Abstract: A plurality of bar-code candidate areas are calculated from scan data that is acquired by scanning a bar code. Feature data, which represents a specific feature, is calculated for each of the bar-code candidate areas. The bar-code candidate areas are evaluated based on their feature data to thereby determine a bar-code candidate area that has the highest probability of being a bar code. The specific feature includes any one or more of length of a differential waveform, average energy, and number of peaks in the differential waveform.

Abstract: The image forming apparatus and method subject image data to predetermined image processing to obtain processed image data and execute both of outputting a print according to the processed image data and outputting the processed image data to an image file. The apparatus and method create information for identifying an original before an image of the original is read to input the image data and storing the original identifying information in a data base in relation to the image file, read out, when a reprint is requested by designating the original identifying information, predetermined processed image data from the image file of the data base based on the original identifying information and output the print according to the predetermined processed image data. As a result, the apparatus and method are capable of easily designating a corresponding image file when a reprint is requested and capable of easily outputting the reprint from the image file without the need of an original film.

Abstract: An omnidirectional optical code reader employs two or more line photo sensor arrays orientated at an angle to one another. Electrical signals from the photo sensor arrays may be converted to digital signals by circuitry located on the die of each of the line photo sensors. Code reader circuitry is located on a circuit board orientated vertically in a backwardly sloping handle of a gun-shaped housing.

Abstract: An imaging optical code reader is adapted for use in producing video displays and for use in motion detection surveillance using video compression and narrow band width communication links. An optical system including a plane parallel plate may be employed to change the system focal distance.

Abstract: A bar code system is composed of a bar code display device 100 and a bar code reader 110. The bar code display device 100 has a operation unit 101 which divides transfer information to be transmitted into a plurality of pages of divisional information, converts them into bar codes, and successively displays the bar codes on a display unit 104. The bar code reader 110 has a operation unit 111 which converts bar codes successively read by a scanner 116 into divisional information, connects the divisional information, and restores the divisional information into transfer information.

Abstract: A bar code reading system comprises a first bar code label and a second bar code label. The first bar code label is positioned on an object at a first location and in a first orientation. The second bar code label is positioned on the object at a second location and in a second orientation. The first and second bar code labels each have indicia thereon representative of a label data set. Bar code reading apparatus positionable next to the object has a limited field of view such that the bar code reading apparatus reads only first and second portions of the first and second bar code labels. The bar code reading apparatus produces first and second data sets representative of the first and second portions. A data processing system operatively associated with the bar code reading apparatus combines the first and second data sets to produce a combined data set representative of the label data set.

Abstract: A method for improving the readability of composite images by determining available areas on a document where no text or graphics will be printed in visible ink and printing one or more 2-D bar code with invisible ink at a size pre-determined based on the available areas. The one or more auxiliary 2-D bar codes are printed in luminescent ink, either invisible or lightly colored when viewed under white light.

Abstract: An apparatus is provided for determining the orientation of documents based upon the acquisition of images of the documents and the detection of barcode images from the documents. A document transport conveys documents along a selected path of movement. A document imaging system is provided along the path of movement for imaging a document conveyed along the path of movement to generate image data representative of the document. A system controller processes the image data to detect the presence of a barcode image. The location and/or orientation of the barcode image is then used to determine the orientation of the document along the path of movement. A document orientor may be provided along the path of movement to orient documents into desired orientations along the path of movement based upon the location and/or orientation of the detected barcode images.

Abstract: Fiducial mark patterns for graphical bar codes (i.e., images that contain inconspicuous graphical modulations that encode embedded information) that are characterized by high detection robustness and good local deformation tracking are described. In one bar coding method, a base image is modulated with a graphical encoding of a message to produce a graphical bar code, and a fiducial mark pattern comprising a plurality of dots arranged to track one or more reference locations and local deformation across the graphical bar code is generated. In another bar coding method, fiducial mark candidates are identified in a fiducial mark pattern, a fiducial mark path is computed based upon one or more of the identified fiducial mark candidates, and one or more reference locations are identified based upon the computed fiducial mark path.

Abstract: A system and method for obtaining selected image information from a digital image and providing that selected image information for selective handling. In one aspect, the present invention automatically locates and segments an item identifier from an image caught by a digital camera and provides image information related to the item identifier for processing. Alternatively, a user can designate what areas of an image comprise the item identifier of interest for further viewing or processing.

