阅读说明：本技术 实时监测建筑构件耐火试验过程中炉内温度及缺陷的方法 (Method for monitoring furnace temperature and defects in fire resistance test process of building component in real time ) 是由 曹沁智 缪汉良 徐梓程 韦灵达 于 2019-09-24 设计创作，主要内容包括：本发明公开了一种实时监测建筑构件耐火试验过程中炉内温度及缺陷的方法,包括图像采集部分和图像处理部分。图像采集系统由光源组成的照明系统、镜头、摄像机等组成,而图像处理系统则通过编写软件算法实现。在一定的光照条件下,成像设备将物体成像并放大,然后由图像采集系统将数字图像信号送入计算机内,形成二维灰度矩阵,图像处理单元首先对采集到的原始图像进行预处理以改善图像的质量,然后通过边缘检测进行边缘定位,再进行缺陷的特征提取,最后构建分类器进行特征的识别完成对图像的分析,达到所要求的监测任务。本发明能够较为及时、准确地推定出构件易丧失耐火完整性或耐火隔热性的位置,进而提高耐火性能检测的准确度。(The invention discloses a method for monitoring the temperature and the defects in a furnace in the fire resistance test process of a building component in real time, which comprises an image acquisition part and an image processing part. The image acquisition system consists of an illumination system consisting of a light source, a lens, a camera and the like, and the image processing system is realized by compiling a software algorithm. Under a certain illumination condition, an object is imaged and amplified by an imaging device, then a digital image signal is sent into a computer by an image acquisition system to form a two-dimensional gray matrix, an image processing unit firstly preprocesses an acquired original image to improve the quality of the image, then edge positioning is carried out through edge detection, then defect feature extraction is carried out, and finally a classifier is constructed to identify features to complete the analysis of the image so as to achieve the required monitoring task. The method can accurately and timely estimate the position of the member which is easy to lose the fire-resistant integrity or the fire-resistant heat insulation property, thereby improving the accuracy of the fire-resistant property detection.)

1. a method for monitoring the temperature and the defects in a furnace in the fire resistance test process of a building component in real time is characterized in that: the method comprises the following steps:

(1) Before the test is ignited, a tested building component and a machine vision detection system are installed in a detection furnace for a fire resistance test of the building component, and the system comprises an image acquisition system and an image processing system; simultaneously starting a cooling device;

the image acquisition system comprises an illumination system consisting of a light source and an imaging device, the imaging device is used for monitoring the temperature and the defects of the back fire surface of the detected building component, and the view angle of the imaging device covers the whole detection furnace inner area;

(2) The method comprises the following steps of (1) test ignition, wherein under the illumination condition, an imaging device images and amplifies an object, and then an image acquisition system sends a digital image signal into a computer to form a two-dimensional gray matrix, namely an original image;

(3) The image processing system firstly preprocesses the acquired original image to improve the quality of the image, then carries out edge positioning through edge detection, then carries out defect feature extraction, and finally constructs a classifier to carry out feature recognition to finish the analysis of the image so as to achieve the required monitoring task, and specifically comprises the following steps:

Setting a temperature detection area, detecting the real-time temperature of each measuring point of the fire surface of the component through a high-temperature monitoring device in the furnace, wherein the display temperature of each measuring point is the average temperature in the setting area;

Selecting a region needing to be monitored for defects, selecting a known size in a monitoring range, and setting the size as the length of an image ruler; setting defect monitoring parameters as required: minimum crack width, minimum crack length, minimum crack area; when the defect size of the fire surface of the component exceeds the defect monitoring parameter, the system automatically records the size and the position of the defect.

2. the method for real-time monitoring of furnace temperature and defects in the fire resistance test process of building components according to claim 1, wherein: the illumination in the step (2) comprises visible light and infrared rays.

3. the method for real-time monitoring of furnace temperature and defects in the fire resistance test process of building components according to claim 1, wherein: the exact value of the average temperature in the zone set in step (3) is 1 ℃.

4. The method for real-time monitoring of furnace temperature and defects in the fire resistance test process of building components according to claim 1, wherein: and (4) the area for monitoring the defects in the step (3) comprises the back fire surface of the whole building component to be detected.

