GB/T 20733-2022 Digital camera—Vocabulary
1. Scope
This document defines terms and definitions related to technical requirements, test methods and use of digital cameras. This document is applicable to standard setting, documentation, teaching material writing, book editing and document translation related to digital cameras.
2. Normative reference documents
The contents of the following documents constitute an essential clause of this document through normative references in the text. Among them, only the version corresponding to the date of the reference document is applicable to this document; The undated reference document whose latest version (including all amendments) applies to this document.
Measurement of Resolution of GB/T 19953-2005 Digital Camera
Determination of Exposure Index, ISO Sensitivity Value, Standard Output Sensitivity and Recommended Exposure Index of GB/T 20224 Digital Camera
ISO 12234-2 Electronic still image imaging Removable memory-Part 2: Electronic still-picture imaging-Removable memory-Part 2: TIFF/EP image data format
ISO15739 Photography-Electronic still image imaging-Noise measurements
ISO 21550 Photography-Electronic scanners for photographic images
ISO/IEC 10918-1 Information technology Digital compression and coding of continuous-tone still images: requirements and guide-lines
GB/T 20733-2022
IEC 61146-1 Camera (PAL/SECAN/NTSC) Measurement Methods-Part 1: Video cameras (PAL/SECAN/NTSC)-Methods of measurement-Part 1: Non-broadcast single-sensor cameras
IEC 61966-2-1 Multimedia systems and equipment-Color measurement and management-Part 2-1: Color management-Default RGB color space-sRGB (Multimedia systems and equipment-Colour measurement and management-Part 2-1: Colour management-Default RGB color space-sRGB)
EBU Tech3249 Measurement and analysis of the performance of film and television camera lenses
3. Terms and Definitions
3.1 Digital Cameras and Devices
3.1. 1
opto-electronic digital image capture system
A system that converts the spatial distribution of exposure or scene brightness (scene) on the focal plane into digital information. [Source: ISO 14524: 2009, 3.12]
3.1. 2
electronic still camera
electronic still-picture camera
A camera having an image sensor capable of outputting an analog or digital signal describing a photograph and recording this signal on a storage medium (such as a memory card or a magnetic disk, etc.).
[Source: ISO 12233: 2017, 3.6]
3.1. 3
digital still camera; DSC
A device includes an image sensor and generates a digital signal representing a still image.
GB/T 20733-2022
Note: Digital cameras are usually portable handheld devices. Digital signals are usually recorded on removable memory, such as solid-state memory cards or magnetic disks. [Source: GB/T 20224-2006, 3.1, with modifications]
3.1. 4
image sensor
image transducer
An electronic device that can sense optical image information and convert it into an output signal.
Examples: Charge Coupling (CCD), Complementary Metal Oxide Semiconductor (CMOS), etc.
[Source: GB/T 13964-2008, 10.3]
3.1. 5
charge coupled device; CCD
A silicon integrated circuit that converts optical signals into electronic signals.
3.1. 6
Complementary metal-oxide-semiconductor device; CMOS
Semiconductor array with complementary effect of silicon and germanium to convert optical signals into electronic signals.
3.1. 7
analog to digital converter; A/D; ADC
A circuit for converting an analog-digital signal with continuously varying amplitude into a binary digital quantized output signal.
3.1. 8
addressable photo elements
The number of effective photoelectric elements contained in the image sensor is equal to the number of effective lines of photoelectric elements multiplied by the number of effective photoelectric elements
GB/T 20733-2022
er line. Note 1: In order to avoid confusion, the term resolution will not be used when referring to the number of effective photoelectric elements contained in the image sensor.
Note 2: The number of addressable optoelectronic elements may be different for different color recording methods of images. When the signal of the photoelectric element is digitized, the digital value can be used as a reference for the photoelectric element or pixel value.
[Source: ISO 12233: 2017, 3.1]
3.1. 9
pixel pixel
A physical unit on an image sensor that can receive light independently.
[Source: GB/T 29298-2012, 3.4]
3.1. 10
total pixels
The total number of pixels on the image sensor.
3.2 Photographic Optics
3.2. 1
photography
The process of acquiring, processing, or optically reproducing images using chemical or electronic techniques.
3.2. 2
focal length
The distance between the main point of the image side of an optical system and the main focus.
