JP2002324090A - Producing method and apparatus for three-dimensional model - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that it is complicated to produce a three dimensional 3-D model from drawings based on raster data. SOLUTION: In a producing method, the raster data of a three-view drawing is acquired (S10), a geometric adjustment is performed (S12), features of a plan view are extracted by an image processing (S14), corresponded points of the features of the front and side views (S16), coordinates of the features are calculated (S18) and the model is produced by applying a free curbed surface based on the coordinates (S20).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a technique for generating a three-dimensional model from raster data. In particular, the present invention relates to a method and an apparatus for easily generating a three-dimensional model for a three-dimensional shape including a complicated shape.

[0002]

2. Description of the Related Art A technique for reproducing a three-dimensional shape from CAD data (hereinafter also referred to as "vector data"), which is vectorized drawing data, has been established mainly in the field of construction and parts design. On the other hand, conversion of a drawing described in raster data (hereinafter also referred to as “raster drawing”) into vector data is performed by picking up the position of a point on the drawing with a digitizer. In recent years, there has been an increasing number of structures that frequently use curved surfaces from the viewpoint of design, mainly in the field of architecture, and in order to model such structures in three dimensions,
The number of input points by the digitizer increases, and labor and patience of the operator are required.

[0003]

There have been many researches on a method of three-dimensionally modeling a structure including a complicated curved surface from a plurality of drawings. However, as described above, these are premised on the use of vector data. Therefore, when a building having a roof with a free-form surface is targeted, for example, this does not lead to a reduction in the amount of work described above.

[0004] In the field of construction, material estimation and construction period planning are performed based on drawings. In order to perform this operation quickly and accurately, there is a growing demand for confirming the actual three-dimensional shape, especially on the site side. Especially in large buildings, if the curved surface is simply polygonally approximated, the absolute amount of material is large, resulting in a large amount of money error,
For the person actually in charge of the construction, it has hindered the smooth execution of work.

There are similar problems in other fields. For example, in the CG field, three-dimensional drawings
In order to generate a dimensional model, drawing data is acquired by a digitizer. However, since a CG often has a more complicated shape than a building, a heavy load is imposed on the data input process.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a technique for easily generating a three-dimensional model of a three-dimensional shape described two-dimensionally by raster data from a plurality of drawings. .

Japanese Patent Laid-Open Publication No. 6-243202 discloses a "system for automatically generating a three-dimensional image from three views", but differs from the present invention in that vector data is used. Similarly, JP-A-11-134
In Japanese Patent Publication No. 509, reference is made to "a drawing recognition method and an architectural drawing recognition processing method". However, the point different from the present invention is that only the vector data is handled.

[0008]

According to one aspect of the present invention, there is provided a method comprising:
The present invention relates to a dimensional model generation device. The apparatus includes an image input unit for inputting a drawing in which a three-dimensional shape is two-dimensionally represented by raster data from different angles, a geometric adjustment unit for matching a plurality of input drawings from a geometrical point of view, and a plurality of these. It includes a feature point extraction unit that extracts a feature point in any of the drawings, and a corresponding point detection unit that detects a corresponding point of the extracted feature point or a candidate thereof on another matched drawing.

The image input unit may input raster data of a drawing optically acquired by, for example, a scanner, or input raster data from a file in a format such as a bitmap. Here, “raster data” mainly refers to numerical data for an arrangement of points formed in a grid on an image. However, in the present specification, the definition is not limited to the definition, and widely used in formats other than “vector data”. Data shall be included. “Feature points” only have characteristics in the sense that they are easy to extract, and do not necessarily depend on subjective factors. The "corresponding point or its candidate" may be a candidate because the corresponding point may not be uniquely specified or may not be specified due to an external factor such as an error, depending on the relationship of the drawing and the position of the feature point. Is what you do. In this case, the apparatus may include a “corresponding point determining unit” that receives selection of a corresponding point or manual input from an operator.
Note that “corresponding points or their candidates” will be simply referred to as “corresponding points” hereinafter.
Also called.

