，将其应用于超声波成像的次奈奎斯特采样。
结合B扫描型相控阵列超声波成像的数学特点，将多通道傅立叶系数间接采样方法进行改造，得到基于多通道傅立叶系数间接采样方法的B型相控阵超声波低频成像方法和装置。不但节省存储空间，而且降低了电能损耗，对船体的所有盲区都可以进行清晰成像。
发明内容
因此本发明的目的一方面在于提供一种无人船监控区域相控阵超声波低频成像装置，包括：传感器阵列，传感器阵列由多个独立传感器单元组成，发送器，传感器单元可以在收到发送器产生的脉冲激发时产生一阵超声波能量；接收器；发送/接收开关，从无人船船体反射回传感器阵列的超声波能量被传感器单元转换成一个电信号并通过发送/接收开关单独施加到接收器上；数字控制器，发送器，接收器和发送/接收开关在操作员操纵的数字控制器的控制下运行；以及显示系统，通过获取一系列回音进行每次的完整扫描，发送器门控暂时打开， 激发每个传感器单元，然后发送/接收开关门控打开以接收随后每个传感器单元产生的回音信号，这些单独的回音信号在接收器中合并产生一个单独的回音信号用来在显示器上显示图像的一个像素或一条线。
优选的，发送器驱动传感器阵列，产生的超声波能量通过光束被导向或偏转，B型扫描可以通过点到点移动该光束而不是物理移动传感器阵列而执行。
优选的，发送器将一个时间延迟Ti对应的应用到后续的传感器单元发出的脉冲，时间延迟是0或递增。
优选的，发送器包括一组通道脉冲码记忆体。
优选的，通道脉冲码记忆体有128个独立传感器单元，每个脉冲码记忆体优选的是一个1字节乘512字节的记忆体，储存决定要产生的超声波脉冲的字节样本。
优选的，每个脉冲被延迟适当的量，延迟由发送控制器通过从数字控制器接收开始，主时钟，RT和θ四种控制信号提供。
优选的，接收器由三段组成：时间增益控制段，波束形成段和中间处理器，时间增益控制段包括一个针对每个接收器通道的放大器和一个时间增益控制电路，每个放大器的输入耦合到对应的传感器单元来接收和放大它收到的回音信号，由放大器提供的放大倍数通过一个由时间增益控制电路驱动的控制线控制。
优选的，接收器的波束形成段由一组接收器通道组成，每个针对一个传感器单元。
本发明的目的还在于提供一种无人船检控区域相控阵超声波低频成像的方法，其特征在于包括如下步骤：
(1)发送器驱动传感器阵列，产生的超声波能量通过光束被导向或偏转， 并将一个时间延迟Ti对应的应用到后续的传感器单元的脉冲，如果时间延迟是0(Ti＝0)，所有的传感器单元被同时激发，产生的超声波束沿着垂直于传感器面的一条轴传导并且传导到传感器阵列的中央，如果时间延迟(Ti)是递增的，超声波束从中轴偏向下θ角度传播，连续地加到从传感器阵列的一端(i＝1)到另一端(i＝n)的每第i个信号的时间延迟增量Ti的关系由如下关系式给出：
Ti＝-(i-(n-1)/2)dsinθ/c+(i-(n-1)/2)2d2cos2θ/2RTc+T0      (1)
其中：
d为相邻的传感器单元12中心间相等的距离，
c为声波在研究对象里的速度，
RT为发送束聚焦到的区域，
T0为保证所有计算值(Ti)为正值的延迟偏移；
(2)从位于沿着确定为角度θ的超声波束距离为R的聚焦点P反射出的回声产生的电信号求和，对每个接收器单独的传感器单元通道引入时间延迟，在每个通道引入的延迟可以分成两个分量，一个分量为波束偏转时间延迟，另一个分量为波束聚焦时间延迟，对每个接收器通道引入的聚焦时间延迟分量在接收回音过程中连续变化，来提供接收回音信号发出的区域R处的接收波束的动态聚焦。动态聚焦延迟分量如下：
Tk＝(k-(n-1)/2)2d2cos2θ/2RC      (2)
R＝从阵列11中央到聚焦点P的距离；
C＝被测对象里的声波速度；
Tk＝与从第k个单元的回音信号相关联的时间延迟；
(3)在数字控制器(16)的导向下，接收器(14)在扫描中提供延迟以动 态地聚焦于沿着波束的P点，每一个超声波脉冲的发生产生一系列代表位于沿着超声波束的一个对应序列的P点的反射声波量的数据点；
(4)超声波低频成像装置对每一个相控单元接收到的信号
Figure PCTCN2016095099-appb-000001
都进行多通道傅立叶系数间接采样，得到
Figure PCTCN2016095099-appb-000002
定义长度为P的采样向量cm＝{c1,m,...,cp,m}；
(5)在得到各个相控阵单元的采样之后，对它们进行相加，得到最终的采样向量
