Abstract: A method of re-identifying a rough gemstone comprises providing a 3D model of a first rough gemstone; generating a series of virtual 2D silhouette images of the 3D model; processing each 2D image of the series of virtual 2D silhouette images to obtain a dataset associated with the first rough gemstone; and comparing the dataset of the first rough gemstone with an existing dataset of a rough gemstone. Where the dataset of the first rough gemstone and the existing dataset match each other, the method comprises re-identifying the first rough gemstone as the same rough gemstone from which the existing dataset was obtained.

Abstract: A method of determining an optimal target gemstone to be obtained from a rough gemstone comprises obtaining a first series of 2D images of the rough gemstone; providing a 3D model of a target gemstone to be obtained from the rough gemstone; and generating a second series of 2D images of the target gemstone from the 3D model thereof. The method then comprises comparing the first and second series of 2D images to determine an optimal transformation to be applied to the 3D model of the target gemstone.

Abstract: A method of re-identifying a rough gemstone comprises providing a 3D model of a first rough gemstone; generating a series of virtual 2D silhouette images of the 3D model; processing each 2D image of the series of virtual 2D silhouette images to obtain a dataset associated with the first rough gemstone; and comparing the dataset of the first rough gemstone with an existing dataset of a rough gemstone. Where the dataset of the first rough gemstone and the existing dataset match each other, the method comprises re-identifying the first rough gemstone as the same rough gemstone from which the existing dataset was obtained.

Abstract: A plurality of texture maps for a 3D computer model of an object are generated by processing images of the object, data defining the computer model, and data defining the relative positions and orientations of the images and computer model. A respective texture map is generated for the viewing position and direction of each image. Each texture map stores texture data for all parts of the computer model which are visible from the associated viewing position and direction and also texture data for all invisible parts of the computer model. Each texture map therefore stores texture data that can be used for rendering accurate images of the 3D computer model over a wide range of viewing positions and directions.

Abstract: View-dependent texture images and view-independent texture data for a 3D computer model are processed to compress each view-dependent texture image by subtracting the view-dependent data and view-independent data in a common 2D image space to generate a difference image, and compression encoding the difference image. The difference images, 3D computer model and view-independent texture data are transmitted to a second apparatus, where the difference data and view-independent texture data are recombined in a common 2D image space as part of the processing to render an image.

Abstract: A texture map for texturing the polygon mesh of a 3D computer model during rendering is generated by defining a respective triangle within the texture map for each triangle in the polygon mesh to create a texture coordinate map, and allocating image data to each defined triangle. To generate the texture coordinate map, the triangles are defined so that the area of each triangle is dependent upon the content of texture data to be stored therein. More particularly, triangles required to store texture data with a relatively large amount of detail have a relatively large area and triangles which are required to store texture data with relatively little detail have a relatively small area. In this way, more area is allocated for the storage of detailed texture data, thereby reducing the amount of information which is lost from the texture data during the creation of a texture map.

Abstract: A texture map (188) for texturing a polygon mesh 3D computer model (150) during rendering is generated by defining a respective triangle within the texture map for each triangle in the polygon mesh to create a texture coordinate map (170), and allocating image data to each defined triangle. To generate the texture coordinate map, the triangles in the polygon mesh are processed to generate a plurality of lists, each list identifying adjacent triangles in the mesh having shapes which can be packed into strips (173-179) of the texture coordinate map without significant shape distortion. The triangle lists are then packed into the texture coordinate map strips. No padding is defined between triangles in the same list, only between triangles of different lists. Image data is allocated to each triangle.

Abstract: There is disclosed an apparatus and method for combining three or more texture maps 200–208 together to generate a single, combined texture map 220. The texture maps are repeatedly combined together in pairs, with each pair generating a larger texture map for subsequent combination with another texture map, until only one texture map remains containing all of the original texture maps.

Abstract: This invention relates to a method for segmenting a pixellated image, comprising: (a) selecting at least one first region from a first reference image; (b) deriving from values of pixels of the at least one first region a first threshold such that a first predetermined proportion of the pixels have values on a first side of the first threshold; (c) forming a difference image as a difference between each pixel of the image and a corresponding pixel of an image of a non-occluded background; and (d) allocating each difference image pixel to at least one first type of region if the value of the difference image pixel is on the first side of the first threshold and the values of more than a first predetermined number of neighboring difference image pixels are on the first side of the first threshold. An apparatus for performing the foregoing method is disclosed.

Abstract: A texture map for texturing the polygon mesh of a 3D computer model during rendering is generated by defining a respective triangle within the texture map for each triangle in the polygon mesh to create a texture coordinate map, and allocating image data to each defined triangle. To generate the texture coordinate map, the triangles are defined so that the area of each triangle is dependent upon the content of texture data to be stored therein. More particularly, triangles required to store texture data with a relatively large amount of detail have a relatively large area and triangles which are required to store texture data with relatively little detail have a relatively small area. In this way, more area is allocated for the storage of detailed texture data, thereby reducing the amount of information which is lost from the texture data during the creation of a texture map.

Abstract: In an image processing apparatus 2, images of a subject object 210 and data defining the positions and orientations at which the images were recorded are processed to generate a three-dimensional computer model of the subject object 210. As part of the processing, image data relating to the subject object 210 is segmented from other image data in each input image to define the silhouette of the subject object in each image, and the silhouettes are processed to generate the three-dimensional computer model.

Abstract: There is disclosed an apparatus and method for combining three or more texture maps 200-208 together to generate a single, combined texture map 220. The texture maps are repeatedly combined together in pairs, with each pair generating a larger texture map for subsequent combination with another texture map, until only one texture map remains containing all of the original texture maps.

Abstract: A method is provided for detecting a human face in an image, such as a sequence of images supplied by a video camera. The method comprises locating in each image a candidate face region and analyzing the candidate face region for a first characteristic indicative of a facial feature. The locating step may comprise detecting uniformity saturated regions of predetermined shape in a reduced resolution version of the image. The analyzing step may comprise selecting a signal color component, forming a vertical integral projection profile and detecting an omega shape in the profile characteristic of an eye region of a face.

Abstract: In order to segment a pixellated image having foreground and background regions, a uniform visual characteristic, such as color, of the background is determined and, from this, a non-occluded background image is generated (55). The generated background image 60 and the image to be segmented 61 are compared, for example using a two-shot segmentation technique 62, and the pixels of the image are allocated as foreground or background pixels.

Abstract: A method of detecting a face-like region of a colour image, comprises reducing the resolution of the colour image by averaging the saturation to form a reduced resolution image and searching for a region of the reduced resolution image. The searched region has, in a predetermined shape, a substantially uniform saturation which is substantially different from the saturation of the portion of the reduced resolution image surrounding the predetermined shape.

Abstract: This invention relates to a method for segmenting a pixellated image, comprising: (a) selecting at least one first region from a first reference image; (b) deriving from values of pixels of the at least one first region a first threshold such that a first predetermined proportion of the pixels have values on a first side of the first threshold; (c) forming a difference image as a difference between each pixel of the image and a corresponding pixel of an image of a non-occluded background; and (d) allocating each difference image pixel to at least one first type of region if the value of the difference image pixel is on the first side of the first threshold and the values of more than a first predetermined number of neighboring difference image pixels are on the first side of the first threshold. An apparatus for performing the foregoing method is disclosed.

Abstract: An image tracking system which is configured to present a sequence of images, determine the position of a target image in a previously presented image, determine movement of the target image between the previously presented image and a subsequently presented image, and indicate the position of the target image in the subsequently presented image as the aforementioned determined position modified by the determined movement.