A method of estimating non-linearity in a response of an optical detector comprises emitting optical radiation at different intensities. The method includes, at each intensity: amplitude modulating the emitted optical radiation at a modulating frequency to produce amplitude modulated optical radiation; detecting the amplitude modulated optical radiation with the optical detector to produce a detected waveform; and generating a Fourier transform of the detected waveform that includes a fundamental frequency equal to the modulating frequency and harmonics thereof. The method further includes estimating the non-linearity in the response of the optical detector based on a change in an amplitude of a second harmonic of the fundamental frequency relative to an amplitude of the fundamental frequency across the Fourier transforms corresponding to the different intensities.

Reduces an increase in temperature of the blade member. Comprises: a blade supporting member, disposed forward of a photodetecting sensor that acts as a thermal source, having an opening 1a through which passes light that is to be incident into the photodetecting sensor; a blade member, supported movably on the blade supporting member, for opening and closing the opening; an actuator for driving the blade member open and closed, wherein: wherein the blade supporting member comprises a containing portion 1b, for containing the blade member and the actuator on a front or rear surface that is perpendicular to the optical axis of the opening, and an exposed portion that is arranged in parallel to the containing portion.

A pyroelectric presence identification system includes focal plane array and a processor coupled to the focal plane array. The focal plane array includes a first image sensor and a plurality of second image sensors configured to convert radiant energy into an electrical signal. The processor is configured to control the focal plane array in a sleep mode wherein the first image sensor is utilized to detect gross motion of at least one presence and the plurality of second image sensors are de-energized.

A chopped PIR (C-PIR) sensor is capable of detecting both stationary and moving objects with a high degree of accuracy using a narrow infrared semi-transparent chopper to temporally shutter incident radiation received by pyroelectric sensing elements. Demonstrating a field of view of 110 (horizontal) and 90 (vertical), the C-PIR sensor can detect stationary objects located within 4 m of the sensor, and moving objects located within 8 m of the sensor with 100% accuracy.

A camera, computer program, and method for determining and displaying temperature rates of change for regions within the camera's field of view. More specifically, the embodiments provide for the continuous, real-time temperature measurement and display of a plurality of objects within the camera's field of view, and further for the real-time processing and display of the temperature rates of change for the region.