Abstract: A gamma camera (8, 180) includes at least one radiation detector head (10, 12, 210, 212). At least one such radiation detector head (10, 12, 210, 212) includes a plurality of capacitive elements (60, 260, 76, 276) disposed over at least a radiation sensitive portion (50) of the radiation detector head. A proximity sensor monitor (62) is coupled with the plurality of capacitive elements to detect proximity of a subject to the radiation detector head based on a measured electrical characteristic of the capacitive elements. A collision sensor monitor (64) is coupled with the plurality of capacitive elements to detect conductive electric current flowing between spaced apart parallel conductive plates (66, 67) of the capacitive element responsive to mechanical deformation of the spacing between the plates.

Abstract: A radiation converter is disclosed. In at least one embodiment, the converter is for x-ray or gamma radiation and includes a multiplicity of scintillation elements which are separated from one another by separating septa. To reduce cross-talk between adjacent scintillation elements, the separating septa have a layer structure. The layer structure includes two backscatter layers, between which an absorber layer which is essentially opaque to the radiation, to scatter radiation and/or scintillation light is disposed.

Abstract: A system is provided for radiographic inspection of an object comprising multiple having different material properties. The system comprises a radiation source configured to generate radiation, a display unit for generating a graphical user interface (GUI) including multiple fields. A user enters input data via the fields in the GUI. The input data relates to one or more material properties for each of the regions. A processor is configured to compute a plurality of exposure parameters based on the input data.

Abstract: Apparatus for inspecting an article comprising: a controller configured to generate a drive signal having a periodic amplitude variation; a source, the source being operable by the controller to emit a source beam thereby to irradiate an article, the source beam comprising a beam of electromagnetic radiation having a periodic amplitude variation corresponding to that of the drive signal; and a detector, the detector being configured to detect a portion of the source beam that has been transmitted through at least a portion of the article, and to generate a detector signal having an amplitude variation corresponding to the amplitude variation of said portion of the source beam, the controller being further configured to generate a difference value corresponding to a difference between the amplitude of the detector signal and the amplitude of a reference signal.

Abstract: An apparatus for detecting gamma ray (GR) radiation having a plurality of detector cells arranged in an array is disclosed. Each cell includes a housing having an aperture, the housing comprising a GR absorbing material, and a GR detector disposed within the housing such that external gamma rays are received at the GR detector via the aperture. The apertures of each cell are aligned.

Abstract: A remote sensing device for detecting materials of varying atomic numbers and systems and methods relating thereto. A system for identifying a material includes a photon beam flux monitor for resolving a high-energy beam. A method for identifying a material includes casting an incident photon beam on the material and detecting an emerging photon beam with an array of fission-fragment detectors, a first set of scintillator paddles, and a second set of scintillator paddles.

Abstract: The invention relates to an Anti-Scatter-Grid (ASG) with lamellae (2) that absorb incident radiation (1, 8) and that produce an electrical signal proportional to the amount of absorbed radiation. The lamellae (2) may particularly consist of a semiconductor material in which photons produce electron-hole pairs that can be detected with the help of electrodes (3, 4, 6) on the sidewalls of the lamellae (2). The amount of absorbed scattered (8) or primary (1) radiation may thus be determined in a spatially resolved way, allowing to correct the image generated by an array (5) of sensor units (9).

Abstract: The transmission of photons through a target produces “holes” in the transmitted energy spectrum that are characteristic of the NRF energies of the nuclear isotopes in the target. Measuring the absorption via the transmission of these photons through a target allows the production of tomographic images that are associated with specific nuclear isotopes. Thus three-dimensional density patterns are generated for the elements in a container. The process is very much like standard X-ray tomography but it identifies specific nuclear isotopes as well as their densities.

Abstract: An X-ray detection device for detecting whether or not foreign matter is mixed in on the basis of the transmission amount of X-rays that have penetrated an examination subject article by applying X-rays, at a predetermined detection position to an examination subject article being conveyed in a pipe (7), wherein a test-piece table (17) capable of passing by the detection position at substantially the same speed as that of the examination subject article is installed in the vicinity of the pipe (7), with a test-piece (21) placed thereon. X-ray detection sensitivity can be detected without mixing the test-piece in the actual examination subject article.

