HoloVID
Encyclopedia
HoloVID is a tool originally developed for the holographic dimensional measurement of the internal isogrid
webbing of the Delta Series of (launch vehicle
) Space Craft skins by Mark Slater in 1981.
was produced by McDonnell Douglas
Astronautics, until the line was purchased by Boeing Aircraft. Milled out of T6 Aluminum, on huge 40 foot by 20 foot horizontal mills, the inspection of the huge sheets took longer than the original manufacturing. It was estimated that a real time
in-situ
inspection device could seriously cut costs so an IRAD (Independent Research and Development
) budget was generated to solve the problem. Two solutions were worked simultaneously by Mark Slater, a photo-optical techniques utilizing Holographic lens, and an ultrasonic technique utilizing configurable micro-transducer multiplexed arrays.
A pair of HoloVids for simultaneous frontside and backside weld feedback, was later used at Martin Aerospace to inspect the long weld seams which hold the external fuel tank
s of the Space Shuttle
together. By controlling the Weld bead profile in real time as it was TIG generated, an optimum weight vs. performance ratio could be obtained, saving the launch engines from having to waste thrust energy, while guaranteeing the highest possible web strengths.
, Johnson and Johnson, Aerospace Corp., Silverline, and others) use customized versions of the Six Dimensional Non-Contact Reader w/ Integrated Holographic Optical Processing, for applications from SuperComputer
Surface Mount
pad assessment, to Genetic Biochemical Assay Analysis.
The use of multiple planes and multiple points of light to measure shapes and construct volumetric estimates of objects has also been widely reported.
The use of segmented phase holograms to selectively deflect portions of an image wave front
... is unusual. The holographic optical components used in this device, split tessellated segments of a returning wave front in programmable bulk areas and shaped patches to achieve a unique capability, increasing both the size of an object which can be read and the z-axis
depth per point which is measurable, while also increasing the simultaneous operations possible which is a significant advance in the previous state of art.
is made to impinge onto a target surface. The angle of the initially nonlinear optical
field can be non-orthogonal to the surface. This light beam
is then reflected by the surface in a wide conical spread function which is geometrically related to the incidence angle
, light frequency, wavelength and relative surface finish. A portion of this reflected light enters the optical system
coaxially, where a 'stop' shadows the edges. In a single point reader, this edge is viewed along a radius by a photodiode array.
The output of this device is a boxcar output where the photodiodes are sequentially lit diode by diode as the object distance changes in relation to the sensor until either no diodes are lit, or all diodes are lit. The residue product product charge dynamic value in each light diode cell is a function of the bias current, the dark current
and the incident ionizing radiation
(in this case, the returning laser light).
In the multipoint system, the HoloVid, the cursor point is acousto-optically scanned in the x-axis across a K theta monaxial transformer. A monaxial holographic lens collects the wave front and reconstructs the pattern onto the single dimensional photodiode array and a two dimensional matrix sensor. Image processing
of the sensor data derives the correlation between the compressed wave front and the actual physical object.
Isogrid
An isogrid is a plate with triangular integral stiffening ribs . The stiffeners of an isogrid are generally machined from a single sheet of material with a milling machine, though below 0.004 in. thickness chemical milling processes must be used...
webbing of the Delta Series of (launch vehicle
Launch vehicle
In spaceflight, a launch vehicle or carrier rocket is a rocket used to carry a payload from the Earth's surface into outer space. A launch system includes the launch vehicle, the launch pad and other infrastructure....
) Space Craft skins by Mark Slater in 1981.
History
Delta Space CraftSpacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
was produced by McDonnell Douglas
McDonnell Douglas
McDonnell Douglas was a major American aerospace manufacturer and defense contractor, producing a number of famous commercial and military aircraft. It formed from a merger of McDonnell Aircraft and Douglas Aircraft in 1967. McDonnell Douglas was based at Lambert-St. Louis International Airport...
Astronautics, until the line was purchased by Boeing Aircraft. Milled out of T6 Aluminum, on huge 40 foot by 20 foot horizontal mills, the inspection of the huge sheets took longer than the original manufacturing. It was estimated that a real time
Real-time computing
In computer science, real-time computing , or reactive computing, is the study of hardware and software systems that are subject to a "real-time constraint"— e.g. operational deadlines from event to system response. Real-time programs must guarantee response within strict time constraints...
in-situ
In situ
In situ is a Latin phrase which translated literally as 'In position'. It is used in many different contexts.-Aerospace:In the aerospace industry, equipment on board aircraft must be tested in situ, or in place, to confirm everything functions properly as a system. Individually, each piece may...
inspection device could seriously cut costs so an IRAD (Independent Research and Development
Research and development
The phrase research and development , according to the Organization for Economic Co-operation and Development, refers to "creative work undertaken on a systematic basis in order to increase the stock of knowledge, including knowledge of man, culture and society, and the use of this stock of...