Abstract: A method is provided for decoding data stored in a partial area of a coding pattern on a surface, based on a recorded image of the partial area. The coding pattern contains elements which each have at least two possible decoding values. The method identifies in the image a plurality of elements. The method further calculates, for each identified element, an associated value probability for each possible decoding value that the element has this decoding value. Additionally, the method performs the decoding of data based on the decoding values and the corresponding value probabilities. A device and a memory medium storing a computer program with instructions for performing such a data decoding technique are also provided.

Abstract: A digital information recording carrier has a planar recording surface having an information recording area in which cells corresponding to bits are virtually set in a matrix form, each cell being provided with an optically recognizable mark corresponding to digital information so that the digital information is recorded in the information recording area as a two-dimensional pattern. The carrier also has specific patterns each consisting of a plurality of cells which are linked together and which are given marks in a given pattern. Some of the specific patterns are placed in an inner portion apart from a perimeter of the information recording area.

Abstract: A method of producing a digital image of a machine readable optical code symbol having areas of different spectral characteristics and which is printable on differing printers having differing dot pitches. A desired nominal unit dimension is selected for each area of the optical code symbol; a resulting nominal unit dimension for each area is defined as a function of the dot pitch of a target printer; and a vector representation of the optical code symbol is provided using the resulting nominal unit dimension.

Abstract: A bar code is scanned and a line of image data is extracted in a process 1. The line of extracted image is divided into patterns forming characters in a process 1. The divided patterns are converted into characters in a process 3. In the process 3, a pattern is divided by the number of modules having the smallest width forming a black bar or a white bar, a module value indicating each module as black or white is determined, and each pattern is converted into a character, thereby correctly recognizing a bar code using general-purpose optical equipment for reading a bar code.

Abstract: A system for improved detection and decoding of a supplemental bar code label accompanying a primary bar code label is described. A supplemental label is affixed to a product in the vicinity of a primary label. A scanner in a bar code reading system, such as a point of sale system, scans for a primary label. Upon detection of a primary label, the system looks for the bar code encoded on the label in a database containing a set of bar codes with a value associated with each bar code. The value determines how long a search is to be conducted for a supplemental label accompanying the primary label which was scanned. The duration may suitably be based on the probability that a supplemental label will be present. It may also be influenced by the difficulty of detecting a supplemental label which may be present.

Abstract: A method for rapid and precise detecting of an omnidirectional postnet bar code on an object by digital signal processing is provided. In order to rapidly and accurately detect omnidirectional postnet bar codes, a two-dimensional digital image containing the postnet bar code is acquired, filtered and dilated to form a block dominated by a plurality of black-colored pixels. Then a down sampled image is provided and match filtered with a two-dimensional matched filtering output to indicate a best-matched filter, thus determining a postnet bar code location and orientation by associating matched filters with an orientation angle of the omnidirectional postnet bar code.

Abstract: A timing and mirror position detector for use in a bar code scanner having a rotating optical assembly. The optical assembly is rotated by a motor which produces a fixed number of pulses per rotation, at least one of the pulses occurring each time the motor passes through a reference position as it rotates. The pulses are continuously monitored and counted. Elapsed time from the time a reference pulse occurs is accurately measured and correlated by a processor with events of interest. When an event of interest, such as a bar code scan, occurs, the timing and pulse count are evaluated and processed to determine the angle of rotation of the motor at the time the scan occurred.

Abstract: A method and apparatus for aligning a scan pattern to a two dimensional bar code having parallel rows of codewords. The two dimensional bar code is scanned with a scanning pattern oriented such that a plurality of lines thereof cross the bar code rows. A determination if there is a non-zero angle between at least one of the plurality of lines and the rows by decoding codewords in rows intersected by the at least one line is made and the orientation of the scanning pattern is adjusted to reduce the absolute value of the angle.

