OBJECT RECOGNITION USING ULTRASONIC SENSOR Jeniffer Arias Sarasty – 1110099 Pedro Luis Muñoz Murillo – 1210061 Cristian David Munera Cardona – 1210060 Juan Fernando Huertas B. - 1124820

INTRODUCTION The digital signal processing is an area that has been making progress in recent years, thanks to the development of the devices used for this purpose, such as integrated circuits or computers. This work is focused on the proposal for implementation in hardware and software of a recognize objects by ultrasound. The hardware is composed by the step of sensing and signal conditioning, then by analyzing and signals processing the object will be classified. OBJECT RECOGNITION USING ULTRASONIC SENSOR

Real aplications of ultrasound Ultrasonic obstacle detector for blind people Object detection radars. Measuring distances Internal characterization of materials Diagnostic ultrasound imaging in general hospital detectors cracks in metallic materials

OBJECTIVES GENERAL Design a hardware and software system recognition of volumetric objects by their shape OBJECT RECOGNITION USING ULTRASONIC SENSOR

OBJECTIVES SPECIFIC Select the appropriate sensor that meets the project requirements. Study and implement the proper way to the conditioning and representation of the signals from the sensor. Implement a communication protocol between the signal acquisition system and the computer. OBJECT RECOGNITION USING ULTRASONIC SENSOR

OBJECTIVES SPECIFIC Develop a script with the proper technique for analyzing the information obtained from the data acquisition. Designing the GUI that shows the shape of the sensing object. OBJECT RECOGNITION USING ULTRASONIC SENSOR

Graphical User Interface (GUI) METHODOLOGY The solution is presented in 5 stages Graphical User Interface (GUI) Processign Data Collection Signal Conditioning Sensing OBJECT RECOGNITION USING ULTRASONIC SENSOR

Sensing They can point to two types of gauges, which have a transmitter and a separate receiver, and the alternating function, through a switching circuit, on the same transmitter / receiver piezo.

Sensing A scanning technique in which the object via a sensor wave which is reflected on the object is output is used, which causes an echo signal to be generated changes in characteristics. For the transmitter will apply a pulse train of 40 KHz, for it to emit a signal which is then reflected in the object to be identified, generating an echo is detected by the receiver

Ultrasound propagation Change the surface characteristics as reflected.

Data Collection For data acquisition the Arduino Mega 2560, which is in charge of generating 9 pulses 40 kHz is used for the transmitter. Then through an analogue channel signal from the receiver is taken, which is converted to digital format (10 bits) for subsequent communication with Matlab through serial port.

Arduino-Matlab communication

Signal Conditioning Problems: Noise Removal Amplifying the signal obtained Information extraction Problems: OBJECT RECOGNITION USING ULTRASONIC SENSOR

Signal Conditioning High Pass Filter Envelope Detector Section 𝑓 𝑐 = 1 2𝜋𝑅𝐶 =1.3𝐾𝐻𝑧 Voltage proportional to retrieve a message OBJECT RECOGNITION USING ULTRASONIC SENSOR

Signal Conditioning OBJECT RECOGNITION USING ULTRASONIC SENSOR

Signal processing digital filter it was implemented a digital filter to eliminate the ripple in the obtained signal

Signals obtained Obtained signals for a plane Obtained signals for a corner Obtained signals for a cilinder

Characteristics extraction in several works consulted is used temporal analysis of signals, getting nice features for further classification

Characteristics extraction

Artificial Neural Network MLP type network is widely used for classification in different applications. There are several algorithms for training this network backpropagation algorithm gradient descent algorithm with variable alpha Levenberg Marquardt algorithm

Artificial Neural Network

Artificial Neural Network

Graphical User Interface

Test protocol

Scope Detection of three different shaped objects (plane, cylinder, corner) with inexpensive devices. Object detection sizes. It can be used as a basic prototype for a navigation system. When used as a neural network processing, you can train better this network by adding more sensors so that a better description of the object is obtained OBJECT RECOGNITION USING ULTRASONIC SENSOR

Limitations Away for good signal acquisition was established by 30 cm. Less distance for interference due to echo presented. Location of the object relative to the sensor: For a correct reading of the sensor, the object must be located so as to produce a signal reflection as only it has a sensor When acquiring the object data must be in a space where there are no other objects that may cause echoes affecting the acquisition. Shape between different objects must be very marked for the received echo is different, this is because the use of a single sensor. OBJECT RECOGNITION USING ULTRASONIC SENSOR

performance compared to other solutions Analysis and processing of ultrasonic signals to classify surfaces: The recognition is done through an ultrasonic sensor rotation. The areas are characterized edges, corners, walls and empty. Signal characterization Wavelet Transform. OBJECT RECOGNITION USING ULTRASONIC SENSOR

Conclusions For good operation of the neural network must acquire signals so that they can obtain certain characteristics, it is essential for a good filtering the signal from the sensor. The combination of analog filters with digital filters is a way to eliminate unwanted signals such as ripple receiver signal acquired. Implementing digital filters reduces costs and facilitates the signal processing as this is done by software, not by hardware. OBJECT RECOGNITION USING ULTRASONIC SENSOR

SIMILAR JOBS Object recognition with ultrasonic sensors [http://www.cs.cmu.edu/~motionplanning/papers/sbp_papers/integrated1/ihsan_object_rec_w_sonars.pdf] Shape Recognition and Position Measurement of an Object Using an Ultrasonic Sensor Array [http://cdn.intechopen.com/pdfs-wm/37176.pdf] OBJECT RECOGNITION USING ULTRASONIC SENSOR