Multi-dimensional symbologies and related methods

The present invention relates to a method of encoding and decoding information. In particular, the present invention relates to a multidimensional matrix coding technique. (Cross-reference to related applications) This application claims the priority of US Provisional Patent Application No. 60 / 8,13,769 filed on June 14, 2006, all of which is incorporated herein by reference. , In all senses incorporated herein.

Research on modern barcodes began in 1948. On October 20, 1949, Woodland and Silver filed a patent application entitled "Classifying Amplifier and Method." The inventors describe their invention as relating to "via a medium for identifying patterns ... a technique for classifying articles". Woodland and Silver barcodes are bull's, a symbol of a series of concentric circles. It was a symbol of eye). Woodland and Silver also describe linear patterns that are very similar to current one-dimensional barcodes. The Symbology of this straight line pattern consisted of four white line patterns on a black background. The first line of the four white lines was the data line, and the positions of the remaining three lines were fixed in relation to the first line. The information was encoded by the presence or absence of one or more of the four lines. This allowed seven different classifications of goods. However, the inventors note that it is possible to encode more classifications if more lines are added. For example, according to 10 lines, it would be possible to code 1023 classifications. The aforementioned Woodland and Silver patent applications were issued on October 7, 1952 as US Pat. No. 2,612,994. All of this disclosure is incorporated herein in every sense by reference in this specification.

Barcodes were not commercialized until 1966. The first commercialized product code was represented by the bull's-eye bar code. It includes a set of concentric circular bars and spaces with variable widths. It was quickly recognized that the industry must agree on a standard coding scheme that is open for use by all equipment manufacturers and is acceptable to all food manufacturers and food sellers. .. In 1969, NAFC urged Logicon, Inc. to push forward with its industry-wide barcode system planning. The result was Part 1 and Part 2 of the UGPIC (Universal Grocery Products Identification Code) in the summer of 1970. The US Supermarket Ad Hoc Commission on Unified Food Product Codes (US) based on the recommendations of the Logicon, Inc. report. Supermarket Ad Hoc Committee on a Uniform Grocery Product Code) was organized. Three years later, the Commission recommended the adoption of the UPC symbol set, which is still in use in the United States.

The first attempt at industrial use of automatic identification was initiated by the Association of American Railroads in the late 1950s. In 1967, the American Railroad Association adopted optical barcodes. Vehicle labeling and scanner installation began on October 10, 1967. It took seven years to complete the labeling of 95% of the vehicles. Such a system did not work at all for many reasons and was abandoned in the late 1970s. An important event in which barcodes were actually used in industry took place on September 1, 1981, which is Code 39 for marking all products sold to the U.S. military. Was adopted by the United States Department of Defense. This system was called LOGMARS.

The linear barcode is a binary code. Lines and spaces have variable thickness and are printed in different combinations. Accurate printing and sufficient contrast between the bars and spaces must be present for the scan to take place. Scanners use a variety of techniques to read code. The two most common are lasers and cameras. The scanner, like most supermarket counter scanners, may be fixed or often a handheld device used for inventory management. There must be a clear distinction between the code, which is the structure for transmitting data, and the symbol, which is a representation of the code so that it can be read by a machine (although this is usually not the case). Absent). The code is text, which can be translated into a number of languages such as English, French, Japanese, or symbols.

Despite the unfortunate beginnings mentioned above, barcodes have been extremely successful and have become useful in many different areas of use. Developed by one of the first successful barcodes, Dr. David Allais, Code 39 is widely used in logistics and defense applications. Code 39 isn't as sophisticated as some new barcodes, but it's still in use today. Code 128 and Interleaved 2 of 5 are other codes that have had some success in the niche market.

The mapping between messages and barcodes is called symbolism. The symbolology specifications include the encoding of individual numbers and / or letters in the message, the encoding of start and stop markers in bars and spaces, and the size of the quiet zone required before and after the barcode. Includes encoding and checksum or error correction operations.

