WO2017174838A1

WO2017174838A1 - Lighthouse identification system

Info

Publication number: WO2017174838A1
Application number: PCT/ES2017/000045
Authority: WO
Inventors: Carlos BARRANCO MOLINA; Ignacio GUSTAVO DIAZ; José Antonio POLO AVILA
Original assignee: Universidad De Huelva
Priority date: 2016-04-08
Filing date: 2017-03-30
Publication date: 2017-10-12
Also published as: ES2641596B2; ES2641596A1

Abstract

The invention relates to a system for the identification of lighthouses (10), comprising light-capture means (1) for detecting a light signal formed by an alternating sequence of flashes and eclipses emitted by the lighthouse (10) over a time interval. The system also includes processing means (2) coupled to the light-capture means (1), for the purpose of extracting a frequency spectrum from the detected light signal and consulting a database (3) to see if a particular lighthouse corresponds to said frequency spectrum.

Description

HEADLIGHT IDENTIFICATION SYSTEM

DESCRIPTION

Technical Field of the Invention

The present invention relates generally to guidance instruments for nautical navigation More specifically, the present invention relates to an instrument that allows a headlamp to be recognized automatically.

Background of the invention or State of the Art

Human beings have always had the need to orient themselves on Earth to reach their destination. To this end, several methods of orientation have been developed that have been passed from generation to generation throughout history (orientation through stars, compasses, lighthouses , navigation charts, ...) and that have given rise to the current geolocation methods used in instruments such as GPS (Global Position System) systems.

A problem with geolocation systems such as GPS is that it offers information on the point from which data acquisition is made, but it does not inform us of the point we are looking at.

Traditional media are still used as technology is not always a constant ally when adversities arise. Currently, the identification of lighthouses and light signals from a vessel is done by visually observing the light source and counting the time it takes each on and off of said light until the cycle is completed. Generally speaking, a lighthouse is a powerful source of light, which has openings around it like windows, which give out light or prevent it.

Normally, a local navigator does not even have to count, because he knows it. Even so, if there are several lighthouses in the area or if there is fog or total darkness, the navigator must be fixed to discern which one he is seeing When the boat navigates areas not known, it is necessary to know what lighthouse it is.

In some boats, and according to the length, it is mandatory by regulation to carry on board nautical charts, GPS and even sextant marine. Pleasure boats of small dimensions are not required so many requirements. Through nautical charts and a compass can know which lighthouse it is; as with digital cartography and with GPS. A disadvantage is that such mapping must be available and it is also a laborious task.

In view of the limitations observed, it would be desirable to have an additional navigation aid mechanism that avoids manual queries in existing headlight catalogs and does not depend on satellite signals.

Brief Description of the Invention

An instrument is proposed for the automatic identification of nautical lighthouses in river or sea navigation, also applicable, on land. The invention must face a specific problem consisting in the optimization in the adjustment of the Optical system for the different intensities of light that arrive.

For this, the invention uses a light sensor (phototransistor or photodiode) that detects when there is light in one direction and when there is no (flash and concealment). A nautical lighthouse emits time intervals of light and intervals without light. In the time it takes for the lighthouse system to take a full turn, the observer perceives moments of light and dark moments; Each of these moments has a duration. Thus a pattern is formed with a sequence of lights and darkness each with its duration. This accounting of times, until now has been timed in a personal way to estimate or with stopwatches

The instrument proposed in this document has processing means that deal with the serial emitted by the lighthouse, to determine said intervals and thereby extract the characteristic information of the lighthouse in question. In a database where headlamp information is stored, which one corresponds to the observed pattern and this information can be retrieved along with the corresponding geographical coordinates.

The system incorporates an electronic-optical mechanism that allows you to point towards the headlamp and identify which headlamp it is for a better capture of the emitted signal.

The object of the invention is a headlamp identifier system with light collection means for detecting a light signal formed by an alternating sequence with flashes and concealments emitted by a beacon for a period of time. It also includes processing means coupled with the light collection means, to extract a frequency spectrum in the light signal detected, and to determine by statistical analysis if a particular beacon of the database corresponds to said frequency spectrum.

Optionally, the statistical analysis performed comprises a regression of the extracted frequency spectrum.

Preferably, the system comprises an interface, coupled with processing means, to show the result of the query made in the database.

Preferably, the light collection means comprise a light sensor and a sight glass to direct the light sensor towards the headlamp.

The light sensor preferably comprises a phototransistor

Alternatively, the light sensor comprises a photodiode.

Optionally The processing means comprise a memory module where the database is stored.

Optionally, the processing means comprise a reduced board computer with an analog-digital converter, a graphics card and a plurality of connections for connecting peripherals

Other variants and exemplary embodiments are set forth in the following sections for a better understanding of the present invention.

Brief description of the figures

Figure 1. Block diagram of the invention according to a schematic representation.

