Abstract: A code printing and recognition system for printing, reading, and decoding a code on an article while the article is rotated and conveyed along a predetermined path. The system includes a code printing unit for printing a code in a printing area of the article. The code printed on the article consists of a plurality of code signs, while the printing area is a portion of a circle having a predetermined radius and centered at the central point of the bottom surface portion or the top surface portion of the article. The printing area is divided into a plurality of concentric-circular portions, so that each code sign is encoded by placing a number of dots in a respective circular portion. The system also includes an image pickup unit for acquiring an image of the printing area of the article and a code recognition unit for detecting dots in each circular portion, counting the detected dots in each circular portion, and decoding each code sign on a basis of the dot count in a respective circular portion.

Abstract: This invention provides self-clocking glyph shape codes for encoding digital data in the shapes of glyphs that are suitable for printing on hardcopy recording media. Advantageously, the glyphs are selected so that they tend not to degrade into each other when they are degraded and/or distorted as a result, for example, of being photocopied, transmitted via facsimile, and/or scanned-in to an electronic document processing system. Moreover, for at least some applications, the glyphs desirably are composed of printed pixel patterns containing nearly the same number of ON pixels and nearly the same number of OFF pixels, such that the code that is rendered by printing such glyphs on substantially uniformly spaced centers appears to have a generally uniform texture. In the case of codes printed at higher spatial densities, this texture is likely to be perceived as a generally uniform gray tone.

Abstract: A hand-held portable data collection system integrates ideal design features to improve and optimize the data collection process. The operator interface of the hand-held portable data collection system incorporates somatic feedback between the hand-held portable data terminal and the operator, thereby facilitating operation of the data terminal such as reading of optically readable indicia. The hand-held portable data collection system further provides optimal data collection by allowing for variable orientation of the reading field of view of the data file reader allowing for optimal positioning of the reader during the data collection process. Optically readable indicia may be disposed within the reading field of view of the data file reader without having to sight along the terminal as is typical with prior aim and shoot type data readers. The optically readable indicia may be readable regardless of orientational disposition.

Abstract: A bar code (10) has primary information (46, 48, 50, 51) encoded in one direction (e.g., horizontally) and secondary information (13,21,36) encoded in another direction (e.g., vertically) in single (11) or multiple tracks (35) in selected ones of the vertical bars (11) of a bar code (10). Using a non-linear, variable amplitude scanner, all of the primary bars are scanned in the one direction to obtain all of the primary information and all of those vertical bars having secondary information are scanned in the other direction to obtain all of the secondary information. The one direction which is perpendicular to the vertical primary bars (11), is determined by first rotating the scan path axis (86,87) until both start (46) and end (48) code bars are read thereby placing the scan path entirely within the total bar code, and, then, further rotating the scan path (88,89) to determine the direction of the minimum crossing width (Lsc 80) of the total bar code (10).

Abstract: A self-clocking glyph code is provided for encoding n-bit long digital values (where n>1) in a logically ordered sequence of composite glyphs that are written, printed, or otherwise recorded on a hardcopy recording medium in accordance with a predetermined spatial formatting rule. As used herein, a "composite glyph" is a graphical symbol that has a plurality of predefined, substantially orthogonal, graphical characteristics; each of which is capable of assuming any one of a plurality of predefined graphical states. An n-bit long digital value is distributively encoded in a glyph of this type by decomposing its n-bits, prior to or during the encoding, into a plurality of shorter, ordered, non-overlapping bit strings. The digital values of these bit strings, in turn, are encoded in the states of respective graphical characteristics of the composite glyph in a predetermined logical order, thereby preserving the logical ordering of the bit strings.

Abstract: A two-dimensional code reading apparatus uses the image of a reference pattern of a known shape in the two-dimensional code to compute areas, shapes and positions of cells in the image of the two-dimensional code and corrects these computed values using correction values obtained by identifying cells isolated from cells of the same type in at least one direction whenever they appear and extracting their actual boundary coordinates directly from the image data. As a result, even if there is distortion in the image of the two-dimensional a reading scope for each cell to be read is set to a suitable area and the reading position of each cell is determined accurately in correspondence with the distortion and the content of the two-dimensional code is thereby read correctly.

