Reading an optical code

1 . A method of reading an optical code, said method comprising:

recording image data having the optical code, wherein code modules in the image data each have a module size that indicates how large the respective one of the code modules is in picture elements of the image data;

determining defects, wherein a defect is a region in the image data in which at least one of the code modules is not recognizable; and

evaluating the image data by reading code words, wherein each of the code words comprises a plurality of the code modules,

wherein the defects are determined using an edge criterion and/or a binarization criterion, wherein the edge criterion evaluates whether one of the code modules is in an edge-free region of the image data that is larger than a specified multiple of the module size corresponding thereto, an edge detection in the image data being further performed, wherein a distance from a next edge is determined for a picture element per position of one of the code modules, the edge criterion being deemed satisfied in the picture element when the distance corresponds to at least a specified distance, and

wherein the binarization criterion evaluates whether one of the code modules having gray scale values close to a binarization threshold has been recorded, wherein the binarization criterion is deemed satisfied at the picture element when the gray scale value of the picture element remains within an expected fluctuation range around the binarization threshold.

2 . The method in accordance with claim 1 ,

wherein an edge correction in the image data is carried out for the evaluation with the edge criterion.

3 . The method in accordance with claim 2 ,

wherein the edge correction in the image data is carried out after blur has been artificially produced beforehand.

4 . The method in accordance with claim 1 ,

wherein the optical code is read using an error correction method.

5 . The method in accordance with claim 4 ,

wherein the error correction method comprises a Reed-Solomon process.

6 . The method in accordance with claim 4 ,

wherein the defects are communicated to the error correction process as additional input values.

7 . The method in accordance with claim 6 ,

wherein a number of the code words affected by defects corresponding to an error correction capacity of the error correction process are communicated to the error correction process.

8 . The method in accordance with claim 6 ,

wherein a plurality of reading attempts are made with the error correction process and respective different ones of the code words affected by defects are communicated to the error reading process in the reading attempts.

9 . The method in accordance with claim 6 ,

wherein a decision as to which of the code words affected by defects are communicated to the correction process according to a confidence value.

10 . The method in accordance with claim 9 ,

wherein the confidence value is calculated from the edge criterion and/or the binarization criterion.

11 . The method in accordance with claim 10 ,

wherein the edge criterion in accordance with the formula

1

-

(

1

2

)

n

1

contributes to the confidence value, with n 1 being the number of the code modules affected by a defect.

12 . The method in accordance with claim 10 ,

wherein the binarization criterion contributes the more to the confidence value, the closer to the gray scale value of the picture element looked at with the binarization criterion is to the binarization threshold.

13 . An optoelectronic code reader having at least one light reception element for generating image data from received light and having a control and evaluation unit configured to implement the method of reading an optical code in accordance with claim 1 .

14 . A method of reading an optical code said method comprising:

recording image data having the optical code, wherein code modules in the image data each have a module size that indicates how large the respective one of the code modules is in picture elements of the image data;

determining defects, wherein a defect is a region in the image data in which at least one of the code modules is not recognizable;

evaluating the image data by reading code words, wherein each of the code words comprises a plurality of the code modules; and

reading the optical code using an error correction method, the defects being used as input values for the error correction method such that correction is performed for the defects,

wherein the defects are determined using an edge criterion and/or a binarization criterion, wherein the edge criterion evaluates whether one of the code modules is in an edge-free region of the image data that is larger than a specified multiple of the module size corresponding thereto, and

wherein the binarization criterion evaluates whether one of the code modules having gray scale values close to a binarization threshold has been recorded.