Figure 2. Example of real signal capture and computable values over noise threshold.

Figure 3. Common points between the frequencies captured and a sample of the database: similar spectra and identified beacon

Figure 4: Lens scheme of a headlight.

Figure 5: Scheme of the lens 'screen'

Figure 6. Representation of the light pattern generated by the lighthouse windows and screens (they act as a barcode). Figure 7: Scheme as the observer "sees times" on and off that translates into the "DNA" of the lighthouse.

Figure 8. Schematic diagram of the main components of an embodiment. Detailed description of the invention

With reference to the figures, a device formed by a hardware part is presented as an embodiment, which is responsible for capturing the light signal of the headlamp and processing it, and a software part, which is responsible for reading the processed information and showing the user the information you need legibly

Figure 1 shows a simplified scheme of functional blocks according to the invention formed by means of capturing light 1 that detect a light serial emitted by the headlamp 10 for a period of time for said headlamp 10 to turn completely. Processing means 2 perform an algorithmic analysis of the signals captured by the device, which consist of performing a Fourier transform to the signal to obtain its frequency spectrum, which will be processed generating a kind of easily comparable fingerprint, through a regression statistical, with the frequency spectra stored in a database 3, resulting in a number that symbolizes the proximity of the collected serial of the headlamp 10 with each of the available headlamps in database 3 (at lower index, lower it's the difference and more similarities exist). Finally, the search result is emitted through interface 4 of a graphic device (Computer, mobile or tablet).

The frequency spectrum captured by a real signal is shown in Figure 2 The algorithm of the processing means 2 iteratively compares the frequency data of the collected signal, considering those frequencies that exceed a noise threshold with close frequencies in the various samples of headlights of the database 3.

Figure 3 shows the common points between the frequencies captured from a signal and a sample from database 3, whose comparison, by statistical regression, results in a number that symbolizes the similarity of said signals, so that The lower the index, the smaller the difference. In this way the lighthouse of the nearest database 3 is chosen as long as the difference is less than a predetermined margin of error. In Figures 4-5 the headlamp 10 is shown in several views. The light patterns it generates are due to the presence of screens 7 of different lengths.

As Figure 4 shows, the headlight lens 10 has embossed recordings 8 that direct the light horizontally and vertically as well. These recordings act as windows, which when turning create several beams of lights of different angles on the horizon (times) as shown in Figure 5

For the observer this sequence of on and off is similar to a "barcode" as illustrated in Figure 6 that must be interpreted for identification.

Figure 7 summarizes in a diagram how the observer sees intervals of on and off time (flashes and concealments) that translate into a Unique pattern to identify the lighthouse.

With reference again to Figure 1 and more particularly to Figure 8, an embodiment is illustrated in more detail. The hardware for the processing means 2 is implemented with a Raspberry Pi, which is a low-cost reduced plate computer (or tunic plate) of 85x54 mm, developed in the United Kingdom by the Raspberry Pi Foundation, whose design includes a Broadcom BCM2835 System-on-a-chip, which contains a 700 MHz ARM1176JZF-S central processor (CPU), a VideoCore IV graphics processor (GPU), as memory module 31 uses an external SD card. Depending on the model you choose, there are more or less connection options, but it is recommended for most applications at least one HDMI video output port and another RCA type, audio minijack and a USB 2.0 port to connect to A keyboard and mouse. For the network connection, Ethernet is available to plug an RJ-45 cable directly to the router or use wireless WiFi adapters.

The lighthouse 10 emits luminous serials in the form of flashes, which form cycles composed of concealments and flashes with a certain duration that make each lighthouse unique in front of others. The light signal emitted by the headlamp 10 with each flash is captured through an electrical circuit composed of a phototransistor or a photodiode, responsible for capturing said signal, and an analog-digital converter 22, which processes the signal by means of the components that form to recognize that specific lighthouse emits said signal

For this particular embodiment, the B model of the Raspberry Pi has been chosen, since it has two USB ports and an Ethernet port, with a RAM capacity of 512 Mbytes. Using this board as a base, a circuit consisting of a phototransistor and an analog-digital converter 22 (model ADS1015) The phototransistor is a component of the light collection means 1 and a device that allows the passage of an amount of electric current in proportion to the light that affects it is treated. For this first prototype a phototransistor has been used, but it is also possible to use a photodiode. In turn, the ADS1015 analog-digital converter allows you to work with analog signals on boards without this type of converter, such as the Raspberry Pi. The ADS1015 gives 12-bit accuracy over 3300 samples per second in I2C, includes a gain amplifier to increase small signals up to 16 times. It is connected by I2C, being able to change the address to 4 possible, so you can use up to 4 ADS1015 simultaneously. It is powered from 2V to 5V and has a consumption of 150uA.

