2011年10月21日 星期五

IR cameras see-through divers from the Beijing Olympic Games

15 video clips are widely spreading over the Internet, of 10 to 20 minutes long each, capturing divers from the Beijing Olympic Games practicing in “Water Cube”. What makes it special is that it sees-through the divers’ swimsuits, resulting in a picture of the decades of both male and female athletes hang around naked.

Very few is known about who was capturing the video, and how. Communities from the Internet reproves the act, stating that it is an infringement on privacy, and urging the police to investigate, and to stop these things from happen again. But before the police does their jobs, how can the others protect themselves? We gonna be familiar with how the see-through thing works.

It is infra-red
You likely have heard about infra-red. In fact, it is a mature technology that is widely used in our daily life. Your TV remote control probably has an infra-red light bulb in front of it. It sends signals to the TV receiver, to tell the TV to turn on/off, or to change channels. “But I can’t see the light?” you said. Well, it is because infra-red is invisible. To be precise, let’s rephrase it to: our eyes cannot see infra-red.

The trick here is that, while human eyes cannot see infra-red, our digital cameras can!

In order to make see-through works, one must separate the visible light entering the camera lens from infra-red light. One common way to do it is to use IR-through filters. A better way is to use computer software to filter out the visible light from the raw data collected by the camera's CCD; the advantage of using software is that it can do an optimal cut, resulting in much clearer pictures. The down-side of the software approach is that you cannot reprogram a digital camera; it only works on customized (programable) devices.

Does it work with web cams/my phone’s camera?
Yes. And in fact, they do better. It is a common misconception that expensive cameras give better IR images. They do not. Because of the smaller form factors, web cams and phone cameras have thinner IR-cut filters and let go more infra-red. Web cams may be limited by their resolutions, but phone cameras do a great job!

Update: Eventually, someone has implemented the idea in a iPhone app; anyone interested can try it yourself:


あなたは可能性が赤外線について聞いたことがある。実際に、それは広く日常生活で使用されている成熟した技術です。お使いのテレビのリモコンは、おそらくそれの前に赤外線電球を持っています。それは、オン/オフにする、またはチャンネルを変更するには、テレビを伝えるために、テレビの受信機に信号を送ります。 "しかし、私は光を見ることができないか"と言った。赤外線は目に見えないものなので、それはです。正確に言うと、それをする言い換えるてみましょう:私たちの目は赤外線見ることはできません。



はい。そして実際に、彼らはもっと良い。それは、高価なカメラは、より良いIRのイメージを与えることは容易によくある間違いです。彼らはしないでください。ために小型のフォームファクタで、Webカメラや携帯電話のカメラは薄くIRカットフィルターを持ち、より多くの赤外線手放す。 Webカメラは、その決議によって限定されるものではなく、携帯電話のカメラは素晴らしい仕事をすることができます!

Update: Eventually, someone has implemented the idea in an iPhone app; anyone interested can try it yourself:

Japanese Team Wins World Solar Challenge

To say the 2011 Veolia World Solar Challenge — a 1,900 mile race for solar powered cars across the center of Australia from Darwin in the north to Adelaide in the south — has been an explosive event is not only true, but something of an understatement.
The winner, Team Tokai from Japan, crossed the finish line after a 32 hour, 45 minute journey in their car Tokai Challenger 2. They were followed by a close second place Nuon team from the Netherlands, who drew a time of 33.5 hours.

image via World Solar Challenge
Even for the winners this race, from the beginning, has been a grueling one. On Sunday October 16, 42 teams from 21 countries took to the starting line in Darwin. Everyone must have known how difficult this race was going to be. After all, the Australian outback is a brutal, unforgiving landscape and 1,900 miles is a long way. But the race rules haven’t made the job any easier. The event is conducted in a single stage from Darwin to Adelaide and all teams must be fully self-sufficient. During the journey there are seven mandatory check points where observers are changed and team managers may update themselves with the latest information on the weather and their own position in the field. Here teams may perform the most basic of maintenance only – checking and maintenance of tire pressure and cleaning of debris from the vehicle.
As the race revved up toward its conclusion, no one could have imagined how tough it was going to be. On day two, according to race organizers, the three leading teams, Tokai, Nuon and the University of Michigan, were forced to call stop at Wauchope after police closed the route in both directions due to arson fires raging in the desert and burning across the highway.
Day three was just another day in the outback. The sun beat down as usual, but wind gusts kicked up dust devils and made handling the low-slung, winged vehicles a chore to pilot. As if that wasn’t enough, the vehicle of Team Philippines began to overheat just after its team had called it a day. The battery pack generated enough heat to set the car on fire. Fortunately, the fire was extinguished and the crew was able to get the vehicle moving again.