CN108490029B - Method for detecting hollowing of outer wall finish coat - Google Patents
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- CN108490029B CN108490029B CN201810229483.0A CN201810229483A CN108490029B CN 108490029 B CN108490029 B CN 108490029B CN 201810229483 A CN201810229483 A CN 201810229483A CN 108490029 B CN108490029 B CN 108490029B
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Abstract
The invention belongs to the technical field of building engineering safety detection, and provides a method for detecting hollowing of an outer wall finish coat. (1) A method for finding suspicious positions with defects by using infrared temperature gradient images. (2) And in the case of poor detection conditions, an auxiliary technical means of heating the surface by laser irradiation is adopted, and the surface temperature difference is amplified to detect the defects. (3) And for the suspicious regions with abnormal temperature, identifying and judging whether the facing layer hollowing defects exist or not by utilizing temperature difference change comparison in the temperature rising and reducing processes. The method for detecting the defects of the veneer layer of the facade of the building can realize remote detection in the actual detection operation, avoid high-altitude dangerous operation of personnel and has simple and convenient operation. The subjectivity and instability brought by artificial temperature image color identification can be overcome in the aspect of data analysis processing, and batch processing of image analysis or real-time detection and analysis can be realized through software.
Description
Technical Field
The invention belongs to the technical field of building engineering safety detection, and relates to a technical means of wall quality detection, in particular to a field detection method for detecting whether hollowing potential safety hazards exist on a decorative surface layer of an outer vertical surface of a building, such as a ceramic tile and the like.
Background
The sticking of the exterior wall facing brick is a common exterior wall decoration form in the high-rise buildings of the city at present, and is widely used with the advantages of beauty, economy and the like, but the hollow bulge can be formed and fall off to bring potential safety hazards. The main problem is that the bonding strength between the facing layer and the concrete or brick wall base layer is gradually reduced along with the time due to the fact that the construction quality does not reach the standard or the construction quality is aged for a long time, and when the bonding strength does not meet the requirement, the facing layer can be partially separated from the base layer to form hollowing; if the reinforcement is not carried out, the hollowing area can be gradually increased, and finally, the decorative layer is completely separated from the base layer, and accidents such as high falling are caused. Due to the large detection area, the requirement on detecting defects is fine, and the high-altitude operation of the outer vertical surface is limited, a detection means which can quickly diagnose and generally check the defects of the decorative surface layer of the outer vertical surface of the building is needed.
At present, the defects of the outer wall veneer of the building are mainly detected by a knocking method, a drawing method and an infrared thermal imaging method, and although the knocking method and the drawing method have accurate detection results, high-altitude operation is required for the outer vertical surface of the high-rise building, the detection time is long, the efficiency is low, and the detection is greatly influenced by the subjective judgment of detection personnel; compared with other methods, the infrared imaging method has the characteristics of high efficiency, intuition, rapidness, low manpower and material cost and the like, has obvious advantages in the application of hollowing of the facing bricks of the general investigation exterior walls, and related detection regulations and standards are promulgated by related departments, but the existing infrared method is limited in the actual detection application process, and has the following main problems:
1. when the hollowing of the exterior wall facing brick is detected by an infrared method, the detection result which is judged by simply depending on the color difference of the shot infrared image is easily influenced by meteorological conditions, particularly solar radiation, so that the restriction of the detection condition is formed.
Under the irradiation of stronger solar radiation intensity, the temperature difference between the hollow area and the normal area on the surface of the outer wall continuously changes along with time, and only the proper detection time interval of part of cities in the whole country is regulated in technical regulation for detecting the bonding quality of the outer wall facing of the building by infrared thermography (JGJ/T277-2012), but the rule of universality is lacked. Chinese patent No. 201610523425.X (an infrared quality detection method for hollowing defects of an external wall) proposes a method for reducing the temperature of a whole wall surface by spraying a cooling liquid after irradiation of sunlight to reduce detection errors. Although feasible, the temperature of the outer wall surface needs to be reduced for 5-15 minutes, and the spraying is uniform, so that the operation difficulty and the cost are relatively high in the actual implementation process.
