WO2014051417A1

WO2014051417A1 - High user accessibility traffic light system using optical manipulation and vlc technology

Info

Publication number: WO2014051417A1
Application number: PCT/MY2013/000206
Authority: WO
Inventors: Mohd Saiful Bahri IBRAHIM; Noor Aisyah MOHD ARKIB; Mazlaini Yahya; Mohd Kamarulzaman SALLEH; Syed Al Firdaus SYED AHMAD; Faizin ABU BAKAR
Original assignee: Telekom Malaysia Berhad
Priority date: 2012-09-27
Filing date: 2013-11-26
Publication date: 2014-04-03

Abstract

This invention embodies an advanced LED traffic light system using VLC technology light variables to distinguish colours and shapes. The system uses a polarizer, a protective screen filter, pixel's arrangement related to structural layout of light emission, representing an improvement from the prior art. These features assist in effectively communicating especially to colour blind users true and correct traffic/light signals in real time clearly distinguishing the different light signal variables. This effective and correct light communication system that generates the desired human, response from users is further enhanced by the use of transceiver that transmit text and audio messages, further enabling almost seamlessly and simultaneously speed and distance control, distance calculation between vehicles and to the traffic light position itself.

Description

High User Accessibility Traffic Light System Using Optical Manipulation and VLC Technology

FIELD OF THE INVENTION

The invention consists of an LED based smart traffic light system that would generate the desired human response in road/ vehicular users in particular in colour blind users that would enable them to distinguish much more easily and clearly the light signals emitting from the traffic light. Traffic flow and status awareness are therefore enhanced.

The invention consists of a system transmitting via visible light (VLC) technology, different light wave polarization that would indicate real time traffic light status informing users (including colour-blind users) of traffic condition.

BACKGROUND OF THE INVENTION

Every year globally, majority of fatal accidents happen at road intersections failing to adhere to traffic lights signal. Since traffic lights transmit visible light of red, yellow and green color to indicate status of road usage to motorist, a great majority of motorists after many counts of road safety campaigns still fail to heed to such road safety campaigns for awareness. Governments worldwide acknowledge the seriousness of. this situation which involves loss of lives that also cause casualties to surrounding properties. One of the critical factors that contributes to the above problem is color blindness among the motorists and pedestrians at the traffic light junctions. Most color blind persons cannot differentiate between red color and green color on normal light wave without polarization. By transmitting different light wave polarization indicating the red and green color of traffic light status, a color blind person may differentiate between red and green color.

Another contributing factor is the attitude of the motorists ignoring the traffic light indication road safety status. A mechanism to highlight or amplify road safety indication to motorists is therefore required.

Problems of compliance and human attitudes, being the above two critical factors lead to this invention. The main intention of this invention is to attempt to control as far as possible, both humans and vehicles to adhere to road safety measures.

The superiority of traffic light using LED (light emitting diode) is its high level brightness, long expectancy, high tolerances to humidity, low power consumption and minimal heat dissipation. The advantages of the LED lies in its ability to make use of the existing standard colors of Green, Yellow and Red. Recent researches also show the. other advantages flowing from the use of LED. These involve their applications to the communication network system for example communication between devices.

The technique is using LED and photo sensor as transmitting and receiving device respectively using visible light. This technique is called "Visible Light Communication". In order for the light to become visible to human eye the wavelength should be 380 - 750 nm. In most modern cities, the traffic light signals emit traffic flow light indications based on preset timer. But nowadays it also incorporates various network infrastructure such Xsdl, Fiber and Wireless Communication system. It enables each traffic light operations to be controlled by a central server depending on the traffic flow expectation or experience at certain designated locations. Therefore, the communication systems existing between traffic light system and central server have created a larger network that is called Wide Area Network (WAN) . Ramifications from the new usage of LEDs in the modern 21^st century world are found in car lamps and mobile phones backlighting, just to name a few simple everyday usage as examples.