According to this apparatus, a three-dimensional model of a three-dimensional shape is realized based on a raster drawing, for example, a drawing in bitmap format formed by taking in a drawing printed on paper. Therefore, even at a site where only a paper drawing is present at hand, a three-dimensional shape can be relatively easily checked if, for example, a scanner is provided.

The apparatus may further include a coordinate calculator for calculating three-dimensional coordinates of the feature point based on a positional relationship between the feature point and the corresponding point.

[0012] Further, it may include a data output unit for outputting data including the calculated three-dimensional coordinates in a standard file format, for example, a file format used in another general CAD system.

Further, based on the calculated three-dimensional coordinates,
It may include a display processing unit that performs processing for plotting and displaying feature points three-dimensionally, and a curved surface generation unit that generates a free-form surface that indicates the external shape of a three-dimensional shape.

The geometric adjustment unit may perform any processing such as correction of the inclination of the drawing, correction of the origin, adjustment of the scale, etc. The essence thereof is to improve the detection accuracy of the corresponding point detection unit or to determine the corresponding point by the operator. The purpose is to make the determination easier.

The feature point extracting section may automatically detect at least one of an intersection, a corner point, and an end point by employing an image processing technique. That is, in a technical field in which absolute data is originally handled as vector data, such as CAD, a technique based on an error of image processing is introduced. The “image processing method” here may be any method as long as the characteristic point can be detected, such as a spatial filter process.

Another embodiment of the present invention also relates to a three-dimensional model generation device. The apparatus includes an image input unit for inputting a three-view drawing representing a design object, and a geometric adjustment unit for aligning a plurality of input drawings by processing including at least one of tilt correction, origin position alignment, and scale adjustment. A feature point extraction unit that extracts a feature point using an image processing technique in any of the plurality of drawings; and a corresponding point of the extracted feature point or a candidate for the extracted feature point on another drawing. A corresponding point detection unit for detecting based on the consistency realized by the adjustment unit. “Based on the consistency realized by the geometric adjustment unit” means, for example, utilizing that the scales of the three views are matched and the origin position is also matched. For example, if the plan view is drawn on the xy plane and the front view is drawn on the xz plane, the feature points taken in the former and the corresponding points in the latter have the same x coordinate, so that the corresponding point detection process is easy. become.

Still another preferred embodiment according to the present invention relates to a method for generating a three-dimensional model. The method includes the steps of: matching a plurality of drawings, which represent a three-dimensional shape two-dimensionally as raster data from different angles, from a geometrical viewpoint; defining a feature point in one of the plurality of drawings; Detecting corresponding points of the set feature points or candidates thereof on another matched drawing.

It is to be noted that any combination of the above-described components and any expression of the present invention as a method, a system, a computer program, a recording medium, or the like is also effective as an embodiment of the present invention.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a preferred embodiment of the present invention, a three-dimensional model generation process from a three-sided view of a building will be described below.

FIG. 1 shows a configuration of a three-dimensional model generating apparatus 10 according to the embodiment. The device 10 includes a scanner 12
Input unit 16 for acquiring three-view raster data from the external storage device 14, a geometric adjustment unit 18 for geometrically adjusting the input image, and intersections, end points, and corner points from the adjusted plan view. Feature point extraction unit 2 for extracting feature points such as
6, a corresponding point detecting unit 28 for detecting corresponding points in the front view and side view of the extracted feature points, and a coordinate calculating unit 52 for calculating three-dimensional coordinates of the feature points based on the detected corresponding points. A three-dimensional model generation unit 54 that generates a three-dimensional model based on the calculated coordinates; a display control unit 30 that displays the generated three-dimensional model; A data output unit 32 for outputting to the storage device 14 and a communication unit 34 for transmitting the data to the network 44 are included.

The geometric adjustment unit 18 includes a tilt correction unit 20, an origin correction unit 22, and a scale adjustment unit 24.