[Source: GB/T 13964-2008, 2.13]
3.2. 3
equivalent focal length
GB/T 20733-2022
When the diagonal length of the image area of the digital camera is equivalent to the diagonal length of the 35 mm camera frame (43.27 mm), the nominal focal length of the lens corresponds to the focal length of the 35 mm camera. Namely:
Equivalent focal length = (43.27 mm/diagonal length of image area) × nominal focal length of lens.
Note: The equivalent focal length is expressed in millimeter (mm).
[Source: GB/T 13964-2008, 2.36]
3.2. 4
digital zoom
Digital camera can enlarge the image in the middle part of the field of view by logical operation interpolation and other methods.
3.2. 5
geometric distortion; GD
In the stored image of a digital camera, the displacement from the theoretical shape of an object (in a plane parallel to the image plane).
Note: The geometric distortion basically comes from the camera lens, and the result is that the straight line is reduced to a curve. There are other factors that can cause geometric distortion, such as the rotational asymmetry of the camera lens or the change of position during the imaging process of the camera.
3.2. 6
TV distortion TV distortion
Linear distortion measured by conventional methods in the field of television as defined in IEC 61146-1 (24 geometric distortion) or EBU Tech 3249 (2.11 photo height distortion).
3.2. 7
Stray flare
In an imaging system, light that falls on an image instead of coming from a corresponding point.
GB/T 20733-2022
Note: flare sometimes refers to Veling glare.
3.2. 8
image flare
Light from the target point and scattered by the optical system beyond the appropriate image point in the image plane area.
Note: The image-spot difference generated by any target point is determined by the image point spread function. Point spread functions are variable for different image points, and often decrease rapidly with the increase of the distance to the image points, and they are usually not radially symmetric for image points at a certain distance from the optical axis.
3.2. 9
Soft stray light veiling flare
Relatively uniform but unnecessary irradiation on the image plane of an optical system caused by a portion of scattered and reflected light from within or outside the field of view of the system entering the system through the entrance pupil.
Note: Light leakage from the optical system shell may cause extra unwanted radiation in the image plane. This kind of radiation may be similar to soft glare.
[Source: ISO 3664: 2009, March 19]
3.2. 10
Soft glare veiling glare
Reflected light from the imaging medium, which will not form an image without modulation.
Note 1: Soft glare brightens the dark part of the image and reduces the contrast.
Note 2: In CIE 122, the soft glare of CRT display is called ambient glare.
3.3 Exposure and Photoelectric Conversion
GB/T 20733-2022
3.3. 1
opto-electronic conversion function; OECF
The relationship between the logarithm of the input value and the corresponding digital output value of the photoelectric digital image acquisition system.
Note: If the interval between the input logarithmic exposure points is very small and the output noise relative to the interval value is small, the OECF may exhibit stepped characteristics. This phenomenon is an illusion of quantitative processing, which should be eliminated by smoothing algorithm or curve fitting of data.
[Source: ISO 14524: 2009, 3.11]
3.3. 1.1
camera opto-electronic conversion function
Camera OECF
The relationship between logarithmic luminance of input scene and digital output value of photoelectric digital image acquisition system.
Note: The unit of measure for this function is lg cd/m ®.
[Source: ISO 14524: 2009, 3.1]
3.3. 1.2
focal plane opto-electronic conversion function; focal plane OECF
Relationship between digital exposure value and digital output value of input focal plane of photoelectric digital image acquisition system.
Note: The unit of measurement for this function is lg lx · s
[Source: ISO 14524: 2009, 3.5]
3.3. 2
digital output level digital output level
digital code value
A digital value assigned to a specific output level.
GB/T 20733-2022
[Source: ISO 14524: 2009, 3.2]
3.3. 3
incremental output signal
The product of the input signal (non-logarithmic brightness or exposure) and the corresponding system gain.
Note: See incremental gain function.
[Source: ISO 14524: 2009, 3.8]
3.3. 4
incremental gain function
A function expressed as the quotient of the change in output level (digital value) divided by the change in input level (brightness or exposure). Note 1: Logarithmic input values are not used for gain determination.
Note 2: If the input exposure point interval is very small and the output noise relative to the quantization interval value is very small, the gain function may exhibit a step-like characteristic. This phenomenon is an illusion of quantization processing, which is eliminated by quasi-leveling operation or data fitting curve. Sometimes it is necessary to fit the input-output data curve, and then determine the gain function by finding the first derivative of the fitting curve equation.
