Abstract: For displaying a selected zone of images belonging to a sequence of video images, each in the form of a matrix of pixels, on a display unit, a signal is generated by a fixed large-field camera having a definition that is greater than that of the display unit. A TV user or an operator at a control station selects a zone of format corresponding to that of the display unit in a field of view of the camera. The pixels of a modified image having the size and definition of the display unit are generated by interpolation from the pixels in the selected zone of the image supplied by the large-field camera. A device for implementing the method includes a module for warping the selected zone by operations of interpolation and resampling.

Abstract: A television system is provided wherein a target region in successive video images is replaced by a matching pattern adapted to be inserted into the target region, using a virtual insertion unit located downstream of the originating site. The system includes television cameras for, when active, producing a sequence of video images of a scene, and a switcher or multiplexer for switching between camera images. A broadcast image processor located with the multiplexer in an outside broadcast van receives the video images and adds layers of graphics and special effects to the video images to produce a broadcast feed. The virtual insertion unit, which is located off-site from the van, receives the broadcast feed and modifies the video images of the broadcast feed by replacing the target region of these images with a replacement pattern adapted to be inserted into the target region.

Abstract: The method for replacing a target billboard in the frames of a video sequence is usable while the billboard undergoes changes of position in the scene. Assuming that the speed of change is constant, a global transformation from a reference image stored in memory is predicted. A modified image is generated by applying the transformation to the reference image and the prediction is adjusted by a global analysis of the image. Then the representation of the billboard is recovered from its color, and its boundaries are extracted by segmentation. The representation of the billboard is substituted by the representation of the model, after the model is warped by a transformation.

Abstract: A process modification of the content of a sequence of images which can be represented as a matrix of pixels. For that purpose a non-deformable target zone to be replaced in the scene is identified and is characterized, both in position and in dimensions, by reference to marks located close to each other and connected to the target zone in each image. The position with respect to the marks to be assigned to a model which can be superimposed on the target zone, stored in digital form, is determined. For each particular image, the geometrical transformation to be carried out on the model so that it corresponds to variations in the appearance of the target zone in all the successive images in the same shot is determined automatically using a correlation calculation based on the marks. Data suitable for enabling replacement of each current representation of the target are derived from the transformation and output. Apparatus for carrying out the method is also described.

Abstract: A method and an apparatus for substituting a representation of a target, identified by a set of points of interest stored in a memory, with a matching representation of a predetermined stored pattern in successive TV frames are described. The apparatus has a buffer for storing successive frames of a sequence, constituting a first in-first out memory having a length sufficient for storing all frames over a period of some seconds. Points of interest in each current frame are extracted and an attempt is made to find at least a subset of the extracted points of interest matching with a respective subset of the stored set. Global motion of the image between successive frames is evaluated and the location of the target in the frames following and preceding a frame in which the pattern is found is predicted. A target finder locates the target in the frames where it is found, based on the prediction.