Figure PCTCN2016095099-appb-000003
(6)计算傅立叶系数向量x＝S+c，其中矩阵S是P×K的矩阵，其第(i，k)的元素为sqk；
(7)利用公式y＝H-1x得出方程组
Figure PCTCN2016095099-appb-000004
解方程组求出
Figure PCTCN2016095099-appb-000005
将其代入方程组，利用最小而成求解
Figure PCTCN2016095099-appb-000006
(8)利用等式
Figure PCTCN2016095099-appb-000007
重建信号Φ(t；θ＝0)；
(9)显示系统(17)接收接收器(14)产生的一系列数据点并转换数据到产生所需图像的形式。
优选的，如果需要一个A扫描，系列数据点的量仅仅作为时间的函数绘图。如果需要B扫描，系列中的每个数据点被用来控制图像中一个像素的亮度，进行由对连续偏转角度(θ)一系列测量组成扫描来提供显示所必需的数据。
优选的，结果图像数据被写入存储转换后扫描数据的二维阵列的记忆体155中，记忆体控制件提供对记忆体的双口访问，数字扫描转换器可以在显示处理器读取更新数据的同时持续地用新数据连续更新值，显示处理器对从控制面板接收到的操作员命令响应，对记忆体里的转换后扫描数据执行传统的图像处理函数。
根据下文结合附图对本发明具体实施例的详细描述，本领域技术人员将会 更加明了本发明的上述以及其他目的、优点和特征。
附图说明
后文将参照附图以示例性而非限制性的方式详细描述本发明的一些具体实施例。附图中相同的附图标记标示了相同或类似的部件或部分。本领域技术人员应该理解，这些附图未必是按比例绘制的。本发明的目标及特征考虑到如下结合附图的描述将更加明显，附图中：
图1是采用本发明的一个超声波成像系统的框图；
图2是组成图1中发送器部分的框图以及发送器任意通道中信号的图形化说明；
图3是本发明时间频率控制滤波器的一个优选实施例的电路框图；
图4是组成图3的时间频率控制滤波器的带通滤波器的方案图；
具体实施方式
对于图1，一个超声波成像系统包括一个传感器阵列11，传感器阵列11由多个独立传感器单元12组成，驱动单元12可以在收到发送器13产生的脉冲激发时产生一阵超声波能量。从无人船船体反射回传感器阵列11的超声波能量被每个传感器单元12转换成一个电信号并通过一组开关15单独施加到接收器14上。发送器13，接收器14和开关15在操作员操纵的数字控制器16的控制下运行。通过获取一系列回音进行每次的完整扫描，发送器13门控暂时打开，激发每个传感器单元12，然后开关15门控打开以接收随后每个传感器单元12产生的回音信号，这些单独的回音信号在接收器14中合并产生一个单独的回音信号用来产生显示器17上图像的一个像素或一条线。
发送器13驱动传感器阵列11，产生的超声波能量通过光束被导向或偏转。 一个B扫描可以通过点到点移动该光束而不是物理移动传感器阵列11而执行。至此，发送器13将一个时间延迟Ti对应的应用到后续的传感器单元12的脉冲20。如果时间延迟是0(Ti＝0)，所有的传感器单元12被同时激发，产生的超声波束沿着垂直于传感器面的一条轴21传导并且传导到传感器阵列11的中央。如果时间延迟(Ti)是递增的，如图1所示，超声波束从中轴21偏向下θ角度传播。连续地加到从传感器阵列的一端(i＝1)到另一端(i＝n)的每第i个信号的时间延迟增量Ti的关系由如下关系式给出：
Ti＝-(i-(n-1)/2)dsinθ/c+(i-(n-1)/2)2d2cos2θ/2RTc+T0      (1)
其中
d为相邻的传感器单元12中心间相等的距离，
c为声波在研究对象里的速度,
RT为发送束聚焦到的区域,
T0为保证所有计算值(Ti)为正值的延迟偏移。
这个表达式的第一项将波束按设定角度θ偏转，当发射束需要被聚焦到一个固定区域时用第二项。通过渐进的改变连续激发的时间延迟Ti来执行段扫描。角度θ可以小增量的被改变来在连续方向上偏转发送波束。当波束的方向在中央轴21上方时，脉冲20的计时倒转，但方程(1)的公式仍然适用。
仍然参照图1，从位于沿着超声波束的连续位置的反射对象发射超声波能量产生的回音信号。这些信号被传感器阵列11的每个传感器单元感知，从特定点及时的回音信号量的样本代表了在特定区域(R)的反射量。由于聚焦点P与每个传感器单元12之间传播距离的差异，无论如何，这些回音信号不会同时发生，它们的幅度不相等。接收器14的功能是放大和调制这些单独的回音信号，对每 个给予合适的时间延迟，把它们加起来提供一个单独的回音信号，该信号精确显示出超声波能量从位于沿着确定为角度θ的超声波束距离为R的聚焦点P反射出。
