WO2012159633A1

WO2012159633A1 - Sensor unit for intelligent street lamp and application

Info

Publication number: WO2012159633A1
Application number: PCT/DK2012/000031
Authority: WO
Inventors: Steen Rasmussen
Original assignee: S-Light A/S
Priority date: 2011-05-23
Filing date: 2012-03-28
Publication date: 2012-11-29

Abstract

The invention includes a sensor unit (5) for intelligent streetlights where the sensor unit (5) contains one or more of the following components: - Optical sensor (8) - Light emitter (9) - Meteorological sensor (10) - Acoustic sensor (11 ) - Calculation unit (13) The invention also includes application of sensor unit (5) for calculation by application of calculation unit (13) of data from optical sensor (8), meteorological sensor (10) or acoustic sensor (11) and forwarding (12) of calculated values to one or more intelligent lamps. With the invention it becomes possible to optimise the street lighting such that the light emission automatically is adjusted to the traffic, the weather and the light conditions with a consequently maximised traffic safety and minimised energy consumption.

Description

Sensor unit for intelligent street lamp and application.

The invention relates to a sensor unit for intelligent street lamps. Moreover, the invention relates to application of sensor unit.

The light in the cities has been a determinant for how the city has been perceived. The light has been what has separated the civilization from nature. In the Antiquity, there was for example talk about the lighthouse in Alexandria and today about the metropolises, which can be seen from space. The lighting has been an important part of the identity of the cities, and has been used by the cities to show the surroundings their capabilities. For example, Paris was one of the first cities to put up electrical lamps and is today known as the city of light. The light of the city consists a large part of the experience for those who go in the city. The light in the cities increase the traffic safety and creates safety for those who go in the streets. Light is used behaviour regulating consisting of signal lights, warning lights and marking lights. Other light has decorative purposes or emphasises monuments or architecture in the city.

The lighting must be pleasant. Pleasant light is mostly compared, at least in the North, with warm light, as is known from a filament bulb. Warm and cold light is defined from the colour temperature. Warm light has a large content of light with a long wavelength, red light, while cold light has a higher content of light with short wavelength - blue-violet light.

Good light must have a good representation of colours. Good representation of colours means that an illuminated object has the same colour, as if it was viewed in sunlight. Good representation of colours is significant for the traffic safety and the feeling of safety. The ability of the lighting for representation of colours is closely connected to how large a part of the colour spectrum the light contains. Sunlight contains the whole visible spectrum; while the lighting can lack one or more colours, and therefore does not emphasise these colours on the lighted. The temperature of the colour and representation of colours are in the following termed as one as the light colour.

Good street lighting provides a uniform light on the street where the intensity along the road does not vary in a bothersome way. The light is not to act blinding and the lamps are only to light up that, which is desired, lighted.

The users of the street lighting are pedestrians, cyclists and motor vehicles. The motor vehicles are mopeds, motorcycles, cars and trucks. Different users have different needs. The traffic density and the composition of the traffic varies depending on the traffic distance and the time.

Intelligent street lighting interacts with the users, the road users, and takes consideration of the weather conditions' influence on the light and the switch between daylight and nightly darkness. Also, intelligent street lighting minimises those resources, the energy, which is consumed for the light in the cities. Intelligent street lighting registers the type, composition and density of the traffic and adapts the lighting. If there is heavy and fast traffic, there is for example a need for light, where road users and road can be seen from a long distance.

Lighting designed for pedestrians and cyclists must emphasise particulars and surface structures in short distance. The daylight increases at dawn and decreases at dusk. The daylight is affected by the cloud cover and rain. Intelligent street lighting compensates when the daylight is insufficient for lighting the road. Fog, rain or snow have influence on spreading and dimming of the light from the lamps.

Intelligent street lighting counteracts the unfortunate effects of fog and rain on the light on the road. Also, consideration is being taken to the effects of wet reflecting surfaces or snow-covered surfaces on the effect of the lamp's light.

The known lamps for street lighting consist of a lamp casing, a light source and optics. The lamp casing protects against the effect of the surroundings on the lamp, rain and wind, and is attachment for mast or fixture. The optics distributes the light from the light source. The classical light sources for street lighting use mercury lamps, high-pressure sodium lamps, metal halogen lamps or strip lights. Most recently, light sources have come, which are based on high intensity light emitting diodes. The illuminant consists of the very light source for example the strip light or the LED and an electrical circuit, which converts the voltage from the supply network to a suiting supply of the light source.