Abstract: A quantum detector module for the quantitative and energy-resolved determination of quantum absorption events, a quantum detector, a method for determining quantum absorption events, a computer program product and a radiation detection device are disclosed. In at least one embodiment, the quantum detector module includes a multiplicity of detector pixels. In order to determine the quantum absorption events particularly precisely, in at least one embodiment it is provided that the detector pixels have at least two mutually different pixel apertures.

Abstract: Disclosed is a multi-array detector module structure pertaining to the technical field of radiation detecting. The multi-array detector module structure comprises a casing, a bottom plate to which a bottom end of the casing is fixedly connected, and a multi-array detector composed of a plurality of detectors, wherein a mounting frame is disposed on the bottom plate, and the mounting frame includes an upper plate and a lower plate. The multi-array detector comprises two rows of peripheral detector arrays fixed to the upper plate and the lower plate of the mounting frame, respectively, and at least one row of middle detector array disposed between the two rows of peripheral detector arrays and fixed to the same. Heavy metal sheets are provided between respective detector arrays in respective rows of detector arrays, for reducing cross talk.

Abstract: A lightweight cassette system comprises a cassette for detecting radiation image and a control unit for communicating with a console, the control unit being connected to the cassette. The control unit, which includes electronic components such as an interface circuit, a cassette controller, and a communication unit, is separably connected to the cassette which includes a radiation detector by connectors and a cable.

Abstract: Contrast agents developed specifically for x-ray diagnostics provide dose-enhanced radiotherapy and radiosurgery. The presence of heavy elements, for example, gold or iron, from these contrast agents, even small quantities, leads to a major dose increase in target tissue when combined with in vivo calibration of the amount of contrast agent. The technique can also be used in combination with other techniques, such as focused x-rays, to achieve further enhancement of therapeutic ratio. The technique is enhanced by employing oil-based contrast agents, which will remain in the target much longer than conventional agents. Through optimization of the equipment it is possible to achieve very large ratios of dose in target to dose in healthy tissue.

Abstract: A collimator panel comprises: a solid panel having a first face for receiving uncollimated radiation and a second opposite face for providing collimated radiation; and a plurality of elongate particles disposed in the panel and orientated to provide the collimating function. A method of manufacturing a collimator panel comprises the steps of: suspending a plurality of elongate particles in a liquid; applying an electric or magnetic field to the suspension to orientate the particles; and solidifying the liquid to fix the orientation of the particles, thereby forming a collimator panel. A method of manufacturing the elongate particles is also provided.

Abstract: An X-ray imaging inspection system for inspecting items comprises an X-ray source (10) extending around an imaging volume (16), and defining a plurality of source points (14) from which X-rays can be directed through the imaging volume. An X-ray detector array (12) also extends around the imaging volume (16) and is arranged to detect X-rays from the source points which have passed through the imaging volume, and to produce output signals dependent on the detected X-rays. A conveyor (20) is arranged to convey the items through the imaging volume (16).

Abstract: An operating method for an X-ray machine is disclosed for carrying out a preliminary examination by using a contrast agent, in the case of which a number of heartbeats are determined within a time interval between a first instant of a contrast agent administration and a second instant of a maximum in a concentration of the contrast agent. An operating method for the X-ray machine is also disclosed for carrying out a main examination by using a contrast agent, in the case of which the scanning of the examination region is not started until the number of heartbeats coincides with a preset value such that the scanning is performed at a high concentration of the contrast agent inside the examination region, without the need to adapt the value to the heart rate currently present.

Abstract: X-ray monochromators and electron probe micro-analysis (EPMA) systems using such monochromators are disclosed. A turretless x-ray monochromator may have a cassette of reflectors instead of a turret. The cassette stores a plurality of reflectors that can be inserted into a conventional Rowland circle monochromator geometry. A transfer mechanism selectively moves reflectors from the cassette to a reflector positioner. The use of the cassette allows each reflector to be placed closer to a source of x-rays, thereby allowing a larger solid angle for x-ray collection. An alternative x-ray monochromator uses a non-focusing reflector that can be fixed, scanned axially or scanned radially to provide large solid angle detection of x-rays at various energies with a single reflector.