为瞬时对从聚焦点P的回音产生的电信号求和，对每个接收器单独的传感器单元通道引入时间延迟。在线性阵列11的情形中，在每个通道引入的延迟可以分成两个分量，一个分量指的是波束偏转时间延迟，另一个分量是波束聚焦时间延迟。接收的波束偏转和聚焦时间延迟就是与上面描述的发送延迟同样的延迟(Ti)。但是，对每个接收器通道引入的聚焦时间延迟分量在接收回音过程中连续变化，来提供接收回音信号发出的区域R处的接收波束的动态聚焦。动态聚焦延迟分量如下：
Tk＝(k-(n-1)/2)2d2cos2θ/2RC      (2)
R＝从阵列11中央到聚焦点P的距离；
C＝被测对象里的声波速度；及
Tk＝与从第k个单元的回音信号相关联的时间延迟，用来和其它回音信号连续相加
在数字控制器16的导向下，接收器14在扫描中提供延迟，因而接收器14的偏转跟踪发送器13的波束偏转的方向并且它在连续区域内对回音信号采样并提供合适的延迟来动态地聚焦于沿着波束的P点。因此，每一个超声波脉冲的发生产生一系列代表位于沿着超声波束的一个对应序列的P点的反射声波量的数据点。
B型超声波低频成像装置对每一个相控单元接收到的信号
Figure PCTCN2016095099-appb-000008
都进行多通道傅立叶系数间接采样，得到
Figure PCTCN2016095099-appb-000009
定义长度为P的采样向量 cm＝{c1,m,...,cp,m}；在得到各个相控阵单元的采样之后，对它们进行相加，得到最终的采样向量
Figure PCTCN2016095099-appb-000010
计算傅立叶系数向量x＝S+c，其中矩阵S是P×K的矩阵，其第(i，k)的元素为sqk；利用公式y＝H-1x得出方程组
Figure PCTCN2016095099-appb-000011
解方程组求出
Figure PCTCN2016095099-appb-000012
将其代入方程组，利用最小而成求解
Figure PCTCN2016095099-appb-000013
利用等式
Figure PCTCN2016095099-appb-000014
重建信号Φ(t；θ＝0)。
显示系统17接收接收器14产生的一系列数据点并转换数据到产生所需图像的形式。例如，如果需要一个A扫描，系列数据点的量仅仅作为时间的函数绘图。如果需要B扫描，系列中的每个数据点被用来控制图像中一个像素的亮度，进行由对连续偏转角度(θ)一系列测量组成扫描来提供显示所必需的数据。
对与图1相连的图2，发送器13包括一组通道脉冲码记忆体集合标注为记忆体50。在优选实施例中，有128个独立传感器单元12，因此，有128个独立通道脉冲码记忆体50。每个脉冲码记忆体50典型的是一个1字节乘512字节的记忆体，储存决定要产生的超声波脉冲52的字节样本51。在该优选实施例中，通过40MHz的主时钟从每个脉冲码记忆体50中读出字节样本51并应用到放到信号到适合驱动传感器11的功率水平的驱动器53。字节样本是一个4个1字节与4个0字节交替的序列来产生一个5MHz的超声波脉冲52。这些超声波脉冲52应用到传感器单元12并产生超声波能量响应。如果所有512字节都被用，一个中心位于载波频率(如5MHz本例中)带宽窄至40kHz的脉冲会被发射。
如上所示，为了将超声波能量的发送波束偏转到所需方向(θ)，对N通道中每个的脉冲52，必须被延迟适当的量。这些延迟由从数字控制器16(图1)接收四种控制信号(开始，主时钟，RT和θ)的发送控制器54提供。采用输入控制信号θ，固定发送焦点RT和上述方程(1)，发送控制器54计算连续发送通道之 间所需的延迟增量Ti。当接收到开始的控制信号，发送控制54选通40MHz主时钟信号四种可能相位中的一个到第一个发送通道50。在随后的每一个相继的延迟时间间隔Ti，40MHz主时钟信号四种可能相位中的一个被选通传到下一个通道脉冲码记忆体50直到所有N＝128个通道都产生它们的超声波脉冲52。每个发送器通道50被复位，在它整个的字节样本都已经被发送后，发送器13然后等待从数字控制器16来的下一个θ和下一个开始控制信号。如上所示，在本发明的该优选实施例中，一个完整的B扫描由128个超声波脉冲一0.7的Δθ增量偏转通过一个中心位于中央轴21(图1)的90度段组成。