Abstract: A data well arrangement for storing data and for interfacing with a writing implement having a writing end with a writing tip and data transfer end with a data transfer tip is described. The data well arrangement has a housing with an inlet opening for receiving an end of the implement. A data reader resides in the housing for facing the data transfer tip to exchange data with the implement when the data transfer end of the implement is received in the opening. A shutter in the housing is engageable with an engagement portion of the implement for moving of shutter between a writing end storage position in which the data reader is inaccessible, and an interface position in which the data reader is accessible to the data transfer tip with the shutter being engaged by the engagement portion of the implement, only when the data transfer end is received in this opening.

Abstract: The issue of bingo paper as controlled by producing packages of multiple sheets each including multiple bingo cards, with each card provided with a uniformly located machine readable index number, the index number of cards on a sheet, and on sheets within a package being related to each other and to a matrix of numbers appearing on each card such that the index number of each card uniquely identifies a number matrix appearing on that card, and that of other cards within the sheet, as well as the sheet and package to which it belongs, checking each package into inventory, machine reading the index numbers of sufficient of said cards as they are sold to identify which cards have been sold, and placing the said cards in play. Verification of cards is provided by machine reading the index number of a card claimed to be a winning card, verifying that it is a card in play, and identifying the number matrix carried by the card to verify that it is a winning card.

Abstract: Machine readable fragments of a code pattern that is parameterized in N-dimensional space, where N.gtoreq.2, are affixed to two or three dimensional physical objects, such that the objects are uniquely identified by the addresses of the machine readable address space fragments affixed thereto.

Abstract: A system for processing a plurality of response forms containing subsets of questions from an entire set of question is disclosed. This system includes an optical scanner for creating an optical image of the response form. The optical image is stored in an image file within a storage means by a processor. The form contained in the optical image is identified by comparing vertical and horizontal histograms of the image within the image file to vertical and horizontal histograms of prototype form images in a prototype library using the processor and a form recognition engine. Data is extracted from the form based on a comparison of response zones on the image to a library of sets of response prototypes describing completed and uncompleted responses. The closest response zone match using the histogram technique to describe the response zone and the samples becomes the data, yes or no; that is reported.

Abstract: A dot-code recording method includes a step of generating a plurality of one-block dot patterns, each of which comprises a plurality of dots. The plurality of one-block dot patterns are then arranged to represent multimedia information, and a specific range of the plurality of one-block dot patterns are distributed according to specific rules to thereby arrange the one-block dot patterns within the specific range in non-time sequence. The non-time sequence distributed one-block dot patterns are then recorded on a recording medium.

Abstract: Inventive two-dimensional barcodes, each having encoded digital information in a bitmap representing preferably randomized encoded data bits, are printed onto a printed medium. The bitmap may further include a plurality of block identifiers, spaced a predetermined number of encoded data bits apart, which are used to make corrections for missing or added data bits when the barcode is decoded. Upon decoding a barcode printed on the printed media, the digital information is scanned and the number of horizontal and vertical edges in each respective column and row of the barcode are determined. An edge is determined by selecting a pixel and determining if the two pixels adjacent to the selected pixel are of different colors. After all of the edges are counted, selected groups of columns and rows are analyzed to determine local minimas in the number of counted horizontal and vertical edges in each selected group which provide the column and row center line for each selected group.

Abstract: The glyphs of self-clocking glyph codes are written on regular hexagonal or pseudo-hexagonal lattice-like patterns of centers to reduce the risk of interglyph interference during the read process while also enabling the glyphs to be packed more densely while maintaining a given center-to-center spacing between them.

