ISO 13473-4:2024 表面プロファイルを使用した舗装テクスチャの特性評価 | ページ 6

3.1

drop-out

data in the measured profile indicated by the sensor as invalid

3.2

drop-out rate

percentage (%) of measured points within the evaluation length (3.3) which are identified as being invalid

3.3

evaluation length

l

length of a portion of a profile which has been or is to be analysed

Note 1 to entry: The evaluation length may or may not be equal to the profile measurement length (3.5) (but never greater).

Note 2 to entry: Evaluation length is normally expressed in metres (m) or millimetres (mm).

3.4

measurement speed

v

speed at which the profilometer (3.6) sensor traverses the surface to be measured

Note 1 to entry: Measurement speed is normally expressed in kilometres per hour (km/h) or metres per second (m/s).

3.5

profile measurement length

l_p

length of an uninterrupted profile measurement

Note 1 to entry: Profile measurement length is normally expressed in metres (m) or millimetres (mm).

3.6

profilometer

device used for measuring the two-dimensional (2D) profile of a pavement surface

Note 1 to entry: Any design of profilometer could be used if the requirements in ISO 13473-3 is fulfilled for the specific purpose of the analysis.

Note 2 to entry: Profilometers can be divided into stationary, mobile low speed or mobile high speed devices.

3.7

power spectral density

PSD

quantity expressing the power contained in a signal per unit frequency or per unit wavelength as a function of frequency or wavelength

Note 1 to entry: In the case of a discrete Fourier transform of a sampled signal, the PSD may be defined as the squared magnitude of the components of the Fourier series divided by the effective bandwidth of the (narrow) bands of the Fourier spectrum (see C.4).

Note 2 to entry: In the case of spectral analysis of a pavement surface profile, the signal is not a function of time but of evaluation length l. The Power Spectral Density may then be given as a function of the spatial frequency or the (texture) wavelength and will be expressed in the unit m²/m⁻¹ = m³ or in the unit m²/mm, respectively.

Note 3 to entry: The word “Power” in this designation originates from electric and acoustic signal terminology where signals incorporate actual power and where the squared amplitude is a measure of this power.

3.8

sampling interval

ΔX

distance between two adjacent data points of the surface profile, which is equal to the measurement speed divided by the sampling frequency of the sensor

Note 1 to entry: Sampling interval is normally expressed in millimetres (mm).

3.9

spatial frequency

f_sp

number of sinusoidal cycles per unit length

Note 1 to entry: Spatial frequency is normally expressed in reciprocal metres (m⁻¹); see also 3.12, Note 3.

Note 2 to entry: The term “frequency” used in the time domain, corresponds to “spatial frequency” in the space domain.

3.10

surface profile

texture profile

Z(X)

upper contour of a vertical cross-section through a pavement

Note 1 to entry: Texture profile is similar to surface profile but limited to the texture range.

Note 2 to entry: The profile of the surface is described by two coordinates: one in the surface plane, called distance (the abscissa), and the other in the direction normal to the surface plane, called vertical displacement (the ordinate). The distance may be in the longitudinal or lateral (transverse) directions in relation to the travel direction on a pavement, or in a circle or any other direction between these extremes.

3.11

surface profile spectrum

texture spectrum

spectrum obtained when a profile curve has been analysed by either digital filtering or Digital Fourier Transform (DFT) techniques to determine the magnitude of its spectral components at different wavelengths (3.12) or s patial frequencies (3.9)

Note 1 to entry: Wavelengths between 0,5 mm and 500 mm belongs to the texture spectrum and 0,5 m to 50 m belongs to the unevenness spectrum^[12].

Note 2 to entry: A texture spectrum presents the magnitude of each spectral component as a function of either texture wavelength or spatial frequency.

3.12

texture wavelength

λ

quantity describing the horizontal dimension of the amplitude variations of a surface profile (3.10)

Note 1 to entry: (Texture) wavelength is normally expressed in metres (m) or millimetres (mm).

Note 2 to entry: Wavelength is a quantity commonly used and accepted in electrotechnical and signal processing vocabularies. Since many users of this document might not be accustomed to use the term wavelength in pavement applications, and because electrical signals are often used in the analyses of road surface profiles, there is a possibility of confusion. Hence, the expression “texture wavelength” is preferred here to make a clear distinction in relation to other applications.

Note 3 to entry: Texture wavelength in ISO 13473 is the reciprocal of the spatial frequency, the unit of which is reciprocal metre (equivalent to cycles per metre). See also 3.9.

Note 4 to entry: Wavelengths are represented physically as the various lengths of periodically repeated parts of the profile.

3.13

texture profile level

L_tx,λ

logarithmic transformation of an amplitude representation of a surface profile curve Z(X), the latter expressed as a root mean square value

Note 1 to entry: Octave-band and one-third-octave-band filters are specified in ISO 13473-2:2002, 4.4.

Note 2 to entry: Texture amplitudes expressed as root-mean-square values, whether filtered or not, may have a range of several magnitudes, typically 10^‑5 m to 10^‑2 m. Spectral characterization of signals is used frequently in studies of acoustics, vibrations and electrotechnical engineering. In all those fields, it is most common to use logarithmic amplitude scales. The same approach is preferred in this document.

Note 3 to entry: Texture profile levels in practical pavement engineering typically range from 20 dB to 80 dB with these definitions.