Abstract: A cache system improves performance by limiting the number of dirty entries in a cache. The cache system may further improve performance by limiting the number of dirty entries in the cache that might be subject to a cache-to-cache transfer. In a first example, a cache system counts the total number of dirty entries in the cache and preemptively evicts at least one dirty entry when the count exceeds a predetermined threshold. In a variation, a cache system counts dirty cache entries that result from a cache-to-cache transfer, and evicts at least one dirty entry that results from a cache-to-ache transfer when the number exceeds a predetermined threshold.

Abstract: An apparatus for mounting an object precisely in a specific plane. An object is mounted on small support points rather than flat pads or other flat surfaces. The support points are stiff but not completely rigid. Exactly four support points are used. Mechanical forces are sufficient to slightly compress the two higher support points on a diagonal and to slightly compress the object so that the object presses against all the support points, with a higher amount of compression for one pair of diagonal points relative to the other two points. In an example embodiment, the support points are formed at the intersection of curved surfaces or at the intersection of multiple planar surfaces. In a specific example embodiment, the points are formed at the intersection of cylindrical surfaces. The points are fabricated by a cylindrical cutting bit that has partial-cylinder grooves formed circumferentially in the bit.

Abstract: A representative method for scanning comprises: exposing a first linear array of photodetector elements to light for a first exposure time to acquire first, second, third and fourth accumulated charges; transferring the first, second, third and fourth accumulated charges to first, second, third, and fourth stages, respectively, of a charge shift register; exposing the first linear array to light for a second exposure time to acquire fifth, sixth, seventh and eighth accumulated charges; and transferring the fifth, the sixth, the seventh and the eighth accumulated charges to fifth, sixth, seventh, and eighth stages, respectively, of the charge shift register to interleave the first and second accumulated charges with the seventh and eighth accumulated charges.

Abstract: A camera, at power-on, determines elapsed time since power-off. The camera restores at least one control setting to a persistent value when the elapsed time is less than a predetermined threshold. The camera restores the at least one control setting to a default value when the elapsed time exceeds the predetermined threshold.

Abstract: A photosensor array has transfer gates that are logically divided into sections, with separate control over each section. Sequential control of the transfer gate sections, coupled with shifting the charge shift register, enables each stage of the charge shift register to accumulate charges from multiple sensor elements. Multiple scanlines are then interleaved into the charge shift register. Because charges from multiple sensor elements are accumulated, the exposure time can be reduced. Because multiple scan-lines are interleaved, the amount of subsampling for lower sampling rates can be reduced or even eliminated. As a result, the overall time required to acquire just the data that is needed for lower sampling rates is substantially reduced.

Abstract: An optical image scanner uses one or more reflecting surfaces to provide a light path through a lens array, where the optical path through the lens array is non-perpendicular to the surface of the image being scanned. As a result, the distance, from the surface where an image is being scanned, to the opposite outer surface of the scanner, is relatively short compared to scanners in which lens arrays are perpendicular to the image being scanned. An illumination source may be provided as part of an assembly that includes the lens array. Alternatively, the assembly may be integrated with a video display, or placed adjacent to a video display, and the video display may be used as the illumination source. The assembly may optionally monitor the intensity and color of the illumination source during scanning. The assembly may also optionally image the display.

Abstract: In an optical disc drive, signals from two satellite spots are used to cancel DC offset from a tracking error signal, and for generating a quadrature signal for determining direction of radial movement. The two satellite spots generate signals that are out of phase with the main tracking error signal by about one-fourth period.

Abstract: Various backgrounds, forms, or templates are scanned, features are extracted, and the features are stored in memory. When a composite image is scanned (image of interest plus part of background), features are extracted from the composite image. Features in the composite image are correlated to stored background features to identify which background is present. If necessary, background features from memory are shifted in two dimensions to accommodate displacement of the background. Features corresponding to the background are deleted from the features in the composite image. For forms and templates, features are used to identify the background, and then the information is directly extracted from the composite image.

Abstract: In a computer system with caching, memory transactions can retrieve and store groups of lines. Coherency states are maintained for groups of lines, and for individual lines. A single coherency transaction, and a single address transaction, can then result in the transfer of multiple lines of data, reducing overall latency. Even though lines may be transferred as a group, the lines can subsequently be treated separately. This avoids many of the problems caused by long lines, such as increased cache-to-cache copy activity. In one alternative, when a cache memory requests a group of lines, and when the group of lines is partially owned by another cache memory, then the requesting cache receives fewer than all the lines in the requested group.

Abstract: An optical disc has spatial features (notches, bumps, etc.) that intentionally distort the analog Read Data signal. For a mark or space that is centered on a spatial feature, the distortion does not affect the resulting binary Read Data signal. If an edge of a mark or space is near the spatial feature, the resulting binary Read Data signal is altered. For calibration, marks or spaces are written adjacent to spatial features, with a range of times for initiating the writes. The result is a range of write times that do not alter the binary Read Data signal. From these known times and spatial locations, it is known when a mark or space must be written to ensure accurate spatial placement.

Abstract: An optical disc has spatial features (notches, bumps, etc.) that intentionally distort the analog Read Data signal. For a mark or space that is centered on a spatial feature, the distortion does not affect the resulting binary Read Data signal. If an edge of a mark or space is near the spatial feature, the resulting binary Read Data signal is altered. For calibration, marks or spaces are written adjacent to spatial features, with a range of times for initiating the writes. The result is a range of write times that do not alter the binary Read Data signal. From these known times and spatial locations, it is known when a mark or space must be written to ensure accurate spatial placement.

