Raphael L Levien has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
Abstract: A halftone screen pattern generation system for computing halftone screened images with rotated screens including multiple angle and ruling combinations, including irrational tangent angles, is disclosed. A screen pattern is generated by storing a plurality of strips from an ideal angled screen pattern, and then concatenating a sequence comprising a selected order of the plurality of strips in a sequence. The error between the actual generated screen and ideal desired screen is computed. Each subsequent strip is selected from the plurality of strips so as to reduce the accumulated error. In one embodiment, a screen pattern is generated by storing one strip of an ideal angled screen pattern, and then concatenating a selected sequence comprising the strip and substrips of the strip.
Abstract: Internal moire artifacts found in digital halftoning of photographic images are diffused by rearranging the order of grayscale levels in an original screen pattern cell to generate a new screen pattern cell having a different grayscale order of stored screen pattern pixels. The grayscale order of the original cell is modified by the addition of a bump function at each point in the original cell in order of grayscale. The new grayscale order is stored in the new cell. Adding the bump function at the chosen point in the original cell influences the choice of the next pixel in the grayscale so that the grayscale order in the new cell is, in general, somewhat different from the grayscale order in the original cell. Errors caused by internal moire effects are thus both diffused in the grayscale dimension, and also diffused isotropically in the spatial dimension.
Abstract: The present invention is directed towards a method and apparatus for permitting human perception of more of the spectrophotometric values which define the color of an observed object. A first optical filter, worn over the left eye is provided having a spectral response containing three peaks; one for each of red, green, and blue, tuned to the maximum responsiveness of the human eye to red, green, and blue colors. A second optical filter, worn over the right eye, is similar to the left optical filter, but with the peaks tuned to complementary portions of the visual spectrum. In this manner, a dimension of color perception is added, because each eye sees different colors for the same object which when combined represent the actual color of the object.
Abstract: Tone values of a photographic image are stored in a frame store and retrieved from the frame store to produce a corresponding video display. A mouse or trackball is used to locate a point on display and a gamma correction curve look up table is used to interactively show the effect of color correction. Adjustment can be made via lighter and darker switches on the mouse or trackball. These switches subtract or add a bump function to the gamma correction curve in the selected color density plane. The bump function is displaced by the measured tone value in order to achieve more flexible control over the color correction.
Abstract: In the generation of screened halftones of photographic images for low resolution marking devices, conventional screen techniques are too coarse, and adaptive dither techniques are too fine. The present invention preserves the advantages of the adaptive dither techniques, while creating screen patterns with an adjustable degree of coarseness. The invention applies a hysteresis constant and recursion techniques previously limited to adaptive screening with fixed dot patterns to vary the size of dots in the screened image, thereby allowing adjustment of the image coarseness by adjusting the hysteresis constant.
Abstract: In a microprocessor system, data stored in a protected memory (12) within the same housing as the microprocessor (10) are secured by enabling access to the contents of the memory in response to an instruction only if the instruction was previously fetched from the memory (12). Protection circuitry (14) comprises a decoder (22, 24) responsive to the output of a status register in the microprocessor to operate a status signal when the microprocessor is in an instruction fetch machine cycle. The status signal is stored (26) until the protected memory (12) is selected by the microprocessor (10). Access to data in the protected memory (12) is enabled only if the status signal is stored during memory select or the microprocessor is in an I/O machine cycle for communication with a peripheral. In addition, voltage controlled switches within the housing place the bus in a HALT state during memory select unless the microprocessor is in an I/O machine cycle.