Cameras can be divided into digital cameras and analog cameras. Digital camera can convert analog video signals generated by video acquisition equipment into digital signals, and then store them in computer. The video signal captured by the analog camera must be converted into digital mode by a special video capture card and com...[Detailed]

Sunglasses effect Sunglasses can block uncomfortable strong light and protect eyes from ultraviolet rays. All this is due to the metal powder filtering devices, which can "select" the light when it enters. Colored glasses can selectively absorb some of the bands that make up the suns rays because it uses very fine meta...[Detailed]

Modern civilization should really thank the American inventor Thomas Edison, who made the first white lamp with commercial value and brought light to mankind. However, Conrad Hubert deserves the same respect. He immigrated to the United States from Russia 100 years ago and invented the flashlight. Hubert came home from work, and...[Detailed]