A nephelometric turbidimeter for measuring a turbidity of a liquid sample in a sample cuvette. The nephelometric turbidimeter includes a measurement light source configured to emit an axial parallel light beam directed to the sample cuvette, a scattering light detector arranged to receive a scattered light from the sample cuvette, and a diffuser comprising a diffuser body and a diffuser actuator. The diffuser actuator is configured to move the diffuser body between a parking position in which the diffuser body does not interfere with the axial parallel light beam and a test position where the diffuser body is arranged between the measurement light source and the sample cuvette so that the diffuser body interferes with the axial parallel light beam and generates a diffuse test light entering the sample cuvette.

A method for the quantitative and/or qualitative detection of particles in fluid, with which the fluid to be examined is introduced into a beam path of an optical device, between at least one light source and the image acquisition sensor with a matrix of light-sensitive cells. Pixel values of the cells are detected and the distribution of the pixel values is at least partly determined. The pixel value or values which have been determined most often are used as a value or average value for a background signal. A signal is outputted or the method is interrupted, on reaching a maximal permissible value for the background signal.

A method is provided for diagnosing the operation of a photometric particle analyzer. The method may determine when the operation is degraded from normal operating conditions, automatically, and the result displayed locally as well as being transmitted to a remote observer. The present invention may be used by optical photometric particle analyzers, or by analyzers that measure other properties of particles collected on filters.

Certain embodiments provide a self-checking photoelectric sensor that is configured to determine a characteristic (e.g., an amount of blockage and/or wellness/decay) of an optical pathway (e.g., an electro-optical pathway). An example method generally includes increasing, over a time period that starts at a first time, a current input to a light emitting element (LEE). The method generally includes receiving, by a light detection element, an output of the LEE via the optical pathway during the time period. The method generally includes converting, during the time period, the LEE output to a voltage output. The method generally includes determining a second time in the time period when the voltage output crosses a threshold. The method generally includes determining the characteristic of the optical pathway between the LEE and the light detection element based on a difference between the second time and the first time.

A gas sensor (2) distinguishes between a target gas and a contaminant and includes a light source (8), a measurement volume (4), a detector (22), and an adaptable filter system (20) with a first optical filter and a second optical filter. The filter system switches between a first composite state, with both filters in a reference state, a second composite state, with the first filter in a first reference state and the second filter in a second measurement state, a third composite state with the first filter in a first measurement state and the second filter in a second reference state, and a fourth composite state, with both filters in a measurement state. The gas sensor detects a target gas and makes a determination as to a presence of the contaminant by comparing the respective detector signals, generated during at least three of the composite states, with each other.

Systems and methods are disclosed for identifying a dirty camera in a monocular camera comprising n cameras. For each of one or more cycles, a dirty counter variable for each of the n cameras is set to 0. For each of the n cameras, an image is captured from the camera and an image metric is determined for the image, e.g. brightness and/or contrast. If the image metric is 10% greater, or 10% less, than the image metric for any of the other n−1 cameras in the monocular camera, then that camera is determined to be dirty and a corrective action is taken, such as sending an alarm to an occupant the vehicle or initiating a cleaning operation. If the dirty condition persists for a camera that has been cleaned within a threshold period of time (i.e., recently), then an alarm is sent to an operator of the vehicle.

A measurement apparatus for mounting within an enclosure of a machine is described. The apparatus includes a measurement device and a protection means for protecting the measurement device from contaminants present within the machine enclosure. The protection means is switchable between at least a first mode that protects the measurement device from contaminants and a second mode that provides less protection of the measurement device from contaminants than the first mode. A contaminant sensor is used for sensing contamination within the machine enclosure and thereby determining when the protection means can adopt the second mode. A corresponding method is also described.

A device for detecting a soiling of a transparent cover of at least one transmitting window and/or one receiving window of an optical sensor. The device includes at least one hologram structure, an image sensor, and a processing unit. The at least one hologram structure is designed to at least partially deflect light beams incident through the transparent cover, or light beams reflected by an inner side of the transparent cover, in the direction of the image sensor. The image sensor is designed to detect at least one image signal as a function of the deflected light beams, and the processing unit is designed to detect a soiling of the transparent cover as a function of the at least one detected image signal. An optical sensor including the device, and a method for detecting a soiling of the transparent cover, are also described.

A sensing apparatus monitors a cover optic on a laser processing head for contamination, indicating the need to replace the cover optic. The apparatus includes at least one reflector and at least one sensors that are disposed in the processing head adjacent a periphery of the cover optic. The reflector reflects radiation from the laser beam deflected from contamination on the cover optic and incident thereagainst. The sensor is offset from the reflector and detects at least a portion of the radiation reflected by the reflector. A controller in communication with the sensor can determine the contamination on the cover optic based on the detected radiation.

A system to localize debris on an optical surface of a vehicle includes a first array along a first side of a perimeter of the optical surface and including a light source to emit light into a thickness of the optical surface. A second array is along a second side of the perimeter, opposite the first side, and includes a light detector to detect light scatter in the thickness and provide a corresponding output. A third array is along a third side of the perimeter and includes a light source to emit light. A fourth array is along a fourth side of the perimeter, opposite the third side, and includes a light detector to detect light scatter and provide a corresponding output. A controller identifies a presence of the debris, determines a position of the debris based on the output from the light detectors, and remediates the debris.