JPS6124882Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to hot moiré shape measurement using a heat-resistant grid.

As is well-known, the so-called contour moiré is a process in which a grating with periodic transmission characteristics in one direction is placed in front of the object to be measured, and light is directed from a point (line) light source through the grating onto the surface of the object to be measured. When a shadow of a grating (deformed grating image) is created on the surface of an object, and the deformed grating image is further passed through the grating and imaged from the same height as the light source, interference fringes are generated as a result of spatial frequency modulation of the deformed grating image and the grating. These interference fringes represent the contour pattern of the object to be measured, like contour lines on a map, and are used for three-dimensional shape measurement. Also,
There are two methods for generating contour moiré. One is, as shown in FIG. This is a method of creating moiré by doing this, and is generally called the irradiation method. The other method, as shown in Fig. 2, is to not place the grating directly in front of the object to be measured 1, but instead to project the grating 4 onto the surface of the object from a distance through a projector, etc., to form an image on the surface of the object to be measured. This is a method of generating moiré by imaging the deformed grating image through another grating 5 placed at an optically equivalent position to the grating 4. 6 is placed in the equivalent position. This method is called a projection method as opposed to an irradiation method.

By the way, when the object to be measured is cold, both of the above two methods of generating contour moiré are effective, but when the object to be measured is hot, the following problems occur, so moiré generation in hot conditions is Shape measurement has been considered difficult.

(b) In the irradiation method, the grid is placed directly in front of the object to be measured, so the heat resistance of the grid in hot conditions becomes an issue. In moiré shape measurement, the lattice plane serves as the reference surface for shape measurement, so elongation or damage of the lattice system due to heat, deformation of the lattice frame, deviation of the lattice system pitch, etc. are fatal to the nozzle. Furthermore, in order to improve the transmission characteristics of the grating, the grating system is generally coated with a coating that increases the emissivity, but this coating peels off due to heat.

(b) In the projection method, since the grating is not placed directly in front of the object to be measured, there is no problem with the heat resistance of the grating, but due to the radiant energy emitted by the hot object to be measured, the contrast of the deformed grating image is As a result, the generated moiré also has low contrast and poor resolution. In addition, the distance between the measurement object and the grating is longer in the projection method than in the irradiation method, so it is more susceptible to diffraction. The contrast of the deformed lattice image decreases as a result. On the other hand, the resolution of three-dimensional information obtained by a contour moiré pattern is determined by the pitch of the threads of the grid, and the smaller the pitch, the higher the resolution. Therefore, it is difficult to generate high-resolution, contour moiré with good contrast using the projection method in hot conditions. In addition, in order to improve the contrast, it is possible to use a light source with a spectrum that does not overlap with the radiation spectrum of the hot measurement object, or to cut out the radiation spectrum components with a filter, but in reality, the radiation spectrum Since it is widely distributed,
Not very effective.

The purpose of the present invention is to generate moiré fringes with good contrast and temporal and spatial stability using an irradiation method. The irradiation method is improved by using a heat-resistant grid that does not cause any changes in the grid plane, such as elongation or damage of the grid threads due to heat, deformation of the grid frame, or displacement of the grid thread pitch, even in front of the object, and by using a heat-resistant grid. The method is characterized in that a high-contrast, high-resolution, constant-height moiré can be generated stably and easily under heat by using a powerful light source with a normal wavelength distribution.

The heat-resistant lattice in this invention is a lattice thread,
Metal wires such as SUS, which are resistant to deterioration and breakage due to oxidation due to heat, should be used.In order to keep the pitch of the lattice threads constant, the lattice threads should be hung one by one in the grooves of screws etc. that have a constant periodicity of the lattice. In order to pull and fix the threads, to prevent the lattice threads from expanding and sagging due to heat, making the lattice surface no longer flat, or from coming off from the recesses of the screws and causing the pitches of the lattice threads to twist. A heat-resistant lattice is formed by applying tension to the lattice threads using springs, shape memory alloys, etc., the lattice threads have the function of absorbing expansion, and the lattice surface is air-cooled to protect the coating of the lattice threads. to do,
In order to prevent the lattice frame from deforming due to heat, a heat shield is provided in front of the lattice and the inside of the heat shield is air-cooled, or the frame itself is made into a pipe structure and water, air, etc. are passed through the pipe for cooling. shall be.

Hereinafter, the present invention will be explained in detail with reference to the drawings. 3 and 4 are a front view and a side view of the heat-resistant grid. In both figures, 7 is SUS
It is a lattice thread that utilizes interlocking wires such as, etc., and is hung on a screw 8 and then pulled by a spring 9. 10a-10
C is an air cooling pipe for protecting the lattice threads and springs, and cooling air comes out from holes drilled in the pipe. Reference numeral 11 denotes a lattice frame that supports the whole, and this lattice frame has a pipe structure, and circulates cooling water and cooling air through the pipe.

