阅读说明：本技术 一种复用型超声内镜回波数据传输及图像重建装置及方法 (Multiplexing type ultrasonic endoscope echo data transmission and image reconstruction device and method ) 是由 陈晓冬 杨晋 周智峰 邓惟心 汪毅 蔡怀宇 邹慧玲 于 2019-09-19 设计创作，主要内容包括：本发明公开一种复用型超声内镜回波数据传输及图像重建装置及方法；装置包括中央控制模块、高压隔离模块、通道复用模块、回波预处理模块、数据采集模块、数据上传模块和图像重建模块；中央控制模块用于控制通道复用模块、回波预处理模块、数据采集模块、数据上传模块完成相应功能；高压隔离模块用于滤除换能器端口处的高压电脉冲,实现回波信号与高压脉冲的分离；通道复用模块由n2个低压模拟开关芯片组成,共包含n1路信号通道,分别连接在超声换能器的n1个阵元上；回波预处理模块,采用n4个多路集成模拟前端芯片,接收所述通道复用模块所传输的n3路模拟信号；所述数据采集模块,由两个DDR2存储器构成；图像重建模块采用GPU为计算平台。(The invention discloses a device and a method for transmitting echo data and reconstructing an image of a multiplexing ultrasonic endoscope; the device comprises a central control module, a high-voltage isolation module, a channel multiplexing module, an echo preprocessing module, a data acquisition module, a data uploading module and an image reconstruction module; the central control module is used for controlling the channel multiplexing module, the echo preprocessing module, the data acquisition module and the data uploading module to complete corresponding functions; the high-voltage isolation module is used for filtering high-voltage electric pulses at the port of the transducer to realize the separation of echo signals and the high-voltage electric pulses; the channel multiplexing module consists of n2 low-voltage analog switch chips, totally comprises n1 signal channels, and is respectively connected to n1 array elements of the ultrasonic transducer; the echo preprocessing module receives n3 paths of analog signals transmitted by the channel multiplexing module by adopting n4 multipath integrated analog front-end chips; the data acquisition module consists of two DDR2 memories; the image reconstruction module adopts a GPU as a computing platform.)

1. A multiplexing type ultrasonic endoscope echo data transmission and image reconstruction device is characterized by comprising a central control module, a high-voltage isolation module, a channel multiplexing module, an echo preprocessing module, a data acquisition module, a data uploading module and an image reconstruction module; the echo data transmission and image reconstruction device is used for carrying out data acquisition, uploading and imaging processes on echo signals; the echo signal is received by an ultrasonic transducer positioned at the most front end of the echo data transmission and image reconstruction device; the ultrasonic transducer is a device which is commonly used in the field of ultrasonic detection and transmits or receives ultrasonic waves;

the central control module is used for controlling the channel multiplexing module, the echo preprocessing module, the data acquisition module and the data uploading module to complete corresponding functions and controlling the time sequence of the echo data transmission and image reconstruction device;

the high-voltage isolation module is used for filtering high-voltage electric pulses at the port of the transducer to realize the separation of echo signals and the high-voltage electric pulses;

the channel multiplexing module consists of n2 low-voltage analog switch chips, totally comprises n1 signal channels, and is respectively connected to n1 array elements of the ultrasonic transducer; under the configuration of the central control module, the ultrasonic transducer finishes the first sound wave transmission and receives echo signals, the signals are converted into analog electric signals by the sound signals of the transducer, the analog signals of array elements No. 0 and No. 1 … … n3-1 are sequentially received by the channel multiplexing module after being processed by the high-voltage isolation module, and n3 paths of analog signals are output to the echo preprocessing module; the ultrasonic transducer finishes the second sound wave transmission, the low-voltage analog switch chip switches channels, sequentially receives array element echo signals of n3, n3+1 … … 2n3-1, and outputs n3 paths of analog signals to the echo preprocessing module; and so on until all n1 groups of echo signals are received; assuming that a single low-voltage analog switch chip can provide N receiving channels, the ultrasonic transducer continuously emits sound waves and the channel switching times are M, the relationship among N1, N2, N3 and M, N is satisfied:

n1＝N*n2，M＝n1/n3

the echo preprocessing module receives n3 paths of analog signals transmitted by the channel multiplexing module by adopting n4 multi-path integrated analog front-end chips, performs filtering, denoising, amplifying and digital-to-analog conversion processes on n3 paths of analog signals under the control of the central control module, and outputs n3 paths of digital signals to the data acquisition module;

the data acquisition module consists of two DDR2 memories, namely a memory A and a memory B, and is used for caching the n3 paths of digital signals transmitted by the channel multiplexing module; under the control of the central control module, with the switching of a front-end channel, two DDR2 memories alternately store echo data through ping-pong operation, when a single memory A receives data, the other memory B uploads the stored data and empties the memory, thereby ensuring the continuous data acquisition;

the data uploading module is in a USB3.0 transmission mode; under the control of the central control module, a USB3.0 transmission protocol is adopted to transmit the data in the DDR2 memory to the image reconstruction module;

the image reconstruction module adopts a GPU as a computing platform and is used for carrying out parallel computation on n3 paths of echo data in a single DDR2 memory transmitted by the data acquisition module and the data uploading module and outputting a transient image matrix alpha; and continuously iterating and updating the transient matrix alpha along with the switching of the channel, and reconstructing a complete image matrix delta.

2. A multiplex type ultrasonic endoscope echo data transmission and image reconstruction method based on the multiplex type ultrasonic endoscope echo data transmission and image reconstruction device of claim 1,

(1) the ultrasonic transducer continuously emits ultrasonic waves for M times to scan human tissues;

(2) the central control module controls the multiplexing circuit to complete channel switching once when ultrasonic waves are transmitted once; specifically, the ultrasonic transducer finishes the emission of the 1 st infrasound wave, the channel multiplexing module sequentially receives array element echo signals of 0, 1 … … n3-1, and outputs a 1 st group of n3 analog signals to the echo preprocessing module; the probe finishes the 2 nd sound wave emission, the channel multiplexing module switches receiving channels, sequentially receives array element echo signals of n3, n3+1 … … 2n3-1, and outputs a 2 nd group of n3 analog signals to the echo preprocessing module; sequentially transmitting until the Mth time is finished, receiving array element echo signals of numbers (n1-n3), (n1-n3+1) … … and (n1-1), and outputting an Mth group of n3 analog signals to an echo preprocessing module;

(3) echo signals are stored in two DDR2 memories of a data acquisition module after passing through a channel multiplexing module and an echo preprocessing module, and the 1 st group of data is stored in a memory A; after the channel is switched, the 2 nd group of data is stored in the memory B, and meanwhile, the data in the data A is uploaded through the USB3.0 module and alternately reciprocates;

(4) the echo data is uploaded to a GPU to complete image reconstruction; based on the mode of alternatively uploading the echo data in the step (3), the GPU calculates the received data to obtain a transient image matrix alpha, and continuously updates the alpha along with the uploading of subsequent data; the synchronous operation of scanning and image calculation is realized, and the imaging speed is improved.

Technical Field

The invention relates to the field of phased array ultrasonic endoscope signal receiving and processing, in particular to a multi-array element ultrasonic endoscope receiving, transmitting and image reconstruction device suitable for a phased array medical ultrasonic endoscope system, and provides a real-time data receiving and imaging method based on the device.

Background

The modern medical ultrasonic endoscope system comprises a single-array ring-scan ultrasonic endoscope and a phased-array ultrasonic endoscope. The single-array-element switching-scanning endoscope utilizes a single transducer array element to carry out rotary scanning, transmits ultrasonic waves and receives echo signals, so that the function can be realized only by one path of data receiving channel. The phased array endoscope adopts an array transducer, deflection scanning is realized through delayed emission among a plurality of array elements, and data receiving is realized by a plurality of groups of receiving channels. With the development of the technology, the number of array elements integrated by the array transducer is increasing, which makes the scale of the signal receiving and transmitting system at the back end increase, and the limited number of I/O ports of the chip also makes it impossible to provide a dedicated receiving channel for each array element. The existing mode of using a plurality of small-scale receiving systems for parallel expansion also has the problems of high data synchronism and high system complexity, and the expansibility of the system is greatly influenced.