Linear symbols can be generally classified according to two characteristics: (1) continuous or discrete, and (2) two-width or multiple-width. .. Multiple characters in continuous symbolism are adjacent to each other, one character ending with a space, the next character starting with a bar, and vice versa. Multiple characters in discrete symbolism are started and ended by bars, and the spaces between the characters are ignored unless they are wide enough to look like the end of the code. Bars and spaces in two-width symbols are wider or narrower, and the width of a wide bar depends on the requirements of the symbolology for wide bars. (Usually, wide bars are 2-3 times wider than narrow bars), but not necessarily important. The bars and spaces in the wide-width symbolology are both multiples of the basic width called modules. Most of the code in such a wide-width symbolology uses four widths, consisting of one, two, three, and four modules. Stacked symbols consist of predetermined linear symbols that are repeated in parallel in the vertical direction.

There are various two-dimensional symbols. The most common is the matrix code. These matrix codes feature square or dot shaped modules arranged on a grid pattern. There are also two-dimensional symbols that have various other visual formats. In addition to circular patterns, some two utilize steganography by concealing an array of modules of different sizes or shapes within a user-defined image, such as DataGlyph. There is a dimensional symbolology. Steganography is the technique of writing a hidden message in such a way that no one but the intended recipient knows about the existence of the message. This steganography is in contrast to cryptography, where the existence of the message itself is not hidden, but the content is hidden.

The linear symbolology is optimized to be read by a laser scanner, which reads a slice of the light-dark pattern of the barcode by sweeping a beam of light linearly across the barcode. Stacked symbolism is also optimized for laser scanning. In this case, the laser is scanned multiple times across the barcode. Laser scanners use polygonal mirrors or galvanometer-mounted mirrors, initially linearly, but ultimately in complex patterns that allow the reader to read the barcode at any angle. , Perform a laser scan across the barcode. Two-dimensional symbols cannot be read by a laser because there is usually no sweep pattern that can contain the entire symbol. Therefore, a two-dimensional symbol is usually scanned by a camera capture device.

In the 1990s, some barcode reader manufacturers began researching digital cameras that capture both linear and two-dimensional barcodes. Since then, this technology has been improved and now often outperforms laser scanners in performance and reliability. Nowadays, commercial cameras have sufficient resolution to capture both one-dimensional and two-dimensional barcodes. More and more companies are moving towards incorporating barcode scanning software into camera phones. However, camera phone optics are not well suited for standard codes designed for industrial dedicated scanners. Therefore, new cord designs for mobile phones are being made.

Barcodes, and in particular two-dimensional symbolology codes, are designed to hold data. Code users continue to need the increased data needed to provide an increase in the amount of data held within their code and the code that holds that data. Due to such increased data and the need for codes to hold such data, the people who supply these codes are expanding their data capacity. However, there are basic technical problems that make it difficult to generate and print the increased data and the code that holds the data, as well as to read and extract the information. Increased levels of data usually require improved quality of symbol cells in the code to hold that data. This improvement can be achieved by generating code that uses a relatively large area or by making the symbol cells in the code relatively small.

<p><patcit num="1"><text>U.S. Pat. No. 2,612,994</text></patcit><patcit num="2"><text>U.S. Pat. No. 5,612,524</text></patcit><patcit num="3"><text>U.S. Pat. No. 4,972,475</text></patcit><patcit num="4"><text>U.S. Pat. No. 4,924,078</text></patcit></p>