[Source: ISO 14524: 2009, 3.7]
3.3. 5
noise noise
Undue changes in the response of the imaging system.
[Source: GB/T 34074-2017, 3.9]
3.3. 5.1
total noise
All undesirable changes in the digital output obtained by single exposure shooting, including mode noise and random noise. [Source: GB/T 34074-2017, 3.9. 1]
GB/T 20733-2022
3.3. 5.2
fixed pattern noise
Undesired changes in digital output that remain unchanged during exposure.
[Source: GB/T34074-2017, 3.9. 2]
3.3. 5.3
Random noise temporary varying noise
Undesired changes in the digital output from one exposure to the next due to sensor dark current, shot noise, analog processing, and quantization.
[Source: GB/T 34074-2017, 3.9. 2]
3.3. 6
output noise
For a constant input level, the root mean square fluctuation of the median of the digital output level.
[Source: ISO 14524: 2009, March 13]
3.3. 7
Noise spectrum energy distribution
Curve or equation representation of spatial frequency function of two-dimensional image of camera output noise.
3.3. 8
incremental signal to noise ratio
Increments the ratio of the output signal to the electrical mean root of noise (rms) at a specific signal level.
Note: The incremental signal-to-noise ratio is typically expressed as a curve or table showing the relationship between the electrical mean root of noise and the output signal over the entire output signal level range.
3.3. 9
maximum exposure limit
GB/T 20733-2022
A minimum exposure of a digital output level corresponding to the maximum measurable exposure is generated.
Note 1: Maximum measurable exposure is also called saturation or quantization upper limit.
Note 2: See Minimum Exposure Limit.
[Source: ISO 14524: 2009, March 9]
3.3. 10
minimum exposure limit
An incremental output signal equal to the magnitude of the output noise is generated and below the saturated maximum exposure.
Note: See Incremental Output Signal, Maximum Exposure Limit, Output Noise.
[Source: ISO 14524: 2009, 3.10]
3.4 Image Evaluation
3.4. 1
resolution resolution
Measure the ability of the camera system or camera system components to represent picture details.
Note: The indicators of resolution measurement include visual resolution, limit resolution, spatial frequency response (SFR), modulation transfer function (MTF) and optical transfer function (OTF), etc.
[Source: ISO 12233: 2017, 3.22]
3.4. 2
visual resolution visual resolution
The spatial frequency of the black and white lines in the test map reproduced on the display or photo that can be distinguished by the human eye; Due to the influence of false signals, the spatial frequency that can be reproduced is lower than the spatial frequency of the corresponding area in the test diagram.
[Source: ISO 12233: 2017, March 29]
GB/T 20733-2022
3.4. 3
limiting resolution
The number of linewidths per image height measured for a specific resolution test pattern, corresponding to an average degree of modulation equal to the specified reference frequency and its degree of modulation percentage.
3.4. 4
spatial frequency response; SFR
Amplitude response measured by an imaging system as a function of the corresponding input spatial frequency.
Note 1: SFR is generally expressed by the output response curve of input sine wave brightness distribution per unit amplitude in spatial frequency range. Note 2: SFR is reduced to 1 when the spatial frequency is zero.
Note 3: In the equation, the symbol RSFR is used instead of the abbreviation SFR for clarity.
[Source: ISO 12233: 2017, 3.24]
3.4. 5
gray scale
The camera's ability to distinguish neutral spectra (gray light) with different reflectivity (or transmittance).
[Source: GB/T 29298-2012, 3.11]
3.4. 6
cycles per millimetre
cy/mm
A unit of spatial frequency, defined as the number of spatial periods per millimeter.
[Source: ISO 12233: 2017, 3.3]
3.4. 7
GB/T 20733-2022
Line width per image height line widths per picture height
LW/PH
A unit of measure used to specify the width of a feature on a test chart, relative to the height of the effective area of the test chart, which is equal to the effective area of the test chart
GB/T 20733-2022
Appendix A
(File)
Domestic and foreign brand number approximate comparison
The comparison with GB / T 20887.2-2010 and foreign standard are shown in Table A.1.