The software was created using the Netbeans IDE development environment, a tool that allows you to write, compile and execute programs in various programming languages. For this embodiment, the Java programming language has been used, given its compatibility with Raspberry Pi and its many utilities. A desktop application has been created that will allow the user to interact with the device that reads the headlight flashes.

Operation of the chosen hardware

The device is built on the basis of a Raspberry Pi model B, which has 26 GPIO pins. GPIO connectors allow the connection of external devices directly connected to the microprocessor, being able to use buses, peripherals (internal to the processor such as the UART for serial communication) or digital outputs / inputs. The GPIO translation is General Purpose Input / Output, General Purpose Input / Output, which is a generic pin on a chip, whose behavior (including if it is an input or output pin) can be controlled (programmed) by the user at runtime to perform a wide variety of functions as well as elements can be connected to the pins. These pins are not disserted with a predetermined function, so you can have a large number of possibilities depending on the combinations that are created based on the need of the moment.

All pins are "unbuffered", that is, they do not have protection buffers, so you have to be careful with the magnitudes of voltage, intensity, etc., when connecting external components to them so as not to damage the board. For this embodiment, the valid pin scheme is that of model B revision 2.0 Generally, the characteristics of the pins are as follows:

Power pins: 5v, 3v3 (limited to SOmA) and ground (GND or Ground) pins can be seen, which provide power to these voltages for the circuits that are built. They can be used as a power supply, although other sources (batteries, external power supplies, etc.) can also be used.

DNC (Do Not Connect): they are pins that at the moment have no function, but in future implementations they are used for other purposes, they are only found in more primitive models of the Raspberry Pi. In the current plates they have been marked as GND.

Normal GPIOs: these are configurable connections that can be programmed to create projects, as shown below.

• Special GPIO, within these are some pins intended for a UART interface, with TXD and RXD connections that are used for serial communications, such as connecting with an Arduino board. You can also see others like SDA, SCL, MOSI. MISO, SCLK. CEO, CE1, etc.

Use of GPIOs: The Raspberry Pi allows you to program your GPIO pins with flexibility, since you can use many tools with different programming languages (Python, Java, C,). or from the console using simple scripts and commands.

Usually, Raspberry Pi uses Linux distributions. Your operating system will treat all the elements, including the hardware, as a file. For example in Windows there are drives (C, D,.) Or hardware devices, but in a * nix everything is files, such as the hard disk (/ dev / sda), the DVD drive (/ dev / dvd), SD cards (/ dev / mmcblkO), etc.

Well, GPIO ports will also be treated as one more file, even if they are not in the 7dev directory ". Therefore, you can use the basic commands of the console to manage files. For example, if you want to control an LED, You could enter the console and type the following:

echo 17> / sys / class / gpio / export

With this line a file with the corresponding GPIO structure would be created so that it can be manipulated. Then it should be configured as input or output, depending on what you want You can also create scripts for Bash (or any other interpreter). For this, a text file is opened and the code is written so that the functions desired by the circuit element are performed. Then the file is saved in the form of "file_name sh" and to execute it simply access the directory through the console, typing the following for execution: ./nombr>e_fíchero.sh

Software operation

The software part of the device of this embodiment is a desktop application created through the Netbeans IDE 8 0.2 development environment, using Java programming language. The device analyzes the converted digital signal and compares it with all the stores in the database that is in the SD card, emitting by a graphic device (Computer, mobile or tablet) the data of the lighthouse or signal displayed, Name and location geographical

Claims

1. Headlight identification system (10) comprising

- light collection means (1) configured to detect a light signal formed by an alternate sequence of flashes and concealments emitted by the headlamp (10) over a period of time,

- processing means (2) coupled with the light collection means (1), said processing means (2) being configured to extract a frequency spectrum in the detected light signal, with the processing means (2) being further configured to determine by statistical analysis if there is correspondence between the spectrum extracted and any specific lighthouse in the database (3).

2. System according to claim 1, characterized in that the statistical analysis performed comprises a regression of the extracted frequency spectrum.

3. System according to claim 1 or 2, characterized in that it comprises an interface (4), coupled with processing means (2), configured to show the result of the query made in the database (3).

System according to any one of the preceding claims, characterized in that the light collection means (1) comprise a light sensor (11) and a sight glass (12) to direct the light sensor (11) towards the headlight ( 10).

5. System according to claim 4, characterized in that the light sensor (1 1) comprises a phototransistor.

6. System according to claim 4, characterized in that the light sensor (11) comprises a photodiode

System according to any one of the preceding claims, characterized in that the processing means (2) comprise a memory module (31) where the database (3) is stored.

System according to any one of the preceding claims, characterized in that the processing means (2) comprise a reduced-plate computer (21) with an anaiotic-dtgital cutter (22), a graphics card (23) and a plurality of connections to connect peripherals (4).