Ultrasound Boat Detection System A Worcester Polytechnic Institute Major Qualifying Project Advisor: Fabio Carrera Advisor: Peder Pedersen Students:Mark Johnson Jonathan Lovisolo Yasuhiro Okuno

Presentation Overview System Block Diagram Real Environment Object Detection Boat Detection Multiplexing (MUX) Software Environment Signal Processing Intelligent System Logging

Presentation Overview Development Stages Stage 1: Lab Environment Stage 2: Portable System Stage 3: Real Environment Future Improvements Wake Height Detection Pressure Sensing

Boat P/R MUX Real Environment Signal Processing Intelligent System Echo signal Logging System Echo Signal: TRUE Delay: 2 (ms) Strength: 92 Width: 96.2 (us) Boat detected at: :23:42 Speed of boat: 14.1 (km/h) Length: 6.3 (m) Data after Signal ProcessingLogged data System Level Block Diagram Software Environment on System MUX:Multiplexer P/R:Pulser/Receiver

Real Environment Design The following slides will depict the system’s operation in the canal setting, including: Boat Detection Transducer Multiplexing

Object Pulser/Receiver (P/R) Beam Path Transducer Electric pulse sent by P/R to transducer Object Pulser/Receiver (P/R) Ultrasound pulse Transducer Transducer reacts by sending ultrasound pulse Object Pulser/Receiver (P/R) Echoed pulse Transducer Pulse hits object and echoes Real Environment: Object detection

Object Pulser/Receiver (P/R) Echoed pulse Transducer Echo reaches transducer The transducer turns echo into electric pulse and sends it to P/R Pulser/Receiver (P/R) Transducer Electric pulse sent to the signal processing unit Signal Processing unit Real Environment: Object detection

Boat Ultrasound Beam Canal Transducer Boat is not intersecting the path of either ultrasound beam System is idle Boat is intersecting the path of left ultrasound pulse System starts tracking the boat Real Environment: Basic Boat Detection method

Canal Transducer Boat just cleared off of the left ultrasound pulse A boat just passed by! Length of the boat can be calculated by: Boat Canal Transducer Boat is intersecting the path of both ultrasound pulses Calculate speed of the boat: Boat d Real Environment: Basic Boat Detection method

Multiplexer Switch signal from PC Pulser/Receiver (P/R) Connected to P/R Disconnected from P/R After receiving one switch signal from PC Multiplexer Switch signal from PC Pulser/Receiver (P/R) Disconnected from P/R Connected to P/R Multiplexer Allows one P/R to alternately read from 2 transducers Real Environment: Multiplexer

Boat Real Environment: To the next step Time Echo from transducer A Echo from transducer B The signals received from the transducer by the pulser receiver are sent to the PC in the form of Electrical signals to be processed by Signal Processing Unit Multiplexer Switch signal from PC Pulser/Receiver (P/R) Transducer A Transducer B

Software Environment The following slides will describe the software used in this system including the: Signal Processing Intelligent System Logging System

Signal Processing This begins the outline of the Signal Processing Section

Ultrasound pulses such as this are sent into the canal from the transducer Multiple Pulses Individual Pulse Transducer System

When the pulses strike an object, echoes are reflected back towards the transducer. Transducer Pulses Transmitted Pulses Returning Water Side Of Boat Canal Wall

If this pulse is sent: The returning echo will look the same:

Canal Wall Transducer System Transmitted Into Canal Returning From Canal Pulses This is a possible setup of the transducer system

Canal Wall Transducer System Transmitted Into Canal Returning From Canal Pulses This represents what is being transmitted into the canal

Canal Wall Transducer System Transmitted Into Canal Returning From Canal Pulses This represents what is being reflected from the canal

Canal Wall Transducer System Transmitted Into Canal Returning From Canal Pulses When the canal is empty, there is nothing for the pulses to reflect off of. Thus, the return is empty

Canal Wall Transducer System Transmitted Into Canal Returning From Canal Echoes When a boat travels in front of the transducer system, echoes begin returning.

Canal Wall Transducer System Transmitted Into Canal Returning From Canal Echoes As the boat continues to pass, more and more echoes are recorded

Canal Wall Transducer System Transmitted Into Canal Pulses When the boat passes, the transducer system stops receiving echoes. Returning From Canal

At this point, the system has recorded a series of echoes, such as this:

When we receive an echo, we are measuring its: Presence Is there an echo or not?

