Patent ID: 7742656

Claim:
An observation system, comprising: a camera part for photographing an observation area; an operation part for receiving a user-set command for selecting a privacy zone within the observation area, the privacy zone requiring no observation; a control part for outputting a control signal for setting a mask area for masking the privacy zone according to the user-set command; an area set part for generating a plurality of vertexes forming the mask area according to the control signal; an image signal process part using a mosaic scheme to mask the privacy zone photographed by the camera part according to the mask area formed by the plurality of vertexes set by the area set part; and an output part for displaying the mask area masked by the image signal process part, wherein the area set part includes an area storage part for storing position data corresponding to the plurality of vertexes, the position data including a rotating angle of the camera part in a horizontal direction, a rotating angle of the camera part in a vertical direction, and a zoom value of the camera part, each of the position data corresponding to one of the plurality of vertexes, wherein the area set part includes a calculation part for calculating the mask area corresponding to a position and a size of the privacy zone when the privacy zone is photographed by the camera part, wherein the calculation part models the rotating angle in the horizontal direction, the rotating angle in the vertical direction, and the zoom value of the camera part into the position data corresponding to the plurality of vertexes on a hemispheric three-dimensional coordinate system, and wherein the calculation part converts the rotating angle in the horizontal direction, the rotating angle in the vertical direction, and the zoom value corresponding to the plurality of vertexes modeled on the hemispheric three-dimensional coordinate system into the position data with x and y coordinates on a two-dimensional coordinate system by using the following equations: x coordinate of each vertex= R*Z *cos( T )*sin( P−Pc ), and y coordinate of each vertex= R*Z *cos( Tc )− R*Z *cos( T )*cos( P−Pc ), in which R is a radius of a circle modeled on the two-dimensional coordinate system when the hemispheric three-dimensional coordinate system is projected to the two-dimensional coordinate system, Pc is the rotating angle in the horizontal direction corresponding to a center of a camera screen photographed by the camera part, Tc is the rotating angle in the vertical direction corresponding to the center of the camera screen photographed from the camera part, P is the rotating angle in the horizontal direction corresponding to the position having the x and y coordinates with respect to the Pc, T is the rotating angle in the vertical direction corresponding to the position having the x and y coordinates with respect to the Tc, and Z is the zoom value used in obtaining each vertex.