Barcode Glossary R


Barcode-Glossary R

  • Range

  • The maximum distance, up to which a scan-unit is able to read a symbol with given characteristics. Identical with the sum of optical throw and depth of field.
    See "Depth of Field", "Optical Throw", "Reading Distance".

  • Raster Scanner

  • A scanner with a moving beam emitting several parallel scanner beams.

  • Reading Direction

  • Most of the barcode character sets can be read in two directions (bi-directionally). This is achieved through the barcodes partly having differing start and stop characters.

  • Reading Distance

  • The distance (or the spectrum of distances) from the output area of the scanner in which the scanner is still able to unfailingly read a symbol.
    See "Depth of Field", "Optical Throw", "Distance".

  • Ratio

  • See "Ratio Between Narrow and Wide".

  • Redundancy

  • A feature, according to which information is repeated to increase the certainty that a message is read or transmitted correctly. In a barcode symbol, the bar height creates a vertical redundancy by enabling multiple scanning at various areas of the symbol, even though a single reading process in one row would theoretically suffice for the decoding of a symbol.

  • Reference-Decode Algorithm

  • The decoding algorithm, displayed in the relevant symbology specification as basis for the derivative of tolerances, decidability values, etc.

  • Reference Threshold

  • A reference point in a decoding algorithm, to which - relevant to the width of an element - an allocation to one of two possible values is made.

  • Reflectance

  • 1. The amount of light of a specific wavelength or wavelength range that is reflected by a substrate, a color or another means of depicting the bars and spaces of a barcode.
    2. The reflectance (partly also called reflectance factor) is measured with a scale of 0 to 1 over a wavelength or a band width of light (spectral scale factor), that is determined in the relevant user specifications.
    Reflectance = R/I
    with R = reflected light
    I = emitted light.
    Sulphate of barium or magnesium oxide serve as a white-reference (a perfect white would achieve a reflectance of 1.00 with each wavelength of light). The absence of light in a vacuum is set as a reference to black. Samples (such as substrates, colors, etc.) are tested against the standards under approximately similar light conditions.

  • Resolution

  • The grade of detailing an image that a device can produce. The narrowest bar width that can be created by a certain device or using a certain method, or the narrowest bar width that can be successfully read by a certain scanner. The resolution is specified in dots or lines per mm or inch.