接收器14由三段组成：一个时间增益控制段100，一个波束形成段101，和一个中间处理器102。时间增益控制端100包括一个对每个接收器通道的放大器105和一个时间增益控制电路106。每个放大器105的输入耦合到对应的传感器单元12来接收和放大它收到的回音信号。由放大器105提供的放大倍数通过一个由时间增益控制电路106驱动的控制线107控制。作为本领域所公知的，当回音信号的范围增加，它的幅度减小。其结果是，除非从更远距离反射器发送的回音信号比从近处的反射器的被放大更多，图像的亮度最为距离(R)的函数迅速减小。这个放大通过操作员控制，他手动设置8(典型值)个TGC线性电位计到提供一个在整个扫描段区域相对均一的亮度的值。回音信号获取的时间间隔决定了它发射来自的范围，并且这个时间间隔被TGC控制电路106分成了8段。8个电位计的设置被用来在8个对应的时间间隔的每一个中设置放大器105的增益，因此回音信号在获取时间间隔内以一个一直增加的量被放大。如下面将讨论的，本发明采用与用来设置放大器105增益的TGC控制信号107相同的数字形式。这个数字TGC增益控制信号在到中间处理器的总线109上提供。
接收器14的波束形成段101包括N＝128个独立的接收器通道110。如下面将更详细的解释，每个接收器通道110在输入111接收从其中一个TGC放大器105模拟回音信号，并且在I总线112和Q总线113上产生一连串数字化的输出值。这些I和Q值的每一个代表每个信号包络在特定距离(R)上的回音信号的样本。这些样本已经被按照上述方法延迟因此当它们在加法点114和115与从其它接收器通道110的每个I和Q样本样本相加时，它们代表从偏转光束(θ)上距离为R的点P反射的回音信号的量和相位。在该优选实施例中，每个回音信号在整个扫描线(典型为40至200mm)区域以约150μm的相等间隔进行采样。
中间处理器段102从加法点114和115接受波束采样。每个波束采样的I和Q值是16字节的数字代表着从一点(R,θ)反射的声波的1量的同相和二次分量。中间处理器102可以对这些波束样本执行多种计算，根据待重建的图像的类型决定选择。例如，如果要生成一个传统的量图像，120所示的检测过程通过如下实现，每个数字量M用每个波束样本和121的输出计算，中间处理器102也可以包括一个修正处理器122。这种修正处理器122检查接收到的波束样本并计算出发送器13和接收器14可以在随后的测试中用的修正值来提高波束聚焦和偏转。这种修正是必要的，例如考虑到从每个传感器单元出发的声波在扫描中途径介质的非均一性。
本发明也采用如TFC(时间频率控制)滤波器所示的修正处理器123。如下面将详细介绍的，TFC滤波器123在它的输入124和125接收从加法点114和115的I和Q信号，在它对应的输出126和127生成对应的I”和Q”信号流。典型地，TFC滤波器123的输出126和127将直接练到检测处理器120的输入来在处理器输出121生成波束值样本。
特别参考图1和4，接收器14在它的输出121产生一系列8字节的数字化数字，被应用到显示系统17的输入。这“扫描数据“以矩阵形式存储在记忆体150中，扫描数据阵列150的行与获取的对应的波束角(θ)一致，扫描数据阵列150的列与对应的样本沿着每个波束获取的距离(R)相一致。从接收器14的R和θ控制信号151和152显示每个输入值在阵列150要存储的位置，一个记忆体控制电路153把那个值写到阵列150中合适的记忆位址。扫描可以连续地重复，从接收器14的数据流将连续更新扫描数据阵列150。
阵列150里的扫描数据被一个数字扫描转换器154读取并转换到产生所需图像的形式。如果要产生传统的B扫描图像，例如，存储在扫描数据阵列150里的量值M(R,θ)被转换成显示图像中位置(x,y)像素的量的量值M(x,y)。如此的一个超声波图像数据从极坐标到笛卡尔坐标的转换被描述。