Next, the constituent elements of the present invention will be explained. The lattice threads are metal wires such as SUS, and their surfaces are painted black to increase the emissivity. Both ends of the lattice threads are hung on something having irregularities of a constant period, such as screws, and the pitch of the lattice threads is determined by the period of the irregularities. Both ends or one end of the lattice threads are pulled by an elastic material such as a spring so that they are constantly under tension. It is not necessarily necessary to pull the lattice threads one by one; the lattice threads may be turned several times at both ends and then both ends and one end may be pulled. Tensioning mechanisms such as lattice threads and springs and screws are cooled by cooling air. The lattice frame has a pipe structure as a whole and circulates cooling water and air through the pipes. Alternatively, as shown in FIG. 5, a heat shield plate may be attached between the grating surface and the object to be measured.

In the present invention, the lattice threads are pulled with an elastic material such as a spring because the lattice threads expand and sag when hot, causing the lattice surface to no longer be flat, or coming off the recesses of the screws and causing pitch. This is to prevent it from rolling. The purpose of air-cooling the grid surface is to prevent the paint from peeling off on the metal wires. When the paint peels off, the emissivity of the grid threads decreases, reflecting light and deteriorating the transmission characteristics, resulting in a moiré pattern with good contrast. is not obtained. The purpose of cooling the lattice frame or protecting the lattice frame with a heat shield is to prevent distortion of the lattice plane due to distortion of the lattice frame due to heat.In moiré shape measurement, the lattice plane is used to obtain 3D information. Since the lattice plane serves as a reference plane, distortion of the lattice plane must be prevented.

When such a heat-resistant grating as described above is used, the grid threads will not be damaged even with respect to a hot measurement object, and the elongation of the grid threads will be absorbed by the springs, so the grid threads will not sag. Further, since the tension in the grid threads is kept approximately constant, the grid threads are stably fixed in the recesses of screws, etc., and as a result, the pitch is kept constant.
In addition, since the lattice frame is not distorted due to heat due to cooling and heat insulation, the lattice plane that is the reference plane for shape measurement is
remains stable and flat.

The present invention uses a heat-resistant grating having the above-described configuration to generate moiré, so (1) the grating can be stably placed for a long time directly in front of the object to be measured during hot measurement; (2) Since the distance between the grating and the measurement target can be made small, it is less susceptible to diffraction effects, and as a result, it is possible to easily generate high-resolution, high-contrast contour moire just by using a strong light source with a normal spectral distribution. (3) Unlike the projection method, multiple gratings are not used, so nozzles such as optical axis misalignment are avoided.

Next, an example of measuring CC (continuous caster) bulging using the measuring device of the present invention will be shown. CC bulging refers to the unsolidified part 1 of the slab as shown in Figure 5.
This refers to the phenomenon in which the solidified slab 15 swells between the rolls 14 due to the static pressure 13 acting on the solidified slab 15. In addition, as shown in FIG. 6, a heat-resistant grid 16, a halogen lamp 1
7. When moiré is generated and imaged using the TV camera 18, a contour pattern of the bulging part as shown in 19 in FIG. By counting the information and the number of stripes, the amount of swelling (quantitative information) can be measured simultaneously. The resolution of contour moiré is approximately 0.25 mm when using a grid with a pitch of 0.5 mm and the distance between the heat-resistant grid 16 and the halogen lamp 17 is 1 m, and the distance between the halogen lamp 17 and the TV camera 18 is 2 m, and is generally the maximum. Since the amount of bulging is several mm, highly accurate shape measurement is possible.

In this way, if the measuring device according to the present invention is used,
For the hot measurement target, as in the cold case,
By using the irradiation method, it is possible to stably generate high-resolution, high-contrast, contour moiré.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the generation of a contour moiré by the irradiation method, and FIG. 2 is a side sectional view showing the generation of a contour moire by the projection method. 3 and 4 are a front view and a side view of the heat-resistant grid used in the present invention, FIG. 5 is a vertical cross-sectional view showing how bulging occurs, and FIG. 6 is a perspective view showing an embodiment of the present invention. Figure 7 is a schematic diagram of the CC bulging contour moiré obtained thereby. 1... object to be measured, 2... grating, 3... deformed grating image, 4... grating, 5... grating, 6... grating, 7
... Lattice thread, 8 ... Screw, 9 ... Spring, 10a ~
10c... Air cooling pipe, 11... Lattice frame, 12
...Unsolidified part of the slab, 13... Static pressure, 14... Roll, 15... Solidified part of the slab, 16... Heat-resistant grid, 1
7...Halogen lamp, 18...TV camera,
19... Contour pattern.

Claims (1)

[Scope of utility model registration request] In addition to placing heat-resistant grids with grid threads under tension at predetermined intervals on the high-temperature measurement target,
A light source directed toward the high-temperature measurement target is provided behind the grating, and the three-dimensional shape of the high-temperature measurement target is visualized by illuminating the measurement target from the light source and imaging the measurement target through the grating. A device for measuring the shape of high-temperature objects using moire, configured to measure with high resolution as dimensional contour pattern information.