When the meteorological conditions are not good (such as cloudy days and heavy fog), the temperature difference of the wall surface is very small, and particularly, the detection effect of the infrared thermal imager on the north outer vertical surface is greatly reduced; the Chinese patent with the application number of 200810207217.4 discloses a non-contact nondestructive testing method for detecting the hollowing position of ancient murals, the surface of an outer wall is heated through a bulb, and a thermograph is obtained through infrared thermal imaging, so that the area with unobvious heat rise is judged to be a hollowing area. Although the direction can be used for detecting the hollowing of the outer wall, the detection efficiency of the hollowing of the outer wall is improved, detection conditions such as power supply and distribution are needed when the bulb is reheated, the detection conditions are complex, the temperature rise amplitude of the surface of the outer wall is very small, heating is uneven, and the effect is not obvious.
2. The existing technical means is that the color difference of the detected infrared image caused by the temperature difference is used for judging the defect position, the common problem exists all the time is that the color difference has a great relationship with factors such as the value range of the color development temperature selected in the later image processing process, manual setting and adjustment are needed, the labor cost and the time consumption are greatly increased for the whole general investigation of the building outer wall, the efficiency is low, the subjectivity in the identification process can be overcome by using an analysis method of batch processing calculation by using a computer, and the reliability of detection and identification is improved.
3. When the hollowing of the exterior wall facing brick is detected by an infrared method, the radiation of the surrounding environment, the emissivity of the outer surface of the wall surface, the surface color and the shooting angle can have great influence on the detection result, and a temperature abnormal area which is not caused by the hollowing can appear on an infrared picture, so that the higher misjudgment rate exists only by depending on the comparison of an infrared thermal image and a visible light picture, the bonding defect of the facing layer cannot be fully determined, and other auxiliary detection methods such as a hammering method, a drawing method and the like are also needed to carry out necessary verification.
Disclosure of Invention
The purpose of the invention is:
(1) a method for finding suspicious positions with defects by using infrared temperature gradient images.
Because the temperature testing precision of the infrared camera is not high, but the temperature resolution ratio can reach more than 50mK, the invention provides a method for converting an original infrared temperature image into a temperature gradient image through data processing, the temperature on the boundary of a normal area and an abnormal area obviously steps, the temperature gradient of the position is obviously higher than the gradient in the area, the gradient image is filtered, and the texture contour is filtered by combining with a visible light contour line comparison method, and the position and the contour of the area which possibly have defects can be identified through further processing.
(2) And in the case of poor detection conditions, particularly in the case of an unsatisfactory north facade or unsatisfactory solar radiation intensity, an auxiliary technical means of heating the surface by laser irradiation is adopted to amplify the surface temperature difference for defect detection. The auxiliary means realizes non-contact detection by utilizing the remote transmission characteristic of the laser beam, has rapid heating, uniform heating quantity, controllable adjustment and accuracy, and can identify and judge the hollowing by utilizing the relationship between the temperature rise condition after irradiation and the radiation quantity.
(3) And for the suspicious regions with abnormal temperature, identifying and judging whether the facing layer hollowing defects exist or not by utilizing temperature difference change comparison in the temperature rising and reducing processes.
Due to the existence of the decorative surface layer hollowing area, the surface of the hollowing is quickly heated to form hot spots during heating, the surface of the hollowing is quickly cooled to form cold spots during cooling, the change characteristic that positive and negative reversal can occur due to the temperature difference between the defective position of the hollowing and the normal surface is utilized, the influence of other factors such as surface emissivity and wall material is eliminated, and then whether the hollowing exists is determined. The technical means improves the accuracy and reliability of the traditional infrared detection method, avoids high-altitude operation danger caused by contact detection compared with a tapping method and a drawing method, and has high detection efficiency.