不管数字扫描转换器154产生的特定转换，结果图像数据被写入存储转换后扫描数据的二维阵列的记忆体155中。一个记忆体控制156提供对记忆体155的双口访问，因此数字扫描转换器154可以在显示处理器157读取更新数据的同时持续地用新数据连续更新值。显示处理器157对从控制面板158接收到的操作员命令响应，对记忆体155里的转换后扫描数据执行传统的图像处理函数。例如，记忆体155里的转换后扫描数据显示的亮度水平区域可能远超过显示设备160的亮度区域。甚至，记忆体155里的转换后扫描数据的亮度分辨率可能远超过人眼的亮度分辨率，一般提供手动操作的控制，使操作员能选择一个亮度值的窗口，通过窗口得到最大图像对比度。显示处理器从记忆体155读取转换后扫描数据，提供所需图像优化并写优化的亮度值到一个显示记忆体161中。
显存161被显示控制电路162通过记忆体控制电路163共享，那里的亮度值 被映射来控制显示器160上对应像素点的亮度。显示控制器162是一个商业可供的积分电路，设计来操作显示器160用的特殊型号。例如，显示器160可以是一个CRT，其中显示控制器162是一个提供所需水平和竖直扫描电路的CRT控制芯片并在扫描中在合适的时间将显示数据映射到CRT上。
对本领域的技术人员是显而易见的，显示系统17可以采用多种形式中其一依赖于特定超声系统的容量和灵活性。在上述的优选实施例中，用程序化微处理器实现数字扫描转换器和显示器功能，导致的显示系统，因此是很灵活和强大的。
接收器14的波束形成段101由一组接收器通道110组成，每个对传感器11的单元12(图1)。每个接收器通道对从数字控制器16(图1)开始命令、40MH在主时钟，距离信号(R)和波束角信号(θ)响应来实现数字波束生成功能。这些包括：在模拟至数字转换器200对模拟输入信号采样，在解调器201对采样得信号调制；用低通滤波器202对解调器201产生的高频率和信号滤波；在抽取器203降低数据速率；在延迟FIFO(如先进/先出记忆体)204和相位旋转器205里产生的数字数据流进行时间延迟和相调节。所有这些单元被一个接收通道控制206控制，它响应从数字控制器16(图1)来的命令产生所需的时钟和控制信号。在该优选实施例中，所有这些单元包含在一个单个的积分电路上。
模拟至数字转换器200对波形210图像化的模拟输入信号采样，以从接收通道控制206的延迟采样时钟的上升边缘决定的规则间隔。在优选实施例中，采样时钟信号是40MHz时钟信号使能使用高达20MHz的超声波频率而不违背奈奎斯特采样准则。当使用5MHz的超声载波频率时，例如，在每个载波周期采样8次，以40MHz速率在模拟至数字转换器的输出端产生一个10字节的数字 信号。这些样本被供到将每个样本与发送的超声载波的参考共相和控制信号206相混的解调器。SINE(正弦)值被数字化地乘以采样得输入信号来产生一个供给低通滤波器202的解调、共相的值(I)，COSINE(余弦)值被相同的采得输入信号数字相乘来产生供给单独低通滤波器202的解调二次相值(Q)。低通滤波器202是有限脉冲响应滤波器调试至穿过解调器201提供的不同频率，但拦截更高的和频率，每个低通滤波器的输入信号，因而是显示每个回音信号包络的I或Q分量的量的40MHz的数字值流。
回音信号的解调I和Q分量采样的速率被抽取器203降低。12字节的数字信号以40MHz的速率供到抽取器，从精确的观点看不足够高，但是整个系统难以维持的数据速率。相一致的，抽取器203每8个数字样本选取来降低数据速率至5MHz。这对应着接收通道控制器206产生的基带时钟信号的频率，并被用来操作接收器通道的其余单元。抽取器203的I和Q输出信号因而回音信号包络的数字化样本219。抽取比例和基带时钟频率可以更改值8:1和5MHz之外的其它值。
解调和抽取的数字样本代表的回音信号包络气候被延迟FIFO204和相位旋转器205延迟来提供所需的波束偏转和波束聚焦。这些延迟附加在上述施加到模拟至数字转换器200的延迟采样时钟信号提供的粗延迟上。也就是说，由接收器通道110提供的总延迟是供给模拟至数字转换器200，延迟FIFO204和相位旋转器205的延迟采样时钟信号提供的延迟之和。延迟FIFO204是连续数字样本值在由抽取器203以5MHz产生的同时写入的记忆体设备。这些存储的值被写至连续的记忆体地址，然后从记忆设备读出并提供给相位旋转器205。延迟的量，从数字样本正被提供的记忆地址和正被接收的数字样本存储的记忆地址的差别 决定。5MHz基带时钟信号建立了存储数字样本间200纳秒的间隔，因此FIFO204可以以200纳秒的增量提供最大为25.6微妙的时间延迟。相位旋转器205使回音信号的数字化再现能被延迟FIFO204少于200纳秒的分辨率的量延迟。供给相位旋转器205的I和Q数字样本可以通过一个相矢量221，并且产生的旋转后的I和Q数字样本可以用相矢量222再现。相矢量的量(如I和Q分量每个的矢量和)是不变的，但I和Q的值相对于彼此被改变了因而输出相矢量222是从输入相矢量221旋转了量Δθ。相位可以被提前了+Δφ)也可以是被推迟了(-Δφ)，作为对从接收通道控制器206的总线上接收的相位控制信号的响应。