Abstract: Verification patterns are associated with barcodes to provide rapids visual confirmation that a barcode is printed within acceptable tolerances. A master of a barcode to be produced includes at least one verification pattern including a wedge formed by an unprinted area or areas bounded by a printed area or areas. During reproduction, an anticipated degree of ink-spread will cause a predetermined degree of shortening of the wedge, while abnormal degrees of shortening are an indication of press and/or pre-press errors and/or an inappropriately specified master. With a suitably dimensioned wedge, compliance with bar and space width tolerances can be assessed. Two types of verification patterns may be used in conjunction with a single bar code to enable detection of different types of errors.

Abstract: The apparatus for reading a symbol of a 2-dimensional code has a diffusion plate and a diffuse reflection surface between a light source unit and an opening to prevent light emitted from the light source unit from directly reaching the opening. Illumination light from the light source unit reaches the diffuse reflection surface while the central axis of the light is shifted from the optical path to the diffusion plate. With this arrangement, nonuniformity of illumination light irradiated on a a symbol on object can be prevented, and a halation of light can be prevented. The symbol of the 2-dimensional code can therefore be accurately read.

Abstract: An image pickup unit optically reads, from an information recording medium having a portion that records multimedia information including at least one of audio information, video information, and digital code data in the form of an optically readable code pattern, the code pattern. A conversion unit converts the code pattern read by the image pickup unit into code data as an image. A block extraction unit extracts a block as a predetermined data unit from the code data by processing the code data converted by the conversion unit. A reference coordinate calculation unit calculates a reference coordinate position for determining the data reading coordinate position in the block by approximation using an Nth-degree curve passing the centers of a plurality of dots arranged at predetermined relative positions on the image upon extraction of the block as the predetermined unit of data from the code data by the block extraction unit.

Abstract: An information recording/reproducing apparatus records and/or reproduces information with a card-like information recording medium in which a plurality of guide tracks are formed. The apparatus includes an optical head for recording or reproducing information along the guide tracks, a head moving device for moving the optical head to and from along the guide tracks, and a recording medium moving device for moving the recording medium in a direction perpendicular to the guide tracks. The recording medium moving device is an ultrasonic motor.

Abstract: An information recording and/or reproducing apparatuses for performing recording and/or reproduction of information on a recording medium with a light beam emitted from an optical head, includes a vibration wave driving device for relatively moving the optical head to the medium, and a device for detecting information corresponding to a relation between a control signal for driving the vibration wave driving device and a relative movement velocity in the relative movement. The vibration wave driving device is controlled based on the information detected.

Abstract: An optical head irradiates a light beam on an optical recording medium having a plurality of tracks on which data is recorded and a plurality of guide tracks for separating the plurality of tracks, and receives a response light beam from the optical recording medium. A count control signal generation circuit performs predetermined calculation of an output from the optical head, thereby generating three binary count control signals having different phases, which represent the position of the light beam on the tracks and the guide tracks along a direction of the light beam crossing the tracks. A count pulse generation circuit generates a count pulse on the basis of a transition path for positioning the light beam, which is defined by the three count control signals from the count control signal generation circuit. A track count circuit counts the count pulse output from the count pulse generation circuit while recognizing the moving direction of the light beam.

Abstract: An information recording method in which a recording start position of a data section in which file data of a recording medium such as an optical card has been recorded is calculated on the basis of a directory for managing a file of the information recording medium recorded in a directory section and, when the data has been recorded at the calculated recording start position, a retry operation to judge whether the data has been recorded at the next recording position or not is repeated a predetermined number of times, thereby retrieving the final recording position of the data section. When the final recording position of the data section cannot be detected even if the retry operation was repeated the predetermined number of times, the information indicative of the recording position at which the retry operation was finally executed is recorded to the directory section.