Abstract: System and methods for measuring the density, level, or interface position of a fluid or fluids in a vessel using gamma-ray backscatter are disclosed. The gamma-ray instruments disclosed may account for vessel wall buildup or deterioration. Methods disclosed herein include detecting gamma rays backscattered by a fluid from a gamma-ray source positioned proximate to a vessel with at least two gamma-ray detectors positioned proximate to the vessel and to each other; and determining a density, level, or interface value of the fluid based upon intensities of backscattered gamma rays received by the two or more gamma-ray detectors; wherein the vessel wall is subject to at least one of buildup and deterioration. The density, level, or interface may be a function of a ratio of the intensity of backscattered gamma rays received by two or more of the detectors.

Abstract: A method and apparatus for using a flat panel detector to determine bone mineral density are provided. The apparatus includes a dual energy X-ray emitter, a flat panel detector for receiving X-rays sent from the X-ray emitter, and may optionally include an image corrector, adapted to emit corrected image information. The apparatus also includes a basis material decomposer that includes a calibration database, the decomposer being adapted to create a bone image and a soft tissue image. The apparatus further includes a bone mineral density calculator that is adapted to compute bone mineral density from the first image, and a display for displaying at least the computed bone mineral density. A method for using a flat panel detector to detect multiple disease states is also provided. The method includes emitting X-rays from a dual energy X-ray source through an area of a patient's body sought to be imaged and receiving X-rays with a flat panel detector.

Abstract: An apparatus and method calibration method, particularly to determine an x-ray generation technique to acquire a hand x-ray image using a mammography x-ray system for assessing Radiographic Absorptiometry (RA) based BMD (Bone Mineral Density).

Abstract: An imaging device comprising a scintillator and a first and second imaging elements. The scintillator emits scintillation light in response to an incident of an energy beam. The imaging elements take an image of the scintillation light. These imaging elements have imaging faces opposing to each other, and the scintillator is disposed between these imaging faces so that the scintillator overlaps with these imaging faces.

Abstract: The invention relates to a coordinate measuring apparatus (110) for measuring an object (3), comprising an x-ray sensory mechanism as a first sensory mechanism that is provided with an x-ray source (10) and at least one x-ray sensor (7) which detects the x-rays, and a second sensory mechanism such as a tactile and/or an optical sensory mechanism (8, 11; 9) that can be placed in the x, y, and/or z direction of the coordinate measuring apparatus in relation to the object. In order to be able to easily measure also large-size test objects, the x-ray sensory mechanism (7, 10) can be positioned in the coordinate measuring apparatus (10) according to the second sensory mechanism (8, 11; 9).

Abstract: A multifunctional hard x-ray nanoprobe instrument for characterization of nanoscale materials and devices includes a scanning probe mode with a full field transmission mode. The scanning probe mode provides fluorescence spectroscopy and diffraction contrast imaging. The full field transmission mode allows two-dimensional (2-D) imaging and tomography. The nanoprobe instrument includes zone plate optics for focusing and imaging. The nanoprobe instrument includes a stage group for positioning the zone plate optics. The nanoprobe instrument includes a specimen stage group for positioning the specimen. An enhanced laser Doppler displacement meter (LDDM) system provides two-dimensional differential displacement measurement in a range of nanometer resolution between the zone-plate optics and the sample holder. A digital signal processor (DSP) implements a real-time closed-loop feedback technique for providing differential vibration control between the zone-plate optics and the sample holder.

Abstract: An apparatus and method for determining the phase fraction of a fluid collected downhole is shown comprising an x-ray generator, a filter, a sample cell, and a radiation detector. The filter produces a radiation spectrum with a high energy portion and a low energy portion. Filtered radiation is passed through a sample fluid and the resulting attenuated radiation signal is used in calculating the phase fractions of oil, water, and gas in the sample fluid. In one embodiment, a second reference radiation detector measures the radiation directly from the x-ray generator and this measurement is used in normalizing the fraction result. The ratio of the high energy signal to low energy signal of the reference detector is used in controlling the input voltage of the x-ray generator thus ensuring a stable spectrum.

Abstract: The present invention provides a method comprising recursively partitioning an intensity modulated beam into plateaus; and partitioning the plateaus into segments. The present invention also provides a method for controlling administration of radiation therapy to a patient based on static leaf prescriptions. In addition, the present invention provides a method for partitioning an IMB.

