JPH11326057A - Method and apparatus for measuring a three-dimensional object - Google Patents

Abstract

(57) [Problem] To provide a measuring device that measures the shape and color of a three-dimensional object in synchronization with each other by measuring the surface reflected light and the internal diffused light separately, so that the color can be accurately measured. I do. In addition, the color value and the spectral reflectance of the three-dimensional object can be obtained, and the glossiness can be evaluated. SOLUTION: In a three-dimensional object measuring device 1A which includes a three-dimensional shape measuring device such as a range finder 20 and a colorimetric device 40, and outputs the measured values in synchronization with each other, the colorimetric device 40 is a measuring object. It comprises a polarized light irradiator 41 for irradiating the object 2 with polarized light, and a light receiver 43 for receiving the reflected light of the polarized light from the measuring object 2 through a polarizing filter 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a three-dimensional object for measuring the three-dimensional shape and color of a measurement object in synchronization.

[0002]

2. Description of the Related Art A person simultaneously recognizes a three-dimensional shape of an object and its color. For this reason, in order to mechanically and objectively grasp the appearance of an object, it is necessary to perform measurement in a state where the shape and color of the object are synchronized.

The shape of an object is positional information on the surface of the object, and there are various practical distance measuring systems for the measurement. The color is a reflection characteristic of the surface of the object, and a color TV camera or a color scanner can be used for the measurement. As a device for measuring a three-dimensional object in a state where these are synchronized, a measuring device 1 shown in FIG. 7 has been proposed (NTT R & D, Vol. 42, No. 4, 465 (1993)). FIG.
FIG. 2 is an explanatory diagram of an optical system of the measuring device 1.

The measuring apparatus 1 includes a center table 3 for fixing a measurement object 2 such as a human face, and a digitizer unit that rotates around the measurement object 2 to measure the shape and color of the measurement object 2. It consists of ten. The digitizer unit 10 incorporates a shape measurement light source 21 that emits laser light, a lens system 22 that changes laser light into vertical slit light, and a monochrome CCD camera 23, which are measured by a known slit light projection method. A range finder 20 for measuring the three-dimensional shape of the object 2 is configured.
The digitizer unit 10 also incorporates a colorimetric non-flicker light source 31 and a color CCD camera (color TV camera) 32, which are
Is configured.

[0005] In this measuring device 1, the laser light source 21
Is converted into vertical slit light by the lens system 22 and projected onto the measurement target 2. Then, by observing the slit light with the black-and-white CCD camera 23, the distance of the surface portion of the measuring object 2 is measured, and the distance is scanned in the circumferential direction of the arrow A to obtain the three-dimensional shape of the measuring object 2. Is measured. On the other hand, the color C provided in the digitizer unit 10
The CD camera (color TV camera) 32 receives the reflected light of the light emitted from the color measurement non-flicker light source 31 from the measurement target 2 and gives color information. Therefore, according to the measuring device 1, it is possible to obtain a full-color cylindrical projection image in which the three-dimensional shape and the color of the measurement object 2 are completely synchronized.

[0006]

As shown in FIG. 9, when natural light L is generally incident on an object such as skin S, a part of the light is reflected on the surface (surface reflected light L ₁ ), and the other is reflected on the object. It enters the interior, repeats scattering and absorption, and exits from the surface again (internal diffused light L ₂ ). Here, the surface reflected light L ₁
Has a roughness information such as fine lines and pores on the skin surface, internal diffusion light L ₂ has the information age spots, freckles, regarding the color such as color unevenness. Therefore, regardless of the surface unevenness of the object,
When measuring the color itself, the internal diffused light L _{2 of the} object
Needs to be measured.

However, in the measuring device 1 shown in FIGS. 6 and 7, since the surface reflected light is used in addition to the internal diffused light originally required for color measurement, the color of the measurement object 2 is changed. It cannot be measured accurately. Therefore, in full color cylindrical projection image obtained when for example the face was measured object 2, and darkness of the color darkness and skin itself becomes difficult to be distinguished by shading, as shown in FIG. 8, the portion of the shadow S ₁
Is measured like a portion having a dark skin color.

The present invention solves the above-mentioned problems of the prior art by using a measuring device that measures the shape and color of a three-dimensional object in synchronization with each other, and measures the color by differentiating the surface reflected light and the internal diffused light. The purpose is to enable accurate measurement. Further, it is another object of the present invention to obtain a color value and a spectral reflectance based on the measured value, so that the gloss can be evaluated.

