Patent ID: 8098282

Claim:
A method for maintaining a privacy zone on a PTZ dome camera, said method comprising: locating an object to be masked on a camera display screen; superimposing a known rectangle for masking the object, said rectangle having four corners, each corner having pixel coordinates; translating each of the pixel coordinates into absolute angular coordinates; moving the camera and displaying a second camera view/screen; and if the object is on the second camera view/screen, translating each of the absolute angular coordinates into pixel coordinates, creating a newly formed rectangle having the translated pixel coordinates, and displaying the newly formed rectangle to mask the object wherein translating pixel coordinates into absolute angular coordinates comprises: δΦ=Tan inv(Tan V FOV *( Y 1 pixels/ V pixels)) δΘ=Tan inv(Tan H FOV *( X 1 pixels/ H pixels)) Θ 1 =Θ+Sin inv(Sin δΘ1/Cos Φ 1 ) and Φ 1 =Sin inv(Cos δΘ1 Sin(Φ+δΦ)), where H FOV =Horizontal Field of View V FOV =0.75*H FOV Vpixels=one half of the total number of vertical pixels Hpixels=one half of the total number of horizontal pixels Θ=azimuth angle of camera optic axis Φ=elevation angle of camera optic axis.