JP2002031512A - Three-dimensional digitizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relieve a restriction to an object by expanding the allowable area of the sizes and irregular surface height differences of the object allowing the shape data with a specified accuracy to be obtained. SOLUTION: This three-dimensional digitizer 1 capable of obtaining the three-dimensional data on an object comprises an imaging means 10 for imaging several times while varying a focusing distance relative to the object, a data selection means 15 for extracting clear imaged data from the imaged data obtained by several times of photographing operations, and a calculation means 16 for generating the shape data by a triangular ranging calculation based on the extracted imaged data G.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional digitizer for inputting a three-dimensional shape to a data processing device.

[0002]

2. Description of the Related Art An optical three-dimensional digitizer for measuring a three-dimensional shape of an object in a non-contact manner by triangulation is used for data input to a CG system or a CAD system, body measurement, and the like. In particular, a small digitizer capable of obtaining a three-dimensional image with the same ease as photographing has attracted attention from Internet users who create 3D content. As a measurement method, a light cutting method (slit light projection method) is generally used, but there are various other active or passive methods such as a spot light projection method and a stereoscopic viewing method.

[0003] Conventionally, there is a type equipped with a light receiving lens having a zoom function. In this type of three-dimensional digitizer, the field of view of light reception (that is, the angle of view that determines the measurement range) is adjusted without changing the positional relationship with the object. Can be. Zooming is convenient when it is desired to obtain general information of the entire object and detailed information of a part. However, since the measurement accuracy decreases as the angle of view decreases, it is necessary to select an appropriate distance. Even if there is no zoom function and the angle of view is constant,
By moving the three-dimensional digitizer closer or further away, the range of the measurement portion on the object can be adjusted.

[0004]

Conventionally, during the measurement operation, the position of the light receiving lens is fixed, and an object is photographed under a constant focusing condition. In triangulation, the focusing state of a captured image affects measurement accuracy. Generally, the closer the object is, the narrower the focused area becomes, and the depth of field in close-up photography is very shallow. Therefore, in order to capture a clear image as a whole, it is necessary to separate them appropriately. That is, there is a limitation on the shortest shooting distance. For this reason, there has been a problem that the shape of a small object cannot be measured with high accuracy. This is because if the object is far enough to focus on the whole, the area occupied by the object (subject) in the field of view becomes smaller.

SUMMARY OF THE INVENTION It is an object of the present invention to widen an allowable range of an object size and a height difference of unevenness from which shape data with a predetermined accuracy can be obtained, and to relax restrictions on a target object.

[0006]

In the present invention, a plurality of shots are taken while changing the focusing distance, and a shot image with a good focus state is selected and used for triangulation. A plurality of photographed images photographed while changing the focusing distance without changing the angle of view are divided into blocks under the same conditions, and a photographed image with a good focus state is selected and reorganized for each block. If the measurement is performed based on an appropriate photographed image, shape data with a predetermined accuracy can be obtained even for an object having a long depth.

[0007]

FIG. 1 is a configuration diagram of a modeling system according to the present invention. The modeling system 100
It comprises a hand-held optical three-dimensional digitizer 1, a computer 5, and a removable recording medium 7 used for data transfer. As the recording medium 7, a memory card is suitable.

In modeling the target object 90, the user places the three-dimensional digitizer 1 at a position about 0.5 m to 1 m away from the target object 90 and measures the shape. The scene in the field of view projected on the liquid crystal display (LCD) 17 is useful for setting the measurement range. Since measurement is impossible outside the field of view, measurement is performed a plurality of times by changing the angle (arrangement direction) as necessary. Either the three-dimensional digitizer 1 or the target object 90 may be moved. In general, if measurements are made on the six surfaces of front, rear, left, right, up, and down, modeling of the entire external appearance is possible.
In each measurement, the target object 90 is irradiated with the light from the light projecting window 121, and the reflected light is returned to the light receiving window 131. It is desirable to perform the measurement indoors in a dark place to avoid the influence of external light.

[0009] The shape data obtained by the measurement and the two-dimensional image photographed as the texture are input to the computer 5 via the recording medium 7. The computer 5 has a three-dimensional synthesis program installed. The user causes the display 51 to display the shape data on the monitor, synthesizes a plurality of partial shape data, and pastes the texture to complete the shape model.

