|  | G |
SECTION G — PHYSICS

|  | G |
Note(s) In this section, the following term is used with the meaning indicated: "variable" (as a noun) means a feature or property (e.g., a dimension, a physical condition such as temperature, a quality such as density or colour) which, in respect of a particular entity (e.g., an object, a quantity of a substance, a beam of light) and at a particular instant, is capable of being measured; the variable may change, so that its numerical expression may assume different values at different times, in different conditions or in individual cases, but may be constant in respect of a particular entity in certain conditions or for practical purposes (e.g., the length of a bar may be regarded as constant for many purposes). Attention is drawn to the definitions of terms or expressions used, appearing in the notes of several of the classes in this section, in particular those of "measuring" in class Fulltext... Hierarchy... Expanded...G01 and "control" and "regulation" in class Fulltext... Hierarchy... Expanded...G05. Classification in this section may present more difficulty than in other sections, because the distinction between different fields of use rests to a considerable extent on differences in the intention of the user rather than on any constructional differences or differences in the manner of use, and because the subjects dealt with are often in effect systems or combinations, which have features or parts in common, rather than "things", which are readily distinguishable as a whole. For example, information (e.g., a set of figures) may be displayed for the purpose of education or advertising (Fulltext... Hierarchy... Expanded...G09), for enabling the result of a measurement to be known (Fulltext... Hierarchy... Expanded...G01), for signalling the information to a distant point or for giving information which has been signalled from a distant point (Fulltext... Hierarchy... Expanded...G08). The words used to describe the purpose depend on features that may be irrelevant to the form of the apparatus concerned, for example, such features as the desired effect on the person who sees the display, or whether the display is controlled from a remote point. Again, a device which responds to some change in a condition, e.g., in the pressure of a fluid, may be used, without modification of the device itself, to give information about the pressure (Fulltext... Hierarchy... Expanded...G01L) or about some other condition linked to the pressure (another subclass of class Fulltext... Hierarchy... Expanded...G01, e.g., Fulltext... Hierarchy... Expanded...G01K for temperature), to make a record of the pressure or of its occurrence (Fulltext... Hierarchy... Expanded...G07C), to give an alarm (Fulltext... Hierarchy... Expanded...G08B), or to control another apparatus (Fulltext... Hierarchy... Expanded...G05). The classification scheme is intended to enable things of a similar nature (as indicated above) to be classified together. It is therefore particularly necessary for the real nature of any technical subject to be decided before it can be properly classified.

INSTRUMENTS

|  | G03 |
PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY (reproduction of pictures or patterns by scanning and converting into electrical signals Fulltext... Hierarchy... Expanded...H04N) [4]

|  | G03 |
Note(s) In this class, the following terms are used with the meaning indicated: "records" means photographs or any other kind of latent, directly-visible or permanent storage of pictorial information, which consist of an imagewise distribution of a quantity, e.g. an electric charge pattern, recorded on a carrier member; "optical" applies not only to visible light but also to ultra-violet or infra-red radiations. [4]

|  | G03H |
HOLOGRAPHIC PROCESSES OR APPARATUS (holograms, e.g. point holograms, used as ordinary optical elements Fulltext... Hierarchy... Expanded...G02B 5/32; producing stereoscopic or other three-dimensional effects Fulltext... Hierarchy... Expanded...G02B 27/22; diffraction-grating systems Fulltext... Hierarchy... Expanded...G02B 27/44; systems using moire fringes Fulltext... Hierarchy... Expanded...G02B 27/60; optical logic elements Fulltext... Hierarchy... Expanded...G02F 3/00; stereo-photography Fulltext... Hierarchy... Expanded...G03B 35/00; photosensitive materials or processes for photographic purposes Fulltext... Hierarchy... Expanded...G03C; apparatus for processing exposed photographic materials Fulltext... Hierarchy... Expanded...G03D; analogue computers performing mathematical operations with the aid of optical elements Fulltext... Hierarchy... Expanded...G06E 3/00; authentication, by radiation, of concealed information carried by holograms or diffraction gratings Fulltext... Hierarchy... Expanded...G06K 19/16; holographic digital storage Fulltext... Hierarchy... Expanded...G11C 13/00) [2]

|  | G03H |
Note(s) This subclass covers means for producing a record of the phase and amplitude information of a wave-front, which information can be used to reconstruct the original wave-front, or means to reconstruct the original wave-front from a record containing the phase and amplitude information of the wave-front. [2]

|  | G03H 1/00 |
Holographic processes or apparatus using light, infra-red, or ultra-violet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto [2]

|  | G03H 1/02 |
· | Details [2]

|  | G03H 1/04 |
· | Processes or apparatus for producing holograms (Fulltext... Hierarchy... Expanded...G03H 1/26 takes precedence) [2]

|  | G03H 1/06 |
· · | using incoherent light [2]

|  | G03H 1/08 |
· · | Synthesising holograms (using electric digital computers Fulltext... Hierarchy... Expanded...G06F, Fulltext... Hierarchy... Expanded...G06T) [2]

|  | G03H 1/10 |
· · | using modulated reference beam [2]

|  | G03H 1/12 |
· · · | Spatial modulation, e.g. ghost imaging [2]

|  | G03H 1/14 |
· · · | Temporal modulation, e.g. extending depth of field or phase compensation for object motion [2]

|  | G03H 1/16 |
· · | using Fourier transform (Fulltext... Hierarchy... Expanded...G03H 1/12, Fulltext... Hierarchy... Expanded...G03H 1/14 take precedence; analogue computers Fulltext... Hierarchy... Expanded...G06G, e.g. Fulltext... Hierarchy... Expanded...G06G 7/19) [2]

|  | G03H 1/18 |
· · | Particular processing of hologram record carriers, e.g. for obtaining blazed holograms [2]

|  | G03H 1/20 |
· · | Copying holograms by holographic means [2]

|  | G03H 1/22 |
· | Processes or apparatus for obtaining an optical image from holograms (Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G03H 1/26-G03H 1/34 take precedence) [2]

|  | G03H 1/24 |
· · | using white light [2]

|  | G03H 1/26 |
· | Processes or apparatus specially adapted to produce multiple holograms or to obtain images from them, e.g. multicolour technique [2]

|  | G03H 1/28 |
· · | superimposed holograms only [2]

|  | G03H 1/30 |
· · | discrete holograms only [2]

|  | G03H 1/32 |
· | Systems for obtaining speckle elimination [2]

|  | G03H 1/34 |
· | Systems for reducing the space-spatial bandwidth product [2]

|  | G03H 3/00 |
Holographic processes or apparatus using ultrasonic, sonic, or infrasonic waves for obtaining holograms; Processes or apparatus for obtaining an optical image from them (Fulltext... Hierarchy... Expanded...G03H 1/22 takes precedence) [2]

|  | G03H 5/00 |
Holographic processes or apparatus using other electromagnetic waves or subatomic particles for obtaining holograms; Processes or apparatus for obtaining an optical image from them (Fulltext... Hierarchy... Expanded...G03H 1/22 takes precedence; construction of electron microscopes Fulltext... Hierarchy... Expanded...H01J 37/26) [2]