The three colour Red, Green and Blue light emitting diode are used in the application of the traffic light and street light to support visible light communication. To produce the Yellow and White color the additive color theory from James Clark Maxwell are used. The Yellow color is the combination of Red and Green LED. The white color is the combination of the three fundamental color Red, Green and Blue. The wavelength of Red colour is 750 - 610 ran at frequency 480 - 505. THz. The wavelength of the Green colour is 570 - 500 nm at frequency 580 -530 THz. The wavelength of the Blue color is 500 - 450 nm at frequency 670 -600 THz. To avoid flickering to human retinal the frequency of the light source must be above 300 THz. The term THz refers to terahertz or one trillion cycles per second.

In case of the street light using the conventional street light, it is proposed that they be converted to LED light. The LED will arrange in sequence at very fine gap to form a panel for much improved illumination.

Using light is always not the best way for traffic sign indicators. This is because there are. some section in human communities comprising people afflicted with colour- blindness. The colour blindness is caused by the failure in the retina when the cells in the retina do not respond appropriately to the variation in wavelength of light that enable normal people to see an array of defined colours.

Solutions abound proposing that each colour variance of the LED light to be distinguished by shapes of colour illumination light on the traffic display (Figure 1) .

In terms of maintainability and costs the traffic light with three illumination panels does not promote the energy usage that support the green initiatives. Many governments in the world are already aware that colour blinded persons are not safe travelling under the current traffic system. Accidents have increased every year due to the inefficiency of the conventional traffic light systems.

DISCLOSURE OF INVENTION

A smart LED traffic light system emitting via VLC light variables in terms of shapes and colours. This system uses a polarizer, a protection screen filter and pixels arrangement of the lightings with alternate structural layout of the light emitting hardware.

The system involves the use of optical transceiver system that communicates via text and audio messages, effective safe distance warning to front vehicles, and number of front vehicles.

The transceiver that are installed in the user/ reader's vehicle will translate and interpret from the light signals emission the correct vehicular distance to the traffic light thus enabling control of vehicle speed.

The sequence of traffic light takes into account the three status of the traffic flow. "Stop" for vehicle to halt, ^xGo" for vehicle to be in motion and "Stand By" status is for a vehicle to slow down and eventually stop.

Every status has its own timing for the vehicle to adhere to accordingly. The transmission of the traffic light status to the receiver will be displayed on the dashboard of vehicle using visible light technology, VLC (Figure

17).

Colour blind motorist cannot distinguish between red and green. So red status is polarized perpendicularly and green status is polarized parallelly. The yellow status is not polarized because a colour blind person is able to comprehend yellow light signal (Figure 18) .

The "STOP" status received will turn ON the Red light on the device. The "GO" status turns ON the green light of the device and the "STAND BY" status received from the traffic light will trigger the yellow light on the device (Figure 19) . For the colour blind motorists to comprehend the traffic light status, translation status from colour to shape. "STOP" will have circle shape and red colour, "GO" is represent by triangle and green color and "STAND BY" is represent by square shape and yellow colour. The shapes are an aid for the colour blind and the colours are maintained for the non-colour blind drivers (Figure 20) .

For better understanding and easier comprehension of the traffic light status, text display and audio are added. "STOP" text is displayed when the red status is taking place, "GO" text is displayed to indicate the car to start accelerating or maintain accelerating and "STAND BY" text will appear on receiving device screen for yellow status (Figure 21) .

The traffic light will transmit signal using visible light communication, VLC to the receiver device in the vehicle. For both "STOP" and "STAND BY" status, the vehicle system will fully take over the vehicle control. The driver is no longer having control over the vehicle. The vehicle system will slow down the speed and come to a halt. However, the status "GO" will not be affected. The driver will still be in charge of the vehicle speed (Figure 22) The traffic light will transmit visible light communication, VLC to every passing vehicle in a timely manner. The traffic light will keep on sending VLC signal for every t seconds (Figure 23) . The receiver will capture the VLC signal from the traffic light. The time interval or delay from the first signal to the second signal is calculated. From the velocity formula, the receiver system will calculate the distance between the earlier ^' traffic light and the subsequent traffic light (Figure 24) using formula where distance equals to light velocity multiplied by the time delayed and that delayed equals to second pulse, subtracted by first pulse.