Abstract: An apparatus for identifying a component (10) carrying a dot matrix code comprises a lamp (14) illuminating the dot matrix code, a video camera (18) for reading the illuminated dot matrix code. A computer (20) has an image grabber card (22) to produce a digitized image of the dot matrix code. The personal computer (20) has algorithms (24, 26, 28, 30 and 32) to measure the distances between every dot located in the digitized image, to determine the fundamental inter dot spacing (D). The dots separated by the fundamental inter dot spacing (D) lie in rows and columns of the dot matrix code. There are means to determine the angles (.beta. and .alpha.) between the dots which are in the rows and columns and a camera datum. There are means to determine the orientation and location of the dot matrix code from the angles (.beta. and .alpha.).

Abstract: A method to detect, process, and evaluate the quality of a succession of spaced bar code symbols. The symbols are disposed on a continuous substrate, moving past a scanner unit arranged to scan each symbol of the succession, one after the other. The method of the invention continuously scans the substrate to detect the entry of a bar code symbol into the field of view of the scanner unit. The presence of the bar code symbol in the scanner's field of view being established by a first valid decode of the symbol. Next, the first decoded scan and a plurality of subsequent decodable and non-decodable scans of the bar code symbol are processed to determine and store at least one evaluation attribute. The scanning and processing of the bar code continues until a predetermined number of consecutive non-decodable scans are processed, thereby indicating the absence of the bar code symbol from the field of view of the scanner and that the symbol has moved past the scanner.

Abstract: To facilitate the recovery data from an embedded data pattern through the use of a appropriately sized capture window that is randomly positioned within the data pattern, the embedded data pattern is composed of a plurality of identical, one dimensionally or two dimensionally regularly tiled embedded data blocks which contain sufficient spatial addressing information to permit the logical reconstruction of a complete data block from any set of fragments that collectively provide a full cover for the surface area of any one tile. To this end, the capture window is sized to include a shape which is completely registered with the data pattern in which is capable of tiling the recording medium in accordance with the tiling vectors.

Abstract: A scanner determines whether a target is a bar code symbol and, if so, whether that symbol is one-dimensional or two-dimensional. For two-dimensional symbols, the scanner aligns a scanning pattern with the symbol and expands the scanning pattern to reach only to the top and bottom edges of the symbol, not beyond. The scanner also has a microprocessor-control scanning engine that uses a coil to drive a scanning element and pick up feed back signals from the scanning element. A pulse-width-modulated regulator also provides fast and efficient operation for driving the coil. The scanning engine can also be designed to generate a pattern that precesses across the target, and a powerful interface to the scanning engine allows decoding and control logic to work efficiently with and independently of the scan engine.

Abstract: To facilitate the recovery data from an embedded data pattern through the use of a appropriately sized capture window that is randomly positioned within the data pattern, the embedded data pattern is composed of a plurality of identical, one dimensionally or two dimensionally regularly tiled embedded data blocks which contain sufficient spatial addressing information to permit the logical reconstruction of a complete data block from any set of fragments that collectively provide a full cover for the surface area of any one tile. To this end, the capture window is sized to include a shape which is completely registered with the data pattern in which is capable of tiling the recording medium in accordance with the tiling vectors.

Abstract: A two-dimensional code reading apparatus including a CCD sensor that captures an image including a two-dimensional code attached on an article being conveyed, for example. The two-dimensional code is formed as a matrix of light and dark cells, and includes at least two orientation symbols at corners of the matrix. Each of the orientation symbols is geometrically defined so that when a scanning line signal of the CCD sensor is binary-coded into a sequence of scanning line pulse signals, they show a given frequency component ratio. The two-dimensional code reading apparatus identifies an orientation of the orientation symbols based on positions of the pulse signals showing the given frequency component ratio in the captured image to determine positions of data cells in a data field of the two-dimensional code adjacent to the orientation symbols for decoding code information indicated by the data cells.

Abstract: An information recording system includes a writing paper having a writing surface and a prerecorded invisible pattern of pixels associated with the writing surface. Each of the pixels contains encoded, optically readable position information which identifies a coordinate position on the writing surface. The system further includes a pen having a tip and including an instrument for writing on the writing surface and a detector for detecting the position of the tip on the writing surface by optically reading the pixels and obtaining position information when the tip is in contact with the surface. The system further includes a recording unit coupled to the pen and responsive to the position information for electronically recording the position of the pen tip on the writing surface as the markings are made on the writing surface so that the recording unit contains an electronic representation of the markings on the writing surface.