Technical Field

the invention relates to the field of detection and research of fire resistance of building components, in particular to detection of surface states of fire resistance test components.

background

With the increasing number of building fires, people pay more attention to the performance change of building components in fire environments. The use of combustion furnaces to study the refractory properties of components is one of the most common methods.

The fire resistance of the building element is determined from the integrity and insulation properties. Refractory integrity refers to the time a component is able to maintain refractory integrity for a duration of a refractory test, and the component is considered to lose integrity when any of the following limitations occur: (1) the cotton pad is ignited; (2) the gap probe can penetrate through the gap; (3) the back fire surface generates flame and lasts for more than 10 s. The refractory heat insulation refers to the time for which the member is kept in refractory heat insulation during a refractory test, and the member is considered to lose heat insulation when the temperature rise of the back fire surface of the member exceeds any one of the following limits: (1) the average temperature rise exceeds the initial average temperature by 140 ℃; (2) the temperature rise at any point exceeds the initial temperature (including the moving thermocouple) by 180 deg.c.

According to the GB/T9978 standard, a certain number of thermocouples are required to be arranged in the combustion furnace for measuring the average temperature in the furnace in the test process, and the average temperature in the furnace must conform to the relation: t345 lg (8T +1) +20, wherein: t-average temperature in furnace/deg.C, T-time/min. And a thermocouple is arranged on the back fire surface of the member according to requirements and is used for monitoring the temperature of the back fire surface of the test piece in the test process.

when the traditional combustion furnace is used for fire resistance test, because the temperature in the furnace can reach 1300 ℃ at most, the change condition of the fire-receiving surface of the component can not be observed, and a tester can only judge whether the component loses fire resistance integrity or heat insulation property by observing the phenomenon of the back fire surface and measuring the temperature. The positions of the measuring points of the thermocouple fixed on the back fire surface of the component are selected mainly according to corresponding standard regulations, and the temperature of the back fire surface can be measured only by a movable thermocouple at the position without the fixed thermocouple. Because the position of the component which is easy to lose fire resistance integrity or heat insulation can not be pre-judged from the back fire surface of the component by means of naked eye identification, when the back fire surface of the component is monitored by using a fixed thermocouple or a movable thermocouple, the selection of the measuring point position has greater randomness, and the highest temperature rise point can not be timely and accurately found. This randomness causes a large error in the detection of the fire endurance of the building element.

In the field of research on the fire resistance of building components, it is particularly critical to find out the position where the surface of the component is easy to lose the fire resistance integrity or the heat insulation, once the weak point of the surface of the component is found out, effective protective measures can be pertinently implemented, and the fire resistance of a fire-resistant component product is further improved. When the traditional combustion furnace is used for fire resistance test, the change condition of the fire-receiving surface of the component cannot be observed in the test process due to high temperature. If the damage condition of the member fire surface is observed, the furnace door is opened to observe the damage condition of the member fire surface only after the temperature in the furnace is reduced to the room temperature after the test is finished.

Disclosure of Invention

the invention aims to monitor the temperature and the defects of a fire surface of a member in real time in the test process, and provides a method for monitoring the temperature and the defects in a furnace in the fire resistance test process of a building member in real time.

The technical scheme adopted by the invention is as follows: a method for monitoring the temperature and the defects in a furnace in the fire resistance test process of a building component in real time comprises the following steps:

(1) before the test is ignited, a tested building component and a machine vision detection system are installed in a detection furnace for a fire resistance test of the building component, and the system comprises an image acquisition system and an image processing system; simultaneously starting a cooling device;

The image acquisition system comprises an illumination system consisting of a light source and an imaging device, the imaging device is used for monitoring the temperature and the defects of the back fire surface of the detected building component, and the view angle of the imaging device covers the whole detection furnace inner area;

(2) The method comprises the following steps of (1) test ignition, wherein under the illumination condition, an imaging device images and amplifies an object, and then an image acquisition system sends a digital image signal into a computer to form a two-dimensional gray matrix, namely an original image;

(3) The image processing system firstly preprocesses the acquired original image to improve the quality of the image, then carries out edge positioning through edge detection, then carries out defect feature extraction, and finally constructs a classifier to carry out feature recognition to finish the analysis of the image so as to achieve the required monitoring task, and specifically comprises the following steps:

Setting a temperature detection area, detecting the real-time temperature of each measuring point of the fire surface of the component through a high-temperature monitoring device in the furnace, wherein the display temperature of each measuring point is the average temperature in the setting area;

and selecting a region needing to be monitored for the defect, selecting a known size in a monitoring range, and setting the size as the length of an image scale. Setting defect monitoring parameters as required: minimum crack width, minimum crack length, minimum crack area; when the defect size of the fire surface of the component exceeds the defect monitoring parameter, the system automatically records the size and the position of the defect.

Preferably, the light in step (2) includes various light sources such as visible light, infrared light, and the like.

Preferably, the precise value of the average temperature in the zone set in step (3) is 1 ℃.

Preferably, the area in which the defect is monitored in step (3) comprises the back fire surface of the whole building element to be tested.

The whole system of the invention consists of two parts: hardware systems and software systems. The main task of the hardware system is to acquire images in real time and convert the image information into digital signals which can be recognized by a computer. The main tasks of the software system are to perform corresponding processing, temperature measurement, defect identification and data storage on the acquired images. The core part of the system is an image processing system. The image processing system is realized by writing software algorithms.

has the advantages that: the method for monitoring the temperature and the defects in the furnace in the fire resistance test process in real time can more timely and accurately estimate the position of the member which is easy to lose the fire resistance integrity or the fire resistance and heat insulation, further improve the accuracy of fire resistance detection and provide reliable technical support for improving the fire resistance of the building member. The method is suitable for popularization and application.

drawings

FIG. 1 is a schematic diagram of the machine vision inspection system of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

As shown in fig. 1, a method for monitoring the temperature and defects in a furnace in the fire resistance test process of a building component in real time comprises the following steps:

(1) before the test is ignited, a tested building component and a machine vision detection system are installed in a detection furnace for a fire resistance test of the building component, and the system comprises an image acquisition system and an image processing system; simultaneously starting a cooling device;

The image acquisition system comprises an illumination system and an imaging device which are composed of light sources, holes with certain sizes are reserved in positions in a fire-resistant detection test furnace of the building component, so that the high-temperature small hole imaging device can conveniently enter the furnace to monitor the temperature and the defects of the back fire surface of the building component to be detected, and the high-temperature small hole imaging is pneumatically pushed into the fire-resistant detection furnace;

the internal size of the fire-resistant detection furnace for the building components is 3000mm 120mm 3000 mm. Two sets of imaging equipment are respectively installed in the furnace from top to bottom according to visual angle requirements, and the whole area with the visual field covering 3000mm × 3000mm is ensured.

(2) the method comprises the following steps of (1) test ignition, wherein under the illumination condition, the test ignition comprises various light sources such as visible light, infrared rays and the like, an object is imaged and amplified by imaging equipment, and then a digital image signal is sent into a computer by an image acquisition system to form a two-dimensional gray matrix, namely an original image;

(3) The image processing system firstly preprocesses the acquired original image to improve the quality of the image, then carries out edge positioning through edge detection, then carries out defect feature extraction, and finally constructs a classifier to carry out feature recognition to finish the analysis of the image so as to achieve the required monitoring task, and specifically comprises the following steps:

And opening temperature and defect monitoring system software, selecting a 'defined temperature area', and framing and setting a temperature detection area. The real-time temperature of each measuring point of the fire surface of the component is detected by a high-temperature monitoring device in the furnace, the display temperature of each measuring point is the average temperature in the frame selection area, and the accurate value is 1 ℃.

3) the "defined defect range" is selected, the area to be monitored for defects, typically the backfire face containing the entire test member, is selected, and the appropriate known dimensions are selected within the monitored range, set to the image scale length. Appropriate defect monitoring parameters are set as required: minimum crack width, minimum crack length, minimum crack area. When the defect size of the fire surface of the component exceeds the defect monitoring parameter, the system automatically records the size and the position of the defect.

The embodiments of the present invention are described in detail above with reference to the drawings, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made on the embodiments without departing from the spirit and scope of the inventive concept.