KR100788910B1 - On-line apparatus and method for measuring a cross-sectional view - Google Patents

Abstract

An apparatus and a method for measuring the cross-section of a target in real time are provided to supply required information to a manager and a worker by systematically managing information on the quality of products. A camera module employs an interference filter to receive laser light as an image. The interference filter receives laser light reflected from the surface of a target and blocks wavelengths except for the wavelength of the laser light. A program module converts an input image from a camera module into data observed on a cross-section, and completes a cross-sectional external shape image using plural images obtained by primary length correction with respect to the converted data according to a photograph angle of the camera module and secondary length correction according to the distance between the camera module and a laser light reflection portion, or converts the cross-sectional external shape image into a vector-type graphic file.

Description

Apparatus and method for non-contact real-time measurement of the external cross section of the object under test {On-line Apparatus and Method for Measuring a Cross-sectional View}

1 is a conceptual diagram showing the relationship between the measuring device and the object to be measured according to the present invention.

2 is a conceptual diagram illustrating a first length correction according to a photographing angle of an image photographed in a section measurement process using a measuring device according to the present invention.

Figure 3 is a conceptual diagram illustrating the second length correction according to the shooting distance of the image taken in the cross-sectional measurement process using the measuring device according to the present invention.

4 is a conceptual view showing a configuration for measuring the external shape cross section of the profile as an embodiment using the device according to the present invention.

Figure 5 is an embodiment using the device according to the invention the image of the profile of the appearance profile cross section taken in 360 directions in four directions.

6 is a conceptual diagram illustrating a process of correcting a length (height) of the image photographed in FIG. 5.

7 is a view showing a cross-sectional view of the profile by combining the four (length) height-corrected in Figure 6 and these combinations.

The present invention relates to a device and a method for measuring a non-contact real-time measurement of the external cross-section of the object (measured object), and more specifically, information required for the manager and operator by systemizing quality information management / analysis / aggregation processing, etc. And a method for non-contact real-time measurement of an external shape cross section of an object (object to be measured) capable of efficient and effective management of quality improvement, productivity improvement, defect rate reduction, cost reduction, etc. by providing timely in real time. .

In order for a manufacturer to defeat several competitors and grow into a world-class company, it requires differentiated customer service and a very high level of quality control. In particular, quality control must be carried out continuously during the operation of the production line. The relevant data and all information should be reflected in the production line in real time and used for quality maintenance and improvement.

The production process of the product generally consists of designing the product, setting up the equipment according to the determined design, checking the productivity of the test product, and producing the product. At this time, in order to smoothly control quality and increase production efficiency, it is essential to sample a part of the produced product and confirm whether the product is produced within the tolerance of the design drawing.

However, even if the product is sampled and measured, the time is not too small, so if there is an error in the production, there is a limit that a considerable amount of the product can be treated as defective even if it is corrected. In the case of profile products produced continuously, it is more problematic because it is practically impossible to measure the value by cutting the middle.

On the other hand, methods for measuring the external cross section of a product include (i) a fracture test for cutting a cross section of the product and (ii) a non-destructive test for measuring a product without cross section cutting. Contact inspection using a measuring tool of (ii-2), and a non-contact inspection method using an image processing apparatus such as a CCD camera. The failure inspection method (i) and the contact inspection method (ii-1) have disadvantages that require a professional worker with considerable time and considerable experience.

On the other hand, the conventional non-contact inspection method (ii-2) analyzes an image sent from an image processing apparatus with a computer to obtain dimensional data for each part of the product, and then compares the dimensional data with reference data for product design 1: 1. It is to determine whether or not. For example, a method of measuring a shape of an object that receives a reflected laser light of a laser beam irradiated at a predetermined inclination angle to a surface of a three-dimensional object to be measured and computes a change in the image data to obtain a numerical value related to the surface shape of the object to be measured is known. have. Korean Patent Publication Nos. 10-1994-7508, 10-1995-33441, 10-1997-47903, and 10-2000-38765 disclose devices for measuring the height of one plane of an object. It is not just measuring the height of one plane of the planar article. In addition, Korean Patent Publication No. 10-2005-74330 provides a non-contact surface shape measuring device and method, but the device is very complicated and real-time measurement is impossible.

