Image acquiring method and device

The invention discloses an image acquiring method and device. The method includes conducting color space conversion on an original image to obtain an initial image space, conducting foreground and background judgment on the initial image space to acquire an initial background image and an initial foreground image, conducting preset frame difference modification on the initial background image and the initial foreground image to obtain a background image and a foreground image. By means of the method and device, the acquired background image and foreground image are accurate, noise is small, the problems in the prior art of foreground error judgment or large background noise caused by the fact that the existing modeling method is slow in response and poor in sensitivity are solved, and the effects of accurately extracting the background image and the foreground image are achieved.