Abstract: Depth information is determined for elements in a light field image, thus allowing for rapid display of visualization tools to communicate such depth information to a user. Depth of strong edges within the light field image is analyzed, providing improved reliability of depth information while reducing or minimizing the amount of computation involved in generating such information. Strong edges can be identified and analyzed by generating epipolar images, or EPIs, from the light field image. Local gradients are determined for pixels in the EPIs. The magnitude of the local gradient is used to determine a confidence as to whether depth can be reliably estimated from the gradient. The orientation of the gradient is used to determine the depth of a corresponding element of the scene. Suitable output is then generated based on the determined depths, for example to provide information and feedback to aid a user in capturing light-field images.

Abstract: A light-field display is provided that renders a light-field at one or more viewing apertures through a microlens array. The light-field display includes a display such as a monitor that is positioned behind the microlens array. The monitor and the microlens array are positioned so that light emitted from a pixel of the monitor reaches the one or more apertures through at most one microlens from the microlens array. For each microlens in the microlens array, the pixels of the monitor visible through that microlens of the microlens array at the one or more apertures is determined, and a light-field is then rendered at each of the one or more viewing apertures by rendering the determined pixels corresponding to each microlens.

Abstract: A light-field display is provided that renders a light-field at one or more viewing apertures through a microlens array. The light-field display includes a display such as a monitor that is positioned behind the microlens array. The monitor and the microlens array are positioned so that light emitted from a pixel of the monitor reaches the one or more apertures through at most one microlens from the microlens array. For each microlens in the microlens array, the pixels of the monitor visible through that microlens of the microlens array at the one or more apertures is determined, and a light-field is then rendered at each of the one or more viewing apertures by rendering the determined pixels corresponding to each microlens.

Abstract: A method and apparatus for multisample dithering is provided. For the method of the present invention, a graphics pipeline generates a series of b-bit color sample values for each pixel that is to be processed. Each color sample is defined to include one or more omitted values. The omitted values allow the color sample values to have a range that exceeds the range that would normally be associated with the b-bits of each color sample value. The extended range of the color sample values allows the color sample values to be summed to exactly reconstruct all color values. At the same time, the values in the color samples are close to exact values. This means that constructed color values are close to their correct values.

Abstract: A computer-implemented method for generating three dimensional line drawings in which only silhouette edges and true edges that are visible are displayed. The color, depth, and stencil buffers are respectively initialized to background color, farthest value, and zero. In a first pass, all polygons are rendered by filling all pixels within their boundaries. At each pixel, only its depth value is modified by selecting the nearer of either the current depth value or the new depth value. This creates a depth image in the depth buffer used for occlusion detection. In a second pass, all the polygons of a particular orientation are rendered by drawing lines from vertex to vertex for each of the polygons. The pixel values are modified only when the depth comparison passes (i.e., the pixel is visible and not occluded). Each time a particular pixel is modified, its corresponding stencil value is toggled from 0 to 1 or from 1 back to 0.

Abstract: In a computer system for creating images of three-dimensional objects, an apparatus and method for processing depth values representing the relative depths of the objects. The depth values are transformed according to projections in order to give the appearance of depth when the objects are displayed on a two-dimensional computer screen. These transformed depth values are then interpolated using N bits of precision. Next, the depth values are encoded into a format whereby the depth values have less than N bits. These encoded depth values are stored into memory. In displaying the objects, the encoded depth values are read from memory and compared to determine the relative depths of the objects.

Abstract: A method and apparatus for controlling the storage of display information into a frame buffer is disclosed. A memory means is provided for storing information for controlling the storage of display information into the frame buffer where the memory means contains a plurality of locations each of which corresponds to and controls the storing of display information in one location of the frame buffer. A pass/fail ALU is coupled to the memory means to obtain a value for a particular pixel; this ALU provides a signal indicative of one of a first or second state which state indicates whether storage of display information to the frame buffer will occur. A first function is stored in a register, which function specifies the first signal. A first storage register and a second storage register store a second function and a third function respectively and provide a second value and a third respectively.

Abstract: In a computer graphics system, a method of generating a geometrically valid point sample mask corresponding to a pixel. A separate mask is generated for each edge of a polygon. These masks specify whether particular subsample points are within a half-plane defined by an edge of the polygon. This information is determined by examining the sign of vertical or horizontal distance metrics corresponding to those sample points. These separate masks are merged to form the final point sample mask. Thereby, the final point sample mask contains information specifying whether particular sample points reside within the polygon. This information is used in rendering the pixel for display by the computer graphics system.

Abstract: A method for determining the coverage of a pixel, which includes determining a function of the distance from the currently sampled point to each edge of a polygon and then adding a predetermined value to the value of the function. This value is then clamped according to a function which provides an output of a predetermined value if the input to the function is not within a predetermined range and otherwise provides the value of the input if the input is within the predetermined range. The coverage of the pixel by the polygon is computed by multiplying the clamped functions. Blending the parameter values is performed if the value of the coverage falls within a predetermined range; otherwise, no blending occurs.

Abstract: A method for scan converting a triangular polygon where information representative of parameter values at each vertex is provided. The method includes the step of selecting an edge of the triangular polygon which is designated as a major edge and calculating parameter values for a first pixel center adjacent to the major edge, and then moving to a next pixel center adjacent to the major edge and calculating parameter values for that next pixel center adjacent to the major edge. The method continues to find pixel centers adjacent to the major edge until all parameter values for pixel centers adjacent to the major edge have been calculated. Then, for each line parallel to an orthogonal axis of the display device which is intersected by the triangular polygon, the method interpolates parameter values for pixel centers within the triangle which have not been calculated by interpolating from the calculated parameter values for one pixel center for each line. Typically, a line is column or a scan line.

Abstract: A method and apparatus for controlling the storage of display information into a frame buffer is disclosed. A memory means is provided for storing information for controlling the storage of display information into the frame buffer where the memory means contains a plurality of locations each of which corresponds to and controls the storing of display information in one location of the frame buffer. A pass/fail ALU is coupled to the memory means to obtain a value for a particular pixel; this ALU provides a signal indicative of one of a first or second state which state indicates whether storage of display information to the frame buffer will occur. A first function is stored in a register, which function specifies the first signal. A first storage register and a second storage register store a second function and a third function respectively and provide a second value and a third respectively.

Abstract: A method and apparatus for producing a visually improved image on a video display in a computer controlled display system. The system and method converts a quadrilateral polygon to a pair of triangles by computing the dot product of the normal unit vectors of one set of opposing pair of vectices and computing the dot product of the normal unit vectors of the other set of opposing pair of vertices and then comparing these two dot products to determine which opposing pair of vertices produces the larger of the two dot products. The pair of opposing vertices which produces the largest dot product is used to form the common edge of the pair of triangles into which the quadrilateral is converted.

Abstract: A system for displaying graphic images comprising an arrangement for clipping polygons against preselected clipping planes, an arrangement for determining when the vertices of a polygon all lie within one of a number of particular subspaces defined by the clipping planes, and an arrangement for disabling the means for clipping so long as all vertices of a polygon lie in the same subspace.