Nowadays, the appearance of a switch chip with high integration makes it possible to realize channel multiplexing, and part of ultrasonic application systems realize signal transceiving by adopting a channel multiplexing mode. The channel multiplexing mode inevitably causes the problem of reduced imaging speed, which is not acceptable in the field of medical ultrasonic endoscope detection.

Based on the problems, the invention analyzes the signal characteristics of echo data in the medical ultrasonic endoscope system, designs a multiplexing type phased array ultrasonic endoscope receiving, transmitting and image reconstruction device suitable for the medical ultrasonic endoscope system, and ensures the imaging real-time performance of the system while realizing the flexible expansion of multiple array elements of the system. The invention also provides a data receiving and real-time imaging method based on the set of device.

The conventional imaging system needs to acquire all echo data before image reconstruction, which needs to occupy large-scale storage space and calculation resources and consumes a long time.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a device and a method for transmitting echo data and reconstructing an image of a multiplexing ultrasonic endoscope.

The purpose of the invention is realized by the following technical scheme:

a multiplexing type ultrasonic endoscope echo data transmission and image reconstruction device comprises a central control module, a high-voltage isolation module, a channel multiplexing module, an echo preprocessing module, a data acquisition module, a data uploading module and an image reconstruction module; the echo data transmission and image reconstruction device is used for carrying out data acquisition, uploading and imaging processes on echo signals; the echo signal is received by an ultrasonic transducer positioned at the most front end of the echo data transmission and image reconstruction device; the ultrasonic transducer is a device which is commonly used in the field of ultrasonic detection and transmits or receives ultrasonic waves;

the central control module is used for controlling the channel multiplexing module, the echo preprocessing module, the data acquisition module and the data uploading module to complete corresponding functions and controlling the time sequence of the echo data transmission and image reconstruction device;

the high-voltage isolation module is used for filtering high-voltage electric pulses at the port of the transducer to realize the separation of echo signals and the high-voltage electric pulses;

the channel multiplexing module consists of n2 low-voltage analog switch chips, totally comprises n1 signal channels, and is respectively connected to n1 array elements of the ultrasonic transducer; under the configuration of the central control module, the ultrasonic transducer finishes the first sound wave transmission and receives echo signals, the signals are converted into analog electric signals by the sound signals of the transducer, the analog signals of array elements No. 0 and No. 1 … … n3-1 are sequentially received by the channel multiplexing module after being processed by the high-voltage isolation module, and n3 paths of analog signals are output to the echo preprocessing module; the ultrasonic transducer finishes the second sound wave transmission, the low-voltage analog switch chip switches channels, sequentially receives array element echo signals of n3, n3+1 … … 2n3-1, and outputs n3 paths of analog signals to the echo preprocessing module; and so on until all n1 groups of echo signals are received; assuming that a single low-voltage analog switch chip can provide N receiving channels, the ultrasonic transducer continuously emits sound waves and the channel switching times are M, the relationship among N1, N2, N3 and M, N is satisfied:

n1＝N*n2，M＝n1/n3

the echo preprocessing module receives n3 paths of analog signals transmitted by the channel multiplexing module by adopting n4 multi-path integrated analog front-end chips, performs filtering, denoising, amplifying and digital-to-analog conversion processes on n3 paths of analog signals under the control of the central control module, and outputs n3 paths of digital signals to the data acquisition module;

the data acquisition module consists of two DDR2 memories, namely a memory A and a memory B, and is used for caching the n3 paths of digital signals transmitted by the channel multiplexing module; under the control of the central control module, with the switching of a front-end channel, two DDR2 memories alternately store echo data through ping-pong operation, when a single memory A receives data, the other memory B uploads the stored data and empties the memory, thereby ensuring the continuous data acquisition;

the data uploading module is in a USB3.0 transmission mode; under the control of the central control module, a USB3.0 transmission protocol is adopted to transmit the data in the DDR2 memory to the image reconstruction module;

the image reconstruction module adopts a GPU as a computing platform and is used for carrying out parallel computation on n3 paths of echo data in a single DDR2 memory transmitted by the data acquisition module and the data uploading module and outputting a transient image matrix alpha; and continuously iterating and updating the transient matrix alpha along with the switching of the channel, and reconstructing a complete image matrix delta.