The technical scheme of the invention is as follows:
a method for detecting hollowing of an outer wall finish coat comprises the following steps:
(1) when the outer wall to be detected is in a good solar irradiation condition, performing infrared temperature image test on the outer facade of the building in a surface heating stage, acquiring an original visible light image and an original infrared image, and recording the number of each image, corresponding shooting position information and solar radiation intensity information;
according to the shooting angle, referring to the identification point of the visible light image, carrying out image shaping calibration on the original visible light image and the infrared image, wherein the calibration is a plane image which is just opposite to the shooting;
(2) converting the infrared image obtained by the last step of processing into a temperature gradient image, adjusting and filtering according to the test condition, removing the influence of the surface texture of the temperature gradient image to obtain a profile map of the surface temperature abnormal region, comparing the profile map with the profile of the original visible light image, and further identifying the outline of the original block of the facade from the infrared image, wherein the remaining other outline closed regions are represented as defect suspicious blocks;
(3) screening out images with defect suspicious blocks, marking suspicious contour lines corresponding to the obtained defect suspicious blocks on the infrared images and the original visible light images, and respectively calculating the areas and the average temperatures of the defect suspicious blocks and the surrounding blocks;
(4) according to the serial number of the recorded image, shooting position information and a defect suspicious area marked on the original visible light image, positioning the suspicious defect part of the building; carrying out secondary examination on the suspicious defect part in a cooling time period, and repeating the operations of the steps (1) to (3);
summarizing each suspicious defect part and surrounding areas, measuring the average temperature of detection for multiple times, calculating the temperature difference, and judging that the suspicious defect part has the empty drum defect if the temperature difference is found to have obvious positive and negative alternation phenomena.
The invention has the beneficial effects that: the method for detecting the defects of the veneer layer of the facade of the building can realize remote detection in the actual detection operation, avoid high-altitude dangerous operation of personnel and has simple and convenient operation. In the aspect of data analysis and processing, the subjectivity and instability caused by artificial temperature image color identification can be overcome, and batch processing of image analysis or real-time detection and analysis can be realized through software.
Detailed Description
The following further describes the specific embodiments of the present invention in combination with the technical solutions.
Examples
The method for detecting the hollowing of the outer wall finish coat comprises the following steps:
(1) when the outer wall to be detected is in a good solar irradiation condition, performing infrared temperature image test on the outer facade of the building in a surface heating stage, acquiring an original visible light image and an original infrared image, and recording the number of each image, corresponding shooting position information and solar radiation intensity information;
according to the shooting angle, referring to the identification point of the visible light image, carrying out image shaping calibration on the original visible light image and the infrared image, wherein the calibration is a plane image which is just opposite to the shooting;
(2) converting the infrared image obtained by the last step of processing into a temperature gradient image, adjusting and filtering according to the test condition, removing the influence of the surface texture of the temperature gradient image to obtain a profile map of the surface temperature abnormal region, comparing the profile map with the profile of the original visible light image, and further identifying the outline of the original block of the facade from the infrared image, wherein the remaining other outline closed regions are represented as defect suspicious blocks;
(3) screening out images with defect suspicious blocks, marking suspicious contour lines corresponding to the obtained defect suspicious blocks on the infrared images and the original visible light images, and respectively calculating the areas and the average temperatures of the defect suspicious blocks and the surrounding blocks;
(4) according to the serial number of the recorded image, shooting position information and a defect suspicious area marked on the original visible light image, positioning the suspicious defect part of the building; carrying out secondary examination on the suspicious defect part in a cooling time period, and repeating the operations of the steps (1) to (3);
summarizing each suspicious defect part and surrounding areas, measuring the average temperature of detection for multiple times, calculating the temperature difference, and judging that the suspicious defect part has the empty drum defect if the temperature difference is found to have obvious positive and negative alternation phenomena.
In the required detection time, under the conditions that weather conditions are not good and surface temperatures are not obviously different, a laser surface light source is used for irradiating the outer wall to be detected for 2-5 minutes, an infrared camera is used for tracking and recording the overall change conditions of temperature rise and recovery of an irradiated area, whether an abnormal temperature area exists in the area or not is observed, if an abnormal area exists, an area surface with an obvious phenomenon is selected, image analysis processing is carried out through the steps (1) to (3), and a temperature change curve of the abnormal area and the surrounding area is drawn; and (4) performing heat transfer calculation on the outer surface of the building by using the laser emission power of the surface light source, and if the calculation result is consistent with the actual test, judging that the area is the empty drum defect position.