The inclination correcting section 20 first obtains a cumulative density histogram in the horizontal or vertical direction of the drawing. The figure is slightly shifted, for example, by 0.1 degrees in a predetermined angle range, that is, a range in which the inclination of the drawing is assumed, for example, -5 ° to + 5 °.
To automatically determine the angle at which the peak of the cumulative density is maximized. In architectural drawings, dimension lines are often drawn in the horizontal and vertical directions, and each element in the drawings often has a boundary surface in the horizontal and vertical directions. Accordingly, when the horizontal or vertical cumulative density histogram is taken, the angle at which the peak value of the histogram is maximum is estimated as the correct attitude, and the drawing is corrected to this angle. This processing is performed on a plan view, a front view, and a side view. FIG. 2 shows a flat screen before inclination correction, and FIG. 3 shows a horizontal screen and a horizontal cumulative density histogram thereof after correction. This shows that the peak value of the histogram is larger after the correction.

FIG. 4A and FIG.
This will be described with reference to FIG. The origin correction unit 22 prompts the operator to surround the figure 60 in the drawing of FIG. Next, the origin correction unit 22
Automatically corrects the origin of the drawing so that the lower left vertex 64 of the rectangle 62 coincides with the origin, resulting in the drawing of FIG. However, the process of providing the circumscribed rectangle in the rectangle 62 may be automated by the origin correction unit 22.

The scale adjuster 24 prompts the operator to select any two points in the drawing and to input the distance. If the operator selects the two points whose dimensions are previously written in the drawing, the operator only needs to read and input the numerical values, and thus these two points are usually selected.

The corresponding point detecting section 28 calculates and displays corresponding points in the front view and side view of the plurality of feature points extracted by the feature point extracting section 26. If the feature point or the corresponding point needs to be corrected, the corresponding point determination unit 50 accepts a manual correction by the operator. This correction is made by dragging an arbitrary point with the mouse and moving it to a position assumed to be correct.
In addition, the “correction” mentioned here includes the deletion of a feature point.

The coordinate calculation unit 52 specifies the x, y, and z coordinates in the three views of the feature point from the positional relationship between the feature point and the corresponding point, and converts the coordinates into the scale determined by the scale adjustment unit 24 described above. Is converted to actual three-dimensional coordinates based on

The three-dimensional model generator 54 calculates a free-form surface using a B-spline function based on the three-dimensional coordinates of the feature points, and generates a three-dimensional model. Here, the function used to calculate the free-form surface is not limited to the “B-spline function”, and any function that can calculate the free-form surface may be used.

The display control unit 30 includes a three-dimensional model generation unit 5
The three-dimensional model generated in step 4 is displayed. Further, the three-dimensional coordinates of the feature points calculated by the coordinate calculation unit 52 may be displayed in a three-dimensional plot.

FIG. 5 shows a three-dimensional model generated by the three-dimensional model generating apparatus 10 based on the three-plane view taken from the scanner.
1 shows an example of a dimensional model. The upper left is a plan view, the lower left is a front view, and the lower right is a side view, in which characteristic points and corresponding points are displayed. Also, feature points are three-dimensionally plotted and displayed on the upper right.

FIG. 6 shows a three-dimensional model of another building generated based on a three-view drawing (not shown) using a wire frame having a different expression form from FIG. The effect of this embodiment can be seen from the figure.

FIG. 7 is a flowchart showing a procedure for generating a three-dimensional model by the three-dimensional model generating apparatus 10 having the above configuration. The image input unit 16 acquires the raster data of the three views (S10). The geometric adjustment unit 18 performs geometric adjustment such as tilt correction, origin correction, and scale correction on the acquired drawing (S12). The feature point extracting unit 26 extracts a feature point in a plan view by an image processing method (S1).
4). The corresponding point detection unit 28 determines the corresponding point of the extracted feature point (S16), and the coordinate calculation unit 52 calculates the three-dimensional coordinates of the feature point (S18). The three-dimensional model generator 54 generates a three-dimensional model based on the three-dimensional coordinates of the feature points, and the display controller 30 displays this (S20).

The present invention has been described based on the embodiments. This embodiment is an exemplification, and it is understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and that such modifications are also within the scope of the present invention. is there.