An object of the present invention is to provide an apparatus for measuring in real time a non-contact real-time cross section of an external shape of an object to be measured.

In addition, an object of the present invention is to provide a method for measuring in real time a non-contact real-time cross section of the external shape of the object to be measured.

The present invention for achieving the above object relates to an apparatus for measuring in real time non-contact in real time the cross section of the external shape of the object to be measured including a laser irradiation unit, a camera unit, and a program unit.

In the present invention, the laser irradiation unit is a device that functions to irradiate the laser in a direction perpendicular to the virtual center line of the object to be measured. The virtual center line means any straight line passing through the object under test, but is preferably a straight line that forms the long axis of the object under test. In particular, in the case of a measured object in the form of a profile, the central axis penetrating the center of the profile is preferable. Since the laser light is irradiated at right angles to the virtual center line of the object to be measured, the portion where the laser light is reflected is coincident with the cut section cut at right angles to the virtual center line. Theoretically, the point where the laser beam and the virtual center line meet is called a 'virtual center line'.

The intensity or thickness of the laser light used may vary depending on the light receiving capability of the camera unit described later, but in particular, the thickness of the laser light is preferably the minimum thickness that can be detected by the CCD sensor of the camera unit to be detected.

In the present invention, the camera unit is a device arranged to be normal to the virtual center line of the object under measurement at a predetermined angle (θ) with respect to the laser irradiation surface to receive a laser beam reflected from the surface of the object as an image. See FIG. 1). The fact that the camera portion is 'arranged at a normal to the virtual center line of the object to be measured at a predetermined angle θ with respect to the laser irradiation surface' means that the camera is arranged as if the virtual center point is taken obliquely at a predetermined angle θ with respect to the surface light. It means. The camera is preferably made of a CCD sensor that accepts an image in digital form for real-time processing of data.

The program unit converts an image from the camera unit into data observed in the cross section, and combines the converted data to complete an appearance profile cross section. At this time, the inputted image information includes ① primary length correction according to camera shooting angle (θ) ② secondary length correction and numerical calculation according to the distance between the camera and the laser beam reflecting part ③ process of combining multiple images with correction It is converted into a numerically sectional view of the figure. Since the length (height) of the object to be measured in the input image is input differently according to the angle of the camera and the distance of the camera, the first and second corrections are performed in the above ① and ②, respectively. Each substep will be described in detail with reference to the accompanying drawings.

① First step of length correction based on camera shooting angle (θ)

As shown in FIG. 2, the length l 'of the object photographed by the camera is smaller than the length l of the object (without considering the shooting distance) according to the photographing angle θ of the camera. Therefore, the length of the object is first corrected by calculating the length of the object (without considering the shooting distance) as shown in Equation (1).

Primary correction length (ℓ) = [length on input image (ℓ ')] ÷ sinθ (1)

② Second step of length correction and numerical calculation according to camera distance

3 is a view for explaining the relationship between the object of length L through the lens of the camera when the image on the opposite side of the lens. In the figure, L denotes the length of the object (substantially the distance from the virtual center point to a specific point on the surface of the object to which the laser is reflected), and l denotes the first corrected length of the image on the CCD sensor (substantially virtual). Distance from the focal point corresponding to the center point to the focal point corresponding to a specific point on the surface of the object to be reflected by the laser, d is the distance from the center of the lens to the virtual center point, and m is the distance from the lens center to the CCD plane. Respectively. Among these values, the desired value is the actual length L of the second-corrected object, and the values given are m, l, d. m is obtained by measuring the distance from the center of the lens to the CCD plane with the mechanically fixed value in the camera, and d is obtained by the coordinate tracking algorithm method. From these values, the actual length L of the second-corrected object can be calculated by the following equation (2).

2nd order calibration length (L) = (ℓ × d) ÷ m (2)

Equation (3) is calculated from equations (1) and (2).