Abstract: A method for reading radiation image information in which a cassette is lowered while keeping each short side of the cassette extending vertically, and then inserted into a radiation image reading apparatus which has a cassette loading inlet in its upper surface and the inserted cassette is taken into the apparatus, and next the front base and the back base are disengaged in the apparatus and both are separated, and after the radiation image information is read from the stimulable phosphor sheet of the back base which are separated from the front base, and then the front base and the back base are joined and ejected from the insertion opening of the apparatus. The apparatus height is smaller than in the method in which the stimulable phosphor sheet is pulled downward from the cassette and is read, and the operation of lifting the cassette against the force of gravity up to the height of the upper surface of the apparatus becomes unnecessary at the time of inserting the cassette.

Abstract: An apparatus for inspecting a semiconductor device may include an external image detector to acquire an exterior image of the semiconductor device, an internal image detector to acquire an interior image of the semiconductor device, and a controller to compare the acquired images with respective references. The apparatus may both inspect the exterior and the interior of the semiconductor device.

Abstract: The invention aims at providing a crane equipped with an inspection device that can maintain excellent inspection conditions without decreasing cargo transporting efficiency. On a container transporting route of a quay crane, a truck (position adjustment device), is provided moveably in a direction across this transporting route. An inspection device, which inspects the container, is provided on this truck. An upper part frame, which projects above the inspection device, and a lower part frame, which projects under the inspection device, are provided on the truck. An upside position detector, which detects the relative position of the container and the inspection device in the direction of movement of the truck, is provided in a position higher than that of the inspection device of the upper frame.

Abstract: Compact, low-power-consuming systems and methods for exposing samples to high-energy radiation, for example, for exposing samples to x-rays for implementing x-ray absorption near edge analysis (XANES). The systems and methods include a low-power-consuming radiation source, such as an x-ray tube; one or more tunable crystal optics for directing and varying the energy of the radiation onto a sample under analysis; and a radiation detecting device, such as an x-ray detector, for detecting radiation emitted by the sample. The one or more tunable crystal optics may be doubly-curved crystal optics. The components of the system may be arranged in a collinear fashion. The disclosed systems and methods are particularly applicable to XANES analysis, for example, XANES analysis of the chemical state of chromium or another transition metal in biological processes.

Abstract: In a method for calculating the temperature T of a solid body or the time t that is needed for a change of the temperature T of the solid body, a solution function to a dimensionless equation corresponding to the differential equation dT/dt=b?aT4?cT, is determined and used to create a matrix A=(aij) with which T or t can be easily calculated.

Abstract: A method for detecting and measuring regions of a secondary material deposited onto a moving substrate. The method employs an x-ray source for directing an x-ray beam at the moving substrate, and an x-ray detector to detect an amount of x-ray energy transmitted by the moving sheet of material. Areas of bare substrate will allow for different amounts of x-ray transmission than areas of the substrate containing the secondary material. These differences in transmission and/or absorption can be used to detect the location of a region of secondary material and to determine if it falls within an acceptable range. According to one particular embodiment of the present invention, the method can be used to analyze burn characteristic modifying bands of a secondary material intermittently and repeatedly deposited to a moving web of smoking article paper.

Abstract: An x-ray densitometry system provides computer assistance to the operator in identifying possible sources of scanning or analysis error through computer review of the acquired data, operator input, and the ultimate diagnostic outputs.

Abstract: An apparatus for measuring hardness of a material that makes it possible to measure hardness of a material having high spatial resolution over a wide area, hardness of tissue of a living body, hardness of micro areas in the entire organ and express the flexibility and robustness of the tissue of the living body based on CT values of an X-ray CT scanner. It includes an X-ray scanning section that scans and irradiates a specimen with X-rays, a CT value output section that calculates and outputs a CT value by measuring intensity of X-rays that have passed through the specimen, a storage apparatus that stores the correspondence relationship between CT value data and hardness data of a plurality of reference portions of tissue of the living body, a hardness conversion operation apparatus that converts to hardness using the correspondence relationship and a display that outputs the converted hardness.

Abstract: In a solid-state radiation detector and a medical examination and/or treatment device having such a solid-state radiation detector, the detector has a pixel matrix, with each pixel supplying an output signal dependent on the incident radiation. The pixel matrix has a conversion layer that converts the incident radiation into charge, a storage capacitor for storing the charge and a transistor for reading out the charge. The capacitance of the storage capacitor is set to be so small that because of the voltage drop across the storage capacitor, the output signal of the pixel exhibits, starting from a specific value of the incident radiation dose, a sublinear response with reference to the radiation dose.

