ISO/IEC 15415:2024 自動識別およびデータキャプチャ技術 — バーコードシンボルの印刷品質テスト仕様 — 二次元シンボル | ページ 6

3.1

binarised image

binary (black/white) image created by applying a threshold to the pixel (3.7) values in the reference grey-scale image (3.9)

3.2

effective resolution

resolution obtained on the surface of the symbol under test and calculated as the resolution of the image capture element multiplied by the magnification of the optical elements of the measuring device

Note 1 to entry: The effective resolution is normally expressed in pixels (3.7) per mm (or pixels per inch).

3.3

error correction capacity

number of codewords, or units of data, in a symbol (or error control block) assigned for erasure and error correction, minus the amount reserved for error detection

3.4

inspection area

portion of an image which contains the entire symbol to be tested inclusive of its quiet zones

3.5

grade threshold

boundary value separating two grade levels, the value itself being taken as the lower limit of the upper grade

3.6

module error

module of which the apparent dark or light state in the binarised image (3.1) is inverted from its intended state

3.7

pixel

individual light-sensitive element in an array

3.8

raw image

plot of the reflectance values in x and y coordinates across a two-dimensional image, representing the discrete reflectance values from each pixel (3.7) of the light-sensitive array

3.9

reference grey-scale image

plot of the reflectance values in x and y coordinates across a two-dimensional image, derived from the discrete reflectance values of each pixel (3.7) of the light-sensitive array by convolving the raw image (3.8) with a synthesised aperture (3.10)

3.10

synthesised aperture

convolutional kernel used to blur an image