2nd order correction length (L) = (ℓ '× d) ÷ (m × sinθ) (3)

On the other hand, ℓ 'can be converted into a unit of mm from the actual number of pixels of the number of pixels and the length and width of the CCD sensor when the object to be measured appears on the CCD. For example, if the length and width of the CCD sensor are 20 mm and 15 mm, respectively, and the number of pixels in the width and length is 640 and 480 pixels, respectively, the length of 320 pixels of the image actually formed on the CCD becomes 10 mm. From this calculation, the secondary correction length L can be digitized in mm units.

Therefore, by the above calculation, the angle and distance with respect to the virtual center line are determined for each flash point of the CCD image. That is, corrected images are made.

That is, as described above, the image photographed in the first and second image correction processes undergoes image vectorization, and then the reference coordinate origin (for example, a virtual center point) of the image is set and the numerical value of the cross-sectional profile is centered around this origin. Is calculated.

③ Small steps to combine the corrected images

In order to make non-contact real-time measurement of the external cross-sectional shape of the object under test, at least three captured images are required to cover 360 ° of the virtual center line of the object under test. At least three corrected images, each of which has a fixed relative angle and distance to the virtual center point, are placed in any planar coordinates for each flash point in the CCD image. do. The shape of the image recognized by each camera unit is combined (combined) in real time through a coordinate tracking algorithm, rather than a pixel position tracking.

The obtained cross-sectional image may be used as it is, but since the relative angle and distance value are calculated for the virtual center point, it may be converted into a vector type graphic file (for example, a CAD file) that can be manipulated in a program such as CAD.

In the apparatus according to the present invention, the laser irradiation unit irradiates a laser beam and the camera unit 360 ° in a manner of three or more (preferably preferably) by irradiating only a portion of the laser in a direction perpendicular to the virtual center line of the object to be measured. 4 ~ 6 images can be taken. In this case, since there is a parallax during image capturing, the object to be measured must be stopped for a while or the apparatus according to the present invention must be moved together in the direction of movement of the object to be measured. That is, it takes a home position after one operation and a home position after operation again.

In addition, in the apparatus according to the present invention, the laser irradiator is installed to irradiate the laser 360 ° in a direction perpendicular to the virtual center line of the object to be measured for substantially real-time cross-sectional measurement, and the camera unit is three or more (preferably 4 ~ 6) can be installed to shoot a plurality of images at the same time.

On the other hand, in order to more accurately photograph the image in the camera unit, or to increase the accuracy of the photographed image is equipped with a filter for blocking light other than the wavelength of the laser light source used in the camera unit, or in the photographed image to the laser light source A program for removing screen portions other than the corresponding image characteristics (colors) may be added to the program portion.

Hereinafter, with reference to the accompanying drawings will be described a process of non-contact real-time measurement of the external cross-section of the object to be measured using the apparatus according to the present invention. As the object to be measured, a rubber strip was selected that is installed in the vehicle window frame and closes the window and the window frame when the window is closed.

The drawings and the following description only show one embodiment of the present invention, and thus the scope of the technical spirit of the present invention is not changed or reduced.

The rubber seal is manufactured by a continuous extrusion method, and the device according to the present invention (one or more laser irradiation units and three or more camera units) is installed around the rubber seal at the end of the production apparatus as conceptually shown in FIG. do. The position, distance, relative angle, and the like of each accessory of the apparatus according to the present invention are appropriately determined in advance. In the figure, four camera units were provided. Subsequently, the device according to the present invention is operated at predetermined time intervals, and at the same time, the external shape of the rubber seal (laser reflected light reflected from) in four directions 360 degrees is captured in each camera unit (FIG. 5). Each photographed image is subjected to a length (height) adjustment process according to the object to be measured (a specific point of the object to which the laser is reflected) and the distance and angle to the camera (FIG. 6). The four length-corrected images are arranged and combined according to the relative angle and length (height) with respect to the virtual center line to complete the external shape cross section of the rubber seal (FIG. 7).