[0009]

Means for Solving the Problems In synchronizing the measurement of the three-dimensional shape of an object to be measured and the measurement of color, the present inventors distinguish the color measurement between surface reflected light and internally diffused light. It has been found that the above object can be achieved by performing the method separately, and the present invention has been completed.

That is, the present invention relates to a method for measuring a three-dimensional object in which the measurement of a three-dimensional shape of a measurement object and the colorimetry are performed in synchronization with each other. Provided is a method for measuring a three-dimensional object, wherein colorimetry of an object to be measured is performed based on internal diffused light or surface reflected light by receiving reflected light from the object through a polarizing filter.

Further, the present invention relates to a three-dimensional object measuring device which comprises a three-dimensional shape measuring device and a color measuring device and outputs the measured values in synchronization with each other. A polarized light irradiating unit that irradiates a polarized light, comprising a light receiver that receives the reflected light of the polarized light from the object to be measured through the polarizing filter, based on the detected value of the polarized light detected by the light receiver,
Provided is a three-dimensional object measurement device, which outputs a measurement value of internal diffused light or surface reflected light of a measurement target.

Here, the color measurement means not only the tristimulus value (XYZ) and the color value (L ^* a ^* b ^* , L ^* u ^* v ^* , hue, lightness, saturation, etc.) of the object to be measured. This has a broad meaning including gloss, texture, unevenness, etc., to which the surface unevenness of the measurement object greatly contributes.

According to the measuring device of the present invention, since the measuring device comprises a three-dimensional shape measuring device and a color measuring device capable of synchronizing output values with each other, the measuring device has information on the three-dimensional shape and color of the object together. The value can be easily obtained. Further, in this case, when the colorimeter measures the internal diffused light of the measurement target, without being affected by surface irregularities, any surface portion constituting the three-dimensional shape of the measurement target can be measured. In addition, it is possible to accurately obtain a colorimetric result based on the internal diffused light. When the colorimetric result based on the internal diffused light is obtained as RGB values, tristimulus values (XYZ), color values (L ^* a ^* b ^* , L ^* u ^* v) are obtained based on the RGB values.
^* Etc.), it is possible to obtain the spectral reflectance characteristics accurately.

On the other hand, when the colorimetric device measures the surface reflected light of the object to be measured, it is possible to evaluate the surface irregularities such as gloss and the texture of an arbitrary surface portion.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method and an apparatus for measuring a three-dimensional object according to the present invention will be described in detail with reference to the drawings. In addition,
In the respective drawings, the same reference numerals represent the same or equivalent components.

FIG. 2 shows a three-dimensional object measuring apparatus 1 according to the present invention.
1A is an external view of FIG. 1, and FIG. 1 is an explanatory diagram of the optical system.

This measuring device 1A is similar to the conventional measuring device 1 shown in FIGS.
Digitizer unit 10 that rotates and moves around the center table 3 and the object 2 to be measured as shown by the arrow A.
A.

The digitizer unit 10A has a range finder 2 for measuring the three-dimensional shape of the measurement object 2 by a slit light projection method known as a three-dimensional shape measuring device.
0 and a colorimetric device 40. The range finder 20 includes a shape measuring light source 2 that emits laser light.
1. A laser system emitted from a shape measuring light source 21 is changed into a vertical slit light, and a lens system 22 for projecting the slit light on a measuring object 2 and a sectional shape when the measuring object 2 cuts the slit light are imaged. Monochrome CCD used for analysis
It consists of a camera 23. Note that a color CCD camera may be provided instead of the monochrome CCD camera 23.

The range finder 20 rotates the digitizer unit 10A around the object 2 in the direction of arrow A and scans the detection site of the object 2 based on the output of the monochrome CCD camera 23. An arithmetic unit (not shown) for calculating the three-dimensional shape of the measurement target 2 is provided outside the digitizer unit 10A.

On the other hand, the colorimetric device 40 in the digitizer unit 10A is a device characteristic of the measuring device 1A, and is emitted from the polarized light irradiating unit 41 for irradiating the measurement object 2 with polarized light. A light receiver 43 for receiving the reflected light of the polarized light from the measurement object 2 through the polarization filter 42
Consists of Further, the colorimetric device 40 includes an arithmetic unit (not shown) that outputs a measured value of the internal diffused light or the surface reflected light of the measurement target 2 based on the detected value of the polarization detected by the light receiver 43, and a digitizer. It is provided outside the unit 10A.

