Research On Recognition Technology And Encoding Theory Of High-Dimensional Bar Code

With the development of computer technology, automatic identification technologies have been widely applied , among which bar code has been the leading one. Recognition technology and encoding theory are two hot spots in bar code technology. In order to solve the problem of limited information capacity of bar code, a new type of bar code, two-dimensional bar code, has been developed. Here, it and three-dimensional bar code presented in this paper are called high-dimensional bar code. This paper discusses the recognition technology and encoding theory of high-dimensional bar code.Bar code detection is an important step. Before its recognition, bar code needs to be located by filtering text and other signs in the image. This paper presents a novel algorithm of bar code detection based on multiple features analysis of subregions. First, the subregions that might contain bar code are found out through features analysis, then after subregions clustering and candidacy test, the bar code is located. Experiments show that this algorithm is of good performance and superior to the algorithm based on gradient feature. After detection, an algorithm of bar code recognition is proposed in this paper. Some strategies introduced in this recognition algorithm are proved to be effective and improve the performance of the algorithm. Experiments show the recognition algorithm based on subpixel edge detection proposed here is advantageous over traditional recognition algorithm and can get a more accurate edge position between bar and space.Bar code recognition is a matter of edge detection, which has long been done through the maximum value of the first derivative or zero crossing of the second derivative. When the bar code is of higher density, adjacent edges interact each other due to the influence of the point spread function of image collection system, therefore, this kind of method becomes invalid. This paper analyses deterioration model of bar code signals after the point spread function convolution, and presents two kinds of recognition algorithm in correspondence to different bluring degrees of bar code signal: one based on midpoints detection and the other based on waveform analysis. Experiments show that the algorithm presented in this paper is able to effectively overcome bluring affects caused by the point spread function and apparently promote the recognition rate, and the algorithm is better than that based on edge detection.A higher demand of bar code's information capacity must be met because of its wider use. Increasing bar code size or increasing its density has limitations. Here, on the basis of two-dimensional bar code, a new type of bar code, three-dimensional bar code is designed. It greatly increases information capacity within limited space by combining the variety of widths, the variety of colors and vertical array. In addition, this paper discusses the recognition of three-dimensional bar code and presents the corresponding recognition algorithm.Finally, using two-dimensional bar code, this paper designs an anti-fake system for bank bills, which enjoys high security and high level of automation.The system has already been patented and used in experimental unit. The results certify its stability and high quality on anti-fake.