为一般描述接收器通道110及详细描述每个接收器通道110的I和Q输出信号是怎样加在一起形成一个波束信号的。
在图3中，实施本发明的TFC滤波器123，显示包括一个输入124和125连接到接收对应的I和Q波束样本的旋转器电路250。旋转器电路250与上述及在前面引用的美国专利No.4,896,287里公开的是完全相同的。它在输入251接收数字的相位偏移指令(Δθ)当每个I和Q数字波束样本在它的输入124和125被接收时。由I和Q输入分量代表的相矢量被旋转一个量Δθ，产生的分量，旋转后的相矢量被生成为总线252和253上的I’和Q’信号。
数字相位便宜命令(Δθ)有一个Δθ处理器254产生。总线109上的TGC增益信号被应用到处理器254开始的地址，存储在对应地址的记忆位址的数据被读出并用来为旋转器电路250计算相位偏移命令Δθ当从读取时钟(未显示)的控制线255的信号走低时。数字化相位偏移命令(Δθ)的值因此是TGC增益信号的函数，如下面更详细地解释。TFC滤波器123也包括一个调整旋转器电路250产生的I’和Q’信号的频率分量的相对值。在短距离内，总信号损失很小， 有很好的信噪比，回音信号旋转后的I’和Q’信号分量是每个都高通过滤的因此整个带宽被用来形成图像。这使得图像分辨率提高，尤其在横向尺寸。相对的，更长距离下总的信号损失大，信噪比差，回音信号旋转后的I’和Q’信号分量是每个都低通过滤，因此在长距离对图像有贡献的信号的带宽被减小。这个滤波提高了穿透率，由于噪音带宽在长距离建设以轴向图像分辨率为牺牲。
执行这些滤波操作的电路，其中第一级260由一个低通滤波器组成，第二级261由一个高通滤波器组成。表示为Z-1的块代表单位延迟，符号+和×分别代表加法器和乘法器。滤波器260和261是传统的有限脉冲响应数字化滤波器其中低通滤波器260有一个脉冲响应(1，A1，1)并且高通滤波器有一个脉冲响应(-1，A2，-1)。在每个块循环，一个新数据值被加到滤波器260。延迟通过数据在每个时钟边沿在寄存器间传输的时钟控制的寄存器实现。在一个时钟周期里，所有的数学运算(例如加法或乘法)被执行。有脉冲响应(1，A1，1)的低通滤波器260执行两个加法和一个乘法在任一给定时钟周期里。进入滤波器的数据被加至两个时钟周期前到达滤波器输入的数据。该运算产生的输出信号被加到一个时钟周期前的滤波器输入信号，与系数A1相乘修改。再一次，所有的数学运算在一个时钟周期内执行，因此对每个到滤波器的输入信号，有一个输出信号(如流水线实现)。低通滤波器260的输出信号沿流水线进入高通滤波器261的输入产生一个流水线的带通滤波器，滤波器的特征完全由系数A1和A2的选择控制。在短距离，低通滤波器260的系数A1被实质上增加超过了高通滤波器261的系数A2，因此高通滤波器261将决定滤波器在近场的响应。另一方面，长距离时，高通滤波器261的系数A2被实质上增加超过了低通滤波器260的系数A1，因此低通滤波器260决定了滤波器258(图3)的响应。在 优选实施例中，超声波传感器11以5MHz的载波频率、带宽约2MHz并且在该带宽上呈高斯能量分布产生脉冲。滤波器260和261是传统的三点FIR(有限脉冲响应)滤波器，其中单系数A1决定了低通的频率特征，单系数A2决定了高通的频率特征。
再一次参考图3，本发明的一个重要方面是旋转器电路250的相位偏移命令和滤波器258的系数命令A1和A2可以作为总线109上的TGC增益信号的函数产生的实现。系数命令A1和A2被储存在对应的记忆体265和266里并且它们被从记忆体中读出并通过控制线255的读时钟信号直接应用到滤波器258。TGC增益信号总线109连接到记忆体265和266的率先地址，TGC增益信号的幅度定制了储存在连续记忆体地址内特定地址的系数值A1和A2。
本发明的时间频率控制滤波器容易在中间处理器中实现并应用到形成的接收波束。它的结构通过将过滤器的控制参数推导成TGC增益信号，一个超声波成像系统已有的信号的控制方程而被可观简化。本领域技术人员可以做出很多并不从这里阐明的宽广概念脱离的修改和变化。所以可以理解附加的声明意在覆盖所有这些在本发明真正精神中的修改和变化。