The polarization irradiating section 41 of the colorimetric device 40 includes a light source 4
4 and a polarizing filter 45.
For example, a halogen lamp, a xenon lamp, a flicker-free fluorescent lamp, or the like can be used. As the polarizing filter 45, a commercially available product can be used without any particular limitation.

As the polarization filter 42 on the front surface of the light receiver 43, the same one as the polarization filter 45 of the polarization irradiator 41 can be used. The angle between the polarization directions of the polarization filter 42 on the front surface of the light receiver 43 and the polarization filter 45 of the polarization irradiator 41 is set to be a right angle or the same direction as appropriate, depending on which one is detected. That is, in order to selectively detect the internal diffused light in order to accurately measure the color of the measurement object 2, the polarization direction of the polarization filter 42 on the front surface of the light receiver 43 and the polarization direction of the polarization filter 45 of the polarization irradiator 41 are perpendicular. So that the surface reflected light is
Do not pass through. Further, in order to selectively detect the surface reflected light of the measurement object 2, the polarization direction of the polarization filter 42 on the front surface of the light receiver 43 and the polarization direction of the polarization filter 45 of the polarization irradiation unit 41 are set to be the same. The surface reflection light, which maintains the polarization direction of the light incident on the light 2, can be transmitted through the polarization filter 42.

As the light receiver 43, a color CCD camera or the like is preferably used. When a color CCD camera is used as the light receiver 43, a method of outputting a measurement value of the internal diffused light or the surface reflected light of the measurement target 2 based on the RGB output values can be performed by a known method ( JP-A-2-206426, JP-A-7-7562
No. 9). However, in this case, the RGB output values of the internal scattered light of the measurement target 2 obtained from the light receiver 43 are not used as they are, but based on the three-dimensional shape of the measurement target 2 measured by the range finder 20. It is preferable to correct the illuminance of the RGB output values as follows and use the corrected R'G'B '.

[0024]

R ′ = R / cos θ G ′ = G / cos θ B ′ = B / cos θ (where θ is the angle between the normal vector of each point of the object 2 and the light source direction (each point) Is the incident angle of the illumination light incident on the light source.)

The output value R'G'B 'after this correction is, if necessary, determined by a known method such as tristimulus value (XYZ) or color value (L ^* a ^* b ^* , L ^* u ^* v ^*). ) Can be converted.
Further, by measuring the main component spectrum of the reflected light of the measurement object 2, the spectral reflectance can also be measured from the tristimulus values XYZ using the principal component analysis method (Japanese Patent Application Laid-Open No. H7-174631). , Journal of the Photographic Society of Japan, Vol. 57, No. 2, 78
(1994)).

For example, as a method of calculating the tristimulus value XYZ from the corrected output value R'G'B ', as shown in the following equation (I), the tristimulus value XYZ is calculated up to the second order term of the output value R'G'B'. R'G 'using
A conversion matrix M between B ′ and tristimulus values XYZ is obtained.

[0027]

(Equation 2)

More specifically, the object to be measured 2 is photographed by a color CCD camera serving as a light receiver 43 and its output value R
After obtaining GB, and further correcting the illuminance, the corrected output value R'G '
Get B '. On the other hand, the spectrocolorimeter also measures the color of the measurement object 2 to determine the tristimulus values XYZ. And the measuring device 1
A conversion matrix M for converting the output value R′G′B ′ by A into a tristimulus value XYZ is represented by a tristimulus value X obtained by the conversion.
Tristimulus value XYZ directly obtained by YZ and spectrophotometer
Is determined by multiple regression analysis so as to minimize the difference from.
In obtaining the transformation matrix M in this manner, it is preferable to use at least the second-order terms of R′G′B ′, but the present invention is not limited to this, and higher-order terms may be used. .

After obtaining the conversion matrix M, the light receiving device 4
The output value R of the measuring object 2 by a color CCD camera
After obtaining GB, and further correcting the illuminance, the corrected output value R'G '
B ′ and R′G ′ obtained using the transformation matrix M
B ′ is converted into tristimulus values XYZ. In addition, measurement object 2
In order to obtain the spectral reflection spectrum of, the principal component analysis is performed based on the average color of the measurement object 2.

