Thermal imaging on night time road safety

INTRODUCTION
  

Traffic  accedents  are  responsible  for  an  unacceptable  huge  number  of  casualities  all  over  the  world.To improve the situation from the technological point of view, vision based system for automotive safety represent one of the most promising development for driver assistance,but in bad weather condition,at night and usully every time the visibility is reduced the number of accedent increassing.while using this system the object was to dectect obstacles coming infront of the vachicle is dectected.many current traffic accedent happen when unpredictable changees occur in the vechicle vicinity.one of the main important task is to dectect those changes.looking at camera screen,by a camera mounted on a vachicle,it apperas that many changes are due to vachicle global motion while monor changes are rather reflacted to moving objects.

 

THERMAL IMAGING TECHNOLOGY

This is the  technology operates by capturing the upper pportion or infra read light spectrum,which is emitted as heat by object instead of simple reflected as light.Hotter bodies such as warm bodies,emitt more of this light than cooler object like trees or building.

    The amount of of energy in a light is refered to the wave length.In the basicis of infraead spectrum,the thermal infrared occupying the largest part of the infrared spectrum,with wave length ranging from 3microns to over 30 microns.

        At the hart of the thermal imaging system a silicon microbollometer,it is an infrared imaging sensor that convert infrared radiation in to images that are visible by a driver,even tiny temperature difference can be easily dectected,resulting in excellent night vision perfomance at a distance more than three times longer than light beam headlight.

SILICON MICROBOLOMETER

Silicon microbolometer is the key component of the thermal imaging system.Microbolometer is a specific type of bolometer used as ‘detector in a thermal camera in thermal imaging technology systems’.IR radiation with wave length in between 7.5 -14µm strikes the detector material, heating it and thus changing its electrical resistance. This resistance changes is measured and processed in to temperatures which can be used to create an image and it do not require cooling.

A micro bolometer is an uncooled thermal sensor these method of cooling made of early images expensive to operate and unwieldy to move.

      A micro bolometer   consists of an array of pixels being made up of several layers. In this si and readout integrated circuit is the absorbing material. Electrical contants are deposited and then selective and etached away. A reflector is created beneath the IR absorbing material.

The quality of the images created from micro bolometer has continued to increase it 320×240 pixels from 1024×768 pixels. There has also been a decrease in the individual pixel dimensions. The pixel size is typically 45µm in older devices and has been decreased to 17µm in current device.As the pixels per unit area is increased.

    The detecting materials have the properties of the device to convert the incoming radiation to electrical signals, and the temperature coefficient of resistance is negative low resistance.

The specification of infrared imaging sensor,

·        High sensitivity         ( <50mk thermal resolution )

·        Fast response time  (> 60hz frame rate )

·        Small pixel size         ( 17µm with low cost )

·        Multiple resolution  ( VGA/16,VGA/4,VGA,XGA )

TECHNOLOGY ON NIGHT TIME ROAD SAFETY

Thermal imaging technology can be used to  create image from the heat is naturally radiated by object such as pedistarians,cyclists,animal,road side object ,since these object may not otherwise be visible beacause of darkness.As a result of the thermal imaging systam can reduce the potential faital collision in bad weather conditions.

The key components working and importents are mention above.So we want to place an IR camera and a thermal sensing unit attached to the ouu using driver assistance and the thermal imaging technology help to dectect the object on road during night time and monitoring the object in a screen using GPS system’s help.

Thermal imaging cameras are excellent tools for night vision. They detect thermal radiation and do not need a source of illumination. They produce an image in the darkest of night and can be see through light, fogy, rain, and smoke. Thermal imaging cameras are widely used to complement new or exiting security network.

      Acording to most accident statics, more than twice as many accidents and casualities occur dark rather than during day light hours, the part of this is due to sleeping or impaired drivers, but another part is also due to the reduced visibility that occur after the sun goes to down.Any technology that improves the night driving visibile, therefor should improve driving safety.Night useful spectral range techniques can be sensed the radiation that is invisible to human observer.

Human can’t detect the spot of object on night time due to high light directly entering to the eyes.

    The sensor system recognizes the living creators by heat radiation. To be able to warn the driver of a hazard in time, a recognizing distance about 100m must be ensured, regardless of weather conditions. To achieve this, the light making system must have a sufficient sensor system. All the currently available night vision system based on infrared require as an input 100w for illuminating the surrounding s in front of the vehicles. This corresponding to an additional co₂ emission of 3g/km which is not acceptable in the present circumstances. So the silicon micro bolometer technology amorphous silicon micro bolometer have been developed using this technology with low cost and high yield. In addition, because they are high sensitive to infrared radiation, they are ideal for use in thermal imaging camera in thermal imaging system.

        So it is not ideal out of the box, but as actually proven it self useful hasn’t Brocken down on the system yet and it posted outside with weather protecting capacity. Both the thermal imager and GPS were integrated in to the Beemer’s electrical system by using a secondary fuse box also incorporated with an ON/OFF switch for the camera to be able to turn the camera off when no requires.

CONCLUSION

Most driving decision are based on what we can see it,we can avoid it.If we can’t see it,there is a chance we might hit it.This including warm bobied objects in the road ahead or anything the might be behind a vechicle when it is breaking up.

     Assumining that the driver n attention ,forword visibility is usully adequate during day light hour provided it is not raining or foggy.During night time on the other hand,can be challenging especily for people who have poor night vision,head light provides additional illumination for seeing the road ahead ,but conventional head lights have some serious illumination.So that thermal imaging technology is more sutable for the during night time driving.The infrared radiation and GPS system detected the objects in road and show in screen with a minimum of safety alarm to the driver to take appropriate action.Then it is clear that the use of thermal imaging technology help to reduce night time road accident and help outsisers from danger and protect the driver from major night time accident.

Displaying the images of the thermal imaging camera for this purpose the thought of GPS and second screen to look at seemed logical and redundant. Not only would it pay more than find a GPS with a video input. The screen is 4:8 diagonal screens which produces and provides usability in both GPS and video modes. The display is designed for mounting out side a vehicle and input to the screen.

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