) budget was generated to solve the problem. Two solutions were worked simultaneously by Mark Slater, a photo-optical techniques utilizing Holographic lens, and an ultrasonic technique utilizing configurable micro-transducer multiplexed arrays.
A pair of HoloVids for simultaneous frontside and backside weld feedback, was later used at Martin Aerospace to inspect the long weld seams which hold the external fuel tank
Fuel tank
A fuel tank is safe container for flammable fluids. Though any storage tank for fuel may be so called, the term is typically applied to part of an engine system in which the fuel is stored and propelled or released into an engine...
s of the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
together. By controlling the Weld bead profile in real time as it was TIG generated, an optimum weight vs. performance ratio could be obtained, saving the launch engines from having to waste thrust energy, while guaranteeing the highest possible web strengths.
Usage
Many corporations (Kodak, Immunex, BoeingBoeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...
, Johnson and Johnson, Aerospace Corp., Silverline, and others) use customized versions of the Six Dimensional Non-Contact Reader w/ Integrated Holographic Optical Processing, for applications from SuperComputer
Supercomputer
A supercomputer is a computer at the frontline of current processing capacity, particularly speed of calculation.Supercomputers are used for highly calculation-intensive tasks such as problems including quantum physics, weather forecasting, climate research, molecular modeling A supercomputer is a...
Surface Mount
Surface-mount technology
Surface mount technology is a method for constructing electronic circuits in which the components are mounted directly onto the surface of printed circuit boards . An electronic device so made is called a surface mount device...
pad assessment, to Genetic Biochemical Assay Analysis.
Specifications
HoloVid belongs to a class of sensor known as a structured-light 3D scanner device. The use of structured light to extract three-dimensional shape information is a well known technique. The use of single planes of light to measure the distance and orientation of objects has been reported several times.The use of multiple planes and multiple points of light to measure shapes and construct volumetric estimates of objects has also been widely reported.
The use of segmented phase holograms to selectively deflect portions of an image wave front
Wavefront
In physics, a wavefront is the locus of points having the same phase. Since infrared, optical, x-ray and gamma-ray frequencies are so high, the temporal component of electromagnetic waves is usually ignored at these wavelengths, and it is only the phase of the spatial oscillation that is described...
... is unusual. The holographic optical components used in this device, split tessellated segments of a returning wave front in programmable bulk areas and shaped patches to achieve a unique capability, increasing both the size of an object which can be read and the z-axis
Cartesian coordinate system
A Cartesian coordinate system specifies each point uniquely in a plane by a pair of numerical coordinates, which are the signed distances from the point to two fixed perpendicular directed lines, measured in the same unit of length...
depth per point which is measurable, while also increasing the simultaneous operations possible which is a significant advance in the previous state of art.
Operational modes
A laser beamLaser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
is made to impinge onto a target surface. The angle of the initially nonlinear optical
Nonlinear optics
Nonlinear optics is the branch of optics that describes the behavior of light in nonlinear media, that is, media in which the dielectric polarization P responds nonlinearly to the electric field E of the light...
field can be non-orthogonal to the surface. This light beam
Light beam
A light beam or beam of light is a narrow projection of light energy radiating from a source into a beam. Sunlight is a natural example of a light beam when filtered through various mediums...
is then reflected by the surface in a wide conical spread function which is geometrically related to the incidence angle
Angle of incidence
Angle of incidence is a measure of deviation of something from "straight on", for example:* in the approach of a ray to a surface, or* the angle at which the wing or horizontal tail of an airplane is installed on the fuselage, measured relative to the axis of the fuselage.-Optics:In geometric...
, light frequency, wavelength and relative surface finish. A portion of this reflected light enters the optical system
Optics
Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...
coaxially, where a 'stop' shadows the edges. In a single point reader, this edge is viewed along a radius by a photodiode array.
The output of this device is a boxcar output where the photodiodes are sequentially lit diode by diode as the object distance changes in relation to the sensor until either no diodes are lit, or all diodes are lit. The residue product product charge dynamic value in each light diode cell is a function of the bias current, the dark current
Dark current
Dark current is the constant response exhibited by a receptor of radiation during periods when it is not actively being exposed to light. It may refer to:...
and the incident ionizing radiation
Ionizing radiation
Ionizing radiation is radiation composed of particles that individually have sufficient energy to remove an electron from an atom or molecule. This ionization produces free radicals, which are atoms or molecules containing unpaired electrons...
(in this case, the returning laser light).
In the multipoint system, the HoloVid, the cursor point is acousto-optically scanned in the x-axis across a K theta monaxial transformer. A monaxial holographic lens collects the wave front and reconstructs the pattern onto the single dimensional photodiode array and a two dimensional matrix sensor. Image processing
Image processing
In electrical engineering and computer science, image processing is any form of signal processing for which the input is an image, such as a photograph or video frame; the output of image processing may be either an image or, a set of characteristics or parameters related to the image...
of the sensor data derives the correlation between the compressed wave front and the actual physical object.