Abstract: An in-situ monitoring system for a bonding process and a method therefor are provided. The monitoring system includes: a light source irradiating rays to a sample; a heating unit heating the sample; a temperature detecting unit detecting the temperature of the sample; a light detecting unit detecting the rays passing through the sample and converting the rays into an image signal; and a controlling unit receiving and outputting the image signal, and transmitting a signal for controlling the light source and the heating unit.

Abstract: A digital image representation of a radiological image is acquired and applied to a display device connected to a computer and displayed. A measurement scheme is retrieved from the computer and activated. Measurements are performed on the displayed image under guidance of the activated measurement scheme.

Abstract: The aim of the invention is an arrangement for the recording of projections, representing the instantaneous condition of a series of instantaneous conditions for the periodically changing distribution of the absorption behaviour, even for objects whose shapes or composition undergo rapidly repeating changes and from which the distribution itself may be reconstructed and which perform the above with a gamma source which continuously emits radiation.

Abstract: The present invention provides an apparatus for measuring hardness of a material that makes it possible to measure hardness of a material having high spatial resolution over a wide area, hardness of tissue of a living body such as an organ in particular, hardness of micro areas in the entire organ and express the flexibility and robustness of the tissue of the living body based on CT values of an X-ray CT scanner. It includes an X-ray scanning section (12) that scans and irradiates a specimen (14) with X-rays, a CT value output section (20) that calculates and outputs a CT value by measuring intensity of X-rays that have passed through the specimen (14), a storage apparatus (23) that stores the correspondence relationship between CT value data and hardness data of a plurality of reference portions of tissue of the living body, a hardness conversion operation apparatus (24) that converts to hardness using the correspondence relationship and a display (25) that outputs the converted hardness.

Abstract: A user-friendly, inexpensive radiation image radiographing apparatus capable of easily switching between absorption contrast image radiography and phase contrast image radiography. The radiation image radiographing apparatus has: a radiation source; a subject platform for supporting a subject so as to face the subject to the radiation source; and a plurality of supporting platforms for supporting a radiation image information detecting member at a side opposite to the radiation source with respect to the subject platform, the radiation image information detecting member for detecting radiation image information based on radiation transmitted through the subject, wherein distances between the plurality of supporting platforms and the radiation source are different from each other.

Abstract: A coincidence transmission source serves to detect coincident activity from a radiation source. The coincidence transmission source includes a detector dedicated to collecting attenuation data. A collimated radiation source and a detector are positioned with respect to a tomography device such that only a selected strip of the imaging detector of the tomograph is illuminated such that events unrelated to the attenuation are eliminated. The coincidence transmission source includes a collimator in which is disposed a radiation source. Fiber optics are interconnected between a plurality of dedicated gamma radiation detectors and a plurality of photomultiplier tubes. The arrangement of fiber optics is designed such that the address of a particular gamma radiation detector is readily discernable while minimizing the number of PMT's required to process data accumulated by the gamma radiation detectors.

Abstract: An electron microscope is offered which is fitted with an X-ray spectrometer having a compact optical system and high resolution. The spectrometer has a spectrometer chamber whose inside is evacuated by a vacuum pumping system. A diffraction grating having unequally spaced grooves is placed in the chamber. An X-ray detector is mounted to an end of the chamber. The X-ray spectrometer is mounted to the sidewall of the electron microscope via a gate valve. A specimen is irradiated with an electron beam and emits characteristic X-rays, which are made to impinge on the face of the grating at a large angle with respect to the normal line to the face. Diffracted X-rays from the grating reach the X-ray detector and are detected.

Abstract: In a method for examining a living subject with an imaging method making use of the concentration of a contrast agent having a physical property that is identifiable with the imaging method in a region of interest (ROI) of the subject presented in time-successive images acquired with the imaging method representing quantitative values of the physical property, a histogram of the quantitative values of the physical property in the ROI is produced for each of the individual images, and the contrast agent concentration in the ROI is determined on the basis of the frequency of occurrence of the quantitative values of the physical property in the ROI.

