JP2021148731A - Shape measuring device - Google Patents

Abstract

To provide a shape measuring device capable of suitably measuring a shape of an object.SOLUTION: A shape measuring device 10 for measuring a shape of an object includes: a three-dimensional shape specification part 12 for specifying a three-dimensional shape of an object; a feature part specification part 13 for specifying a feature part as a part of a shape having a predetermined feature in a three-dimensional shape of an object; a two-dimensional sectional image generation part 14 for extracting a three-dimensional shape of a feature part from a three-dimensional shape of an object and for generating plural two-dimensional sectional images as images obtained by cutting a three-dimensional shape of a feature part by plural mutually parallel planes each; and a feature part measurement part 15 for performing measurement to a feature part on the basis of plural two-dimensional sectional images.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a shape measuring device for measuring the shape of an object.

For various objects having a three-dimensional shape, the feature portion of the three-dimensional shape is extracted and the extracted feature portion is measured. Patent Document 1 discloses a morphological analysis method for analyzing a three-dimensional morphology of a fine structure called a spine of a nerve cell. In this morphological analysis method, first, a section of the brain is photographed while moving the focal plane from a certain direction (z direction), and a three-dimensional image of brain nerve cells is acquired. Next, a three-dimensional image is silhouette-projected onto a two-dimensional plane (xy plane) to obtain a two-dimensional image of the brain nerve cell, and based on the two-dimensional image, the two-dimensional shape of the brain nerve cell is identified, and the brain nerve cell Extract the region of existence of the spine in the two-dimensional plane. After that, the existing region of the spine in the three dimensions is extracted, and the three-dimensional morphology of the spine is determined.

Japanese Unexamined Patent Publication No. 2006-343853

In the method disclosed in Patent Document 1, the shape of an object is specified based on a two-dimensional image obtained by silhouette-projecting a three-dimensional image of an object (brain nerve cell) onto a two-dimensional plane. However, depending on the shape of the object, there may be other relatively large parts near the featured part. When the method disclosed in Patent Document 1 is applied to such an object, the feature portion overlaps with another portion when viewed from the projection direction depending on the projection direction, so that the feature portion is a silhouette of the other portion in the two-dimensional image. It is difficult to identify and measure the featured part because it is hidden inside.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a shape measuring device capable of suitably measuring the shape of an object.

In order to solve the above problems, one aspect of the disclosed technology is a shape measuring device that measures the shape of an object, that is, a three-dimensional shape specifying unit that specifies the three-dimensional shape of the object, and a tertiary of the object. Of the original shape, the feature part specifying part that specifies the feature part that is the part of the shape having a predetermined feature, and the three-dimensional shape of the feature part are extracted from the three-dimensional shape of the object, and the three-dimensional shape of the feature part is obtained. A two-dimensional cross-section image generation unit that generates a plurality of two-dimensional cross-section images that are images cut on a plurality of planes parallel to each other, and a feature portion measurement unit that measures a feature portion based on a plurality of two-dimensional cross-section images. It is a shape measuring device including.

According to the shape measuring device of the present disclosure, the shape of an object can be suitably measured.

Functional block diagram of the shape measuring device according to the embodiment of the present disclosure. Schematic side view of an object photographing unit according to an embodiment of the present disclosure. A flowchart showing the shape measurement process executed by this shape measurement device. Diagram showing an example of information representing the three-dimensional shape of an object The figure which shows an example of the characteristic part of an object The figure which shows an example of a plurality of 2D cross-sectional images generated about a fine protrusion.

[Embodiment]
The shape measuring device according to the present disclosure classifies the three-dimensional shape of an object according to its shape features (plane, curved surface, line shape, etc.), identifies a plurality of grouped feature portions, and then identifies each feature. A plurality of two-dimensional cross-sectional images are generated for each of the three-dimensional shapes of the portions, and various measurements are individually performed for each feature portion using the generated plurality of two-dimensional cross-sectional images. As a result, even when a plurality of feature portions overlap in a predetermined direction in the object, only each feature portion is specified and extracted, so that various measurements for each feature portion are preferably performed. be able to.

Hereinafter, one embodiment of the present disclosure will be described in detail with reference to the drawings.

<Structure>
FIG. 1 shows a functional block diagram of the shape measuring device 10 according to the present embodiment. The shape measuring device 10 illustrated in FIG. 1 includes an object photographing unit 11, a three-dimensional shape specifying unit 12, a feature portion specifying unit 13, a two-dimensional cross-section image generation unit 14, and a feature portion measuring unit 15. Be prepared. FIG. 2 is a diagram schematically showing an example of a side view of the object photographing unit 11.

The object photographing unit 11 includes a camera 111, a camera supporting unit 112 that supports the camera 111, and an object placing unit 113 on which the object 900 to be measured is placed. The camera 111 is, for example, a monocular camera, and the distance from the lens to the in-focus position is fixed. The camera support portion 112 supports the camera 111 so that the height of the camera 111 can be changed. Thereby, the shooting distance, which is the distance between the camera 111 and the object 900, can be changed. The object photographing unit 11 photographs the object 900 placed on the object placing unit 113 with the camera 111 at a plurality of shooting distances. The captured image is stored in a storage unit (not shown) or the like in association with the shooting distance when the image was captured. The object 900 is, for example, a metal part and may have a foreign substance such as a fine protruding portion 901 called a whisker protruding from the surface (see FIG. 2).

