sensor

Self-driving cars require a variety of sensor systems in order for the cars to safely navigate roads and deal with the wide range of objects and conditions that they encounter. Two competing technologies that cars use to identify and locate objects on the scene are radar and LiDAR.

Radar uses transmitted radio waves to locate objects and LiDAR bounces laser beams off of objects. Each has its shortcomings. Radar has the problem that only a small fraction of the transmitted signals gets reflected back to the sensor, so that there is frequently insufficient data to fully characterize a scene. LiDAR has the problem that it is an optical system that does not work well in fog, dust, rain, or snow. It is also much more expensive than radar.

Researchers at the University of California San Diego have developed a new system that they describe as a LiDAR-like radar. The system consists of two radar sensors placed on a car’s hood and spaced about 1.5 meters apart. This configuration enables the system to see more space and detail than a single radar sensor.

Having two radars at different vantage points with an overlapping field of view creates a region of high-resolution with a high probability of detecting the objects that are present. The system also overcomes noise problems of conventional radar systems.

The researchers developed new algorithms that can fuse the information from two different radar sensors and produce a new image free of noise.

Self-driving cars have to combine detection technologies like radar with cameras and ultrasonic sensors. Duplicating the capabilities that people use in order to safely drive a car is a complex problem requiring a combination of multiple sensors and sophisticated software.

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Upgraded radar can enable self-driving cars to see clearly no matter the weather

Photo, posted January 2, 2014, courtesy of Bradley Gordon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A new sensor technology developed at Washington State University may eventually make expiration dates on milk a thing of the past. The sensor essentially can ‘smell’ whether milk is still good or has gone bad.

The sensor consists of chemically coated nanoparticles that react to the gas produced when bacterial growth on milk has taken place. When such bacteria grow, they produce a volatile compound that doesn’t smell good. So, when we open a carton of milk that has begun to spoil, our noses tell us so immediately.

The new sensor does not have to be in contact with the milk. It detects the volatile gases produced by the bacteria and it changes color. So far, it has only been demonstrated in a controlled lab environment.

To really be useful, the sensor would ideally be able to show how long the milk has before it spoils. Currently, it only shows whether it is ok or already spoiled. The researchers are working on the enhanced version of the sensor.

The researchers envision working with the dairy industry to integrate the sensor technology into a milk bottle’s plastic cap so that consumers can easily see how much longer the milk will stay fresh. Current expiration dates on milk are based on best-case scenarios. They are only accurate if the milk has been stored at the correct temperature the entire time. Unfortunately, milk can inadvertently spend time above refrigerator temperature during shipment or transportation home from the store. If the new sensor technology can be successfully developed, it will be possible to know for sure whether that bottle of milk is good.

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Sensor can detect spoiled milk before opening

Photo, posted March 8, 2011, courtesy of Roxanne Ready via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Improved Radar For Cars | Earth Wise

Self-driving cars require a variety of sensor systems in order for the cars to safely navigate roads and deal with the wide range of objects and conditions that they encounter. Two competing technologies that cars use to identify and locate objects on the scene are radar and LiDAR.

Web Links

A Sensor For Spoiled Milk

A new sensor technology developed at Washington State University may eventually make expiration dates on milk a thing of the past. The sensor essentially can ‘smell’ whether milk is still good or has gone bad.

Web Links