[0033]

According to the present invention, a three-dimensional model can be relatively easily generated from raster data.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a three-dimensional model generation device according to an embodiment.

FIG. 2 is a plan view before tilt correction and a photograph of a halftone image in which a cumulative density histogram is displayed on a display in a horizontal direction.

FIG. 3 is a plan view after inclination correction and a photograph of a halftone image in which a cumulative density histogram is displayed on a display in the horizontal direction.

FIGS. 4A and 4B are side views showing the process of the origin correction unit before the origin correction and the process after the origin correction, respectively.

FIG. 5 is a photograph of a halftone image in which a plan view, a front view, a side view, and a view in which feature points are three-dimensionally plotted and displayed on a display after feature point association is completed.

FIG. 6 is a photograph of a halftone image in which a display example of a generated three-dimensional model in a wire frame is displayed on a display.

FIG. 7 is a flowchart showing a procedure for generating a three-dimensional model by the three-dimensional model generation device according to the embodiment;

[Explanation of symbols]

16 image input unit, 18 geometric adjustment unit, 20 inclination correction unit, 22 origin correction unit, 24 scale adjustment unit, 26 feature point extraction unit, 28 corresponding point detection unit,
30 display control unit, 32 data output unit, 50 corresponding point determination unit, 54 three-dimensional model generation unit.

Claims (12)

[Claims] 1. An image input unit for inputting a drawing in which a three-dimensional shape is two-dimensionally represented by raster data from different angles, a geometric adjustment unit for matching a plurality of input drawings from a geometrical viewpoint, A feature point extracting unit that extracts a feature point in any of the drawings, and a corresponding point detecting unit that detects a corresponding point of the extracted feature point or a candidate thereof on another matched drawing. A three-dimensional model generation device, characterized in that: 2. The apparatus according to claim 1, further comprising a coordinate calculation unit that calculates three-dimensional coordinates of the feature point based on a positional relationship between the feature point and its corresponding point. 3. The apparatus according to claim 2, further comprising a data output unit that outputs data including the calculated three-dimensional coordinates in a standard file format. 4. The display device according to claim 2, further comprising a display processing unit that performs a process for plotting and displaying the feature points three-dimensionally based on the calculated three-dimensional coordinates. An apparatus according to claim 1. 5. The apparatus according to claim 2, further comprising a curved surface generating unit that generates a free-form surface indicating the outer shape of the three-dimensional shape based on the calculated three-dimensional coordinates. apparatus. 6. The apparatus according to claim 1, wherein the geometric adjustment unit performs a process including correction of a tilt of the drawing. 7. The apparatus according to claim 1, wherein the geometric adjustment unit performs a process including correction of the origin of the drawing. 8. The apparatus according to claim 1, wherein the geometric adjustment unit performs processing including scale adjustment of a drawing. 9. The method according to claim 1, wherein the feature point extracting unit automatically detects at least one of an intersection, a corner point, and an end point by employing an image processing method.
An apparatus according to any one of claims 1 to 8. 10. An image input unit for inputting a three-view drawing representing an object to be designed, a plurality of input drawings are corrected for inclination, alignment of an origin,
A geometric adjustment unit for matching by processing including at least one of scale adjustment; a feature point extraction unit for extracting a feature point by using an image processing method in any of the plurality of drawings; A three-dimensional model generation apparatus, comprising: a corresponding point detection unit that detects a corresponding point or a candidate thereof on another drawing based on the consistency realized by the geometric adjustment unit. 11. A step of matching a plurality of drawings representing a three-dimensional shape two-dimensionally with raster data from different angles from a geometrical viewpoint, and a step of defining a feature point in any of the plurality of drawings. Detecting a corresponding point of the defined feature point or a candidate thereof on another matched drawing. A method for generating a three-dimensional model, comprising: 12. A step of matching a plurality of drawings representing a three-dimensional shape two-dimensionally from different angles with raster data from a geometrical viewpoint, and a step of defining a feature point in any one of the plurality of drawings. And c. Detecting a corresponding point of the defined feature point or a candidate thereof on another matched drawing.