Abstract: A scanner is provided with a variable aperture lens system. High resolution scans use a relatively small aperture size, and scanning speed is relatively slow. Low resolution scans use a relatively large aperture size, and scanning speed is increased. Fast scans are limited to lower sampling rates, which in turn permit more optical blurring relative to high sampling rates. Accordingly, the incremental cost of the larger aperture is minimized by permitting the lens aberrations specifications to be relaxed at larger apertures. Preferably, an electronic variable aperture is provided, for example, by use of electronically controlled polarization plates or by use of electrochromic substances.

Abstract: In a system having multiple power supplies with outputs connected in parallel, the number of supplies providing current is controlled to improve the overall system efficiency. For example, when the output current of individual power supplies falls below a threshold, one or more supplies may be placed into a standby mode. This increases the output current of the supplies that are in an operational mode, improving the efficiency of the supplies that are in an operational mode.

Abstract: An array of photosensors, used for imaging in a digital camera, is used to detect pressure, for example pressing by a finger, on an attached lens cap. The location of the pressure may be used to directly position a cursor, or the location of the pressure may be used to control direction of movement of a cursor. The lens cap is designed so that pressure on an outer layer changes reflectance or color of an area on an inner layer. For example, an inner layer may be translucent and dark and separated by a gap from a light colored outer layer. When the outer layer is pressed against the inner layer, the area of contact has an increased reflectance. Alternatively, the inner layer may be transparent, and a colored liquid may separate the inner layer from a light colored outer layer. When the outer layer is pressed against the inner layer, the area where all the liquid is displaced has the color of the outer layer.

Abstract: A lower level cache detects when a line of memory has been evicted from a higher level cache. The lower level cache stores the address of the evicted line. When the system bus is idle, the lower level cache initiates a transaction causing all higher level caches to invalidate the line. The lower level cache then places the line into a special state. If a line in the special state is evicted from the lower level cache, the lower level cache knows that the line is not cached at a higher level, and therefore a back-invalidate transaction is not needed.

Abstract: An image scanner uses optical targets within the scanner to characterize imperfections of a lens system and to partially compensate for the imperfections using digital image processing. In one sample embodiment, a series of two-dimensional optical targets are placed outside the document scanning area. Each individual target is suitable for obtaining an estimate of the point-spread function for a small segment of the scan line. Each point-spread function is then used to compute a convolution kernel for the corresponding segment of the scan line. Alternatively, each point-spread function may be used in an iterative solution for a modified image. In an alternative embodiment, a two-dimensional known random pattern is provided for a target. Cross-correlation of a portion of the known random pattern with the scanned image of the same portion of known random pattern provides an estimate of the point-spread function for the portion of the scan line corresponding to the portion of the known random pattern.

Abstract: A method for automatically cropping, rotating, and scaling a scanned image to ensure that a printed copy of the scanned image is the same size as the original, when possible. The method attempts to honor the default or operator designated orientation of the printed image, but will automatically rotate the image if that will eliminate unnecessary image reduction. Optimal orientation and scaling factors are automatically determined based on the target page size and the size and shape of the information of interest in the original image (not the boundaries of the original document). The operator selects a desired printed orientation (or accepts a default orientation) and selects a desired printed paper size (or accepts a default printed paper size). If an image will fit within the printable margins without rotation or cropping, the image is simply printed without modification. If the image will fit without rotation by cropping white space, then white space is cropped.

Abstract: A segmented photosensor array for an image scanner has segments with imperfect alignment. During scanner manufacturing, photosensor segment alignment data, such as segment position offset and segment angle, is measured. The offset and angle are stored in non-volatile memory within the scanner. A position correction system uses the stored alignment data to correct position and angle values before being processed by a rectification system. Most pixels require simple geometry calculations. However, a more complex state machine is needed to handle the transition from one photosensor segment to the next. Correcting for segment position offset and angle errors enables a cost reduction for the sensor array and, in particular, reduces costs associated with scrap.

Abstract: An optical disk medium has a data surface with grooves and lands behind a transparent substrate. Periodically, along radial lines, tilt measurement features are provided in the data surface, wherein the height of the grooves and lands is abruptly changed, preferably over a short circumferential length. For example, along the radial lines, the height of a groove (over a short length) may be changed to the height of a land and the height of a land (over a short length) may be changed to the height of a groove. The optical system and the optical disk medium are designed so that when the focused laser spot is centered on a groove, a radial push-pull tracking error signal is zero even if the disk is tilted. If the focused laser spot is centered on a land, the tracking error signal varies when the disk is tilted. As a result, when the focused laser spot passes over a tilt measurement feature, an abrupt step in the tracking error signal provides a measure of the magnitude and direction of tilt.

Abstract: In an optical disc drive, an analog calibration signal is generated that combines timing reference information and data information. During reading, and during writing of amorphous areas, the drive modulates the normally constant current supplied to the laser diode. The laser intensity is modulated normally during writing of reflective areas. The relative magnitudes of the intensity modulations, as measured in the calibration signal, are used to adjust the timing of writing data relative to a reference signal. Calibration may be made during reading or writing, without interfering with reading or writing.