Abstract: In the present invention, a bar code reader captures an initial image map corresponding to a scene, then subjects the initial image map to an interpolation step wherein values for constructed pixels positionally intermediate pixel values of the initial image map are interpolated as a function of the initial image map pixel values bordering the constructed pixels. After an interpolated image map is constructed, the interpolated image map is subjected to a binarization step wherein grey scale pixel values of the interpolated image map are converted into binary (1 or 0) pixel values by way of a thresholding process. In the thresholding process, grey scale pixel values are compared to a threshold in the grey scale range, then set to 1 if they are above the threshold and set to 0 if below the threshold.

Abstract: A reader for reading optical information is described which includes a housing for supporting a photosensitive array associated with an optical string adapted to focus optical information on the array. Also provided are array and optical string controls for controlling the array and optical string such that the output of selected images on the array may be processed via pattern recognition. Images on the array may be displayed and highlighted on a display. In this fashion a user is assisted in recognizing images of optical information incident on the array to facilitate aiming of the reader.

Abstract: In the present invention, a bar code reader captures an initial image map corresponding to a scene, then subjects the initial image map to an interpolation step wherein values for constructed pixels positionally intermediate pixel values of the initial image map are interpolated as a function of the initial image map pixel values bordering the constructed pixels. After an interpolated image map is constructed, the interpolated image map is subjected to a binarization step wherein grey scale pixel values of the interpolated image map are converted into binary (1 or 0) pixel values by way of a thresholding process. In the thresholding process, grey scale pixel values are compared to a threshold in the grey scale range, then set to 1 if they are above the threshold and set to 0 if below the threshold.

Abstract: A method of the invention reads a bar code based on bar-code data obtained by scanning the bar code with light. The method includes the steps of a) obtaining bar-code data, b) obtaining a sum of bar-data widths with respect to a predetermined number of bar data provided in at least one of a preceding portion and a following portion of the bar-code data, c) repeating the steps a) and b) once to obtain another sum, and d) making a comparison of the sum with another sum. The methods further includes a step of accepting the bar-code data as valid data when a result of the comparison satisfies a predetermined condition.

Abstract: An image of a region is taken which includes a two-dimensional code. A two-dimensional code area is determined in the image. The two-dimensional code area corresponds to the two-dimensional code. Inspection lines are set which connect opposite sides in two pairs among four sides indicating boundaries of the two-dimensional code area in cases where the two-dimensional code is of a cell matrix type. Inspection lines are set which connect opposite sides in one pair among four sides indicating boundaries of the two-dimensional code area in cases where the two-dimensional code is of a bar-code stack type. Information is read from the two-dimensional code area on the basis of the inspection lines. Division points are set on the opposite sides in response to a ratio in length between sides adjacent to the opposite sides and a number of arrangements of cells in the two-dimensional code in cases where the two-dimensional code is of the cell matrix type.

Abstract: An encoded binder strip having an adhesive matrix and an encoded pattern formed on a surface of the matrix to identify the type of binder strip. The encoded pattern includes relatively high reflectivity regions and relatively low reflectivity regions. Preferably, the encoded pattern is read as the binder strip is fed into a binding machine, with the encoded pattern controlling operation of the machine.

Abstract: Data is recorded on a data recording medium as a code that can be optically read by using a manual scanning process. Images to be recorded on the periphery of the code include codes, images, texts, etc., and they respectively have attributes such as the shape, color and density. Then, depending on these attributes, the images are classified into those which cause adverse effects when read together with the code and those which do not cause any adverse effects, and the former images are referred to as interference images, and the latter images are referred to as non-interference image. Here, upon recording the above-mentioned code, on the periphery of the code is placed a non-interference area from which any of interference images having attributes (shape, color, density) that cause adverse effects upon reading the code are not allowed to exist. Any image other than the interference images, that is, any non-interference image, can be recorded within the non-interference area.

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: In the present invention, the control unit of an optical reader analyzes image data being generated by the imaging element of the reader and changes the mode of operation of the reader if the image data indicates that machine readable indicia, such as a bar code symbol or a text character, is likely in the field of view of the reader. Normally, analysis of image data includes the step of detecting for edge transitions in the image information. If the control unit determines that the image data includes more than a predetermined number of edge transitions, then the control unit imparts appropriate control over various reader elements to change the mode of operation of the reader. Normally, the control unit changes the mode of operation of the reader from a first mode, wherein the reader does not operate to decode or recognize image data to a second mode, wherein the reader operates to decode and/or recognize image data.

