Abstract: A digital video switching apparatus has a matrix switch which receives a plurality of input video signals and connects certain of the input video signals as outputs thereof. The input video signals can be externally supplied or can be internally generated by video processors within the switching apparatus. The connection of certain of the input video signals as outputs of the matrix switch is determined by a plurality of first switch signals. The first switch signals are generated by a selection circuit. The selection circuit receives a plurality of second switch signals and in response thereto generates the first switch signals. A plurality of user activatable switches generate the plurality of second switch signals. A plurality of displays is associated with the user activatable switches and displays the functions of the associated user switch.

Abstract: An electronic still store system stores and selectively outputs video image data defining a plurality of signal frame still images. The simultaneous display of up to 16 or more quarter sized images for scanning or sorting by an operator is facilitated by generating a quarter sized copy of each newly received image frame and storing both together on a conventional magnetic disk storage device as is typically employed in general purpose digital computing systems. The quarter sized image can then be recalled directly for a multi-image scan or sort function in which 16 reduced size images are displayed simultaneously without the time delays associated with the retrieval and size reduction of 16 full size images.

Abstract: A method and apparatus for the extraction of luminance information from an analog composite video signal. Non-luminance information in the video signal is 180.degree. out of phase between adjacent lines in adjacent fields of a video signal. Appropriately filtered adjacent fields are summed to cancel non-luminance information, leaving the desired luminance information. A field store is employed to allow the summing of adjacent fields by storing the present field to be summed with the next field of the video signal.

Abstract: A video transformation and filtering system generates for each source image data point a plurality of target image addresses indicating a displacement between a point at which the source image data point maps into the target image and each data point of the target image which is affected by the source image data point. By providing either sequentially or in parallel a separate processing for each target image data point that is affected by a current source image data point values for all of the target image data points can be generated from a single pass of the source image data points. By effectively providing the filtering in the domain of the target image instead of the source image a single filter function with a fixed number of points in the target image domain can be used to attain low pass filtering of the resulting target image irrespective of the degree of size compression of the video image.

Abstract: A font recall system stores a font of alpha-numeric characters in a video display format for selective insertion as a caption into a video image. Characters are stored on a video disk in digital pixel form with full dynamic resolution. Low pass filtering is employed to preserve high image quality and eliminate jagged edge aliasing at character boundaries. A first frame store receives selected characters from the video disk through an image size reducer to store the characters at selected display positions with a selected size to form a caption under control of a central processing unit. A keyer receives the caption video data from the first frame store as well as a background image to form a composite image, which is stored in the second frame store before being output as a continuous television video signal.

Abstract: Apparatus is disclosed for recording real time video information signals on magnetic media by sampling the information signal and converting the samples to a plurality of component digital data streams which are simultaneously recorded on separate surfaces of a single disc pack associated with a generally standard computer disc drive and for thereafter reproducing the plurality of digital data streams and recombining the same in a manner whereby the analog video information signal is reconstructed.

Abstract: A method and apparatus is disclosed for sampling an analog information signal having an associated carrier signal at precise phase positions with respect to said carrier, which involves sampling the information signal at predetermined phase positions relative to the carrier signal using a phase locked loop to maintain the sampling positions reasonably close to the predetermined phase positions and thereafter examining the discrete samples and generating an error signal that indicates any phase deviation and adjusting the sampling so that the error signal approaches zero and the samples are taken at said precise phase positions.

Abstract: Apparatus is disclosed for providing a square wave output signal for use in alternating the phase of a sampling clock signal on successive video lines of a video signal having a horizontal blanking interval at the beginning of each video line and a burst of cycles of chrominance subcarrier in each of said horizontal blanking intervals. The square wave output signal changes between first and second levels during alternate video lines, but the signal is always maintained at one of said levels during the occurrence of the bursts of cycles. The square wave signal controls the sampling clock signal generator so that the clock signal is of a first phase while the square wave signal is at the first level and of an opposite phase while the square wave signal is at the second level.

Abstract: A circuit for digitally encoding an analog television signal by sampling is provided. The circuit includes an analog-to-digital encoder which receives both the analog television signal and a sampling signal generated by the circuit. A clock signal generator is utilized providing a signal of a frequency equal to a first integral multiple of a desired sampling signal frequency and to a second integral multiple of the frequency of a synchronizing component of the television signal. The clock signal is phase-locked to that synchronizing component. A frequency divider is utilized to divide the frequency of the clock signal to provide a sampling signal of a desired frequency. The resulting sampling signal frequency is a non-integral rational multiple of the horizontal sync frequency. The frequency divider is set during each horizontal blanking period to a predetermined state to provide a sampling signal whose phase is the same at the beginning of each horizontal line of the analog television signal.