Electronic pan tilt zoom video camera with adaptive edge sharpening filter

#This invention relates generally to digital image processing and more particularly to a video camera with electronic pan, tilt and zoom and an adaptive edge sharpening filter.

#Video cameras that utilize exclusively solid state components rather than a mechanical movement of lenses and other optical components to pan, tilt, and zoom have numerous economic and functional advantages. An electronic pan, tilt, zoom (“EPTZ”) camera is small, fast, inexpensive, quiet, reliable, durable, easy to manufacture and easy to upgrade. Cameras with electronic EPTZ features can be used in, for example, cameras incorporated in set-top boxes for video conferencing, in surveillance cameras, camcorders and digital still cameras, among other applications.

#A digital EPTZ camera typically has three main independent components: an imager section, a sharpening filter, and a scaling circuit or “scaler”. The imager section typically includes a lens and a solid-state imager chip, such as a charge-coupled device (CCD) or a metal-oxide-on-silicon (MOS) type chip. The imager chip includes a plurality of photosensitive areas (that is, picture elements or “pixels”) arranged as a two-dimensional array which is scanned either interlaced or progressively, as is known in the art. Medium resolution imager chips which perform satisfactorily in video set-top applications have, for example, 640 pixels horizontally and 480 pixels vertically. The imager section preferably includes an analog-to digital section to provide digital serial video information. Imager sections and imager chips of this type are well known in the art.

#Other objects, features, and advantages of this invention will be described in the following detailed description with reference to preferred embodiments and the appended drawings, in which:

#FIG. 1 is an electrical block diagram of a video camera, a control computer, a scaler and a sharpening filter;

#FIG. 2 is an electrical block diagram of the scaler of FIG. 1;

#Referring first to FIGS. 1 and 9, there is illustrated a set-top box 10 which includes a camera 20 and incorporates the edge-adaptive sharpening filter (not shown in FIG. 9) of the invention. The camera 20 is preferably an EPTZ camera which provides electronic pan/tilt and zoom movement. The set-top box 10 can also incorporate an optical receiver 22 for receiving an external optical input, for example an IR signal from a remote control unit (not shown). The set-top box 10 can also be enabled to receive acoustical input through a built-in microphone 30, which is preferably directional. Remote microphone(s) (not shown) can also be used. The camera 20 can then automatically electronically pan, tilt and zoom to capture an image of, for example, a speaker in response to signals received through the directional microphone 30 or through the respective remote microphone(s). The set-top box 10 is preferably placed on top of a video monitor (not shown), with a video output signal from the set-top box 10 connected to the monitor, for example, via a cable (not shown).

#The video camera 20 can also be adapted for movement relative to the set-top box 10 using conventional mechanical actuators and/or motors (not shown). For example, the image could be coarsely panned and tilted by mechanically adjusting the orientation of the camera 20 relative to the set-top box 10, while a fine adjustment is performed electronically.

#In FIG. 1 there is illustrated in the form of a block diagram an embodiment of an EPTZ video camera 90 which includes a conventional imager section 100, a scaler 200, and a sharpening filter 300 which includes a sharpener 305 and an edge detector 320, all of which are in communication with a controller 400.