Abstract: In the present invention, a bar code reader captures an initial image map corresponding to a scene, then subjects the initial image map to an interpolation step wherein values for constructed pixels positionally intermediate pixel values of the initial image map are interpolated as a function of the initial image map pixel values bordering the constructed pixels. After an interpolated image map is constructed, the interpolated image map is subjected to a binarization step wherein grey scale pixel values of the interpolated image map are converted into binary (1 or 0) pixel values by way of a thresholding process. In the thresholding process, grey scale pixel values are compared to a threshold in the grey scale range, then set to 1 if they are above the threshold and set to 0 if below the threshold.

Abstract: A plurality of two-dimensional bar codes are arranged on a traveling plane in a game machine. A self-propelled member travels on the traveling plane so as to trace a programmed traveling path. A bar code reader is provided in the self-propelled member, for reading information provided with each two-dimensional bar code. A position information processor detects a travel position of the self-propelled member in accordance with the information read by the bar code reader, and controls a movement of the self-propelled member in accordance with the detected travel position.

Abstract: Two-dimensional barcodes surrounded by a quiet zone of white space which may or may not include a border, each barcode having encoded digital information in a bitmap representing preferably randomized encoded data bits, are printed onto a printed medium. To extract the encoded digital information from the printed medium, the printed medium is scanned, then the bitmap is located within the printed medium by moving a window, in stepwise fashion in a predetermined pattern across the printed medium. At each step the portion of the printed medium which is encompassed by the window is tested to determine whether it conforms to one or more characteristics of the bitmap. The skew of the bitmap, if any, is determined, by using a finite-state recognizer in combination with a Hough Transform calculation. In one embodiment, the candidate region is divided into a plurality of horizontal regions, preliminary skew angles are calculated for each region, and the actual skew angle is selected using a voting scheme.

Abstract: The invention relates to a system for processing image data corresponding a scene comprising an imaging device and an image reading instruction indicia. In accordance with the invention, image data corresponding to a scene comprising an image reading instruction indicia is processed in a manner that depends on features of the image reading instruction indicia. If the image reading instruction indicia is of a type whose size, scaling, orientation, and distortion can be determined, scaling, orientation, and distortion characteristics determined from the image reading instruction indicia can be used to improve the image reading process.

Abstract: A system for detecting and decoding a supplemental barcode accompanying a primary barcode. A supplemental barcode is affixed to a product in the vicinity of a primary barcode. A scanner in a barcode reading system, such as a point of sale system, scans for a primary barcode. Upon detection of a primary barcode, the system inserts a delay while attempting to detect a supplemental barcode. Upon detection of a secondary barcode, the primary and supplemental barcode information is processed, for example by sending the information to a terminal connected to the scanner. Upon expiration of the delay without detection of a supplemental barcode, the primary barcode information is processed.

Abstract: An apparatus and method for the recognition of codes has a light transmitter for the transmission of light signals in the direction of a scanning region, a light receiver for the reception of a light signal remitted from the scanning region, and a control and evaluation unit for the control of the light transmitter and the light receiver and for the determination of a code from the light signal received. The control and evaluation unit includes a trigger circuit triggering the determination of a code and a distance determination unit or image detection unit (which acts on the trigger circuit) for the detection of an object present in the scanning region which is integrated into the apparatus.

Abstract: Playing cards that include a machine-readable bar code in the form of a number of mutually parallel and juxtaposed bars, wherein the code is adapted to be read by light sensitive detectors. Each playing card includes at least one six-position binary code in which a bar is either present or absent at each of the six positions. The code includes a reference code in the form of an additional bar in at least one further position adjacent to the six-position binary code. The reference code is positioned for detection by a light sensitive detector. The binary code is intended to be read by means of the light sensitive detectors when the existence of the reference code is detected.

Abstract: An exposure substrate of the invention is characterized in that at least one mark representing information related to the exposure substrate is provided on a part of the exposure substrate, and at least one of the marks contains information related to a mark readout operation. This information may include; the number, the position, or the order for reading the other marks to be read, or an end of information to be read. According to the present invention, information for other marks can be obtained from one mark, therefore, an optional number of marks can be read automatically.