Claims (8)

  1. 一种无人船监控区域相控阵超声波低频成像装置，其特征在于：包括
    传感器阵列(11)，所述传感器阵列(11)由多个独立传感器单元(12)组成，
    发送器(13)，所述传感器单元(12)可以在收到所述发送器(13)产生的脉冲激发时产生一阵超声波能量；
    接收器(14)；
    发送/接收开关(15)，从无人船船体反射回所述传感器阵列(11)的超声波能量被所述传感器单元(12)转换成一个电信号并通过所述发送/接收开关(15)单独施加到所述接收器(14)上；
    数字控制器(16)，所述发送器(13)，接收器(14)和发送/接收开关(15)在操作员操纵的所述数字控制器(16)的控制下运行；以及
    显示系统(17)，通过获取一系列回音进行每次的完整扫描，所述发送器(13)门控暂时打开，激发每个传感器单元(12)，然后所述发送/接收开关(15)门控打开以接收随后每个传感器单元(12)产生的回音信号，这些单独的回音信号在所述接收器(14)中合并产生一个单独的回音信号用来在显示器(17)上显示图像的一个像素或一条线。
  2. 根据权利要求1所述的一种无人船监控区域相控阵超声波低频成像装置，其特征在于：所述发送器(13)驱动所述传感器阵列(11)，产生的超声波能量通过光束被导向或偏转，B型扫描可以通过点到点移动该光束而不是物理移动传感器阵列(11)而执行。
  3. 根据权利要求1所述的一种无人船监控区域相控阵超声波低频成像装置， 其特征在于：所述发送器(13)将一个时间延迟Ti对应的应用到后续的传感器单元(12)发出的脉冲(20)，所述时间延迟是0或递增。
  4. 根据权利要求1所述的一种无人船监控区域相控阵超声波低频成像装置，其特征在于：所述发送器(13)包括一组通道脉冲码记忆体(50)。
  5. 根据权利要求4所述的一种无人船监控区域相控阵超声波低频成像装置，其特征在于：所述通道脉冲码记忆体(50)有128个独立传感器单元(12)，每个脉冲码记忆体(50)优选的是一个1字节乘512字节的记忆体，储存决定要产生的超声波脉冲(52)的字节样本(51)。
  6. 根据权利要求1所述的一种无人船监控区域相控阵超声波低频成像装置，其特征在于：每个脉冲(52)被延迟适当的量，所述延迟由发送控制器(54)通过从所述数字控制器(16)接收开始，主时钟，RT和θ四种控制信号提供。
  7. 根据权利要求1所述的一种无人船监控区域相控阵超声波低频成像装置，其特征在于：所述接收器(14)由三段组成：时间增益控制段(100)，波束形成段(101)和中间处理器(102)，所述时间增益控制段(100)包括一个针对每个接收器通道的放大器(105)和一个时间增益控制电路(106)，每个放大器(105)的输入耦合到对应的传感器单元(12)来接收和放大它收到的回音信号，由放大器(105)提供的放大倍数通过一个由时间增益控制电路(106)驱动的控制线(107)控制。
  8. 根据权利要求7所述的一种无人船监控区域相控阵超声波低频成像装置，其特征在于：所述接收器(14)的波束形成段(101)由一组接收器通道(110)组成，每个针对一个传感器单元(12)。
PCT/CN2016/095099 2016-06-22 2016-08-14 无人船监控区域相控阵超声波低频成像装置 WO2017219472A1 (zh)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110664417A (zh) * 2019-09-18 2020-01-10 朔黄铁路发展有限责任公司 列车安全驾驶预警设备和系统

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110286860B (zh) * 2019-06-28 2021-06-15 联想(北京)有限公司 信息处理方法、信息处理系统和电子设备

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5121364A (en) * 1991-08-07 1992-06-09 General Electric Company Time frequency control filter for an ultrasonic imaging system
