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This Regulation was approved by the Ministry of Communications of the People's Republic of China on April 3, 2007, and implemented from August 1, 2007.
The Transportation Industry Measurement Technical Committee is responsible for the explanation of this Regulation.
Contents
1 Scope 1
2 Normative References 1
3 General 1
4 Measuring performance requirement 2
5 General Technical Requirements 2
6 Control over Measuring Instruments 2
Annex A Format of Verification Record 7
Annex B Back Format of Verification Certificate 8
Annex C Content of Verification Certificate 9
Annex D Setting Block 10
Vehicle Bearing Road Laser Video Distress Detecting System
1 Scope
This Regulation is applicable to the first verification, subsequent verification and in-use inspection of vehicle bearing pavement laser video distress detecting system (hereinafter referred to as "distress detecting system").
2 Normative References
JTJ 059 Field Test Methods of Subgrade and Pavement for Highway Engineering
JT/T 678-2007 Vehicle Bearing Road Laser Video Distress Detecting System
For purpose of this Regulation, the current and effective editions of the documents above shall apply.
3 General
Laser video distress detecting system is a device to detect and analyze road pavement deformation and crack through high speed digital camera technique and light source like three-dimensional imaging laser bean, strong light and sun light, and it consists of three-dimensional imaging laser source, strong light source or sun light source, high speed digital high-resolution imaging device, longitudinal distance sensor, road distress computer digital image processing system (as shown in Figure 1).
Figure 1 Diagram of laser video distress detecting system
a) Road deformation detecting system; b) Road crack detecting system
4 Measuring Performance Requirement
4.1 Road crack width discrimination: where road crack width is not less than 2mm, the discrimination rate is 100% and the indication error of crack width value identification shall not be greater than 1mm.
4.2 Indication error of road distress area shall not be greater than 10%.
4.3 Error of longitudinal distance sensor shall not be greater than 0.1%.
4.4 Repeatability test: road distress statistics output disturbance system CV shall not be greater than 5%.
5 General Technical Requirements
5.1 Appearance of all parts of laser video distress detecting system shall be bright and clean, and free of damage and rust; surface paint layer shall be smooth and uniform.
5.2 Nameplate and mark of laser video distress detecting system shall be distinct. The content on label plate shall include product model, product name, manufacturer's name, product technical parameters, production number and manufacturing date; the content on mark shall include use number and latest verification date.
6 Control over Measuring Instruments
6.1 Verification conditions
6.1.1 Environment conditions for verification
The environmental conditions for verification are as follows:
a) Ambient temperature: 0℃ ~ 50℃;
b) Ambient humidity: ≤85%;
c) Requirements of test road section: straight road section free of water accumulation, snow/ice, pollution, and intersection;
d) Running speed of bearing vehicle: ≥100km/h.
6.1.2 Verification tools
6.1.2.1 Steel tape: 0m ~ 50m, with division value 1mm.
6.1.2.2 Temperature & relative humidity indicator: temperature span -30℃ ~ +60℃, with division value 0.2℃;
Humidity range 0 ~ 100%, with division value 1%.
6.1.2.3 Setting block for road crack width video detecting (hereinafter referred to as "setting block"): aluminum alloy made, with the dimensions as specified in Annex D hereto.
6.1.2.4 Road distress area testing panel
Material: made of aluminum alloy, ABS plastic or other suitable material; dimensional requirement: testing panels with a thickness of not less than 5mm and an area of 100cm2 ~ 1600cm2 (square, rectangle, regular triangle, rhomboid and round, 2 pieces respectively).
6.1.2.5 Vernier calipers: 0mm ~ 150mm; with scale division: 0.02mm.
6.2 Verification items
Verification items of laser video distress detecting system are as shown in Table 1 and verification record format is detailed in Annex A.
1 Scope 2 Normative References 3 General 4 Measuring performance requirement 5 General Technical Requirements 6 Control over Measuring Instruments Annex A Format of Verification Record Annex B Back Format of Verification Certificate Annex C Content of Verification Certificate Annex D Setting Block
中华人民共和国交通部部门计量检定规程 JJG（交通）007-2007 车载式路面激光视频病害检测系统 Vehicle bearing road laser video distress detecting system 2007-04-03发布 2007-08-01实施 中华人民共和国交通部发布
6.3 检定方法 6.3.1 外观检查 用目测和手感检查激光视频病害检测系统的外观，应符合5.1和5.2的规定。 6.3.2 路面裂缝宽度辨别检测如下： 路面裂缝宽度辨别检测如下： a) 将调整块横向放置在硬性路面车道中心线上，使条缝垂直车道方向； b) 确定调整块条缝宽度值，在2mm、4mm、6mm、8mm四种宽度（用游标卡尺测量）之间任意变化10次。 c) 条缝宽度每变1次，检测车以80km/h的速度，对准车道中心线驶过调整块，记录检测系统输出条缝宽度值； d) 将调整块纵向放置在硬性路面车道中心线上，使条缝平行车道方向； e) 重复b)、c)的检测过程； f) 统计条缝的辨别应符合4.1的规定。 6.3.3 路面病害面积示值误差检测 路面病害面积示值误差检测如下： a) 准备6块不同形状、不同面积的路面病害面积测试板，计算它们的总面积，然后随机安放在50m长的硬性车道非行车位置的道面上； b) 检测车以80km/h的速度驶过试验路段，检测系统输出检测的全部病害测试板面积的总和； c) 随机变动6块测试板的位置，再重复上述a)和b)的检测过程2次； d) 检测系统3次输出的结果值与路面病害面积测试板总面积的误差，均应符合4.2的规定。 6.3.4 纵向距离传感器误差试验 a) 选择合适的平整直线路段，用钢卷尺准确量取500m长度，并分别在始点、终点画上横线； b) 检测车停放在试验路段的始点处，将纵向距离传感器测距轮的中心线对准始点横线，启动检测系统，检测车出发沿车道线平行方向驶向终点，同时开始距离测量，当测距轮的中心线与终点横线对准时，停车，检测系统输出的行驶距离测试值与试验路段量取的实际值的误差，应符合4.3的规定。 6.3.5 重复性试验 重复性试验如下： a) 选择试验路段，要求长度500m，并包含多种路面病害的路段，在始点、终点作出标记； b) 检测车以80km/h的速度对试验路段重复采集10次图像及数据； c) 计算速度80km/h的条件下，10次路面病害测试结果的偏差系统Cv的计算公式如下：