When we receive an echo, we are measuring its: Signal Width How wide the echo is

When we receive an echo, we are measuring its: Amplitude The maximum strength of the signal

When we receive an echo, we are measuring its: Time Delay Time spent traveling in the water

Correlation How much the echo resembles the original pulse This graph represents the output of the correlation function, a complex signal processing algorithm. The height of the solid line represents the similarity between pulse and echo. The higher the line, the more resemblance that exists. When we receive an echo, we are measuring its:

Presence Amplitude Time Delay Once these four characteristics have been measured, Echo Validity can be determined Correlation Echo Validity

Echo Validity determines if the pulse sent out is the same as the echo received. PulseEcho Received Same? In this case, the echo received is the same as the pulse transmitted. Thus, echo validity is high. Echo Validity

Echo Validity determines if the pulse sent out is the same as the echo received. PulseEcho Received In this case, the echo received is dissimilar from the pulse sent out. Thus, the echo validity is very low. Same? Echo Validity

Echoes from the canal will only have a high validity if they are reflected off of a boat’s smooth, hard sides. Echoes with low validity correlate to reflections off of debris, birds, etc. If there is no echo, the echo validity is 0.

Echo Received Validity Measurement Thus, if a string of echoes is received, all with high validity,

Validity Measurement It can be concluded that a boat has passed in front of the transducer.

Validity Measurement If the echo validity is low, no boat has passed yet.

Intelligent System & Logging The following slides will depict the Intelligent System design used to gather information about the boats, as well as how that information is logged

The intelligent system then takes the signal data and makes final determinations on the presence of a boat. It looks at how many valid echoes are received consecutively with similar time delays. If there are enough valid echoes then a boat has passed.

Validity Measurement There are enough valid echoes here. Therefore there is a boat

Validity Measurement This only has a few valid echoes. This was probably not a boat.

Because debris, bubbles, or other factors can affect a signal we need to make the system allow for some invalid echoes. If a there is one invalid echo amidst a string of valid echoes we ignore it and go on.

Validity Measurement Single bad echoes can be ignored. They could be caused by interference. Bad Echo

If signals return with very different time delays then they are probably reflecting off of different boats. The system uses the time delay as a means of distinguishing between boats in the canal.

Echo 1 Echo 2 The two echoes had different delays because they hit different boats. Time delay

The system sends pulses every 0.01 seconds. The system can keep track of how many pulses happen between when the boat hits Transducer A and Transducer B. The number of pulses tells the system how much time it took a boat to move a fixed distance. From this information we can calculate the speed of the boat. This was depicted earlier.

Boat Ultrasound Beam Canal Transducer Boat is not intersecting the path of either ultrasound beam System is idle Boat is intersecting the path of left ultrasound pulse System starts tracking the boat Real Environment: Basic Boat Detection method

Canal Transducer Boat just cleared off of the left ultrasound pulse A boat just passed by! Length of the boat can be calculated by: Boat Canal Transducer Boat is intersecting the path of both ultrasound pulses Calculate speed of the boat: Boat d Real Environment: Basic Boat Detection method

When the system stops receiving valid echoes from a boat the speed is calculated. This was also shown earlier. Once this happens the information for the boat is logged. This information is printed in the log file like this: Timestamp: Sun Feb 16 14:30: Speed: 9.7 km/h Length: 2.8 m Note: The length of this boat may be inaccurate due to other boats in the system! The note is shown when another boat interferes with the data for this boat.

Once the data is logged to a file it can be retrieved at any time. The system will be capable of retrieval by either disk or remotely through the internet when it is complete.

Development Process The next few slides will depict the development process of this project By the end of the academic year, this group will have completed the second stage of development, ready for testing in Venice.

Digitizer (LeCroy9400) GPIB Fish Tank Pulser/Receiver PC with test software First Generation Test of Theory in lab controlled environment Test that the method works Refine method of detection and data collection Establish a detection software Toy Boat Development Stages: First Generation

Laptop with digitizer card and test software Test Object (i.e. real boat) Pool Pulser/Receiver Second Generation Field testing Test theory established in first generation Deal with any irregularity of the real environment Finalize detection and data collection software Development Stages: Second Generation

Venice Canals Pulser/Receiver Final Generation Deployment Implement all functionality developed in 2 nd generation in a single standalone system. Test all functionality in field Deploy system for usage in Venice canals Standalone Embedded System Boat Research Team Data Transfer Via Network or Removable Media Development Stages: Third Generation

Lateral Wave Force Wake Height Boat Accelerometer or Pressure Transducer In the Future… Use Accelerometer or Pressure Transducer to measure force exerted on the wall. This data can be used to relate traffic and canal damage Future Improvements: Wake height and pressure detection TimeBoat TypeWake height (cm)Pressure (?)*Speed (km/h)Length (m) :23:42Motor-boat C :24:32Gondola A :25:35Freight D With all the information, the log may look like the following for each station: (note: the values in the table is a sample and may not resemble real data) * The pressure measurement unit is unknown at the point of this writing, and the values may be unreasonably off

Conclusions The project is currently in the second phase of development. The second phase will be completed by May 2003, ready for testing in Venice The system will be able to log: Boat Traffic Speed of Boats Boat Size