说明：
Background:Video surveillance technologies started to be used by police authorities to secure public areas and fight crime appeared as early as 1960s, more than 40 years later, the original initiative to use video surveillance technologies to help secure cities remains. Surveillance cameras are getting smarter each day, with features such as Wide Dynamic Range (WDR), P-iris, and image stabilization, accompanied with high megapixel count, which are just some of the inventions that have been made in video imaging. Today, camera resolutions range from 1080P full HD to 4K Ultra HD resolution which aims to become the new evidentiary class standard for wide area surveillance. These features allow cameras to produce higher quality images with greater level of details, while also overc...