Abstract: A method for calibration of an imaging system includes providing a calibration phantom system including a first phantom element material block having a first surface at a first height, wherein the first phantom element material block at least partially includes a first material having a first attenuation coefficient. Providing a calibration phantom system also includes providing a second phantom element material block having a second surface at a second height different than the first height, the second phantom element material block at least partially including a second material having a second attenuation coefficient different than the first attenuation coefficient, wherein the first phantom element material block and said second phantom element material block are co-positioned on a detector. The method also includes imaging the calibration phantom system to obtain phantom images, processing the phantom images, and extracting a plurality of calibration values from the processed phantom images.

Abstract: A detector for detection of ionizing radiation comprises a cathode; an anode; an ionizable gas arranged between these electrodes; a radiation entrance arranged such that ionizing radiation can enter and ionize the ionizable gas; and a readout arrangement. A voltage across the electrodes causes electrons created during ionization of the gas to drift towards the anode, where the readout arrangement detects them. To reduce the risk of occurrence of sparks, and/or to reduce the energy in occurring sparks, one of the cathode and anode has at least the surface layer facing the other electrode made of a material having a resistivity of at least 5×10−8 &OHgr;m.

Abstract: This invention relates to a self diagnostic apparatus for a radiographic imaging system. The system includes a radiographic source and a camera, and the apparatus comprises: a scintillator positioned between the optical pathway of the radiographic source and the camera, and made of a material which fluoresces when struck by x-rays, including one in the group of terbium doped gadollineum oxysulfide or thallium doped cesium iodide; a resolution target located at the periphery of the scintillator and made of a material that passes at least shortwave ultraviolet light; an ultraviolet source positioned in line of sight of the scintillator and target; and, a control system for capturing a self-diagnostic reference image by activating the ultraviolet source, and activating the camera to take an image created by the visible light emitted by the scintillator material when illuminated by the UV light.

Abstract: A method and apparatus for imaging a body by exposing the body to radiation transmitted through the body via successive angular portions from a radiation source on one side of the body to a radiation detector in alignment with the radiation source on the opposite side of the body; the radiation detector including a two-dimensional matrix of detector elements producing electrical outputs corresponding to the magnitudes of the radiation received by each detector element; the radiation source producing a conical beam sufficiently large such that each exposure covers all the detector elements in the two-dimensional array after traversing the body.

Abstract: Apparatus for measuring the lateral yarn density distribution of a yarn uses selected radiation in the X-ray spectrum wavelength. Radiation absorption is determined in a number of narrow planes across the yarn and in two or more rotational orientations. The measuring takes place without any damage to or physical interference with the yarn.

Abstract: A detector for detection of ionizing radiation comprises a first cathode and a first anode between which a first voltage is applicable; an ionizable gas arranged at least partly between the first cathode and the first anode; a radiation entrance arranged such that ionizing radiation can enter and ionize the ionizable gas; and a read-out arrangement. The detector further comprises a second cathode and a second anode between which a second voltage is applicable; and a solid state ionizable material arranged between the second cathode and the second anode such that part of the radiation entered into the ionizable gas can propagate through the gas, enter the solid state material and ionize it; wherein the read-out arrangement is arranged for detection of the electrons and/or holes drifted towards the second anode and/or cathode, respectively, separately of detection of the electrons drifted towards the first anode.

Abstract: An inspection system utilized to inspect a structure for particularities, including defects, includes a first gantry with a detector inspection device that is placed in a known position on one side of the structure, and a second gantry with a source inspection device that is placed on the other side of the structure. In an embodiment, the detector inspection device is an x-ray detector inspection device and the source inspection device is an x-ray source inspection device. The movement of the first and second gantries is controlled by a gantry control system. A data acquisition system controls the data, e.g., image, collection process. During the data collection process, the relative positions of the source and detector inspection devices are initialized. The detector and source inspection devices are then moved in synchronized motion to each data collection position, such that the relative alignment of the inspection devices is maintained.

Abstract: The present invention is an apparatus and method for measuring flow rate of materials, for example the flow rate of agricultural products. The apparatus includes an x-ray generator positioned near flowing materials, a converter for converting the x-ray radiation which passes through the flowing materials into visible light, a camera for capturing images of the visible light, and a processor for processing the images to determine the flow rate. The invention may also include an image intensifier to intensify the images before being converted by the camera. The method directs x-rays through flowing material, converts the x-rays to visible light, records the intensity of the visible light and derives the flow rate from the intensity measures.