<p> One method for providing an increased level of data usually requires an increased area to hold the data. Most barcodes / dot codes are printed on the board. Also, some barcodes / dot codes are read by other monitors such as LCDs and mobile phone screens. The problems caused by printing or writing relatively large codes on readable media are well known. For example, a medium such as a driver's license is small and in this case no additional area is available for the relatively large code. On the other hand, code users usually do not want code, which is large and often annoying, to reduce its appeal in the media market. The physical size of the electronic medium will not be large enough to hold a relatively large code. A mobile phone is an example of a screen having a small area that cannot hold a relatively large cord.</p><p> Other methods for increasing data capacity also have problems adding symbols by reducing the cell size of each symbol. In particular, the printed medium will not have the ability to adapt to the improved resolution required to display relatively small readable symbols. Most printed media have limited DPI (Dots Per Inch) or resolution, so it is not possible to form relatively small symbols well enough to be readable. Is. On the other hand, LCDs and other electronic media have a more limited DPI and have a fixed number of pixels for displaying elements. Relatively small code cells are often difficult to produce correctly in the camera of the reader.</p><p> A two-dimensional code is usually an area comprising a photosensitive element configured as an array containing elements in orthogonal X-axis and Y-axis, or a drive motor that moves the code below a single row of the photosensitive element. Area array camera Read by device). It will be difficult to read a relatively dense two-dimensional symbolology code. When using a relatively large area code or a relatively small but relatively dense symbol, the number of camera elements located on any particular cell is a relatively small code or relative. Less than in the case of low density cords. The more elements that generate an image of any particular cell, the more likely it is that the cell's binary code will be read correctly. For relatively large codes, additional camera arrays need to be replenished to read the code. As more image-generating elements are replenished and moved farther from the center of the camera array, the camera lens will have more distortion. As a result, the image is not accurate at the outer edges. As the code has more cells that need to be read, the total data to be analyzed becomes even larger. As a result, more time will be required based on the increase in the number of elements to be analyzed.</p><p> One commonly used area array camera has an array of 640 x 480 (307,200) elements. These arrays can be used to read code that typically has up to 800 bytes of data. The code chosen for large data content is Veritec. Inc.) is a two-dimensional VS Code® symbolology currently on the market. VS Code® symbols with a capacity of 1200 bytes, like other small data codes, generally cannot be read using a camera with the features described above. It is possible to use a 1.3 mega-element camera for a 1200-byte code, but the increased operating load / reading time associated with using four times the elements, and the greater cost required for the camera. , And all of the poorer image stability make it difficult to read larger codes. Two-dimensional codes for large data are reaching the actual maximum data capacity in current technology, considering cost, complexity, and read speed as well. Furthermore, due to the fact that each cell in the symbolism is restricted by the binary function that the 2D code has only black and white cells that provide only 2 bits of data per cell. It is still restricted.</p>