The other technical scheme provided by the invention is as follows: a multiplexing type ultrasonic endoscope echo data transmission and image reconstruction method comprises the following steps:

(1) the ultrasonic transducer continuously emits ultrasonic waves for M times to scan human tissues;

(2) the central control module controls the multiplexing circuit to complete channel switching once when ultrasonic waves are transmitted once; specifically, the ultrasonic transducer finishes the emission of the 1 st infrasound wave, the channel multiplexing module sequentially receives array element echo signals of 0, 1 … … n3-1, and outputs a 1 st group of n3 analog signals to the echo preprocessing module; the probe finishes the 2 nd sound wave emission, the channel multiplexing module switches receiving channels, sequentially receives array element echo signals of n3, n3+1 … … 2n3-1, and outputs a 2 nd group of n3 analog signals to the echo preprocessing module; sequentially transmitting until the Mth time is finished, receiving array element echo signals of numbers (n1-n3), (n1-n3+1) … … and (n1-1), and outputting an Mth group of n3 analog signals to an echo preprocessing module;

(3) echo signals are stored in two DDR2 memories of a data acquisition module after passing through a channel multiplexing module and an echo preprocessing module, and the 1 st group of data is stored in a memory A; after the channel is switched, the 2 nd group of data is stored in the memory B, and meanwhile, the data in the data A is uploaded through the USB3.0 module and alternately reciprocates;

(4) the echo data is uploaded to a GPU to complete image reconstruction; based on the mode of alternatively uploading the echo data in the step (3), the GPU calculates the received data to obtain a transient image matrix alpha, and continuously updates the alpha along with the uploading of subsequent data; the synchronous operation of scanning and image calculation is realized, and the imaging speed is improved.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects: the device realizes the segmented reconstruction of the local echo data, realizes the synchronous operation of data acquisition and reconstruction and improves the imaging speed in a channel multiplexing mode. Specifically, the device alternately stores and uploads different groups of echo data through two storage modules, and transmits the previous group of data to the image reconstruction module while receiving new data. According to the data characteristics of multi-array element ultrasonic imaging, the image reconstruction module can realize parallel computation on echo data, reconstruct a transient image and continuously update the transient image along with the reception of new data. And finally, giving a reconstruction result in time when the scanning is finished. Therefore, the imaging speed of the device is improved, and the requirements of the back-end data storage and image reconstruction module on memory space and computing resources are obviously reduced.

Drawings

FIG. 1 is a system block diagram of an embodiment of the present invention.

Fig. 2 is a schematic circuit diagram of a high voltage isolation module in accordance with an embodiment of the present invention.

Fig. 3a and 3b are schematic diagrams of a channel multiplexing module according to an embodiment of the present invention.

FIG. 4 is a data acquisition schematic of an embodiment of the present invention.

Fig. 5 is a schematic diagram of image reconstruction in accordance with an embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the figures and specific examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In this example, the front transducer probe is 64 array elements of ultrasonic transducers, and the back end is 32 parallel receiving channels, so the n1, n2, n3, n4, M are 64, 8, 32, 1, 2, respectively. This example is only one implementation manner of the present invention, and the practical use can adjust the value combinations of n1, n2, n3, n4, and M as required, all of which belong to the protection scope of this patent.

As shown in fig. 1, the present invention provides a multiplexing phased array ultrasonic endoscope receiving, transmitting and image reconstructing device, which comprises a central control module, a high voltage isolation module, a channel multiplexing module, an echo preprocessing module, a data acquisition module, a data uploading module and an image reconstructing module.

The central controller module has the core device of FPGA, and is used for allocating the cooperative work and data exchange of the modules of the device and controlling the time sequence of the whole system, and the central controller module specifically works as follows: 1. and configuring starting parameters of each module of the system, wherein the starting parameters comprise sampling frequency and amplification factor of the echo preprocessing module, writing and reading modes of a DDR2 memory and the like. 2. And sending control signals to all parts of the device, wherein the control signals comprise a channel switching signal provided for the switch chip, a read-write enabling signal sent for the DDR2, an uploading initial signal sent for the USB3.0 uploading module and the like.

