A sheet discriminator, which can be included in an image forming apparatus, includes an optical information detector, a sheet distinguisher, and a sheet thickness detector. The optical information detector includes a light emitter to emit light to a recording medium and a light receiver to receive the light and detects information of the recording medium. The sheet distinguisher distinguishes a type of the recording medium based on the information detected by the optical information detector. The sheet thickness detector includes a displacement gauge to sandwich the recording medium with an opposing member disposed facing the displacement gauge and to move from an initial position thereof and a displacement detector to detect an amount of displacement of the displacement gauge. The sheet thickness detector detects a thickness of the recording medium based on detection results obtained by the displacement detector.

An example method includes comparing, via circuitry, a first signal indicative of a first amount of light received by a first light sensor to a second signal indicative of a second amount of light received by a second light sensor, wherein the second light sensor is to compensate for an environmental change by detecting the second amount of light transmitted by a light source regardless of a presence or absence of an object in the conveyance path; determine, via the circuitry, whether a reflection loss is present based on the comparing of the first and second signals; and if the circuitry detects the reflection loss based on the comparing of the first and second signals, generating a presence indication.

An optical monitor includes a target disposed within the optical monitor and exposed to ambient air, wherein exposure to the ambient air produces a change in an optical property of the target. The optical monitor may also include a light emitter to illuminate the target and an optical detector to generate a signal based on light reflected from or transmitted through the target. A processing device may activate the light emitter and receive the signal from the optical detector.

Systems, methods, and apparatuses are disclosed for sensing clear or transparent media in printers. In one embodiment, a media conveyance apparatus is provided comprising a light sensor positioned on a first side of a media conveyance path; a light source positioned on a second side of the media conveyance path; and presence determination circuitry. The media conveyance apparatus is configured such that the light sensor and the light source are positioned such that media may pass between the light sensor and the light source along the media conveyance path. The media conveyance apparatus is further configured such that the light sensor provides signals to the presence determination circuitry indicating an amount of light received from the light source and the presence determination circuitry determines a reflection loss based on the signals received from the light sensor and further determines whether the reflection loss satisfies a loss threshold. The media conveyance apparatus is further configured so that if the presence determination circuitry determines the reflection loss satisfies the loss threshold, the presence determination circuitry outputs a media present indication.

A method for the time-differentiated detection of a spectrum of a test object comprises providing a first conversion dye, which is configured to convert light with a first spectral distribution in the visible range into light with a second spectral distribution in the infrared range. The first conversion dye is excited with a light pulse in the range of the first spectral distribution during a first time period, and a light fraction, reflected or transmitted by the test object, in the range of the first spectral distribution is registered during a first time interval. During a subsequent second time period, a fraction of converted light reflected or transmitted by the test object is registered. According to the invention, the first time interval is selected so that it lies substantially inside a luminescence lifetime for the first conversion dye in the first time period.

Various embodiments are directed to a device for detecting fluid particle characteristics comprising: a fluid composition sensor comprising: an illumination source configured to emit a light beam along a beam axis such that at least a portion of the light beam engages a collection media and illuminates particles disposed within a collection media; an imaging device configured to capture an image of the particles disposed within the collection media; and a light shield comprising: an internal shield portion enclosed within an inner surface of a shield wall; and one or more baffle elements disposed within the internal shield portion and configured to reflect at least a divergent portion of the light beam within the internal shield portion; wherein the light shield extends between the illumination source and the imaging device such that a portion of the light beam emitted along the beam axis passes through the internal shield portion.

A method and apparatus for determining a reflectance, of at least a portion of a target object, in at least one selected wavelength range of electromagnetic (EM) radiation are disclosed. The method comprises, for each selected wavelength range, providing a digital image including at least one target object and a plurality of reference objects, each reference object having respective non-identical predetermined reflectance characteristics, with a digital camera arrangement that provides output image data that comprises digital numbers that are responsive to radiation, in only a selected wavelength range, incident at a sensing plane of the digital camera arrangement. A relationship between a first set of the digital numbers is determined and a first set of the respective predetermined reflectance characteristics of the reference objects. Responsive to the relationship, a further set of digital numbers is transformed to allocate a value of reflectance for each of the digital numbers in the further set. For at least a portion of the target object, a corresponding first group of allocated values of reflectance is determined and responsive to the first group of allocated values, determining a reflectance of the portion of the target object.

An analysis device includes a turntable holding a substrate, an optical pickup driven in a direction perpendicular to a rotation axis of the turntable and configured to emit laser light to reaction regions and to receive reflected light from the respective reaction regions, an optical pickup drive circuit, and a controller. The reaction regions are formed at positions different from the center of the substrate. The center of the substrate is located on the rotation axis of the turntable. The optical pickup detects a reception level of the reflected light to generate a light reception level signal. The controller controls a turntable drive circuit to rotate the substrate, controls the optical pickup drive circuit to drive the optical pickup, and specifies the respective reaction regions in accordance with a positional information signal and the light reception level signal.

A concentration measurement device for measuring the concentration of a measured fluid within a measurement cell by detecting transmitted light that has passed through the measurement cell having a light incidence window and a light emission window disposed opposing to each other, comprising a reflected-light detector for detecting reflected light of the light incidence window.

Implementations disclosed describe a system including a light source, an optical sensor, and a processing device. The light source directs, during a first time, a probe light into a processing chamber through a window. The light source ceases, during a second time, directing the probe light into the processing chamber through the window. The optical sensor detects, during the first time, a first intensity of a first light. The first light includes a portion of the probe light reflected from the window and a light transmitted from an environment of the processing chamber through the window. The optical sensor detects, during the second time, a second intensity of a second light. The second light includes the light transmitted from the environment of the processing chamber through the window. The processing device determines, using the first intensity and the second intensity, a transmission coefficient of the window.