Single charge-coupled-device camera for detection and differentiation of desired objects from undesired objects
US5661817A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1995 |
| Grant date | Aug 26, 1997 |
| Priority date | — |
| Expiry date | Jul 21, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/131
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A conventional color charge-coupled-device (CCD) camera without a near infrared blocking filter is used to detect desired vegetation from undesired vegetation and other background. This detection technique relies on the fact that near-infrared (NIR) wavelengths are received by CCD cameras in predetermined frequency bands. This provides output signals from the green and blue pixels of the CCD camera which are approximately equal in interests to the intensity of the infrared portion of the signal provided by the red pixels. A filter is placed between a target area and the CCD camera to restrict the light received by the camera to a bandwidth (approximately from wavelengths of 600-1400 nm), which allows the NIR signal component of the green or blue pixels in this bandwidth to be compared by a signal processing device to the NIR plus R output of the red pixels. In this bandwidth the intensity of the output from the red pixels due to red light from the target area is maximized. Therefore, a signal processing device can utilize signals from the red, green and blue pixels to detect plants and crops in an area of undesired vegetation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.