The high-voltage isolation module is adopted in the embodiment to filter the high-voltage excitation pulse at the array element. Fig. 2 is a schematic diagram of a circuit of one of the high-voltage isolation modules. The circuit is divided into a two-stage structure, the first stage is composed of D1, D2, E1 and E2, the voltage can be limited within the range of [ E2 and E1], and the values of E1 and E2 can be flexibly adjusted according to the characteristics of signal amplitude. The second stage is a parallel structure formed by D3 and D4, and can further reduce the amplitude of allowed signals on the basis of the first stage, ensure that echo signals enter a post-stage receiving system in a fidelity and lossless manner, and protect the safety of a post-stage circuit.

In the channel multiplexing module of this embodiment, MAX394 of meixin corporation is selected as a low-voltage analog switch chip for channel switching, and a schematic diagram is shown in fig. 3 a. The chip integrates 4 groups of independent single-pole double-throw switches, and can simultaneously complete the switching of 4 groups of channels. For the transducer with 64 array elements in the example, the rear stage is a 32-channel receiving system, 8 chips (numbers 1-8) are selected, and 32 groups of single-pole double-throw switches (numbers 0-32) are used for realizing the channel multiplexing function. Through reasonable grouping, the array elements of the multiplexing channels are connected at two ends of the same switch channel, and the distribution table is shown in the table I. Fig. 3b shows the channel multiplexing mode by taking chip No. 1 as an example.

Table-channel multiplexing mode allocation table

The echo pre-processing module in this example takes an AFE5832 integrated pre-processing chip as a core processing chip, and is configured with peripheral circuits. The integrated chip comprises 32 processing units and can simultaneously process 32 paths of analog data. Each processing unit comprises a time gain compensator, a low noise gain amplifier, a third-order linear phase low-pass filter and a 10-bit AD conversion structure, and the sampling rate is 100 MSPS. The chip receives the configuration of the central controller through the external I/O to realize the function. In this example, 1 chip is used, so that preprocessing of all echo data received at a time can be realized, and the system scale is effectively reduced.

The DDR2 memory chip selected by the data cache module of the embodiment is K4T1G084QA-ZCE 6. The operation mode is shown in fig. 4, in which the arrows with the same color indicate the simultaneous acquisition/transmission operation, and the operations corresponding to the arrows with different colors are not performed at the same time. The two DDRs 2 are alternately read and written using a ping-pong mode of operation. The array element excites ultrasonic waves to scan, DDR 2A is switched to a write enable state first, echo data of array elements 0-31 are received, and at the moment, DDR 2B is in a waiting state. And C, after the acquisition is finished, switching to a read enabling state, uploading the acquired data, and at the moment, switching the B to a write enabling state, and receiving the array element data of number 32-63. Then A is switched to a write enable state again, B is switched to a read enable state, and the process is circulated, and 64 paths of echo data alternately enter a receiving system. The switching of the A state and the B state is controlled by a central controller FPGA, and each switching is kept synchronous with the ultrasonic wave emitted by the front-end ultrasonic transducer.

In the example, the uploading module uses a CYUSB3014 chip, adopts a USB3.0 transmission protocol, and realizes high-speed uploading of 32-channel signals by building a firmware program.

The image reconstruction module of this example adopts NVIDIA RTX 2080TI as a GPU parallel computing platform, and its working mode is shown in fig. 5. According to the working process of the data acquisition module and the data uploading module, the data acquired by the DDR 2A enters the GPU first. And the GPU performs parallel computing processing on the 32 groups of echo data, prestores a time delay lookup table of each path of signal in the GPU, performs the processes of phase alignment, weighted superposition and the like on the signal according to the lookup table, and outputs a transient image matrix alpha. And the transient image matrix alpha is used as a basic matrix to participate in the reconstruction process of the next group of echo data, namely after the data in the DDR 2B enters the GPU, the reconstruction process is repeated, the result and the transient image matrix alpha are subjected to weighted superposition to form a new transient image matrix alpha, the new transient image matrix alpha participates in the next operation until the echo data of all array elements participate in reconstruction, and at the moment, a complete image matrix delta after reconstruction can be obtained.

The present invention is not limited to the above-described embodiments. The foregoing description of the specific embodiments is intended to describe and illustrate the technical solutions of the present invention, and the above specific embodiments are merely illustrative and not restrictive. Those skilled in the art can make many changes and modifications to the invention without departing from the spirit and scope of the invention as defined in the appended claims.