Table 1: Comparison of different light sources' characteristic light efficiency and service life.

From table 1 appears that high intensity LEDs as light source combines long service life with good energy efficiency. Also, high intensity LEDs makes it possible to control the light intensity quickly and possibility to control the light colour. Traffic roads with different needs for quality of the lighting are divided in classes. For example, divisions are motorways, roads with passing through heavy traffic, suburban streets, walkways and so forth. For each class of roads, minimum requirements are defined for the light intensity, light colour and lighting times. A definition of lighting levels for different classes of traffic roads helps to reduce the energy consumption since fewer roads are lighted exceeding the need.

Further limitation in the energy consumption is achieved by time control of the lighting time and turn off time in relation to sunrise and sunset. Alternatively, this adaptation to the season can be achieved by letting a measurement of the intensity of the daylight turn on and turn off the lighting - a dusk relay. It is also used for reducing the lighting in the quiet night hours either by dimming or by turning off for example every other lamp.

It has been found, however ttoat there are some drawbacks connected to this known technique, which are to be explained in the following.

The known systems for street lighting adapt to the appearance and going away of the daylight by turning off at dawn and turning on when it gets dark. From safety reasons, it is however desirable for example to turn on the lighting in connection to a local shower - the known systems for street lighting cannot do this. The potential possibility to supplement the daylight with lighting at dusk and dawn, such that the light colour becomes optimal with regard to traffic safety or feeling of safety cannot be utilised.

At night, the known systems for street lighting cannot adapt the lighting to changing and local weather conditions, neither concerning the light intensity or light colour. A nightly rain shower for example makes the road wet, the light's reflection from the road is increased and it could have been appropriate to adjust the lighting until the road is again dry. This lacking ability to optimise the quality of the lighting is in principle not based on the light source's technology; but in the system's lacking ability to observe the daylight's changing character and the local weather. Adaptation to the type of traffic and intensity occurs in the known systems for street lighting according to a presumed prior knowledge about the traffic. A specific class of roads is presupposed to always have the same traffic composition and periods with little traffic are presumed known in advance. When the current traffic on a given time deviates from the presupposed table, the road is over lighted or under lighted. Over lighting occurs when there is less traffic than presumed and results in unnecessarily large energy consumption. Under lighting occurs when there is more traffic than presumed and worsens the traffic safety. If the type of traffic in a period deviates from the presupposed, lighting will not be optimum for the current traffic on the road.

It is therefore an object of the invention to improve the known technique and application for street lighting. The object of the invention is achieved by a sensor unit of the in the introduction to claim 1 stated type, which is characterized in that the sensor unit contains one or more of the following components:

- Optical sensor

- Light emitter

- Meteorological sensor

- Acoustic sensor

- Calculation unit

In this way, it thus becomes possible via the sensor unit to collect and calculate data for use in the street lighting such that the light emission automatically is adapted to the traffic, the weather and the light conditions with thereof resulting maximised traffic safety and minimised energy consumption.

As mentioned, the invention also relates to application of sensor unit for calculation, by application of calculation unit, of data from optical sensor, meteorological sensor or acoustic sensor and forwarding of calculated values to one or more intelligent lamps.

It hereby becomes possible to use the sensor unit for optimisation of street lighting as stated above.

The invention will now be explained more fully with reference to the drawing, in which: Fig. 1 shows a block diagram concerning a lamp's main constituents.

In fig. 1 is with 1 shown an intelligent lamp, which together with similar lamps 1 can form a system for street lighting. Each lamp 1 automatically adapts the lighting to the daylight, the weather and the traffic and coordinates the light emission with the additional lamps 1 along an arterial road. The intelligent lamp 1 consists, as the known lamps for street lighting, of lamp casing 2, light source 3 and optics 4. Besides this, all the intelligent lamps 1 have an integrated sensor unit 5 dedicated to intelligent street lighting, a calculation unit 6, which controls the lamp's light emission in relation to daylight, the weather and traffic conditions, and a communication unit 7, which makes it possible for the lamp 1 to exchange information with other lamps 1.

The sensor unit 5 detects optical, acoustic and meteorological data from the lamp's 1 surroundings. The sensor unit 5 processes these data and signals are forwarded to the lamp's 1 calculation unit 6. These signals describe the traffic or changes in daylight or the weather.