FIG. 2 is a functional configuration diagram of the three-dimensional digitizer, FIG. 3 is a diagram showing a memory configuration related to the operation of the multiple photographing mode,
FIG. 4 illustrates the principle of triangulation. The three-dimensional digitizer 1 converts the shape of the target object into data by a light section method. In this example, the user can select the normal shooting mode or the multiple shooting mode unique to the present invention. The multiple photographing mode is a mode in which photographing is performed a plurality of times by switching the focusing distance, and is suitable for measuring a relatively small object. The normal photographing mode is a mode in which the focusing distance is fixed during the measurement operation, and has a higher speed than the multiple photographing mode. The designation of the user is notified from the operation switch group 16 to the controller 11.

The light projector 12 includes a light source and a light emission driver, and simultaneously projects a plurality of slit lights U having different wavelengths in response to an instruction from the controller 11. However, a configuration in which the scanner deflects the slit light beam may be employed.

The light receiver 13 includes a light receiving lens, a two-dimensional image sensor, a circuit for quantizing a photoelectric conversion signal, and a focusing mechanism according to the present invention. The controller 11 instructs the light receiver 13 to perform the number of times of shooting according to the mode. The photographing is performed a plurality of times for measuring the shape and taking in the texture. The light receiver 13 and the controller 11 constitute the photographing means 10 of the present invention.

In the multiple photographing mode, the focusing distance Df
The photographing is performed a plurality of times while changing stepwise. Light receiver 13
Of each time (photographed image) G'GT 'output from
Are sequentially stored in the banks 1 to N of the image memory 14, and then sent to the data selection unit 15. The data selection unit 15 includes a contrast determination unit 151 and a reorganization unit 152. The contrast determination unit 151 checks the spatial frequency of the photographing data (captured image) G′GT ′ for a plurality of times for each block obtained by dividing the light receiving surface of the image sensor, and extracts clear photographing data. More specifically, the contrast determination unit 151 divides each bank 1 to N of the image memory 14 into X × Y (3 × 3 in FIG. 3) blocks as shown in FIG. The frequency is calculated, and the calculation result is written to the contrast memory 201. Subsequently, the bank having the highest average spatial frequency among the banks 1 to N is detected for each block, and the bank number is stored in the representative information memory 2.
Write to 02. The reorganization unit 152 refers to the representative information memory 202 for each of the X × Y blocks,
The image data of the bank written in the representative information memory 202 is read from the image memory 14. Then, the read image data is combined to generate one clear image as a whole. That is, one data is reorganized. The image data G rearranged for shape measurement is sent to the measurement operation unit 16, and the image data GT rearranged as texture is sent to the output circuit 18. If clear image data of a predetermined level cannot be obtained for any of the blocks, the contrast determination unit 151 notifies the controller 11 of the fact, and the LCD 17 displays a warning by a picture or a message.

The measurement calculation section 16 performs data processing for triangulation and outputs shape data D1 of a portion of the target object within the photographing range. That is, at the same time the projected slit light U ₁ ~U _M were identified by wavelength, examines whether any slit of the reflected light the light incident on each pixel of the image sensor. Projection angle α of each slit light U ₁ ~U _M
And the light receiving angle β of each pixel is known,
The distance L between the base line and the target object is obtained by triangulation from the angles α and β and the base line length (distance between the reference points of light emission and reception).
If the position on the object irradiated with the slit light is on the perpendicular bisector of the baseline, the distance L from the midpoint of the baseline to the irradiation position can be expressed as L = d / tanβ with the base line length being 2d. it can. A set of calculated distances for the number of pixels constitutes the shape data D1. The shape data D1 is output from the output circuit 18
Is written on the recording medium 7 together with the texture GT.

In the above functional configuration, the controller 1
1. The data selection unit 15 and the measurement calculation unit 15 are realized by a processor and an appropriate program executed by the processor.

FIG. 5 is a diagram for explaining the function of the contrast judging section, and FIG. 6 is a diagram showing an example of the result of measuring the contrast. In FIG. 5, three shootings are performed while changing the focusing distance from a short distance to a long distance. Three captured images G ' ₁ ,
G ′ ₂ and G ′ ₃ are divided into a plurality of blocks and compared for each block. In the illustrated example, the block is divided into rectangular blocks. However, the block shape may be other than rectangular, may be hexagonal, or may be all different. The only necessary condition is that the plurality of captured images G ′ ₁ , G ′ ₂ , G ′ ₃ be divided under the same condition.