The three-dimensional shape specifying unit 12 identifies the three-dimensional shape of the object 900 based on the image of the object 900 photographed by the object photographing unit 11 and the photographing distance at that time. The three-dimensional shape specifying unit 12 may be integrally configured with the object photographing unit 11.

The feature portion specifying unit 13 specifies a feature portion that is a portion having a predetermined feature in the object 900 based on the three-dimensional shape of the object 900 specified by the three-dimensional shape specifying unit 12. The feature part will be described later.

The two-dimensional cross-sectional image generation unit 14 extracts the three-dimensional shape of the feature portion specified by the feature portion identification unit 13 from the three-dimensional shape of the object 900, and the two-dimensional cross-sectional image of the three-dimensional shape of the extracted feature portion. To generate multiple. The two-dimensional cross-sectional image will be described later.

The feature portion measuring unit 15 performs various measurements on the feature portion based on a plurality of two-dimensional cross-sectional images generated by the two-dimensional cross-sectional image generation unit 14 for each feature portion specified by the feature portion specifying unit 13.

It should be noted that some or all of the functions of the three-dimensional shape identification unit 12, the feature portion identification unit 13, the two-dimensional cross-section image generation unit 14, and the feature portion measurement unit 15 described above include one or two having a processor and a memory. It can be achieved by more than one computer.

<Processing>
An example of the process according to the present embodiment will be described. FIG. 3 is a flowchart showing an example of the shape measurement process executed by the shape measurement device 10.

(Step S301)
The three-dimensional shape specifying unit 12 acquires information representing the three-dimensional shape of the object 900. The object 900 is, but is not limited to, a metal part, for example, and may have a foreign object such as a fine protruding portion 901. The three-dimensional shape of the object 900 uses a monocular camera in which the distance from the lens to the in-focus position is fixed, and the object 900 is photographed multiple times while changing the distance from a specific shooting direction to the object 900. It can be measured by doing. In the present embodiment, the three-dimensional shape specifying unit 12 acquires an image and a shooting distance of the object 900 taken by the camera 111 of the object photographing unit 11 as information representing the three-dimensional shape of the object 900. The shooting direction and the number of shootings by the object shooting unit 11 are not limited.

(Step S302)
The three-dimensional shape specifying unit 12 identifies the three-dimensional shape of the object 900 based on the information representing the three-dimensional shape of the object 900. For example, the three-dimensional shape specifying unit 12 includes a portion having a high degree of focus in each image of the object 900 obtained by the above-mentioned multiple shots, and the camera 111 to the target 900 when the image is shot. By calculating the spatial distribution of the in-focus position on the surface of the object based on the shooting distance, the three-dimensional shape of the object 900 can be specified.

(Step S303)
The feature portion specifying unit 13 specifies a feature portion having a predetermined feature in the three-dimensional shape of the object 900 specified by the three-dimensional shape specifying unit 12. Specifically, the feature portion specifying portion 13 obtains features such as the normal direction and curvature of each surface of the object 900 and its distribution based on the three-dimensional shape of the object 900. The feature portion specifying portion 13 can obtain the normal direction and the curvature of the central portion of the local shape of the object 900 with respect to the local shape of the object 900. Then, the feature portion specifying unit 13 classifies and groups the three-dimensional shapes of the object 900 into planes, curved surfaces, line shapes, and the like based on the obtained features, and specifies the shapes of each group as feature portions. do. Such classification of three-dimensional shapes can be performed by using a known method as appropriate.

(Step S304)
The two-dimensional cross-sectional image generation unit 14 extracts the three-dimensional shape of the feature portion from the three-dimensional shape of the object 900 for each feature portion of the object 900 specified by the feature portion identification unit 13.

(Step S305)
The two-dimensional cross-sectional image generation unit 14 generates a plurality of two-dimensional cross-sectional images (two-dimensional cross-sectional image group) of each feature portion based on the three-dimensional shape of each feature portion. Specifically, the two-dimensional cross-sectional image generation unit 14 extracts the outline of the shape (cross-sectional shape) at an arbitrary shooting distance by using the three-dimensional shape of the feature portion to obtain the two-dimensional cross-sectional image of the feature portion. It can be generated. Alternatively, the two-dimensional cross-sectional image generation unit 14 can also generate a two-dimensional cross-sectional image of the feature portion by extracting an image of a region corresponding to the feature portion from the focused image of the object 900. At this time, the two-dimensional cross-section image generation unit 14 uses the brightness value or the in-focus degree of the region having a high in-focus degree to two-dimensionally so that the cross-section can be appropriately obtained even in the region where the in-focus image is out of focus. It is desirable to generate a cross-sectional image. The plurality of two-dimensional cross-sectional images are images obtained by cutting (dividing) the three-dimensional shape of the feature portion into a plurality of planes parallel to each other in a predetermined direction at predetermined intervals. The predetermined direction can be the direction in which the camera 111 moves. The predetermined interval can be any length from which the shape of the feature portion can be extracted. For example, if the feature portion has a linear shape with a thickness of 1 μm, the interval may be less than 1 μm.