Abstract: The present invention teaches a variety of methods and systems for providing computer/human interfaces. According to one method, the user interfaces with an electronic device such as a computer system by engaging a sensor with desired regions of an encoded physical medium. The encoded physical medium is preferably chosen to provide intuitive meaning to the user, and is thus an improved metaphor for interfacing with the computer system. Suitable examples of the encoded physical medium include a data-linked book, magazine, globe, or article of clothing. Some or all of the selected regions have had certain information encoded therein, information suitable for interfacing and controlling the computer system. When the user engages the sensor with a region having certain encoded information, the certain encoded information is interpreted and an appropriate action taken. For example, the sensor or the computer system may provide suitable feedback to the user.

Abstract: A scanner for optically scanning coded symbologies including a signal processing unit for pre-processing the scanned symbology information and a hardware symbology locating unit. An analog signal related to the reflectivity of the different portions of the coded symbology is obtained and is converted to digital gray-scale. The portion of the analog signal which corresponds to the substrate reflectance (absolute contrast) is removed, and the available dynamic range of the analog to digital converter is used only for the information-bearing portion of the signal (relative contrast). Since all of the decodable information is ultimately encoded in binary form, the information-bearing portion of the signal is retained. The hardware symbology locating unit includes a plurality of shift registers, each of which derives a value from an input seed which is based upon the width of a detected coded symbology element. The value of a subsequent input seed is compared to the values generated from a prior input seed.

Abstract: The extraction of barcode area and the recognition of barcodes are enabled with input sheets, on which multiple barcodes of multiple specifications are printed at different positions or in different directions, or with each sheet, on which barcodes of different specifications are printed at different positions or in different directions. The barcode recognition system of the present invention is provided with a barcode area extracting means that decides the image of barcode with the two dimensional pixel distribution and extracts the barcode area, a means of deciding the similarity of barcode stripes that confirms that the image inside the barcode area is barcode with the two dimensional distribution of pixel and infers barcode specification, a barcode recognizing means that recognizes barcodes with multiple barcode specifications, and a recognized result deciding means that narrows down the barcode specifications based on recognition result with multiple barcode specifications.

Abstract: An inventory use recording system and method having an optical reader module for scanning component bar codes of an inventory batch having serialized bar codes, a controller module for storing at least a first tag representation and a second tag representation where the second tag representation is a tag representation from a next available component in the inventory batch after a predetermined time period where a quantity of the components have been withdrawn from the inventory batch, and a display module for displaying inventory use.

Abstract: A timing and mirror position detector for use in a bar code scanner having a rotating optical assembly is rotated by a motor which produces a fixed number of pulses per rotation, at least one of the pulses occurring each time the motor passes through a reference position as it rotates. The pulses are continously monitored and counted. Elapsed time from the time a reference pulse occurs in accurately measured and correlated by a processor with events of interest. When an event of interest, such as a bar code scan, occurs, the timing and pulse count are evaluated and processed to determine the angle of rotation of the motor at the time the scan occurred.

Abstract: A technique for marking media with indicia in such a way as the media may be loaded into the printer in any orientation. These indicia marks are read by a printer for the purpose of identifying the media, determining the orientation of the media, and providing additional information about the media. The indicia encodes the necessary information for the printer to identify the media as well as additional information about the media that may be useful for the printer. In a typical embodiment, the indicia will be invisible to the human eye but machine readable. On sheets of media, indicia are placed in the margin of the media in eight corners of the page, four on the front and four on the back. The indicia are placed and orientated such that the indicia are in the same relative position and orientation to the printer regardless of the orientation in which the media is loaded into the printer.

Abstract: An automatic inspection system using barcode locator and the method thereof which can inspect a colored surface of a three-dimensional object having a barcode. The automatic inspection systems comprises a light source; an image-retrieving device; and an operating and processing device. The image-retrieving device retrieves three-dimensional images of the inspected object from various viewing angles. The three-dimensional images are converted into two-dimensional images, which are then connected to produce a two-dimensional image representing the inspected object by the operating and processing device. The two-dimensional image representing the inspected object is adjusted through the barcode locator. Thereafter, the two-dimensional image is compared with a reference object image previously stored by the operating and processing device to find the defined pre-defects of the inspected object.