For example, the lower left block in each of the photographed images G ′ ₁ , G ′ ₂ , G ′ ₃ is defined as g ₁ , g ₂ , g ₃ .
By performing Fourier analysis on the image data of these blocks g ₁ , g ₂ , and g ₃ , a graph showing the relationship between frequency and intensity is obtained (see FIG. 6). Block g ₁ ,
Data of a block having the highest average frequency among g ₂ and g ₃ is selected. The selection may be made based on the height of the highest frequency instead of the average. Similarly, if the sharpest image is selected for a block at a position other than the lower left, a clear captured image can be obtained as a whole.

FIG. 7 is a diagram for explaining the function of the reorganization unit.
And one sharp texture from three textures
Is generated. Three textures G
T '₁, GT '_Two, GT '_ThreeHas a clear part and a blurred part
Have. The position and size of the clear part
It is determined by the focusing distance. The reorganization unit 152
Based on the determination result of the strike determination unit 151, each texture G
T '₁, GT '_Two, GT '_ThreeThe sharpest part G compared to the others
t₁, Gt_Two, Gt _ThreeExtract and combine them
₁Generate one sharp texture GT. This allows
Depth that only one part is focused in one shot
Even for long objects, clear visual information can be obtained overall.
Paste high-quality textures to shape models
Becomes possible. In addition, if necessary,
Smoothing process to smooth joints
I just need.

FIG. 8 is a flow chart showing the outline of the modeling procedure, and FIG. 9 is a flow chart of the multiple photographing operation. The user specifies the mode in consideration of the size of the object and the state of the unevenness (# 1). According to the designation, the three-dimensional digitizer 1 performs a normal photographing operation or a multiple photographing operation (# 2, # 5). The mode setting and the shooting operation in the predetermined mode are repeated until the shooting of all angles necessary for modeling the entire object or the desired portion is completed (#
3). When the photographing is completed, the 3D conversion of generating the shape data D1 based on the photographing data of each angle is performed (#
4). Then, the computer 5 performs 3D image processing for combining the shape data D1 of different angles (# 5).

The multiple photographing operation includes N photographing operations (# 21) for changing the focusing distance, an image analyzing operation for finding the spatial frequency (# 22), and a contrast judging operation for selecting the sharpest photographed image for each block (# 21). # 23), a reorganization operation of combining N blocks to generate one clear composite image (# 24), and an operation of outputting a composite image (# 25)
Consists of

The present invention is applicable not only to the light sectioning method but also to active or passive optical distance measurement including a pattern light projection method and a stereo vision method.

[0022]

According to the first to fourth aspects of the present invention,
It is possible to widen the allowable range of the object size and the height difference of the unevenness from which the shape data of the predetermined accuracy can be obtained, and relax the restrictions on the target object.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a modeling system according to the present invention.

FIG. 2 is a functional configuration diagram of a three-dimensional digitizer.

FIG. 3 is a diagram showing a memory configuration related to an operation in a multiple photographing mode.

FIG. 4 is a diagram illustrating the principle of triangulation;

FIG. 5 is a diagram for explaining a function of a contrast determination unit.

FIG. 6 is a diagram illustrating an example of a measurement result of contrast.

FIG. 7 is a diagram for explaining a function of a reorganization unit;

FIG. 8 is a flowchart showing an outline of a modeling procedure.

FIG. 9 is a flowchart of a multiple photographing operation.

[Explanation of symbols]

 Reference Signs List 1, 1-dimensional digitizer 90 Target object 10 Imaging means 20 Measurement operation unit (Operation means) G Imaging data GT Texture 11 Controller (Control means) g Block

Claims (4)

[Claims] 1. A three-dimensional digitizer for converting a three-dimensional shape of a target object into data, comprising: a photographing means for photographing the target object a plurality of times by changing a focusing distance; A three-dimensional digitizer, comprising: data selecting means for extracting photographing data; and calculating means for generating shape data by triangulation based on the extracted photographing data. 2. The apparatus according to claim 1, wherein said data selection means divides a photographing range into a plurality of blocks, compares photographing data for a plurality of times for each block, and extracts the sharpest photographing data for each block. Dimensional digitizer. 3. The three-dimensional digitizer according to claim 1, further comprising control means for executing a warning process when clear photographing data of a preset level is not extracted. 4. The three-dimensional digitizer according to claim 1, wherein the photographing data extracted by said data selecting means is output as a texture of a target object.