(Step S306)
The feature portion measuring unit 15 performs various measurements of the feature portion based on a plurality of two-dimensional cross-sectional images (two-dimensional cross-sectional image group) generated for the feature portion for each feature portion, and obtains a three-dimensional shape of the feature portion. Ask. In the measurement, as an example, thinning processing and length measurement are performed. At this time, it is desirable that the feature portion measuring unit 15 extracts a region separated from the contour of the cross-sectional shape in the two-dimensional cross-sectional image by an arbitrary distance inside the shape. As a result, even if the feature portion has a linear shape lying on the surface of the object 900, the central portion of the feature portion can be obtained as a linear shape.

(Step S307)
The feature portion measuring unit 15 calculates information representing the three-dimensional shape of the object 900 from the result of the shape measured for each feature portion. This completes the shape measurement process.

<Specific example>
Hereinafter, a specific example of the shape measurement process will be shown with reference to FIGS. 4 to 6. In this example, the object 900 is a metal part, and the three-dimensional shape of the fine protruding portion 901 is required as a feature portion.

FIG. 4 shows an example of information representing the three-dimensional shape of the object 900 acquired by the three-dimensional shape specifying unit 12 in step S301 described above. As shown in FIG. 4, an image of the object 900 at each shooting distance is captured by the camera 111 using the focusing method, and a plurality of captured images are associated with the shooting distance to form a three-dimensional shape of the object 900. Is acquired by the three-dimensional shape specifying unit 12 as information representing.

FIG. 5 shows an example of the feature portion specified by the feature portion specifying unit 13 in step S303 described above. As shown in FIG. 5, the object 900 of the present embodiment is classified into a fine protruding portion 901 (line shape group) and a portion other than the fine protruding portion 901 (curved surface group), and each is specified as a characteristic portion. NS.

FIG. 6 shows an example of a plurality of two-dimensional cross-sectional images (two-dimensional cross-sectional image group) generated by the two-dimensional cross-sectional image generation unit 14 for the fine protruding portion 901 in the above-mentioned step S305. As shown in FIG. 6, a plurality of two-dimensional cross-sectional images of the fine protruding portion 901 are generated at predetermined intervals. The two-dimensional cross-sectional image generation unit 14 calculates the three-dimensional shape of the fine protruding portion 901 based on the plurality of two-dimensional cross-sectional images (two-dimensional cross-sectional image group). To calculate the three-dimensional shape, each two-dimensional cross-sectional image is thinned into the shape of the fine protruding portion 901, and the shapes of the fine protruding parts 901 of each thinned two-dimensional cross-sectional image are connected to each other to be three-dimensionalized. It is feasible with. Various known methods can be used for the thinning process and the three-dimensional processing.

[effect]
In the shape measuring device 10 according to the embodiment of the present disclosure, the three-dimensional shapes of the object 900 are classified and grouped according to the characteristics of the shape (plane, curved surface, line shape, etc.), and the shapes of each group are grouped. Are specified as feature parts. Then, a plurality of two-dimensional cross-sectional images (two-dimensional cross-sectional image group) are generated for each of the three-dimensional shapes of each feature portion, and various measurements for each feature portion are individually performed using the generated plurality of two-dimensional cross-sectional images. To do.

By this processing, even when a plurality of feature portions (for example, a plane and a line shape) overlap in a predetermined direction (for example, a shooting direction) in the object 900, only each feature portion is specified. Since it is extracted, various measurements for each feature portion can be suitably performed.

The present disclosure can be regarded not only as a shape measuring device, but also as a shape measuring method, a program executed by a computer of the shape measuring device, and a computer-readable non-temporary recording medium in which the program is stored.

The shape measuring device of the present disclosure is useful when measuring the shape of an object with high accuracy and high speed by using the thinning process of an image.

10 Shape measuring device 11 Object imaging unit 12 Three-dimensional shape specifying unit 13 Feature part specifying unit 14 Two-dimensional cross-section image generation unit 15 Feature part measuring unit 111 Camera 112 Camera support 113 Object mounting unit 900 Object 901 Fine protrusion part

Claims (1)

A shape measuring device that measures the shape of an object.
A three-dimensional shape specifying part that specifies the three-dimensional shape of the object,
Among the three-dimensional shapes of the object, a feature portion specifying portion that specifies a feature portion that is a portion of a shape having a predetermined feature, and a feature portion specifying portion.
The three-dimensional shape of the feature portion is extracted from the three-dimensional shape of the object, and a plurality of two-dimensional cross-sectional images, which are images obtained by cutting the three-dimensional shape of the feature portion on a plurality of planes parallel to each other, are generated. Dimensional cross-section image generator and
A feature portion measuring unit that measures the feature portion based on the plurality of two-dimensional cross-sectional images is provided.
Shape measuring device.

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