<p> To solve the above problems, the present invention provides a multidimensional symbolology code and related methods that use a plurality of unique features encoded in a data cell. The method includes a method of encoding, a method of generating, and a method of reading a multidimensional symbolology code using a plurality of such unique features. Such features include, for example, color, grayscale level, cell shape, patterns within cells, or any grouping as can be identified by an area array camera. By using the plurality of features described above, the data content in the cell is increased by a multiple of the number of features in each feature divided by two. On the other hand, the present invention is a method of detecting a code in the field of view, correcting the code for optical distortion, correcting the camera output by recalibration with a known feature at a known location, and reading the above symbols. There is a method of using an area array camera as much as possible.</p><p> The present invention captures more than two data bits of data, respectively, without the need for additional area array camera elements, camera complexity, and the cost or time required to extract data from cells. Provides a method for extracting from a symbol cell. In other words, the present invention presents cells from various optically readable designs and colors or combinations thereof in any combination or array to provide more than two data bits per cell. By generating, it provides the ability to achieve the growth of data bits from a single cell.</p><p> More specifically, in one aspect of the invention, a multidimensional matrix symbol with multiple data cells is provided. At least one data cell preferably has a plurality of unique features, each unique feature representing an encoded data bit. Typical distinctive features include color, grayscale levels, shapes, and geometric patterns. The plurality of data cells are preferably arranged within the internal data field, and the multidimensional matrix symbol may optionally further have a data cell boundary having a plurality of data cells surrounding the internal data field. It is possible. At least one data cell at the data cell boundary preferably has a plurality of unique features, each unique feature representing an encoded data bit.</p><p> In another aspect of the invention is provided a multidimensional matrix symbol having an internal data field with a first plurality of data cells and a data cell boundary with a second plurality of data cells. At least one data cell of the second plurality of data cells has a plurality of unique features, and each unique feature represents an encoded data bit. In one aspect of the invention, the first plurality of data cells comprises a binary data cell.</p><p> In another aspect of the invention, a method of reading a multidimensional matrix symbol is provided. This method is a step of providing a multidimensional matrix symbol with multiple data cells, where at least one data cell has a plurality of unique features and each unique feature is encoded. It has a step of representing a data bit, a step of identifying each unique feature in each data cell, and a step of decoding the data represented by each unique feature. A plurality of data cells of a multidimensional matrix symbol are preferably arranged within an internal data field, and the multidimensional matrix symbol preferably has a data cell boundary having a plurality of data cells surrounding the internal data field. Have more. Another aspect of the invention comprises the step of detecting a multidimensional matrix symbol by identifying at least a portion of a data cell boundary. Yet another aspect of the invention comprises the step of orienting a multidimensional matrix symbol by identifying at least a portion of a data cell boundary.</p><p> In another aspect of the invention, a method of reading a multidimensional matrix symbol is provided. This method is a step of providing a multidimensional matrix symbol having an internal data field having a first plurality of binary data cells and a data cell boundary having a second plurality of multidimensional data cells, the second step. At least one of the plurality of multidimensional data cells of the multidimensional data cell has a plurality of unique features, and each unique feature is a step representing an encoded data bit and a first plurality of unique features. The step of decoding the data represented by the binary data cell, the step of identifying each unique feature of each data cell in the second plurality of multidimensional data cells, and the step of identifying the unique feature of each unique feature, and the data represented by each unique feature. Has a step of decoding. Another aspect of the invention further comprises the step of detecting a multidimensional matrix symbol by identifying at least a portion of the data cell boundary. Yet another aspect of the invention comprises the step of orienting a multidimensional matrix symbol by identifying at least a portion of a data cell boundary.</p><p> Another aspect of the invention is an area array camera method that uses the unique aspects of the code of the invention and is capable of reading the code according to the invention with improved capabilities compared to current code and readers. Is intended for use.</p><p> The multidimensional matrix symbols and methods of the present invention offer a number of advantages over traditional two-dimensional symbols. For example, boundaries are typically used to achieve omnidirectional or omnidirectional code reading by detecting symbols in the field of view and correcting problems with reader rotation and skew with respect to the code substrate. And usually, it has a black line in a known two-dimensional code. Aspects of the invention provide boundaries with new and unique identities compared to black lines, as well as features that can be used to assist in optical distortion correction in known locations. The timing marks in the symbols of the present invention are relatively easy to detect and identify, are more accurate than the black-only cells of conventional data cells, and are compared to other two-dimensional symbolology codes. It is possible to provide good placement for symbol cells. The layered structure of relatively complex information provides an encoding algorithm with greater security based on the placement of data among a number of features. In the case of code that requires only 800 or 1200 bytes of information, the code of the invention is, for example, less than 1% compared to existing structures accepted by the industry while maintaining the same cell size. This can be achieved by area or by significantly larger cells that make reading easier and more tolerant of optical errors. Because the output of a 24-bit element group located on a cell can have up to 256 bits of useful information, for example, compared to the 2-bit information in industry-accepted structures. , The reading speed of information for each cell is much faster.</p>

<figref num="1">FIG. 5 is a diagram showing an internal data field of an exemplary two-dimensional symbol formed on a substrate, particularly a two-dimensional symbol having a plurality of data cells.</figref><figref num="2">It is the schematic of the multidimensional matrix symbol for example which concerns on this invention.</figref><figref num="3">FIG. 5 is a schematic representation of exemplary data cells, each with a different color, that can be used within the multidimensional matrix symbols according to the present invention.</figref><figref num="4">FIG. 6 is a schematic representation of exemplary data cells, each with a different grayscale level, that can be used within the multidimensional matrix symbols according to the present invention.</figref><figref num="5">FIG. 5 is a schematic diagram of exemplary data cells, each having a different shape, that can be used within the multidimensional matrix symbols according to the present invention.</figref><figref num="6">FIG. 6 is a schematic representation of exemplary data cells, each with a different geometric pattern, that can be used within the multidimensional matrix symbols according to the present invention.</figref>

The accompanying drawings included in the present application and constituting a part thereof show some embodiments of the present invention, and are used for explaining the principles of the present invention together with the description of the embodiments. To. A brief description of the accompanying drawings is as described in the section [Brief Description of Drawings] above.