Abstract: An electro-optical sensor senses marks on a sheet which travels longitudinally with respect to a printed circuit board, carrying linear arrays of light sources (LEDs) and photodetectors and optics which define zones displaced laterally across the width of a sheet of paper, longitudinal columns of which can contain marks, the presence and absence of which marks is detected by the sensor. The sensor is especially adapted for use in detecting marks which indicate votes on paper ballots in electronic, computerized vote counting apparatus.

Abstract: According to a two-dimensional code recognition method of the present invention, first, a two-dimensional image is input in step S1, and an edge is detected in step S2. This edge detection is performed by scanning pixels on a scanning line every several dots. A straight line is extracted in accordance with the Hough transform and the least square approximation in step S3, and a combination of straight lines is selected in step S4. Then, the size of a figure is detected in step S5. In step S6, two remaining straight lines are extracted, and the figure is extracted. In step S7, matrix information is extracted from the extracted figure, and codes are recognized. The flow returns to the selection of a combination of straight lines in step S4 until the straight line detection and the figure recognition can be accurately performed in steps S5, S6, and S7.

Abstract: A bar code for mail pieces uses bars each of which has four possible states. Two different bars indicate the start of the code and the same two bars in the same order indicate the end of the code. A data content identifier follows the start bars and this indicates the structure and length of the following data field so that when the code is read it will be recognized and read properly. The use of the data content identifier allows the code to be used for different customer and Post Office applied applications in which the code structure, length and content varies. The data field may contain a postal code with or without an address locator, a machine ID, customer information and service information. The code may include a country code field for mail pieces that are being mailed to a different country. The code may also include a field indicating whether the codeword is complete or whether it has to be concatenated with a preceding or subsequent codeword.

Abstract: A mark sheet reading apparatus is disclosed which can correct the coordinates of a binary signal read from a mark sheet when the mark sheet is in skew with an angle. A mark sheet having a plurality of marking areas arranged in a matrix of rows and columns thereon additionally has a reference row mark in the form of a continuous straight line provided in parallel to a row of the matrix and extending over a length covering the overall length of the row. The mark sheet reading apparatus comprises a reference row mark detection section for discriminating a successive condition of dots from among data read by an image sensor to detect the reference row mark of the mark sheet, a skew detection section for detecting an inclination rate of the reference row mark thus detected, and a skew correction section for correcting coordinates of binary data read by the image sensor in accordance with the inclination rate of the thus detected reference row mark.

Abstract: A data reading apparatus reads data of dots from a recording sheet on which data is recorded in the form of a mesh pattern, and decodes the read data into binary data. The data reading apparatus has an image sensor to read black/white levels of dots of the mesh pattern using the image sensor and to binarize the read levels by a hardware component or CPU processing according to software. An image can have a high recording density by minimizing a dot size.

Abstract: In an encoded symbol reader for decoding a two-dimensional encoded symbol, an image of the symbol is read and primary image data which directly corresponds to the symbol is generated. Further, from the primary data, secondary image data having less information than the primary image data is generated. The edge of the encoded symbol is detected using the secondary image data, and then decoding of the encoded symbol using the primary image data within the area defined by the detected edge.

Abstract: Self-clocking glyph codes encode interleaved or interlaced codes to facilitate the partitioning and correlation of data embedded within such glyph codes.

Abstract: A robust technique for determining whether a field (43, 45, 47a-d) on a form (40'), which has been converted to a binary input image, contains a mark utilizes an approach of making an initial determination of the approximate location of the field, and then refining such determination. The form is assumed to have registration marks (fiducials) with the field at a known location relative to the fiducials. The fiducials are identified (50), and the approximate location of the field is determined (55) from the fiducial positions and the known relation between the fiducials and the field. At this point, a portion of the image (referred to as the subimage) is extracted (57). The subimage is typically somewhat larger than the field so that it can be assumed that the field is within the subimage. The field has machine-printed lines along at least part of the field perimeter.

