IPC분류정보
| 국가/구분 |
United States(US) Patent
등록
|
| 국제특허분류(IPC7판) |
|
| 출원번호 |
US-0265230
(1988-10-31)
|
| 우선권정보 |
FR-0015403 (1987-11-06) |
|
발명자
/ 주소 |
- Raphal Moreno (Marseilles FRX)
|
| 출원인 / 주소 |
- SGS-Thomson Microelectronics SA (Gentilly FRX 03)
|
| 인용정보 |
피인용 횟수 :
20 인용 특허 :
2 |
초록
▼
Disclosed is an improvement in methods for reading bar codes, enabling the codes to be read even under difficult conditions of uneven printing, stained background, poor contrast, cut bars etc. Instead of merely detecting light absorption or reflection spikes when a detector is moved in front of the
Disclosed is an improvement in methods for reading bar codes, enabling the codes to be read even under difficult conditions of uneven printing, stained background, poor contrast, cut bars etc. Instead of merely detecting light absorption or reflection spikes when a detector is moved in front of the code, where the presence of a bar is indicated when a threshold is exceeded, the following method is used: a matrix image of black and white pixels is set up; the sum Tj of black pixels of each column is counted to draw up a curve Tj as a function of the abscissa j of columns; a threshold SDA is established for Tj, below which, in principle, the columns do not contain a portion of a bar code bar; blocks of columns going beyond the threshold SDA are demarcated, and all the other columns of the image are eliminated; then shape recognition is carried out on the remaining blocks to ascertain whether the block truly corresponds to a bar or not. The value SDA is established by a recurrent computation that brings into play the ratio between surfaces Sinf and Ssup, above and below the threshold SDA in the curve Tj= f(j).
대표청구항
▼
A method for the optical reading of bar codes, comprising the following sequence of processing operations: (a) providing, by means of an optical detector, a representation of a zone containing the bar code, in the form of a matrix of pixels in which each pixel represents a binary logic state charact
A method for the optical reading of bar codes, comprising the following sequence of processing operations: (a) providing, by means of an optical detector, a representation of a zone containing the bar code, in the form of a matrix of pixels in which each pixel represents a binary logic state characteristic of a dot of the zone; (b) computing the total Tj of the number of pixels in a first logic state for each column of the matrix, j being the column index of the matrix; (c) establishing a value SDA such that the columns for which Tj is below SDA are not considered as probably containing a bar of the bar code; (d) determining, by making j increase, a sequence of abscissae of columns XA1, XA2, . . ., XAr etc., for which Tj crosses the value SDA in a first direction and a sequence of abscissae of columns XB1, XB2. . . . XBR, etc. for which Tj crosses the value SDA in the other direction; (e) demarcating, in the matrix of pixels, for each index r, a rectangle having, as its sides, the columns of abscissae XAr, XBr or immediately adjacent columns; (f) comparing, for each rectangle, a parameter of the total image represented by the pixels of a defined logic state, contained in this rectangle, with a theoretical, nominal parameter of a bar code bar which would be pointed essentially in the direction of the columns of the rectangle; (g) giving a binary electrical signal of a first logic state or a second logic state as a function of the result of the comparison, said signal representing the presence or absence of a bar.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.