Area symbolism, as described in US Pat. No. 5,612,524, US Pat. No. 4,972,475, and US Pat. No. 4,924,078. symbology) is well known. All disclosures of these US patents are incorporated herein in every sense by reference herein. A typical symbol 10 of such area symbolism is shown in FIG. In general, symbol 10 includes an internal data field 12 having internal data cells 14 arranged as a matrix. The internal data field 12 and the internal data cell 14 are preferably rectangular as shown, but any other shape is also conceivable. As shown, the internal data field 12 has a specific data cell 14 that is ON and a specific data cell 14 that is OFF. As shown, the "on" data cells are black (cells indicated by reference numerals 16, 18, 20, and 22) and the "off" data cells are white (internal data field 12). Remaining cells of). Such on and off designations are used when decoding symbols such as symbol 10. It should be understood that it is possible to use any binary designation, including on and off, 0 and 1, and black and white to distinguish data cells 14.

As shown, the internal data field 12 is preferably surrounded by orientation and / or timing data cell boundaries 24. This data cell boundary 24 is typically used for timing and symbol orientation. Data cell boundaries are usually formed from "on" data cells, as shown. It is possible to provide an external data field 26 that surrounds the data cell boundary 24. This external data field 26 can include an external data cell (not shown) that provides additional information regarding orientation, timing, or symbol identification. Preferably, the one surrounding the data cell boundary 24, i.e., the external data field 26, if provided, is one of the "off" data cells surrounding the outermost pattern of the "on" data cells. A quiet zone that is equivalent to one or more concentric straight rings. The required number of concentric linear rings in this quiet zone can be determined by environmental factors in symbol usage. Alternatively, instead, the external data field 26 can function as a quiet zone or be surrounded by additional quiet zones.

Symbol 10 can also be formed directly on the substrate 28 by printing or controlled deposition of ink or other coating, or on a sticker or label by printing or any other suitable technique. It is also possible to attach it to the substrate by adhesion or other methods after it is formed.

The principles of the present invention are applicable to any symbol from any linear or stacked area or other symbolism, and preferably to symbols formed as an area relief pattern, as described below. Is. Area symbolology as used herein is Vericode® or Data Matrix® or Code, which utilizes a matrix of data cells rather than one or more columns of bars and spaces. It means any symbolism such as one that is commercially known under a registered trademark name such as One (Registered Trademark) or something similar thereto. Stacked symbolism as used herein generally utilizes several adjacent columns of symbols such that each column has several characters defined by groups of bars and spaces of multiple widths. It means any symbolology such as PDF 417.

As used herein, a symbol generally means a matrix of cells containing cell features and data encoded within the tissue. A matrix is a pattern of organized cells. A cell is a single component in a matrix that has the characteristic of holding encoded data. The above features have various attributes or elements applied to the cell structure such as color, grayscale, shape, pattern, or special optical ink. Preferably, the above features can be defined in the software algorithm as separate entities, printable by a digital color printer as separate entities, and / or produce images by a color digital camera. Can be output as a separate entity.

The codes and symbols according to the present invention not only increase the data content, but also enable the implementation of many new encoding and decoding methods, add security, and enhance the correction of data in cell symbols or codes. Improve readability by known placement of types and elements with predetermined characteristics for any species, and achieve countless other improvements not possible with 2-bit cells.

With reference to FIG. 2, an exemplary multidimensional symbol (multidimensional matrix symbol) 30 according to the present invention is schematically shown. The multidimensional symbol 30 has an internal data field 32 having a matrix of data cells 34 and an orientation and / or timing data cell boundary 36 consisting of data cells 38.