Abstract: An apparatus (38) for storing data includes a storage media (14). Also included are a number of vertical bars (40), each providing a vertical edge (50) for defining columns (44), and a number of horizontal bars (42), each providing a horizontal edge (52) for defining rows (46). The vertical bars (40) and the horizontal bars (42) are printed on storage media (14). A number of data blocks (48) are formed, each data block (48) located in a row (46), column (44) position.

Abstract: The apparatus comprises a device for the transfer (13) of containers (12) which takes containers (12) from a magazine for containers (11) to convey them in succession to a delivery station (16) passing through means for labelling (14) and means for checking the labels (25) controlled by a control and data acquisition system (2) so as to univocally label each single container with the data related to a corresponding single patient to a corresponding single sanitary event.

Abstract: A machine readable binary code which is dynamically variable in size, format and density of information is provided. The binary code is formed as a matrix having a perimeter and data contained therein. The perimeter is provided with density indicia for indicating the density of data contained within the matrix. The perimeter is also provided with size indicia for indicating the size of the matrix. By utilizing the density indicia and size indicia, a scanning device is able to calculate the size and information density of the binary code.

Abstract: A machine readable binary code which is dynamically variable in size, format and density of information is provided. The binary code is formed as a matrix having a perimeter and data contained therein. The perimeter is provided with density indicia for indicating the density of data contained within the matrix. The perimeter is also provided with size indicia for indicating the size of the matrix. By utilizing the density indicia and size indicia, a scanning device is able to calculate the size and information density of the binary code.

Abstract: A machine readable binary code which is dynamically variable in size, format and density of information is provided. The binary code is formed as a matrix having a perimeter and data contained therein. The perimeter is provided with density indicia for indicating the density of data contained within the matrix. The perimeter is also provided with size indicia for indicating the size of the matrix. By utilizing the density indicia and size indicia, a scanning device is able to calculate the size and information density of the binary code.

Abstract: A machine readable binary code which is dynamically variable in size, format and density of information is provided. The binary code is formed as a matrix having a perimeter and data contained therein. The perimeter is provided with density indicia for indicating the density of data contained within the matrix. The perimeter is also provided with size indicia for indicating the size of the matrix. By utilizing the density indicia and size indicia, a scanning device is able to calculate the size and information density of the binary code.

Abstract: An optically readable record for storing encoded information comprises (1) a recording medium, (2) a self-clocking data code for encoding the information, with this data code being composed of glyphs that are written in a bounded two dimensional code field on the recording medium on centers that are spatially distributed in nominal accordance with a predetermined spatial formatting rule, and the glyphs being defined by respective symbols that are selected from a finite set of optically discriminable symbols to encode the information, and (3) a self-clocking address pattern written on the recording medium to extend across the code field along at least one axis, with this address pattern being composed of a unique glyph pattern that disambiguates spatial position within the address pattern to a subpattern precision.

Abstract: Recorded data is read by an image sensor from a recording medium on which the data is two-dimensionally recorded in a mesh pattern, and the read data is stored in an image RAM. The stored data is subjected to data decoding and error correction to reproduce target data. A scanning reference pattern of a mesh pattern recorded on the recording medium serves as a guide when the stored recorded data read by the image sensor is reproduced by scanning in the image RAM. A reproduction apparatus has a capability of coping with a partial destruction of the scanning reference pattern. Error checking codes are added to the recording medium in addition to the target data. These items of data are recorded as an encoded image after being subjected to scrambling processing and randomization processing. The reproduction apparatus can easily cope with an error when the encoded image is reproduced.

