OSAC Lexicon
The OSAC Lexicon is a compendium of forensic science terms and definitions. This terminology tool was created to help bring consistency and understanding to the way terms are used by the various forensic science. Use of the OSAC Lexicon does not replace the need to reference the original published source.
The terms and definitions in the OSAC Lexicon come from the published literature, including documentary standards and technical reports. It is continually updated with the latest work from OSAC units, as well as terms from newly published documentary standards and standards elevated to the OSAC Registry.
Gradually terms are evaluated and harmonized by the OSAC to a single term. This process results in an OSAC Preferred Term. An OSAC Preferred Term is a term, along with its definition, that has undergone review and evaluation by the FSSB Terminology Task Group and has been approved by the FSSB. The FSSB recommends that subcommittees use OSAC Preferred Terms when drafting standards.
The OSAC Lexicon should be the primary resource for terminology and used when drafting and editing forensic science standards and other OSAC work products.
in computer forensics, a hardware device connected externally to a computer or other digital device that adds more functionality.
Behavioral qualities of the canine that are relatively constant and reliable, and frame or affect the canine handler's response across contexts.
The association of a set of remains to a known individual.
Equipment worn for protection from discipline-specific environmental hazards, e.g., biological, radiological, chemical. For disaster canine applications in a rubble search, helmet, gloves, long pants/long sleeves, and safety toe/steel shank boots, which must be worn by the canine handler. Canine handler must also have eye protection and knee pads on hand, as they may be required by the hosting task force/agency.
Equipment worn to minimize exposure to a variety of hazards such as body fluids, irritants, or contaminants. Examples of PPE: gloves, foot and eye protection, respirators, and full-body suits. NOTE PPE may also help to minimize contamination and/or alteration of the scene.
A canine trained to detect and alert to the presence of explosives for which it has been trained that may be person borne. The canine team is not EDC certified, however, the canine team may be responsible for searching its intended operational area and/or person(s) separated from their personal property
A canine trained to detect and alert to the presence of explosives and explosives related substances (e.g., propellants, oxidizers, precursors) for which it has been trained that may be person borne. The canine team is not EDC certified, however, the canine team may be responsible for searching its intended operational area and/or person(s) separated from their personal property.
in image and video analysis, camera-to-subject geometry, including both camera-to-subject distance and orientation of the camera relative to the subject.
in image and video analysis, a warping or transformation of an object's appearance in an image introduced by insufficient subject to camera distance (for example, larger nose or smaller ears).
Positron emission tomography.
any product derived from crude oil.
any product derived from crude oil.
one of the three states or conditions in which substances can exist, i.e. solid, liquid, or gas (vapor).
a part of a chemical system that is homogeneous, physically distinct and at least hypothetically separable, and which has single or continuously variable chemical and mechanical properties.
Surface topography measurement method whereby an optical microscope with illumination of aknown effective wavelength is integrated with an interferometric attachment and producesmultiple successive optical images with interferometric fringes from which the profile or arealsurface topography image is calculated.
A method used to obtain digital x-ray images consisting of a photostimulable plate.
in facial identification, the application of anthropometric analysis to images.
process of obtaining dimensional information regarding objects and people depicted in an image.
the art, science, and technology of obtaining reliable information about physical objects and the environment through the processes of recording, measuring, and interpreting photographic images and patterns of electromagnetic radiant energy and other phenomena.
in image analysis and facial identification, the assessment of the correspondence between features in images and known objects or images for the purpose of rendering an opinion regarding identification, elimination, or a qualified conclusion (as opposed to a demonstrative exhibit).
A standard two-dimensional image illuminated and captured in the visible wave lengths (380 to 780 nm). This definition is specific to this standard other references may refer to images captured using non-visible wavelengths converted to visible wavelengths as photographic images, but they are not so classified for purposes of this standard. A photographic image is conveyed in a Type-10 record (unless it is an iris image conveyed in Type-17, or a friction ridge image conveyed in one of Types 4, 13, 14, 15, or 19). A non-photographic image is conveyed in a Type-22 record. Original source images are conveyed in Type-20 records and non-biometric associated context images are conveyed in Type-21 records, regardless of the format or source of the image.
Surface topography measurement method in computer vision for measuring the surface normals ofa surface by observing that surface under different lighting conditions. Given sufficient independentlight sources, the surface normals, and thus surface geometry, can be determined for every positionon the surface.
the measurement of light values of objects in an image.
photosensitive vacuum tube device that quantitatively converts photons of light into electrical energy.
A criterion used to guide the selection of species for comparative analysis and species determination; the selection of species is based on genetic relatedness.
A branching diagram that illustrates putative relationships amongst organisms.
NOTE Phylograms are typically generated using genetic sequences and/or morphological characters.
in computer forensics, an accurate reproduction of information contained on a physical digital data storage device.
an association based upon the realignment of two or more items that demonstrate they were once joined together to form a single object.
Discussion—The term match (for example, physical match, fracture match) is not recommended to be used as it can be misleading to the layperson.
in computer forensics, a bit stream duplicate of data contained on a physical digital data storage device.
Any external storage material of the voice signal and content information in eitheranalog or digital form. Examples include reel-to-reel recording tape, cassette tape,Compact Disc, and phonograph record.
a finely-divided insoluble material used to deluster or color fibers (for example, titanium dioxide and iron oxide).
a finely ground, inorganic or organic, insoluble, and dispersed particle; besides color, pigments provide many of the essential properties of paint such as opacity, hardness, durability, and corrosion resistance; the term pigment includes extenders.
a finely ground, organic or inorganic, insoluble, and dispersed particle. Besides color, a pigment can provide many of the essential properties of paint, such as opacity, hardness, durability, and corrosion resistance (see also effect pigment).
a finely ground, inorganic or organic, insoluble, dispersed particle. Besides color, a pigment can provide many of the essential properties of paint, such as opacity, hardness, durability, and corrosion resistance. The term pigment includes extenders.
clusters of pigment granules.
clusters of pigment granules.
the relative abundance of pigment granules in the hair cortex as described along a continuum (for example, sparse, medium, heavy).
the relative abundance of pigment granules in the hair cortex as described along a continuum (for example, sparse, medium, heavy).
the pattern or arrangement of the pigment granules in the hair shaft, such as uniform, peripheral, one-sided, variable, or central.
the pattern or arrangement of the pigment granules in the hair shaft, such as uniform, peripheral, one-sided, variable, or central.
small particles in hair composed of melanin that impart color. Discussion—Melanin is a natural pigment of which two forms, eumelanin (brown to black) and phaeomelanin (reddish brown to yellow), determine the color of human and animal hair.
a hair disorder causing hairs to appear ringed or banded due to the alternating light and dark bands in the hair shaft; the dark bands are a manifestation of abnormal air spaces in the cortex.
a hair disorder causing hairs to appear ringed or banded due to the alternating light and dark bands in the hair shaft. The dark bands are a manifestation of abnormal air spaces in the cortex.
a hair disorder characterized by the hair shaft being flattened and twisted 180 degrees numerous times along its axis; it is usually found at irregular intervals along the shaft.
a hair disorder characterized by the hair shaft being flattened and twisted 180 degrees numerous times along its axis. It is usually found at irregular intervals along the shaft.
See ignition temperature.
in facial identification, an intrinsic rotation of the head about a horizontal left-to-right (lateral) axis measured in degrees.
Discussion—Frontal poses have a pitch angle of 0. Positive angles represent faces looking down (a counter-clockwise rotation around the axis). The pitch axis is typically defined as the X-axis (positive to the right).