Abstract: A transition signalling communication system suitable for use in a high speed data communication bus between a bus master and two or more peripheral slave devices provides data transfer rates up to twice the maximum clock frequency. The bus architecture permits transition signalling to be used with a plurality of slave devices with tri-state or open collector control signals. The bus master includes a first control signal, which initiates a data transfer request by the transition of the first control signal, and a second control signal which provides an indication whether the first control signal transition is valid. In response, the slave includes a third control signal which acknowledges the first control signal by the transition of the third control, and fourth control signal which provides an indication whether the third control signal transition is valid.

Abstract: A register mark and a system for bringing a pair of register marks into alignment is disclosed. A first register mark comprises a plurality of dots of a first frequency, and a second register mark comprises a plurality of dots of a second, generally higher frequency. When the first and second register marks are overlaid, an interference pattern resulting from the difference in frequency is observed. The first and second register marks are in alignment when the interference pattern produces a maximum bright spot in the center of the register mark. A small relative movement of the first and second register marks results in a larger relative movement of center of the bright spot. The position of the bright spot indicates which direction and how much to move the second register mark in order to achieve image registration. In an alternate embodiment of the present invention, the frequency of dots in each register mark is warped with distance from the center of the mark.

Abstract: A register mark and a system for bringing a pair of register marks into alignment is disclosed. A first register mark comprises a plurality of dots of a first frequency, and a second register mark comprises a plurality of dots of a second, generally higher frequency. When the first and second register marks are overlaid, an interference pattern resulting from the difference in frequency is observed. The first and second register marks are in alignment when the interference pattern produces a maximum bright spot in the center of the register mark. A small relative movement of the first and second register marks results in a larger relative movement of center of the bright spot. The position of the bright spot indicates which direction and how much to move the second register mark in order to achieve image registration. In an alternate embodiment of the present invention, the frequency of dots in each register mark is warped with distance from the center of the mark.

Abstract: A hand-held bar code reader with a two dimensional image sensor for omnidirectional bar code reading, includes variable imaging optics, and flash illumination with variable flash illumination optics. A spotter beam is provided for aiming the hand held bar code reader at a bar code symbol. The spotter beam is also used to measure the range to said bar code from said hand held bar code reader and to determine the focal length of said variable imaging optics and variable flash illumination optics. The imaging optics are adjusted automatically to provide the correct magnification and focus of a bar code regardless of range to the label. The variable focal length flash illumination optics are used to concentrate illumination energy only in the field of view of the bar code reader. The flash illumination energy is conserved by measuring the ambient light and setting the level of flash illumination energy in accordance with the measured level of ambient light.

Abstract: A high speed screening technique is disclosed which can be used to enlarge an image, or when combined with a halftone screen, can be used for high speed screening of stored images. A microcompiler generates customized program code responsive to an input enlargement ratio. The customized program code then performs halftone screening on the input image for the specified desired enlargement ratio. In general, for each different enlargement ratio, a different customized program code is generated. Thus, a parameter of the screening process, the enlargement ratio, which is an input to the microcompiler, is not an input during the run time of the customized program code, thereby permitting the customized program code to run faster since an input parameter has been removed and built into the code itself.

Abstract: A data input device and method for producing signals corresponding to symbols, comprises: at least one manually actuatable switch having a home state and manually actuatable from the home state to one of a set of first states and manually actuatable from the set of first states to one of a set of second states including the home state. A first signal corresponding to a transition from the home state to a selected one of the set of first states is produced and a second signal corresponding to a transition from the selected one of the set of first states to a selected one of the set of second states is produced. An output signal representing one symbol is produced in response to the first and second signals.

Abstract: A time reversal filter uses exponential decay infinite impulse response filters to achieve an approximation to a true Gaussian low pass filter. In one embodiment, a time reversal Gaussian approximation filter performs the forward and backward passes of a time reversal filter in essentially one pass using a segmented signal approach. The input signal is divided into segments, each segment is filtered first in the forward direction, then in the reverse direction, and the segments thus filtered are reassembled to form the output signal. In addition, the overlap in the reverse direction from each filtered segment extending backward into the prior filtered segment is preserved in memory and added to the output of reassembled segments.

Abstract: A method and provides for transmitting a time reference throughout a residence or other facility for use by appliances operating within the facility. A time reference is received from the headend of a cable television (CATV) system at the subscriber converter and is retransmitted to set the internal clock timers of residential appliances throughout the house. The time reference is received by the CATV converter, then encoded and modulated for transmission on the residential AC wiring system which also carries AC power to all of the appliances in the house. Individual appliances receive the encoded time reference from the AC power line, demodulate the received signal and use the received time reference to set its internal clock timer. In such manner, a residential appliance does not need to have its internal clock set by the consumer.

Abstract: A halftone screen with precisely controlled angles and rulings, including irrational screen angles and rulings, for screening photographic images is generated by representing a desired screen pattern in an irregular or non-grid like array of screen elements. In one embodiment, a random array of screen elements is used. In another embodiment, a Poisson-disk distribution of screen elements is used to improve quality. The error between an ideal screen point and an actual screen point in the transformed UV space is calculated and used as the basis for selecting an actual screen point as having the least error between the ideal and actual screen points in UV space. The number of error calculations may be reduced by storing pointers the nearest points to each screen point in transformed UV space, and by storing a plurality of successive screen values at a given angle and screen ruling corresponding to each point in the transformed UV space.