As shown, the data cell 34 of the internal data field 32 has a multidimensional data cell, but can also have a binary data cell (eg, black and white, etc.). Further, as shown in the figure, the data cell 38 at the data cell boundary 36 has a multidimensional data cell, but it is also possible to have a binary data cell if necessary. As used herein, a multidimensional data cell is a data cell that represents a data bit and has a plurality of unique features encoded by data in more than two data bits. Means.

Specific features for illustration that can be used with the multidimensional data cell according to the present invention are shown in FIGS. 3 to 6. These unique features include color, grayscale level, shape, and geometric design. FIG. 3 shows exemplary data cells 40, 42, 44, and 46. According to the present invention, the data cells 40, 42, 44, and 46 each exhibit the unique characteristics of the exemplary colors. Data cells 40, 42, 44, and 46 are shown as squares (another unique feature according to the invention), but may have any desired shape or one or more additional unique features. It is possible. According to one embodiment of the invention, the data cell 40 is yellow, the data cell 42 is green, the data cell 44 is red, and the data cell 46 is cyan, but is optional. It is possible to use the desired color of. FIG. 4 shows exemplary data cells 48, 50, 52, and 54. According to the present invention, the data cells 48, 50, 52, and 54 each exhibit the unique characteristics of grayscale. Data cells 48, 50, 52, and 54 are shown as squares (another unique feature according to the invention), but may have any desired shape or one or more additional unique features. It is possible. According to one embodiment of the invention, the data cell 48 is white, the data cell 54 is black, and the data cells 50 and 52 have a grayscale between white and black. FIG. 5 shows exemplary data cells 56, 58, 60, and 62. According to the present invention, the data cells 56, 58, 60, and 62 each exhibit a unique feature of the shape. Data cells 56, 58, 60, and 62 are shown as white, but can have any desired color or one or more additional unique features. According to one embodiment of the invention, the data cell 56 is square, the data cell 58 is diamond-shaped, the data cell 60 is circular, and the data cell 62 is pentagonal (5). Has sides). FIG. 6 shows exemplary data cells 64, 66, 68, and 70. According to the present invention, the data cells 64, 66, 68, and 70 each exhibit a unique feature of the geometric pattern. Data cells 64, 66, 68, and 70 are shown as having various shapes, but can have any shape or one or more additional unique features. According to one embodiment of the invention, the data cell 64 has a first geometric pattern of lines arranged at predetermined intervals, and the data cell 66 is of lines arranged at predetermined intervals. It has a second geometric pattern, data cell 68 has a concentric geometric pattern, and data cell 70 has a third geometric pattern of lines that are spaced at predetermined intervals. Has.

The multidimensional symbol according to the present invention can use a data cell having an arbitrary combination of a plurality of unique features. For example, if four different colors, four grayscale levels, four different shapes, and four different patterns are available for a data cell, then the number of data bits available per data cell is: Compared to 2 bits in a binary cell (eg black and white, for example), there will be 4x4x4x4, or 256 bits of data, per cell.

The encoding of the data according to the present invention is a well-known area symbolology such as those commercially known under the registered trademark name of Vericode (registered trademark) or Data Matrix (registered trademark) or Core One (registered trademark). It is as feasible as what is being done in. A typical method for encoding data is "Methods for Encoding and Deconding," which was filed on May 3, 2005. Information) is described in U.S. Patent Application No. 11 / 121,762, the entire disclosure of which is incorporated herein by reference in this specification. .. Usually, these techniques encode the information in an appropriate way, including the step of encoding the information into a Reed-Solomon block. The data to be encoded is represented by the binary code that forms the string of the binary code. CRC (Cyclical Redundancy) based on a string of binary code Calculates a value called Check: Cyclic Redundancy Check). The CRC is added to the binary string. The CRC is used by the reader to check that the decoded information is correct. It then generates a 64-bit Reed-Solomon block code based on the binary string. According to the Reed-Solomon block code, it is possible to restore the original data even if some part of the data is damaged. The Reed-Solomon block code is the symbol EDAC (Error Detection and). Correction: Error detection and correction) This is the basis of the function. The bit values from the block chords are preferably interleaved so that speckled damage to the symbols caused by dust, scratches, etc. is distributed across the various blocks. As a result, the symbol is less likely to become unreadable. Then, from the encoded information, a data matrix containing a plurality of data cells is generated. Next, the data matrix is converted into a bitmap image in the form of a symbol, and this bitmap image is printed on an object, a label, a box, or the like. For example, this type of symbol is now commonly used in various fields of use such as inventory management, point of sale (POS) identification, or distribution tracking systems.