Abstract: A method of operating a bar code reader (16) in which one or more bar codes (25,26) are detected at different positions (X1, X2) within a scanning range of the bar code reader (16) by the latter, the scanning distance (d1, d2) between the bar code reader (16) and the respectively detected bar code (25,26) is found anf the position (X0, Y0, Z0) and/or the scanning angle (&agr;, &bgr;, &ggr;) of the bar code reader (16) is foubd from the respectively found scanning distance (d1, d2) and from known position data (X1, X2)of the detected bar code (25,26).

Abstract: A bar code scanner/verifier rapidly analyzes reflections of a scanning laser beam to determine whether or not a scanned line portion contains a bar code, so analysis of a bar code begins only when a legitimate bar code is present. The apparatus reads transitions in reflectance and indicates that a bar code is not present when the transitions are not large enough to qualify for a bar code, and when there are not enough transitions per unit distance. The circuit does this by generating MAX minus MIN, where MAX continually decreases over time but is raised every time a high reflectance is encountered, and MIN continually increases over time but is lowered every time a low reflectance is encountered. When MAX minus MIN drops below a programmable predetermined noise level, the circuit indicates that there is no bar code.

Abstract: A system and method are described to accurately determine input data provided in a plurality of different formats, for example, on different areas of a statement. Where a bar code with check digits is present the sum is displayed, and a confirm key used to confirm the accuracy of the input data. If bar codes with check digits are not present or are not read normally, but an OCR sum area with check digits is present, then this data will be used. If an OCR sum area with check digits is not present (or are not read normally) but a handwritten area is present and normally read, that data will be used, again subject to a confirmation.

Abstract: A method of reading of a bar code consisting of a predetermined number of code elements for the generation of a binary signal with sequential high/low phases, the length of which correspond to the widths of the sequential code elements. The bar code is sensed by at least two scanning beams from different directions along different scanning lines. At least some of the regions of the bar code are scanned by a scanning beam and are respectively detected as a code segment, and wherein at least some of the detected code segments are selected with respect to predetermined decision criteria and combined for the reconstruction of the scanned bar code. Furthermore an apparatus is described for carrying out the method.

Abstract: An apparatus is provided for determining the orientation of documents based upon the acquisition of images of the documents and the detection of barcode images from the documents. A document transport conveys documents along a selected path of movement. A document imaging system is provided along the path of movement for imaging a document conveyed along the path of movement to generate image data representative of the document. A system controller processes the image data to detect the presence of a barcode image. The location and/or orientation of the barcode image is then used to determine the orientation of the document along the path of movement. A document orientor may be provided along the path of movement to orient documents into desired orientations along the path of movement based upon the location and/or orientation of the detected barcode images.

Abstract: An image input section enters a document image including a bar code, and converts the document image into a binary image. A small pattern removing section removes small patterns from a binary image sent from the input section. A labeling section separates the binary image into labeled regions and calculates the feature quantity including a center position of each labeled region. A region detecting section makes a group of labeled regions spaced at a predetermined positional relationship based on their feature quantities and detects a bar code candidate region. A decoding section decodes the bar code based on the feature quantity involved in the bar code candidate region.

Abstract: A two-dimensional code made up of a matrix of cells formed with dark and light squares arranged in a pattern carrying an optically readable binary-coded data, and a method of reading such a two-dimensional code. The two-dimensional code features a structure in which at least two data regions are defined in a data field of the matrix. One of the data regions retains a code represented by the cells having a larger size, while the other data region retains a code represented by the cells having a smaller size. The use of cells of different sizes in representing the codes allows the codes to be read correctly under different conditions.

Abstract: In the present invention, a bar code reader captures an initial image map corresponding to a scene, then subjects the initial image map to an interpolation step wherein values for constructed pixels positionally intermediate pixel values of the initial image map are interpolated as a function of the initial image map pixel values bordering the constructed pixels. After an interpolated image map is constructed, the interpolated image map is subjected to a binarization step wherein grey scale pixel values of the interpolated image map are converted into binary (1 or 0) pixel values by way of a thresholding process. In the thresholding process, grey scale pixel values are compared to a threshold in the grey scale range, then set to 1 if they are above the threshold and set to 0 if below the threshold.