US5142649A (en) * 1991-08-07 1992-08-25 General Electric Company Ultrasonic imaging system with multiple, dynamically focused transmit beams
US5172343A (en) * 1991-12-06 1992-12-15 General Electric Company Aberration correction using beam data from a phased array ultrasonic scanner
US5203335A (en) * 1992-03-02 1993-04-20 General Electric Company Phased array ultrasonic beam forming using oversampled A/D converters
US5235982A (en) * 1991-09-30 1993-08-17 General Electric Company Dynamic transmit focusing of a steered ultrasonic beam
CN1292095A (zh) * 1998-12-31 2001-04-18 通用电气公司 干涉成象的方法和装置
CN1708257A (zh) * 2002-10-10 2005-12-14 视声公司 高频、高帧率超声波成像系统

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5327894A (en) * 1993-03-01 1994-07-12 General Electric Company Wall filter using circular convolution for a color flow imaging system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5121364A (en) * 1991-08-07 1992-06-09 General Electric Company Time frequency control filter for an ultrasonic imaging system
US5142649A (en) * 1991-08-07 1992-08-25 General Electric Company Ultrasonic imaging system with multiple, dynamically focused transmit beams
US5235982A (en) * 1991-09-30 1993-08-17 General Electric Company Dynamic transmit focusing of a steered ultrasonic beam
US5172343A (en) * 1991-12-06 1992-12-15 General Electric Company Aberration correction using beam data from a phased array ultrasonic scanner
US5203335A (en) * 1992-03-02 1993-04-20 General Electric Company Phased array ultrasonic beam forming using oversampled A/D converters
CN1292095A (zh) * 1998-12-31 2001-04-18 通用电气公司 干涉成象的方法和装置
CN1708257A (zh) * 2002-10-10 2005-12-14 视声公司 高频、高帧率超声波成像系统

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110664417A (zh) * 2019-09-18 2020-01-10 朔黄铁路发展有限责任公司 列车安全驾驶预警设备和系统

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