JPS5937762B2 - Object deformation extraction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for extracting the amount of deformation of a three-dimensional object by forming moiré fringes, which can display the amount of deformation of a three-dimensional object as contour lines in real time.

Conventionally, there are two methods for extracting the amount of deformation of a three-dimensional object as moire fringes (contour lines).

In the first method, when a three-dimensional object is transformed from one state A to another state B, the moiré fringes of each state are superimposed.

That is, two films with moire fringes in state A and state B are
This superimposition was achieved through photographic techniques such as heavy printing. Therefore, in addition to the moire fringes representing the amount of deformation, the original moire fringes are also reflected on this film.
This amount of deformation was extracted manually by humans. Also,
The second method is to first project the grating onto an object, image the deformed grating that has been deformed by the shape of the object onto a photographic plate using a lens, develop it without moving its position, and then project it onto the object. By applying deformation and observing through a deformed grid formed on a photographic plate, it is confirmed that moiré fringes are formed only in the deformed parts of the object.

However, even with this method, unnecessary fringes such as deformed lattices are observed, making it impossible to obtain a high-quality moiré fringe image, and it is difficult to extract the amount of deformation in real time. In order to eliminate the drawbacks of the above-mentioned conventional example, the present invention has the following features:
This invention provides a method for extracting the amount of deformation of a three-dimensional object in which the amount of deformation of a three-dimensional object is displayed in real time as moiré fringes that do not include unnecessary fringes.

Hereinafter, embodiments will be described in detail with reference to the drawings. Figure 1 shows
One embodiment of the present invention is shown, in which 1 is a grating projector, 2 is a grating projector;
is an object, 3 is a television camera, 4 is a binarization circuit, 5 is a thinning circuit, 6 is an m-phase linear interpolator, T is a switch circuit, 8 is an n-frame memory, 9 is an AND circuit, 10 is logic 11 is a television monitor, and 12 is a grid generator.

Further, a reference grid (straight line equidistant grid) is projected onto an object 2 by a grid projector 1, and a deformed grid deformed by this object 2 is imaged by a television camera 3. The output of this television camera 3 is binarized by a binarization circuit 4 (the deformed grid is
, the background is set to 0) and supplied to the thinning circuit 5. The line thinning circuit 5 determines the center value of the width of the deformed grid, and supplies that value to the m-phase primary interpolator 6. The output of this m-phase primary interpolator 6 is supplied to the n frame memory 8 (m pieces of Mo-Mm-1) via a switch circuit 7 (m pieces of 50 to 5m-1). The output of the frame memory 8 and the output of the m-phase primary interpolator 6 are connected to an AND circuit 9 (m pieces of P0 to Pm-1).
supply to. All the outputs of this AND circuit 9 (m pieces)
is input to the OR circuit 10, and the output of the OR circuit 10 is displayed on the television monitor 11. On the other hand, grid generator 1
The output of 2 is sent to the n frame memory 8 through the switch circuit 7.
connected to. Next, the operating principle of this embodiment will be explained.
First, when a three-dimensional object is deformed from one state A to another state B, in order to extract the amount of deformation as moiré fringes (contour lines), superimpose the deformation grids of each state and connect their intersection points. good. If the deformed lattice in state A is a straight line equidistant lattice (the deformed lattice is a straight line equidistant lattice, then
(This indicates that the object is a flat surface), and if we consider that the object was created by being deformed from a flat surface, the moiré fringes in that case are conventional contour moiré fringes. Therefore, the equal-height moiré fringes are considered to be a special case in which one of the deformed gratings is a linear equidistant grating. The intersection points between the ten deformed grids can be found by logical product between the deformed grids. However, the intersections are discontinuous and difficult to observe as contour lines. That is, since unnecessary fringes are observed in addition to moiré fringes (equally deformed moiré fringes) representing the amount of deformation, in order to make these intersections continuous, it is necessary to adjust the projection grating of the grating projector 1 to the grating interval of the deformed grating. If we use interpolation to create deformed grids of states A and B that would occur when the grid moves in the pitch direction, and find new intersections using logical product, the moiré fringes will become continuous and unnecessary fringes will disappear. . The above operation will be explained with reference to FIG. First, a deformed grid in state A is obtained as the output of the thinning circuit 5 as shown by the solid line in FIG. Furthermore, the m-phase linear interpolator 6 creates deformed grids for each phase by interpolation as shown in FIG. 2, and stores them in the n-frame memory 8 for each phase through the switch circuit 7. On the other hand, the deformed grid in state B of the object after n frames (in the case of a standard television, n frames is n/30 seconds) is the same as the deformed grid in state A. , a thinning circuit 5, and an m-phase linear interpolator 6, and are input to an AND circuit 9.

The intersection point of the deformed grids is determined by the AND circuit 9 of the deformed grids of the same phase in states A and B. Further, the logical sum circuit 10 calculates the logical sum of the intersection points of each phase, and each is displayed on the television monitor 11. Figure 3 shows the situation in the case of three phases.

It can be easily seen that as the phase number m increases, the uniformly deformed moiré fringes C become continuous. As the other function, if the switch circuit 7 is opened to the grid generator 12 side and the n-phase reference grid is set in the n-frame memory 8 in advance, the television monitor 11 will have a single frame with the reference grid. The amount of deformation from the object is displayed. As described above, in this example,
The amount of deformation of a three-dimensional object during n frame times can be displayed as contour lines in real time.

For example, the amount of deformation of a human body in motion during n frame times can be displayed in real time. Furthermore, by creating not only the observed deformed lattice but also a non-existent deformed lattice at the lattice intervals using an interpolation method, points representing the amount of deformation are continuous, and uniformly deformed moiré fringes without unnecessary fringes can be formed. Moreover, the above processing can be realized using simple electronic equipment, and unlike mechanical methods,
Excellent operability and flexibility. As described above, the present invention has the advantage that unnecessary fringes such as deformed grids are not observed and a high-quality moiré fringe image displayed in real time can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is an explanatory diagram of linear interpolation, and FIG. 3 is an explanatory diagram of uniformly deformed moiré fringe formation. 1...Grid projector, 2...Object, 3.
...TV camera, 4...Binarization circuit,
5... Thinning circuit, 6... m-phase primary interpolator, 7... switch circuit, 8... n
Frame memo 18 9......AND circuit, 10.
......OR circuit, 11...TV monitor, 12...Grid generator.

Claims (1)

[Claims] 1. The first deformed grating obtained by projecting the reference grating onto the object and the second deformed grating after t time are inputted by the imaging device, and the reference grating is determined from the input first and second deformed gratings. The third
, a fourth deformed grid is created by interpolation, and these third,
The logical product outputs of the fourth deformed lattice are obtained one after another as if the lattice was actually moved, and these outputs and the first and second
A method for extracting the amount of deformation of an object, characterized in that the amount of deformation of the object is obtained as moiré fringes by the logical sum of the deformed grid.