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| Breaking down Google's Street View |
| BS Reporter / Mumbai Jun 23, 2011, 00:10 IST |
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The police recently stopped Google from filming streets in Bangalore, citing security concerns. While Google says it would resolve the matter with the government, here’s the low-down on what its ‘Street View’ technology is, how it works and why it’s perceived as controversial.
To start, one can log on to Google Maps, which lets one explore places through 360-degree street-level imagery. Once in Google Maps, one can click and drag the ‘Pegman’ symbol to the place he wants to see. Roads with Street View imagery would appear with a blue border. For areas where Street View imagery is available, one can also zoom in to the spot. There are symbols that indicate options like rotate, walk, jump or exit.
When Google started Street View in 2007 as an experimental project, the company packed several computers into a sports utility vehicle, stuck cameras, lasers, and a GPS device on top, and drove around, collecting the first imagery. Since Street View was launched across five US cities in May 2007, the company expanded its 360-degree panoramic views to include locations on all the seven continents. The company later switched to a fleet of cars that allowed it to scale the project throughout the US and across the world. A rack of computers paved the way for one small computer per car. The system of cameras was later improved to capture higher-resolution panoramic views.
The latest car has 15 lenses to capture 360-degree photos. It also has motion sensors to track its position, a hard drive to store data, a small computer running the system and lasers to capture 3D data to determine distances within Street View. Areas not accessible by cars are filmed on bikes (mountain cycles) and even snowmobiles (for snowy terrains) and trolleys that fit through museum doorways and navigate around sculptures.
The Google team, on its website, says it pays close attention to the movement of the sun when planning the drive to ensure that shadows don’t obscure buildings. It also takes into account the weather and the temperature. The team needs to figure exactly where each image was taken in order to provide images of the right places when one uses Street View. For this, Google combines signals from several sensors on the car, including a global positioning system (GPS) device. The device usually shows the car’s exact location. However, sometimes factors like tall buildings block the signal. Data from the other sensors help the company fill in the gaps in such cases. The company can figure out the car’s route accurately by combining these signals.
Since Google knows exactly when and in which direction each picture was taken, it can then match each image to a specific location and even tilt and align the images with hilly terrain. To account for overlapping and help create a continuous 360-degree image, it ‘stitches’ the images together to create a continuous panorama.
When one navigates through a street, Google needs to determine which image to show. For this, it relies on signals the car collects, such as data from three lasers. How quickly the lasers reflect off surfaces tells it how far each building or object is and also enables it to construct 3D models. When one drags the mouse to an area in the distance, this 3D model determines the best panorama for that location.
On November 21 2008, Street View was added to the Maps application installed on the Apple iPhone, while on December 10 2008, it was added to the Maps application for S60 3rd Edition. Street View has also been added to the Windows Mobile and BlackBerry versions of Google Maps.
PRIVACY CONCERNS While technology is generally perceived as neutral, there are fears of Google knowing too much about us. On the internet, for instance, Google knows what sites one visits and what information one looks for. Now, it also has pictures of your street, your house, your cars and you. Google, on its part, says Street View images are not real time, and claims to apply cutting-edge face and licence plate blurring technology to help ensure that passers-by and cars in photographs cannot be identified.
The Canadian government recently asked Google to conduct a third-party audit after an investigation found Google a party to “serious violation of Canadians’ privacy rights” when it collected personal data such as email addresses and passwords, while photographing cities for its street-level mapping service. Till Google addresses these concerns, skeptics may view its technology differently.
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