The communication unit 7 receives information about the traffic from other lamps and forwards information about the traffic to other lamps 1. Information from several lamps 1 is sum up by the communication unit 7 to signals about occurrences in the traffic. These signals are forwarded to the lamp's calculation unit 6. The calculation unit 6 uses signals from the sensor unit 5 and the communication unit 7 to calculate and control the light source 3 such that the lamp's 1 light emission is optimised according to the current conditions.

Table 2 contains examples of the intelligent lamp's 1 function dependent on different signals from the lamp's sensor unit 5 and table 3 contains examples of the intelligent lamp's 1 function dependent on different signals from the lamp's communication unit 7.

Fig. 2 shows a sensor unit 5 for placement in or by an intelligent street lamp 1 . The sensor unit 5 is dedicated to intelligent street lighting and gives the lamp 1 possibility to register daylight, weather and traffic conditions.

The sensor unit 5 detects optical, acoustic and meteorological data from the lamp's surroundings. These data are processed by the calculation unit 13 and converted to observations about the traffic or changes in daylight or weather.

Optical sensor (8):

The optical sensor 8 consists of optics, which focuses on a picture on a light sensitive element, which digitises the picture. Both visible light and, for the human eye, invisible light is registered, for example infrared light or light in the ultraviolet part of the spectrum. The optical sensor 8 can be a digital camera, which has consideration for in field of vision, resolution, sensitivity and speed is optimised for integrated application in a street lamp.

Light emitter (9):

The surroundings can be lighted. Hereby, important parts of the picture are emphasised. The light emitter 9 sends out light, which is not perceived by the human eye, either since the light is so short-lived that it is not seen or since it lies outside the visible spectrum.

Acoustic sensor (11):

The acoustic sensor 1 1 consists of a microphone and a part, which digitises the sound. Frequencies are being registered, which can be detected by the human ear, but also infrared and sound with frequencies above the audible area.

Meteorological sensor (10):

This sensor consists of several elements, which register temperature, rain, wind and other meteorological conditions. A digitisation of data is being carried out from these elements.

Calculation unit (13):

The calculation unit 13 processes and analyses the signals from the optical 8, the acoustic 1 1 and the meteorological sensor 10.

Data from the optical sensor 8 is processes through image editing algorithms, which finds active objects (road users) in the picture. The objects are identified for example by recognition of silhouette, heat- or light emission. Image editing algorithms are also used, which analyse the steady part of the picture - the background. Hereby, for example cloud cover, dawn, dusk and the light intensity on the road are observed. The calculation unit 13 can activate the light emitter 9 in order to emphasise parts of the picture.

Data from the acoustic sensor 1 1 is processed through sound processing algorithms. For example vibrations (infrasound), engine sound and tire noise or sirens from emergency vehicles are identified. There are similar algorithms, which process data from the meteorological sensor 10. For example, it can be analysed if rain is falling and the rain's type and density.

Based on the result from those analyses, which are carried out by the different processing algorithms, a conclusion is drawn about a particular observation. An observation is often based on data from several sensors. For example, a lorry can be observed with a combination of silhouette recognition with registration of engine sound. Another example is that rain is observed by the meteorological sensor concurrently with the road getting wet, and therefore changes look.

Observations from the sensor unit (5):

Based on the observations from the sensor unit 5, the intelligent street lamp 1 can optimise the light emission according to the current conditions. Table 2 contains examples on the intelligent street lamp's function dependent on different observations from the lamp's sensor unit.

Table 1

Signals from The lamp's patterns of operation.

sensor unit

1 Dawn The light intensity from the daylight is so high that the lamp cannot influence the light quality:

The lamp is turned off

The lamp can influence the light quality:

The lamp remains turned on. The light deviation is adjusted such that the desired lighting intensity on the road is achieved.

The light colour is adjusted to the desired.

2 Dusk The light intensity from the daylight is so high that the lamp cannot influence the light quality:

The lamp remains turned off.

The lamp can influence the light quality:

The lamp is turned on. The light emission is adjusted such that the desired lighting intensity on the road is achieved.

The light colour is adjusted to the desired.

3 The sun breaks The light intensity from the daylight is so high out that the lamp cannot influence the light quality:

The lamp is turned off.

The lamp can influence the light quality:

The light emission is adjusted such that the desired lighting intensity on the road is achieved.

The light colour is adjusted to the desired.

4 Cloud for the sun The light intensity from the daylight is so high that the lamp cannot influence the light quality:

The lamp remains turned off.