The cells can also be organized as a group for convenience. For example, it is possible to use two different organizations in a single code. The first area is located at one or more corners of the symbol, which is called the descriptor block. This descriptor block is constructed from 2x2 cell blocks and is organized as 3x3 blocks for a total of 71 bits of data. This field can contain information about the code, such as the number of cells in the X and Y axes, the CRC number, or the identity of the encryption key used in the code. Data cells are organized as 3x3 cell blocks. The total number of data blocks can be calculated by multiplying the number of cells in the X and Y axes by 9 and subtracting 4 or 16 for one or more descriptor blocks. It is possible. Note that the total number includes descriptor blocks and data blocks. Both the X-axis cell and the Y-axis cell are preferably divisible by 3.

The symbols according to the present invention can be generated by any suitable printing or image forming method. Preferably, by using color as an example, each cell has a color that can be defined in the software as a red, green, and blue (RGB) component, but cyan, magenta, yellow, and black (CMYK). ) It could be in a form that can be specified by the ingredients and can be sent to a color digital printer or something similar. Preferably, the printer has the ability to print a combination of colors so that it can be perceived as a separate color from all the remaining colors used in the matrix. Compared to laser printers, where the spots are relatively large and just overlap each other, in the case of inkjet printers, the primary color droplets are very small and are emitted together to produce even more identifiable color combinations. provide. According to the present invention, it is possible to use similar techniques for grayscale, shape, and geometric patterns.

Another feature when printing code is the use of process colors, which allow all features to be observed by layering transparent colors. Most common printer types, such as lasers and inkjets, use transparent colors.

To read a symbol according to the present invention, the symbol is detected in the field of view, the four corners are identified to determine rotation and skew, and the matrix is adjusted back to be rectangular, or (horizontal cell). And at least set up the intersections of horizontal lines and pairs of vertical lines and lines where cells should be placed, adjusted for rotation and skew (based on the number of vertical cells).

Such an analysis usually starts with what is considered to be the most central pixel and moves outward by reducing the value of the multiplier that is averaged as the pixel moves away from the center. Give weight to the pixels to be used. When a pixel whose color is too far from the average value is identified, the pixel is rejected and not averaged. When a predetermined limit is reached by the matrix or rejected pixels, its average value is the component of its color and grayscale. The shape is determined by observing the color pixels in comparison to the rejected pixels by looking for the shape based on the pattern. The pattern in the cell may be a circle radiating from the center, a square radiating from the center, a triangle radiating from the center, and the transformation to the data from the matrix. It could be another geometric configuration that provides a different signature when applied.

Common print codes and cameras change between codes or cameras and over time. Therefore, a method of adjusting the camera to recognize each feature at the moment of reading a symbol is provided according to the present invention. Preferably, the software algorithm is recalibrated by setting the boundaries as a known array of cells (preferably larger than the cells in the matrix) so that the correct data is output for each feature in the matrix. An example of each feature for is provided to the code reading software. Boundaries can also use additional features to improve rotation and skew determinations. For example, large cells of each primary color and black can be placed at the four corners. The pattern of the large cells identifies the orientation, and the exact shape of the large cells is an indicator of skew. The shape data of the cells at the four corners is added to the data from multiple boundary cells located at known locations where alignment is determined, and the skew found from the observation of the four corners. When added, the information thus combined will be discovered and corrected by the barreling of the lens, where the centers of the four sides of the symbol are rounded outwards, and by observing the corner points themselves. It provides a more accurate picture of imbalanced skew, such as the trapezoidal problem, which results from the lens not facing the symbol in the unattended state. Also, one or more variable cells at one or more known locations on the boundary are the number of cells on each axis, where to detect the descriptor block, the encryption code, and the like. It is also possible to have information about symbols such as.