Abstract: The change between a dispersed state and a flocculated state of a colloidal agent (e.g. Congo Rubin, colloidal gold) is used to provide sensitive visual detection and optionally assay of enzyme in a sample. The test cell includes a substrate for the enzyme, and, depending on the action of the enzyme, polymer which protects the colloid from electrolyte-induced flocculation is either formed or destroyed by the test reaction. In a test for a hydrolytic enzyme (e.g. a protease) the colloid loses protection and flocculates. In a test for a polymer-forming enzyme, the colloid gains protection and is prevented from flocculating by added electrolyte, or alternatively, depending on the polymer's behavior, becomes more sensitive to the flocculating action of the added electrolyte. The measurement may be quantitated using an instrumental monitor. The test uses a natural substrate for the enzyme to be assayed (e.g., gelatin for the gelatinase class of enzymes) and may achieve rapid speed.

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 an oversized strip from an ideal angled screen pattern, and then assembling a sequence comprising selected scan line segments of the oversized strip. Each selected scan line segment corresponds to one of a plurality of offsets of the oversized strip. The error between the actual generated screen and ideal desired screen is computed. Each subsequent scan line segment is selected from the plurality of scan line segments corresponding to the plurality of offsets so as to minimize the accumulated error. In accordance with one aspect of the present invention, the measure of error between the actual generated screen and the ideal angled screen is the length of a vector in a transformed UV space between the actual screen sample point and the ideal screen sample point.

Abstract: An improved adaptive notch filter for removing undesired cochannel FM interference includes in-phase and quadrature signal processing paths in which the undesired FM signal is translated to zero frequency, i.e. to DC. In each of the in-phase and quadrature phase signal paths, a first multiplier translates the input frequency spectrum in a dynamic manner so that the frequency of the undesired FM signal is always centered on DC. The undesired signal, now at DC, is filtered out by a high pass filter with a sharp rolloff. The output of the high pass filter is remultiplied in a second multiplier to translate the desired FM signal back to the original position in the frequency spectrum. In order to eliminate an unwanted difference frequency remodulation signal at the output of the second multiplier, the quadrature phase signal path performs a parallel operation on the same input signal, but with a quadrature phase (90 degree phase shift) control signal.

Abstract: A bar code reader includes an image capture means for storing a two dimensional image in memory, which stored image may include a bar code symbol within the field of view of said image. The present bar code reader further includes method and apparatus for determining the location and orientation of said bar code symbol within the field of view of said image, and then filtering said located and oriented bar code symbol along an axis perpendicular to said detected orientation. Thereafter, the filtered bar code symbol is scanned and applied to a decoder to produce a decoded bar code output.

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: An image recognition system includes a method and apparatus in which images are characterized and compared on the basis of internal structure, which is independent of image size and image orientation. A library of reference images is first generated and stored, then each input image, or test image, is compared to the images stored in the library until a match is found. The image is represented in memory as nodes, lines, and curves. A plurality of descriptors, called reference keys and reference series, are generated for both the reference images and the test image. The reference library is screened for likely matches by comparing the descriptors for the test image to the descriptors in the reference images in the library. Inclusionary and exclusionary tests are performed. After screening, the each of candidate reference images is searched by comparing the pathway thorough the reference image and the pathway through the test image, and by the degree of correlation between the reference and test images.

Abstract: A bar code reader utilizing a two dimensional image capture optical system, includes a method and apparatus for distinguishing a preferred bar code out a plurality of bar codes within the field of view of the bar code reader. The method and apparatus for distinguishing a preferred bar code includes placing a special pattern proximate to the bar code to be distinguished. In one embodiment, a predetermined pattern at a predetermined location and orientation relative to the bar code is placed on a label. The reader includes means for detecting the presence of the predetermined pattern after the bar code has been located. The bar code reader first locates each of the plurality of bar codes, and then checks each located bar code to determine whether the predetermined pattern is present. If the predetermined pattern is detected, then the corresponding located bar code is scanned and decoded as the preferred bar code.

Abstract: A surface mounted diode comprises a pair of slugs pointed toward each other with a die disposed therebetween, at least one of the slugs being truncated cone shape, and a pair of solder wafers being disposed between the die and each slug to form an electrical connection therebetween. Each slug has a terminal formed at the tail thereof. The largest diameter of the truncated cone shape slug is approximately the same as or greater than the diagonal of the die. The function of the truncated shape of the slug is to protect the die from damage during handling and during curing of the encapsulating resin which occurs during the manufacturing process of the surface mounted diode.

Abstract: A remotely retunable receiver for use in a satellite video programming distribution system includes the capability to retune groups of subscribers to different satellite feeds during a blackout of a video programming event. To achieve flexible control over program blackouts, a receiver retune command message is selectively sent to desired groups of descramblers at CATV satellite downlinks. The retune command message identifies an alternate satellite feed and a time for which the satellite receiver is to tune to the alternate satellite feed. The receiver stores the retune command, and at the appropriate time retunes the satellite receiver to the identified alternate feed. By command messages received on the alternate feed, the group of blacked out satellite receivers are returned to the original programming channel at the end of the blacked out event.

Abstract: A multiple resolution optically encoded label is readable at two or more optical resolutions, and is able to store two or more respective channels of optically encode information. Low resolution information is encoded in a plurality of large cells arranged in a predetermined geometric pattern. Each of the large cells includes a plurality of smaller cells for storing high resolution information. Method and apparatus are disclosed for encoding both high resolution data, and low resolution data, as well as for finding and reading both high resolution and low resolution data.