Time-efficient method of analyzing imaged input data to locate two-dimensional machine-readable symbols or other linear images therein

In a computer system having a processor and a data storage device, a computer implemented method of locating one or more predetermined elongated shapes in an image stored in the data storage device, the stored image possibly including additional elongated shapes, the method comprising:

• dividing the stored image into a plurality of analysis regions;
• sampling at least two regions along a plurality of sampling paths in each region, wherein the plurality of sampling paths begin from a selected point in each region and end at approximately a boundary of region;
• locating a first elongated edge based on the sampled sampling paths;
• determining if the located first elongated edge is an edge of the predetermined elongated shape;
• determining a dominant direction of the located first elongated edge;
• and
• defining the location of the predetermined elongated shape based on the located first elongated edge.

An apparatus for decoding a machine-readable symbol representing encoded information, the symbol including a plurality of selectively spaced two-dimensional geometric shapes, the symbol having a predetermined orientation pattern of at least two elongated shapes or spaces, the apparatus comprising:

• a sensor that receives light that is reflected from the symbol and produces an output signal therefrom that resents the reflectance of the shapes and spaces comprising the symbol;
• a receiver that receives the output signal and produces a digital signal representing an image of the shapes and spaces of the symbol;
• a storage device for storing the digital signal;
• a processor for processing the digital signal and producing a signal indicative of the information encoded in the symbol, wherein the processor (a) divides the image into a plurality of analysis regions, (b) samples at least one region along a plurality of sampling paths, (c) locates a first elongated edge based on the sampled sampling paths, (d) determines if the located first elongated edge is an edge is an edge of one of the elongated shapes or spaces, (e) identifies a second elongated edge of another of the elongated shapes or spaces, (f) defines a position of the image of the symbol based on the located first elongated edge and the identified second elongated edge, and (g) decodes the symbol and producing a signal indicative of the information encoded in the symbol based on the defined position of the symbol;
• and
• wherein the processor divides the stored image into at least center, top, bottom, left, and right analysis regions, and wherein the center region has an area larger than areas of each of the top, bottom, left and right regions.

An apparatus for decoding a machine-readable symbol representing encoded information, the symbol including a pluralitv of selectively spaced two-dimensional geometric shapes, the symbol having a predetermined orientation pattern of at least two elongated shapes or spaces, the apparatus comprising:

• a sensor that receives light that is reflected from the symbol and produces an output signal therefrom that represents the reflectance of the shapes and spaces comprising the symbol;
• a receiver that receives the output signal and produces a digital signal representing an image of the shapes and spaces of the symbol;
• a storage device for storing the digital signal;
• a processor for processing the digital signal and producing a signal indicative of the information encoded in the symbol, wherein the processor (a) divides the image into a plurality of analysis regions, (b) samples at least one region along a plurality of sampling paths, (c) locates a first elongated edge based on the sampled sampling paths, (d) determines if the located first elongated edge is an edge is an edge of one of the elongated shapes or spaces, (e) identifies a second elongated edge of another of the elongated shapes or spaces, (f) defines a position of the image of the symbol based on the located first elongated edge and the identified second elongated edge, and (g) decodes the symbol and producing a signal indicative of the infornation encoded in the symbol based on the defined position of the symbol;
• and
• wherein the processor locates the elongated edges by (a) locating an edge point, (b) analyzing an area proximate the located edge point to locate the first elongated edge, (c) determining a dominant direction of the located first elongated edge based on the analyzed area, and (d) applying a vertical searching template for locating a position of the first elongated edge if the dominant direction is horizontal, and applying a horizontal searching template for locating a position of the first elongated edge if the dominant direction is vertical.