Electronic edge detection system using a second derivative signal processor
US6073849A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 1997 |
| Grant date | Jun 13, 2000 |
| Priority date | — |
| Expiry date | Oct 31, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/14
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An electronic edge detection system for use in a barcode scanning system utilizing second derivative signal processing wherein the temporal offset between the first and second derivative signals is eliminated so as to enable edge detection for signal levels down to the noise level of an input signal. In a preferred embodiment, an overall filter network receives an input signal and comprises two real poles as the last elements of two parallel output channels. The first output channel terminates with a low pass filter and produces the first derivative of the input signal. The second output channel terminates with a high pass filter and produces the second derivative of the input signal. Implementing the second differentiator as one real pole of the overall edge detection system filter polynomial and placing the poles of the two output filters at the same frequency eliminates the temporal offset. Substantially constant and equal group delay over the system passband for both first and second derivative signals is also provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.