Abstract: A self-clocking glyph code is composed of data glyphs which encode logically ordered data values, together with one or more multi-glyph synchronization code patterns. Each of the synchronization code patterns is distinguishable from the data glyphs, but the synchronization code pattern or patterns provide an explicit spatial reference for the data glyphs. To this end, the glyphs of the synchronization code pattern or patterns are written on the recording medium in accordance with the same spatial formatting rule as the data glyphs, plus at least one additional formatting rule that establishes a predetermined geometric relationship between the glyphs of the synchronization code pattern or patterns and corresponding ones of the spatially formatted data glyphs, such that the logical order of at least a significant number (>>1) of the data glyphs is inferable from the synchronization code pattern or patterns.

Abstract: An optically readable record for storing encoded information comprises (1) a recording medium, (2) a self-clocking data code for encoding the information, with this data code being composed of glyphs that are written in a two dimensional code field on the recording medium on centers that are spatially distributed in nominal accordance with a predetermined spatial formatting rule, where the glyphs are defined by respective symbols that are selected from a finite set of optically discriminable symbols to encode the information, and (3) at least one additional glyph pattern that is written on said recording medium in nominal accordance with the spatial formatting rule, the additional code pattern providing physical addressing information for random access from any given location within the glyph pattern to any other given location within the same glyph pattern or another glyph pattern on the same or a differnt recording medium.

Abstract: A method of recording information on an information recording medium including a first area having a plurality of sectors for recording data and a second area having a plurality of blocks for recording a directory used for managing the data is disclosed. Data is recorded on a first sector group consisting of at least one sector in the first area of the medium. When there is a defect in at least a part of the first sector group, the data to be recorded is recorded on a second sector group consisting of at least one sector in the first area. A directory corresponding to the data is recorded in the first block of the second area of the medium. When there is a defect in the first sector group, information regarding the defect is recorded into the first block of the second area. When only a part of the information regarding the defect can be recorded in the first block, the remaining information regarding the defect is recorded into the second block of the second area.

Abstract: To determine a read level threshold for discriminating those response bubbles on a scannable answer sheet intended to be marked from those response bubbles not intended to be marked, an adjustable read level threshold is dynamically determined based on the read levels of a designated pool of response bubbles. In an optical scanner the darkness (read level) of each response mark entered for a particular question is determined to make a profile. From this profile showing the various read levels present for the response marks, the system determines read level "gaps," i.e., read levels in the profile for which there are no marks present, and adjusts the threshold for discriminating intended marks based on the read level(s) comprising the gaps.

Abstract: A robust technique for determining whether a field (43, 45, 47a-d) on a form (40'), which has been converted to a binary input image, contains a mark utilizes an approach of making an initial determination of the approximate location of the field, and then refining such determination. The form is assumed to have registration marks (fiducials) with the field at a known location relative to the fiducials. The fiducials are identified (50), and the approximate location of the field is determined (55) from the fiducial positions and the known relation between the fiducials and the field. At this point, a portion of the image (referred to as the subimage) is extracted (57). The subimage is typically somewhat larger than the field so that it can be assumed that the field is within the subimage. The field has machine-printed lines along at least part of the field perimeter.

Abstract: A row and column based storage device stores data at multiple density levels. The bulk of the stored data is record data, and is stored at higher density levels to minimize the storage area required. The control information and system parameters are stored at lower density levels for maximum reliability. Lost or damaged record data may be recovered through error correction parity data. However, lost control information or system parameters results in catastrophic failure of the storage device.

Abstract: A transaction document reader reads image data on a transaction document. The image data includes marking areas employed by a user to record marks and includes characters. A sensor senses, one row at a time, rows of image data as the document is transported across the sensor. Each row includes a number of pixel areas. The pixel areas of the rows being aligned in columns. The sensor generates output signals representative of the pixel areas. The output signals are transformed into bit signals representative of each pixel area. The bit signals are stored in image memory which is organized into rows and columns of bit signals corresponding to the rows and columns of the pixel areas of the image data. The marking areas are located in image memory. The marks are identified in the marking areas while additional rows of bit signals are being stored and while other marking areas are being located by probing the bit signals in image memory.