Table A. 1 Table of domestic and foreign approximate license numbers
The document GB/T 20887.2—2010 EN 10338:2015 VDA239-100:2016 JFS A1001:2014 SAE J2745—2007
Standard
GB/T 20733-2022 Digital camera—Vocabulary (English Version)
GB/T 20733-2022 Digital camera—Vocabulary
1. Scope
This document defines terms and definitions related to technical requirements, test methods and use of digital cameras. This document is applicable to standard setting, documentation, teaching material writing, book editing and document translation related to digital cameras.
2. Normative reference documents
The contents of the following documents constitute an essential clause of this document through normative references in the text. Among them, only the version corresponding to the date of the reference document is applicable to this document; The undated reference document whose latest version (including all amendments) applies to this document.
Measurement of Resolution of GB/T 19953-2005 Digital Camera
Determination of Exposure Index, ISO Sensitivity Value, Standard Output Sensitivity and Recommended Exposure Index of GB/T 20224 Digital Camera
ISO 12234-2 Electronic still image imaging Removable memory-Part 2: Electronic still-picture imaging-Removable memory-Part 2: TIFF/EP image data format
ISO15739 Photography-Electronic still image imaging-Noise measurements
ISO 21550 Photography-Electronic scanners for photographic images
ISO/IEC 10918-1 Information technology Digital compression and coding of continuous-tone still images: requirements and guide-lines
GB/T 20733-2022
IEC 61146-1 Camera (PAL/SECAN/NTSC) Measurement Methods-Part 1: Video cameras (PAL/SECAN/NTSC)-Methods of measurement-Part 1: Non-broadcast single-sensor cameras
IEC 61966-2-1 Multimedia systems and equipment-Color measurement and management-Part 2-1: Color management-Default RGB color space-sRGB (Multimedia systems and equipment-Colour measurement and management-Part 2-1: Colour management-Default RGB color space-sRGB)
EBU Tech3249 Measurement and analysis of the performance of film and television camera lenses
3. Terms and Definitions
3.1 Digital Cameras and Devices
3.1. 1
opto-electronic digital image capture system
A system that converts the spatial distribution of exposure or scene brightness (scene) on the focal plane into digital information. [Source: ISO 14524: 2009, 3.12]
3.1. 2
electronic still camera
electronic still-picture camera
A camera having an image sensor capable of outputting an analog or digital signal describing a photograph and recording this signal on a storage medium (such as a memory card or a magnetic disk, etc.).
[Source: ISO 12233: 2017, 3.6]
3.1. 3
digital still camera; DSC
A device includes an image sensor and generates a digital signal representing a still image.
GB/T 20733-2022
Note: Digital cameras are usually portable handheld devices. Digital signals are usually recorded on removable memory, such as solid-state memory cards or magnetic disks. [Source: GB/T 20224-2006, 3.1, with modifications]
3.1. 4
image sensor
image transducer
An electronic device that can sense optical image information and convert it into an output signal.
Examples: Charge Coupling (CCD), Complementary Metal Oxide Semiconductor (CMOS), etc.
[Source: GB/T 13964-2008, 10.3]
3.1. 5
charge coupled device; CCD
A silicon integrated circuit that converts optical signals into electronic signals.
3.1. 6
Complementary metal-oxide-semiconductor device; CMOS
Semiconductor array with complementary effect of silicon and germanium to convert optical signals into electronic signals.
3.1. 7
analog to digital converter; A/D; ADC
A circuit for converting an analog-digital signal with continuously varying amplitude into a binary digital quantized output signal.
3.1. 8
addressable photo elements
The number of effective photoelectric elements contained in the image sensor is equal to the number of effective lines of photoelectric elements multiplied by the number of effective photoelectric elements
GB/T 20733-2022
er line. Note 1: In order to avoid confusion, the term resolution will not be used when referring to the number of effective photoelectric elements contained in the image sensor.
Note 2: The number of addressable optoelectronic elements may be different for different color recording methods of images. When the signal of the photoelectric element is digitized, the digital value can be used as a reference for the photoelectric element or pixel value.
[Source: ISO 12233: 2017, 3.1]
3.1. 9
pixel pixel
A physical unit on an image sensor that can receive light independently.
[Source: GB/T 29298-2012, 3.4]
3.1. 10
total pixels
The total number of pixels on the image sensor.
3.2 Photographic Optics
3.2. 1
photography
The process of acquiring, processing, or optically reproducing images using chemical or electronic techniques.
3.2. 2
focal length
The distance between the main point of the image side of an optical system and the main focus.