The lamp can influence the light quality:

The light colour is adjusted to the desired. Signals from The lamp's patterns of operation.

sensor unit

Rain The lamp changes the light deviation - intensity and light colour - in order to compensate for the reflections and the deflections, which are caused by the water drops in the air.

Snow The lamp changes the light emission - intensity and light colour - to compensate for the reflections and the deflections, which are caused by the snowflakes in the air.

Wet road The lamp changes the light emission - intensity and light colour - to compensate for the reflections from the wet road.

Snow covered The lamp changes the light emission - intensity road and light colour - to compensate for the reflections from the snow covered road.

Fog The lamp changes the light emission - intensity and light colour - to compensate for the reflections and the deflections, which are caused by the water drops / the ice crystals in the air.

One pedestrian The light emission is adjusted such that intensity and light colour provides good conditions for the walking traffic.

If the pedestrian's occurrence in advance is announced from a neighbour lamp, the current walking speed and direction of movement is found.

Announces the pedestrian's coming and walking speed to the neighbouring lamps in the direction of movement (via the communication unit)

One cyclist The light emission is adjusted such that intensity and light colour provides good conditions for the cycling traffic.

If the cyclist's appearance is announced in advanced from a neighbour lamp, the current speed and direction of movement is found.

Announces the cyclist's appearance and speed to the neighbour lamp in the direction of movement (via the communication unit) Signals from The lamp's patterns of operation.

sensor unit

12 Only weak The light emission is adjusted such that intensity pedestrians and light colour provide good conditions for the walking and cycling traffic.

13 One motor The light emission is adjusted such that intensity vehicle and light colour provide good conditions for the motorised traffic.

If the motorist's arrival in advance is announced from a neighbour lamp, the current speed and direction of movement is found.

Announces the motorist's arrival and speed to the neighbour lamps in the direction of movement (via the communication unit)

14 Only strong road The light emission is adjusted such that intensity users and light colour provide good conditions for the motorised traffic.

15 Only road users The light emission is adjusted such that the light with own lighting. from the road users' own lights are used and the light quality is still as desired.

16 Mixed traffic The light emission is adjusted such that intensity and light colour provide the strong road users the best possible preconditions to see the presence of the weak road users and behaviour.

17 No road users The lighting is dimmed or turned off. The dimmed level is dependent on how much traffic normally occurs on the current time.

Table 2

Signals from The lamp's pattern of functioning.

communication

unit

18 One pedestrian The light intensity is increased such that the road is observed by ahead of the expected road user is lighted neighbour lamp

The light emission is adjusted such that the intensity and light colour provide good conditions for the walking traffic 19 One cyclist is The light intensity is increased such that the road observed by ahead of the expected road user is lighted

neighbour lamp

The light emission is adjusted such that intensity and light colour provide good conditions for the cycling traffic

20 One motor The light intensity is increased such that the road

vehicle is ahead of the expected road user is lighted

observed by

neighbour lamp The light emission is adjusted such that intensity

and light colour provide good conditions for the motorised traffic.

In relation to the known systems for street lighting, street lighting based on intelligent lamps 1 provides the following advantages:

• More energy efficient street lighting since the road is not over lighted in periods with little traffic.

• Increased traffic safety since the road is always lighted, so the needs of the current road users for lighting are taken into account.

· Increased traffic safety since the daylight is supplemented with lighting when the weather makes the daylight insufficient.

• Increased feeling of safety since individual pedestrians or cyclists in periods with otherwise little traffic are considered with sufficient lighting.

· Increased service life for the light sources since these are turned off or turned on when it does not reduce the traffic safety.

These points can be summed up to; the users' experience of the light in the city is improved and the demands of the users for the light's quality is achieved to a higher degree. The intelligent lamp 1 can use those possibilities and advantages, which the application of high intensity LEDs as light source for street lighting provides.

Claims

Patent claims

1. Sensor unit (5) for intelligent street lamps characterized in that the sensor unit (5) contains one or more of the following components:

- Optical sensor (8)

- Light emitter (9)

- Meteorological sensor (10)

- Acoustic sensor (1 1 )

- Calculation unit (13)

2. Application of sensor unit (5) according to claim 1 for calculation, by application of calculation unit (13), of data from optical sensor (8), meteorological sensor (10) or acoustic sensor (1 1 ) and forwarding (12) of calculated values to one or more intelligent lamps.