Patent ID: 8908081

Claim:
A system comprising: an optical filter having an adjustable opacity, the optical filter configured to, when the optical filter is disposed external to a camera housing of a video camera in an optical path of the video camera, vary an amount of light incident on an image sensor within the camera housing based at least on an electronic control signal; and a controller configured to generate the electronic control signal to vary the amount of the light incident on the image sensor over one or more image frame periods so that, during the one or more image frame periods, the opacity of the optical filter ranges from a first opacity level to a second opacity level and transitions through an intermediate opacity level, wherein the image sensor generates digital image data corresponding to the light incident on the image sensor over the one or more image frame periods, and wherein each image frame period of the one or more image frame periods has a duration of a first frame period corresponding to a first frame frequency, and the controller is configured to generate the electronic control signal so as to reduce the amount of the light incident on the image sensor to filter object motion having a frequency above one half of the first frame frequency.