[Source: GB/T 13964-2008, 2.13]
3.2. 3
equivalent focal length
GB/T 20733-2022
When the diagonal length of the image area of the digital camera is equivalent to the diagonal length of the 35 mm camera frame (43.27 mm), the nominal focal length of the lens corresponds to the focal length of the 35 mm camera. Namely:
Equivalent focal length = (43.27 mm/diagonal length of image area) × nominal focal length of lens.
Note: The equivalent focal length is expressed in millimeter (mm).
[Source: GB/T 13964-2008, 2.36]
3.2. 4
digital zoom
Digital camera can enlarge the image in the middle part of the field of view by logical operation interpolation and other methods.
3.2. 5
geometric distortion; GD
In the stored image of a digital camera, the displacement from the theoretical shape of an object (in a plane parallel to the image plane).
Note: The geometric distortion basically comes from the camera lens, and the result is that the straight line is reduced to a curve. There are other factors that can cause geometric distortion, such as the rotational asymmetry of the camera lens or the change of position during the imaging process of the camera.
3.2. 6
TV distortion TV distortion
Linear distortion measured by conventional methods in the field of television as defined in IEC 61146-1 (24 geometric distortion) or EBU Tech 3249 (2.11 photo height distortion).
3.2. 7
Stray flare
In an imaging system, light that falls on an image instead of coming from a corresponding point.
GB/T 20733-2022
Note: flare sometimes refers to Veling glare.
3.2. 8
image flare
Light from the target point and scattered by the optical system beyond the appropriate image point in the image plane area.
Note: The image-spot difference generated by any target point is determined by the image point spread function. Point spread functions are variable for different image points, and often decrease rapidly with the increase of the distance to the image points, and they are usually not radially symmetric for image points at a certain distance from the optical axis.
3.2. 9
Soft stray light veiling flare
Relatively uniform but unnecessary irradiation on the image plane of an optical system caused by a portion of scattered and reflected light from within or outside the field of view of the system entering the system through the entrance pupil.
Note: Light leakage from the optical system shell may cause extra unwanted radiation in the image plane. This kind of radiation may be similar to soft glare.
[Source: ISO 3664: 2009, March 19]
3.2. 10
Soft glare veiling glare
Reflected light from the imaging medium, which will not form an image without modulation.
Note 1: Soft glare brightens the dark part of the image and reduces the contrast.
Note 2: In CIE 122, the soft glare of CRT display is called ambient glare.
3.3 Exposure and Photoelectric Conversion
GB/T 20733-2022
3.3. 1
opto-electronic conversion function; OECF
The relationship between the logarithm of the input value and the corresponding digital output value of the photoelectric digital image acquisition system.
Note: If the interval between the input logarithmic exposure points is very small and the output noise relative to the interval value is small, the OECF may exhibit stepped characteristics. This phenomenon is an illusion of quantitative processing, which should be eliminated by smoothing algorithm or curve fitting of data.
[Source: ISO 14524: 2009, 3.11]
3.3. 1.1
camera opto-electronic conversion function
Camera OECF
The relationship between logarithmic luminance of input scene and digital output value of photoelectric digital image acquisition system.
Note: The unit of measure for this function is lg cd/m ®.
[Source: ISO 14524: 2009, 3.1]
3.3. 1.2
focal plane opto-electronic conversion function; focal plane OECF
Relationship between digital exposure value and digital output value of input focal plane of photoelectric digital image acquisition system.
Note: The unit of measurement for this function is lg lx · s
[Source: ISO 14524: 2009, 3.5]
3.3. 2
digital output level digital output level
digital code value
A digital value assigned to a specific output level.
GB/T 20733-2022
[Source: ISO 14524: 2009, 3.2]
3.3. 3
incremental output signal
The product of the input signal (non-logarithmic brightness or exposure) and the corresponding system gain.
Note: See incremental gain function.
[Source: ISO 14524: 2009, 3.8]
3.3. 4
incremental gain function
A function expressed as the quotient of the change in output level (digital value) divided by the change in input level (brightness or exposure). Note 1: Logarithmic input values are not used for gain determination.
Note 2: If the input exposure point interval is very small and the output noise relative to the quantization interval value is very small, the gain function may exhibit a step-like characteristic. This phenomenon is an illusion of quantization processing, which is eliminated by quasi-leveling operation or data fitting curve. Sometimes it is necessary to fit the input-output data curve, and then determine the gain function by finding the first derivative of the fitting curve equation.
