Technology for generating, reading, and using machine-readable codes is disclosed. There is a method, performed by an image capture device, for reading and using the codes. The method includes obtaining an image, identifying an area in the image having a machine-readable code. The method also includes, within the image area, finding a predefined start marker defining a start point and a predefined stop marker defining a stop point, an axis being defined there between. A plurality of axis points can be defined along the axis. For each axis point, a first distance within the image area to a mark is determined. The distance can be measured from the axis point in a first direction which is orthogonal to the axis. The first distances can be converted to a binary code using Gray code such that each first distance encodes at least one bit of data in the code.

Described is a device formed by at least two layers, one of which is invariable and contains a visual code with error correction capacity, and at least one layer that is variable according to particular physical or chemical conditions. The invention also relates to a method for creating these devices and encoding the messages included in same; a method for reading or decoding the information contained in the devices; and a system capable of analysing and decoding the information contained in the messages of the device.

A system and method for error correction for machine-readable symbols having data codewords, and having error correction (EC) codewords derived from the data codewords and redundantly indicating the location and data contents of the data codewords. The symbols use Reed-Solomon (RS) error correction to retrieve damaged codewords. RS error correction normally requires two EC codewords to identify both the location and data contents of a data codeword. The present system and method perform optical contrast analysis on the codewords, identifying those codewords with the lowest contrast levels (that is, the least difference between the reflectance of the black or white cells and the black/white threshold). Codewords with the lowest contrast levels are flagged as optically ambiguous, thereby marking, in the EC equations, the locations of the codewords most like to be in error. As a result, only a single EC codeword is required to retrieve the data for a flagged data codeword.

A two-dimensional code generation method and apparatus, a two-dimensional code identification method and apparatus, an electronic device, and a storage medium are provided. The method includes generating a data codeword sequence according to input information, encrypting the data codeword sequence to generate an encrypted codeword sequence, determining a number of error correction blocks, and generating the two-dimensional code from the data codeword sequence and the encrypted codeword sequence according to a construction mode corresponding to the number of error correction blocks.

A method for correcting a geometrically distorted QR code include oversampling modules of the QR code by dividing each module to F*F sample elements for forming an oversampling matrix, determining intensity for each sample element in the oversampling matrix, calculating an average intensity of the oversampling matrix, subtracting the average intensity from intensity of each sample element in the oversampling matrix, filtering intensity values for determining an average value for each sample element, tracking a sample element corresponding a center of each module and determining color of each module based on intensities of sample elements corresponding the center of each module by using recursion. The disclosure further relates to a computer program product and device performing the method.

Systems and methods for reading a two-dimensional matrix symbol or for determining if a two-dimensional matrix symbol is decodable are disclosed. The systems and methods can include a data reading algorithm that receives an image, locates at least a portion of the data modules within the image without using a fixed pattern, fits a model of the module positions from the image, extrapolates the model resulting in predicted module positions, determines module values from the image at the predicted module positions, and extracts a binary matrix from the module values.

Methods, systems, and apparatus for combining preprinted information together with coded sensor information within a two-dimensional barcode. The sensor information may be of an environmental, physical or biological nature, and records a cumulative change in status of the environmental or biological condition to which the labeled product has been exposed. A sensor dye chemistry is employed that undergoes a continuous chemical or physical state change in response to the occurrence of the environmental condition. The continuous change is between an initial state and an end state causing a change in the color state of the sensor dye embedded within the sensor-augmented two-dimensional barcode, encoding sensor digital information. Sensor information is recovered utilizing the error-correction feature during barcode decoding.

The present invention facilitates, in a two-dimensional symbol in which a region where additional data is recorded is provided in addition to a region where normal data is recorded, identification of colors of the regions where the respective data are recorded. Vertically and horizontally arranged first modules are provided, and by the coloration patterns of the first module, a finder pattern for detecting a symbol position, a timing pattern for specifying the center position of the first module, and a first recording region where first data can be recorded are formed. In at least a partial region, a second module is disposed in a portion that does not overlap the first module and includes an intermediate point between the first modules adjacent to each other, and a second recording region where second data can be recorded is formed by the coloration pattern of the second module.

Methods for optimizing improper product barcode detection are disclosed herein. An example method, includes analyzing an object-based identification data against an indicia-based identification data to determine if there is a match. Responsive to there not being a match, entering a release condition state, where, instead of automatically sending a failed match signal to a symbology reader, a remote server awaits satisfaction of the release condition, before sending to the symbology reader. In some examples, a release condition is automatically satisfied by identifying a match in a subsequent comparison. In some examples, a user of the remote server is to satisfy the release condition.

In evaluation of the print quality of a symbol, the evaluation processing takes time. A symbol evaluation device (5) includes: a decoding unit (52) that decodes a symbol included in an image and thereby identifies reference position information of the symbol; a module position identification unit (53) that identifies a plurality of module positions included in the symbol on the basis of the reference position information of the symbol identified by the decoding unit; and a quality evaluation unit (54) that evaluates the quality of the symbol on the basis of the plurality of module positions identified by the module position identification unit.