Traditional area array cameras have unique features that can be used to discriminate beyond the single feature of black or white. A typical camera outputs 24-bit information for each element. Normally, 8 bits are used for the grayscale of the element, and the remaining 16 bits are the three primary colors red, green, and blue (RGB), or cyan, magenta, yellow, (and black) (and black). It is divided between complementary colors called CMYK). One embodiment of the present invention comprises the step of using one or several different methods or designs that allow the stacked information to be extracted from a single cell. Known methods use only 2 bits of data bits (black or white) from each element, usually 24 bits, or any subset of up to 4 or 8 colors available. The code according to the invention uses more than two data bits from each element. The cell according to the present invention can be composed of several colors, which can include other colors using a combination of primary colors and transparent primary colors. Each color in the cell can have varying grayscale levels to distinguish each color by a multiple of the number of levels of the grayscale element in the grayscale feature. Each cell can be designed as a different shape, such as a square, diamond, circle, or other shape that is easily discriminated by an array of camera elements. Within the cell, it is possible to generate various patterns that provide different responses when analyzed by known transformations in optical analysis using an array of camera elements. In the case of printed code, infrared light, as well as color, grayscale, shape, or pattern, to elicit a response from a camera element or other device that is recognizable by differentiation from other features. It is possible to use inks having other characteristics such as UV, fluorescence and the like. Using symbol cells with different characteristics, the cell and its exact It is possible to identify the location more accurately. Black cells can be the same color as unwanted artifacts in the code area (assuming a two-color image of black and white) and discriminate from good cells or good cell boundaries. Colored cells are less likely to get into background noise, whereas it is difficult to do.

Another embodiment of the invention is to place all of the features used in the codes in known locations on each code and recalibrate the camera for the code to be read. Redundant placement of features is useful in eliminating problems caused by damage to some of the calibration features, and is also useful in averaging calibrations across many inputs. Timing marks in the code can also consist of different features that provide additional information about the location of the cell, or can be used for added symbol encoding and decoding. is there. By placing the calibration features, for example, on the four boundaries of the symbol, it is possible to set color values, grayscale values, shape signatures, deformation signatures, and any other features used, and , The values or signatures they provide can be used to more accurately calibrate cell readings. Also, analysis of the four boundaries of features shows the differences between known features at comparable positions, which can provide corrections for rotation, skew, and lighting issues based on comparable data. is there. Boundaries can have different elements in known locations, making code detection in the field of view more accurate and reliable. Timing cells with different characteristics can be used to more accurately identify timing marks and their exact locations. Currently, black cells are the same color as the unwanted artifacts in the code area (assuming a two-color image of black and white) and are difficult to distinguish from good cells. As an example, taking boundaries include stacking features on one boundary, detecting features within a box area on the four corners of the code, and numerous other methods according to these embodiments of the invention. It would be possible to utilize a number of methods such as detecting calibration characteristics.

Another feature of the present invention is the use of an area array camera capable of reading the multidimensional symbolology code of the present invention. The camera hardware used may typically be CCD, COMS, or other technology currently on the market, but preferably camera regulators, firmware, software, drivers, and other control methods. Desirably, one or more of the features described herein are used to be optimized to read the multidimensional symbolology code of the invention.

The present invention has been described above with reference to some examples (embodiments). All disclosures of a patent or patent application identified herein are incorporated herein by reference in this specification. The above detailed description and examples are provided only for the sake of clarity of the present invention. These descriptions and examples should not be understood as intended to be limiting. It will be apparent to those skilled in the art that it is possible to make numerous modifications in the described embodiments without departing from the scope of the invention. Therefore, the scope of the present invention is not limited to the structures described herein, but only to the structures described in the claims or equivalents of those structures.