Claims (2)
1. A method for detecting hollowing of an outer wall finish coat is characterized by comprising the following steps:
(1) when the outer wall to be detected is in a good solar irradiation condition, performing infrared temperature image test on the outer facade of the building in a surface heating stage, acquiring an original visible light image and an original infrared image, and recording the number of each image, corresponding shooting position information and solar radiation intensity information;
according to the shooting angle, referring to the identification point of the visible light image, carrying out image shaping calibration on the original visible light image and the infrared image, wherein the calibration is a plane image which is just opposite to the shooting;
(2) converting the infrared image obtained by the last step of processing into a temperature gradient image, adjusting and filtering according to the test condition, removing the influence of the surface texture of the temperature gradient image to obtain a profile map of the surface temperature abnormal region, comparing the profile map with the profile of the original visible light image, and further identifying the outline of the original block of the facade from the infrared image, wherein the remaining other outline closed regions are represented as defect suspicious blocks;
(3) screening out images with defect suspicious blocks, marking suspicious contour lines corresponding to the obtained defect suspicious blocks on the infrared images and the original visible light images, and respectively calculating the areas and the average temperatures of the defect suspicious blocks and the surrounding blocks;
(4) according to the serial number of the recorded image, shooting position information and a defect suspicious area marked on the original visible light image, positioning the suspicious defect part of the building; carrying out secondary examination on the suspicious defect part in a cooling time period, and repeating the operations of the steps (1) to (3);
summarizing each suspicious defect part and surrounding areas, measuring the average temperature of detection for multiple times, calculating the temperature difference, and judging that the suspicious defect part has the empty drum defect if the temperature difference is found to have obvious positive and negative alternation phenomena.
2. The method for detecting the hollowing of the outer wall finish coat according to claim 1, characterized in that under the conditions of bad weather conditions and no obvious difference in surface temperature within the required detection time, a laser surface light source is utilized to irradiate the outer wall to be detected for 2-5 minutes, an infrared camera is utilized to track and record the overall change condition of temperature rise and recovery of an irradiated area, whether a temperature abnormal area exists in the area is observed, if an abnormal area exists, an area surface with obvious phenomenon is selected, image analysis processing is carried out through the steps (1) - (3), and a temperature change curve of the abnormal area and the surrounding area is drawn; and (4) performing heat transfer calculation on the outer surface of the building by using the laser emission power of the surface light source, and if the calculation result is consistent with the actual test, judging that the area is the empty drum defect position.
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| CN110542688A (en) * | 2019-09-24 | 2019-12-06 | 南京工大建设工程技术有限公司 | Method for monitoring furnace temperature and defects in fire resistance test process of building component in real time |
| CN110987992A (en) * | 2020-01-02 | 2020-04-10 | 上海市建筑科学研究院有限公司 | Back-scattering imaging-based quantitative identification method for internal defects of external thermal insulation system of external wall |
| CN111366602A (en) * | 2020-03-19 | 2020-07-03 | 三一筑工科技有限公司 | Method, device and system for detecting compactness of concrete in prefabricated cavity wall |
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| JPWO2022091702A1 (en) * | 2020-10-30 | 2022-05-05 | ||
| CN112927214A (en) * | 2021-03-12 | 2021-06-08 | 深圳信息职业技术学院 | Building defect positioning method, system and storage medium |
| CN113588783A (en) * | 2021-07-07 | 2021-11-02 | 宁波和邦检测研究有限公司 | Cement mortar hollowing detection method and system, storage medium and intelligent terminal |
| CN115598178B (en) * | 2022-12-14 | 2023-05-05 | 天津思睿信息技术有限公司 | Infrared detection method and system for building wall hollowing defect |
| CN117169477B (en) * | 2023-10-25 | 2024-01-12 | 广东省装饰有限公司 | Building indoor ground hollowing degree assessment method |
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