The completed drawing is a vector type graphic file that can be manipulated in a program such as CAD because the obtained cross-sectional image of each line (point on top) is calculated relative angle and distance value to virtual center point. It can be used for quality control of the manufactured product (rubber sealer) by converting it into a numerical value and directly comparing it with the reference drawing.

The process of quality control using the apparatus according to the present invention configured as described above is as follows.

First, as described above, when the (analog type) photographing image (laser light reflection image) obtained by the camera unit is transmitted in real time to the program unit, image (image) processing is performed by an image processor (not shown) (digital form). Is converted into actual measurement data, and the converted actual measurement data is sent to, for example, an inspection management unit (not shown).

The inspection management unit searches whether the inspection data (reference data) for the product is registered in the database and if the inspection data exists, it is called out and compared with the actual measurement data to determine whether NG (No Good), and the inspection data is If a new type of product does not exist, the measurement data is stored as inspection data of the product. In addition, defects in the external cross section found during the inspection process are classified by number of occurrences / frequency / time of occurrence / product length / type and stored in the database as information for future quality control. On the other hand, the administrator can set and manage the inspection conditions (minimum NG pattern size and threshold value) for each product by remote access to the apparatus according to the present invention or by using input means such as a keyboard provided in the processing apparatus. .

As described above, the apparatus and method for measuring in real time the non-contact real-time cross-sectional shape of the object to be measured according to the present invention can measure the external cross-section of the produced product in real time and automatically compare with the standard product to facilitate quality control. It becomes possible. In addition, quality control information and various data obtained during the measurement of appearance cross section can be accumulated and managed in the database, and the information such as quality management / analysis / aggregation processing accumulated in the database can be checked by accessing the Internet whenever necessary. have.

The present invention can obtain accurate product information by storing the cross-sectional shape collected in real time and collecting the data in parallel with the state and conditions of the production equipment at the time of storage and inquiring the status of the corresponding equipment when inspecting the good and defective products. In other words, it is possible to simultaneously collect the speed, pressure, temperature, etc. of the extruder / vulcanizer / take-off during the production of W / S in real time to store the production conditions at the same time when storing the cross-sectional shape.

Therefore, by sharing this quality management information in various departments inside and outside the company and using it in product development, quality control and planning, it is possible to improve quality and productivity, reduce defective rate, and reduce cost.
In addition, various interfaces may be provided for easy integration with the back-up system.

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Claims (10)

Four to six laser irradiation units installed to irradiate a 360 ° laser in a direction perpendicular to the virtual center line of the object to be measured; 4 to 6 are arranged at a normal position with respect to the virtual center line of the object to be measured at a predetermined angle with respect to the laser irradiation surface from which the laser light irradiated from the laser irradiation unit receives only the laser light reflected from the surface of the object to be measured and the wavelength of the laser light source A camera unit provided with an interference filter to block other light and receiving laser light as an image; The image inputted to the camera unit is converted into data observed in the cross section, and the converted data are subjected to the first length correction according to the camera photographing angle and the second length correction according to the distance between the camera and the laser beam reflecting portion. A non-contact real-time measurement of the external shape cross section of the object to be measured, comprising: a program unit for completing the external shape cross section through a process of combining a plurality of images or converting the external shape cross section into a vector type graphic file Device. delete delete delete delete A laser irradiation step of irradiating a 360 ° laser in a direction perpendicular to a virtual center line of the object to be measured; An image capturing step of receiving the laser light reflected from the surface of the object under measurement at an angle with respect to the laser irradiation surface as an image at four to six locations on a normal to the virtual center line of the object under measurement; Converting the captured image into data observed in the cross section, first correcting the length of the converted data according to the camera photographing angle, and second correcting the length according to the distance between the camera and the laser beam reflecting portion. A process of combining the plurality of images using the data obtained through the first and second length corrections to complete the appearance profile, and calculating the numerical value of the finished appearance profile or converting the appearance profile into a vector type graphic file. A data processing step of converting the data; Non-contact real-time measurement of the external shape cross section of the object to be measured, characterized in that it comprises a. delete delete delete delete

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