[Source: ISO 14524: 2009, 3.7]
3.3. 5
noise noise
Undue changes in the response of the imaging system.
[Source: GB/T 34074-2017, 3.9]
3.3. 5.1
total noise
All undesirable changes in the digital output obtained by single exposure shooting, including mode noise and random noise. [Source: GB/T 34074-2017, 3.9. 1]
GB/T 20733-2022
3.3. 5.2
fixed pattern noise
Undesired changes in digital output that remain unchanged during exposure.
[Source: GB/T34074-2017, 3.9. 2]
3.3. 5.3
Random noise temporary varying noise
Undesired changes in the digital output from one exposure to the next due to sensor dark current, shot noise, analog processing, and quantization.
[Source: GB/T 34074-2017, 3.9. 2]
3.3. 6
output noise
For a constant input level, the root mean square fluctuation of the median of the digital output level.
[Source: ISO 14524: 2009, March 13]
3.3. 7
Noise spectrum energy distribution
Curve or equation representation of spatial frequency function of two-dimensional image of camera output noise.
3.3. 8
incremental signal to noise ratio
Increments the ratio of the output signal to the electrical mean root of noise (rms) at a specific signal level.
Note: The incremental signal-to-noise ratio is typically expressed as a curve or table showing the relationship between the electrical mean root of noise and the output signal over the entire output signal level range.
3.3. 9
maximum exposure limit
GB/T 20733-2022
A minimum exposure of a digital output level corresponding to the maximum measurable exposure is generated.
Note 1: Maximum measurable exposure is also called saturation or quantization upper limit.
Note 2: See Minimum Exposure Limit.
[Source: ISO 14524: 2009, March 9]
3.3. 10
minimum exposure limit
An incremental output signal equal to the magnitude of the output noise is generated and below the saturated maximum exposure.
Note: See Incremental Output Signal, Maximum Exposure Limit, Output Noise.
[Source: ISO 14524: 2009, 3.10]
3.4 Image Evaluation
3.4. 1
resolution resolution
Measure the ability of the camera system or camera system components to represent picture details.
Note: The indicators of resolution measurement include visual resolution, limit resolution, spatial frequency response (SFR), modulation transfer function (MTF) and optical transfer function (OTF), etc.
[Source: ISO 12233: 2017, 3.22]
3.4. 2
visual resolution visual resolution
The spatial frequency of the black and white lines in the test map reproduced on the display or photo that can be distinguished by the human eye; Due to the influence of false signals, the spatial frequency that can be reproduced is lower than the spatial frequency of the corresponding area in the test diagram.
[Source: ISO 12233: 2017, March 29]
GB/T 20733-2022
3.4. 3
limiting resolution
The number of linewidths per image height measured for a specific resolution test pattern, corresponding to an average degree of modulation equal to the specified reference frequency and its degree of modulation percentage.
3.4. 4
spatial frequency response; SFR
Amplitude response measured by an imaging system as a function of the corresponding input spatial frequency.
Note 1: SFR is generally expressed by the output response curve of input sine wave brightness distribution per unit amplitude in spatial frequency range. Note 2: SFR is reduced to 1 when the spatial frequency is zero.
Note 3: In the equation, the symbol RSFR is used instead of the abbreviation SFR for clarity.
[Source: ISO 12233: 2017, 3.24]
3.4. 5
gray scale
The camera's ability to distinguish neutral spectra (gray light) with different reflectivity (or transmittance).
[Source: GB/T 29298-2012, 3.11]
3.4. 6
cycles per millimetre
cy/mm
A unit of spatial frequency, defined as the number of spatial periods per millimeter.
[Source: ISO 12233: 2017, 3.3]
3.4. 7
GB/T 20733-2022
Line width per image height line widths per picture height
LW/PH
A unit of measure used to specify the width of a feature on a test chart, relative to the height of the effective area of the test chart, which is equal to the effective area of the test chart
GB/T 20733-2022
Appendix A
(File)
Domestic and foreign brand number approximate comparison
The comparison with GB / T 20887.2-2010 and foreign standard are shown in Table A.1.
Table A. 1 Table of domestic and foreign approximate license numbers
The document GB/T 20887.2—2010 EN 10338:2015 VDA239-100:2016 JFS A1001:2014 SAE J2745—2007
