In a first pixel part, as an incident position is closer to a first end of a first pixel pair group in a second direction, an intensity of a first electric signal decreases. In a second pixel part, as the incident position is closer to the first end, an intensity of a second electric signal increases. In a third pixel part, as the incident position is closer to a second end of a second pixel pair group in a first direction, an intensity of a third electric signal decreases. In a fourth pixel part, as the incident position is closer to the second end, an intensity of a fourth electric signal increases. A calculation unit performs weighting on a first position on the basis of the third and fourth electric signals, and performs weighting on a second position on the basis of the first and second electric signals.

An ambient light sensor for sensing illuminance of ambient light includes: a photo sensor unit, for sensing ambient light to generate a sensing signal; a reference sensor unit coupled to the photo sensor unit, for generating a reference signal in response to a condition of not sensing the ambient light; and a control circuit, which is coupled to the photo sensor unit and the reference sensor unit for generating an ambient light illuminance signal according to the sensing signal and the reference signal. Each of the photo sensor unit and the reference sensor unit includes at least one illuminance sensor device, wherein the at least one illuminance sensor device of the photo sensor unit and the at least one illuminance sensor device of the reference sensor unit are arranged in common centroid in a circuit layout.

A detection unit includes multiple detection elements, which are configured to output intensities of received light as detection signals, and a light shielding portion, which is configured to regulate an incident angle of light with respect to the detection elements. The storage unit is configured to store a reference distribution indicating a distribution of intensity of light detected with the detection units caused by irradiation of reference light having a reference directivity characteristic on the detection unit. The calculation unit is configured to input the detection signals from the detection elements, to calculate the detection distribution of the intensity of received light, to input the reference distribution from the storage unit, to calculate a deviation of the detection distribution from the reference distribution, and to calculate a directivity characteristic of received light on the basis of the deviation.

Systems and methods are disclosed for protecting a UV-transmissive window. The system includes a first light source for emitting UV energy. The system also includes a UV transmissive window having a planar dimension and a thickness direction perpendicular to the planar dimension, the window positioned so that UV energy from the UV light source passes through the thickness dimension of the window. The system further includes a second light source for introducing a beam of light transverse to the thickness dimension of the window, a detector for detecting light received from the second light source after the light passes through the thickness dimension, and a control system responsive to changes in the detected light received from the second light source and configured to transmit an alert when a change in the detected light exceeds a threshold.

An apparatus comprising at least one pair of a first inner and second outer photodetector, each photodetector comprising a channel member, respective source and drain electrodes configured to enable a flow of electrical current through the channel member between the source and drain electrodes, and a plurality of quantum dots configured to generate electron-hole pairs on exposure to incident electromagnetic radiation to produce a detectable change in the electrical current flowing through the channel member. The first inner and second outer photodetectors are configured to generate electron-hole pairs which produce an increase and decrease in electrical current through the channel members. The first inner and the second outer photodetectors share a common channel member, which is partitioned by one or more of the respective source and drain electrodes respectively extending in two dimensions such that the first inner photodetector is defined within the second outer photodetector.

Two separate schemes are used for detecting light intensity in low light conditions and high light conditions. In high light conditions, two threshold voltages are set and the time between the crossing of a sensor voltage at the two threshold voltages is measured to determine the light intensity in the high light conditions. In low light conditions, a comparator is used to compare the voltage level of the sensor voltage relative to a reference voltage that increase over time. The time when the reference voltage reaches the sensor voltage level is detected to determine the light intensity in the low light conditions.

A technique and apparatus for monitoring a plant canopy over a field is disclosed. The technique includes receiving first sensor values from a plurality of plant canopy sensors disposed in or on a ground of the field under the plant canopy. The first sensor values are indicative of near-infrared (IR) light reflected or reradiated from the plant canopy. Second sensor values are also received from the plant canopy sensors. The second sensor values are indicative of red light that is incident through the plant canopy. A map of the plant canopy may be generated based upon the first and second sensor values.

An integrated quantum random noise source includes a substrate, an optical oscillator that may be integral to the substrate coupled by an optical waveguide to an optical directional coupler. The optical directional coupler has two outputs that are coupled by optical waveguides to a pair of photodetectors that are part of a balanced photodetector. The balanced photodetector in response outputs an analogue signal proportional to the difference in photocurrents of the two photodetectors. The analogue output signal from the balanced photodetector is a random Gaussian-distributed signal representative of quadrature measurements on the quantum vacuum state of light. The random noise source can be coupled other apparatus to provide a source of random bits.

A method of identifying the presence of a first gas such as methane within a sample, for example containing natural gas. A detector is provided having a sensor responsive to a first wavelength, a sensor responsive to a second wavelength, and a sensor for collecting reference readings. A gas sample is analysed to obtain a first absorption reading corresponding to the first wavelength, a second absorption reading corresponding to the second wavelength and a reference reading. A first absorption figure is calculated using the first absorption reading and the reference reading, and a second absorption figure using the second absorption reading and the reference reading. The sensor for each wavelength is calibrated for detecting the first gas such that the data collected at each wavelength gives the same reading when only said first gas is present in a sample.

An ambient light detector, a detector array and a method are disclosed. In an embodiment an ambient light sensor includes a first plurality of sensor elements, each sensor element configured to provide a signal in response to a level of illumination and a second plurality of reference elements, each reference element configured to provide a reference signal and each including a blocking element configured to shield the respective reference element from being illuminated, wherein the first plurality is larger than the second plurality and the first plurality of sensor elements and the second plurality of reference elements are arranged in an array, and wherein a sensor element and a reference element are laterally arranged on or in a common layer substrate sharing at least one common first contact.