Surveillance camera system with infrared and visible light bandpass control circuit
First Claim
1. A surveillance camera system having a control circuit that switches a camera between an infrared radiation imaging mode and a visible light imaging mode, based on an ambient light infrared sensing system having an infrared radiation and visible light bandpass filter that essentially blocks all of the infrared radiation and the visible light in a stop band comprising both infrared radiation and visible light wavelengths, the stop band spectrum covering a range of approximately 100 nanometers between approximately 680 nanometers of wavelength and approximately 790 nanometers of wavelength, the stop band thereby significantly differentiating by approximately 100 nanometers passed bandwidths of infrared radiation on a longer wavelength side of the stop band from passed bandwidths of visible light on a shorter wavelength side of the stop band, the significantly differentiated passed bandwidths of infrared and visible light respectively being allowed to proceed toward the camera for further processing.
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Accused Products
Abstract
A camera system switches electronically between infrared radiation sensing and visible light sensing depending on ambient conditions, to optimize visible picture quality for surveillance. An electronic CCD camera has an optical bandpass filter having a stop band between the infrared radiation spectrum and the visible light spectrum to provide high quality visible light images when not in the infrared mode and high quality mono infrared images when not in visible light mode. A control circuit compares the camera signal with a photocell signal and controls the camera'"'"'s sensing mode and an if illuminator'"'"'s operation in accordance with the ambient conditions.
74 Citations
22 Claims
- 1. A surveillance camera system having a control circuit that switches a camera between an infrared radiation imaging mode and a visible light imaging mode, based on an ambient light infrared sensing system having an infrared radiation and visible light bandpass filter that essentially blocks all of the infrared radiation and the visible light in a stop band comprising both infrared radiation and visible light wavelengths, the stop band spectrum covering a range of approximately 100 nanometers between approximately 680 nanometers of wavelength and approximately 790 nanometers of wavelength, the stop band thereby significantly differentiating by approximately 100 nanometers passed bandwidths of infrared radiation on a longer wavelength side of the stop band from passed bandwidths of visible light on a shorter wavelength side of the stop band, the significantly differentiated passed bandwidths of infrared and visible light respectively being allowed to proceed toward the camera for further processing.
Specification