BRIEF DESCRIPTION OF THE DRAWINGS

The Figure 1 illustrates the sequence of the shapes illumination of the traffic light system. The motorist can distinguish the colour and the shape at the same time. This will aid a colour blind person/users to become alert to the traffic condition as they approach the traffic light system. This traffic light consisting of sequential dedicated shapes for each panel.

Figure 2 shows an example of the round red light

illumination .

Figure 3 shows an example of the triangular green light illumination.

Figure 4 shows an example of a rectangular yellow light illumination . Figure 1, Figure 2, Figure 3 and Figure 4 therefore sequentially show representations of the different graphical shapes and colours for the proposed traffic light system under the proposed invention, but which may be emitted through a single square display panel.

Figure 5 shows another example that the different "shapes and colours" of the traffic light system can also be designed with the text message to aid/ enhance mental understanding for the colour blind motorist who may be first time travelers who might not understand visual shapes and colour messages.

Figure 6 and Figure 7 show the vehicle equipped with optical receiver/transmitter for the visible light communication link. This is another aid for the travelling motorist approaching the traffic light as well as^■ assist in controlling further situation speed limit with sufficient time to brake before stopping sufficiently safely before any front vehicles. The front vehicle affixed with rear lamp optical transmitter will provide another communication link for the desired alertness of the barrier in front and relay the traffic condition in real time thus enhancing safety precautions.

Figure 8 shows a "STOP sign for traffic flow in- single congruous and parallel display of text and light panel illumination system. The optical receiver box inside the vehicle will have a display panel, which will display the shape, colour and message of the traffic condition as explain in the Figure 8, Figure 9 and Figure 10. The alternative sound message is also incorporated in the optical receiver device.

The system as shown in the Figure 11 will interpret the visible communication received to control the speed of the vehicle or stop the vehicle depending the programmed condition in the system. Figure 12 shows a simplified/amplified top screen lamination, showing a cross-section if panels comprising a protective screen, a lamination filter and a polarizer for angle viewing.

Figure 13 shows the attached display panel with the filter to allow only the selected or intended LED wavelength to pass through. This way, the intensity of light will be reduced.

Figure 14 shows the control angle of polarization. The effect after the polarization will help the colour blind motorist to detect the colour to its closest real colour, that to differentiate between red and green colour namely by using vertical lines to show red colour and both vertical and horizontal lines to show green colour.

Figure 15 shows examples of both shapes and colours for "STOP" (horizontal) .

Figure 16 shows examples of both shapes and colours for "GO" (vertical) .

As in the Figure 15 and Figure 16, the traffic light display could be further improved to have shapes and colours in different artistic illustrations to show the condition of the traffic status. By having the different display shape, colour and orientation the motorist can have more justification and recognition of the traffic status. The outer casing can be of different shapes and the display obj ect shapes can also be of different shapes .

DESCRIPTION OF THE PREFERRED E BODIEMENT

Figure 17 shows a VLC traffic light transmitting system. Figure 18 shows the polarization of the VLC traffic light. Figure 19 shows VLC traffic light receiving system that translate signals into green, yellow and red light display. Figure 20 shows how the VLC traffic light receiving system translates/ interprets from light viewable display shapes variable display. Figure 21 shows how the VLC traffic light receiving system translates/ interprets from light variable display to text display and audio transmission. Figure 22 shows how the traffic light receiving system translates/interprets from light variable display to effect vehicular speed control. Figure 23 shows how the VLC traffic light transmitting system upon initiation calculates distance between vehicle and traffic light. Figure 24 shows how the VLC traffic light receiving system upon initiation calculates distance between vehicle and traffic light.

Claims

An LED traffic light system applying visible light technology (VLC) variables distinguishing colours and shapes.

A system using optical polarization comprising both perpendicular/parallel polarizations to differentiate colour variables.

A system as in Claim 2, characterized in that a protective screen filter and pixels arrangement are applied.

A system as in Claim 2 and Claim 3 comprising alternate structural layout of light emission, transceiver transmitting text and audio messages enabling speed control, distance warning and calculation .