Further, the glossiness can be evaluated based on the amount of RGB surface reflected light measured by the light receiver 43.

In the measuring device 1A, the measured value based on the internal diffused light or the surface reflected light obtained by the colorimetric device 40 is output in synchronization with the measured value obtained by the range finder 20 as described above. Color, brightness, spectral reflectance, and color accuracy for each point of the three-dimensional shape of the measurement object 2
An image having information such as gloss and texture can be formed.

Therefore, for example, a human face is measured
In this case, as shown in FIG. 3, the full-color cylindrical projection image obtained by the measuring apparatus 1A is different from the conventional full-color cylindrical projection image shown in FIG. Darkness is distinguished.

According to the conventional measuring apparatus 1 shown in FIGS. 6 and 7, when the measuring object 2 has surface reflected light in addition to the internal diffused light, therefore, almost any object is set as the measuring object. Even in this case, the color value and the spectral reflectance based on the internal diffused light cannot be measured, and the glossiness based on the surface reflected light cannot be calculated. However, according to the measuring device 1A of the present invention, these are determined. It becomes possible.

Further, according to the measuring device 1A, data such as color, lightness, spectral reflectance, gloss, texture, etc. at each point of the three-dimensional shape of the measuring object 2 can be obtained. The result is extremely useful for research on the appearance of the object to be measured. Also,
By using the computer graphics technology, for example, it is possible to easily and accurately simulate the effect of the appearance under an arbitrary illumination, the difference between the appearances inside and outside, and the like.

The measuring apparatus 1A shown in FIGS. 1 and 2 and the measuring method using the same have been described above.
The present invention can take various aspects.

For example, a range finder that projects pattern light may be used in place of the range finder 20 of the slit light projection method in the above-described measuring apparatus 1A, or an optical radar method or other various range finder. May be used.

In the above-described measuring apparatus 1A, the measurement object 2 is fixed to the center table 3, and the digitizer unit 10A is rotated around the measurement object 2 to scan the measurement site of the measurement object 2. Instead of such scanning of the measurement site, the digitizer unit 10A is fixed, and the center table 3 on which the measurement object 2 is fixed is rotated so that the entire surface of the measurement object 2 is scanned as the measurement site. Good. Alternatively, the measurement of the three-dimensional shape and the measurement of the color of the measurement target 2 may be separately performed, and the two measurement values may be combined so that the two measurement values are synchronized later.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments.

Example 1 and Comparative Example 1 A three-dimensional object measuring apparatus 1A shown in FIGS. 1 and 2 was manufactured. In this case, the range finder 20 is
Color 3D Digitizer 3030.

The colorimeter 40 uses a DC fluorescent lamp as the light source 44 and Polaroid HN3 as the polarizing filter 45.
2 was used. A color CCD camera is used as the light receiver 43, and Polaro is used as the polarizing filter 42 on the front surface thereof.
HN32 manufactured by id was used.

As a measurement object 2, a makeup doll (a uniform flesh-colored doll) was used, and its head was used as a measurement range. In addition, points at which 512 pixels were sampled from the vertical direction and the rotation direction in the measurement range were defined as measurement points.

For each measurement point, the output value RGB of the internal diffused light is obtained by the light receiver 43, and the value is corrected for illuminance based on the three-dimensional shape, so that R'G'B 'is obtained as a corrected value. I asked. On the other hand, for each measurement point, a tristimulus value XY was measured with a spectral colorimeter (CM1000, manufactured by Minolta).
Z was determined. Then, the R′G ′ obtained by this measuring device 1A
From B ′ and the tristimulus values XYZ obtained by the spectrophotometer,
A conversion matrix M between R'G'B 'and XYZ was obtained by (I), and XYZ was obtained from R'G'B' using the obtained conversion matrix M, and further, lightness L ^{* was} obtained. Then, an average (△ L ^* ) of each difference between the lightness obtained by the measuring device 1A and the lightness obtained by the spectrophotometer was obtained (Example 1). The result is shown in FIG.

Other than that the illuminance correction based on the three-dimensional shape of the measuring object 2 was not performed without using the range finder 20 of the measuring device 1A of the three-dimensional object and using only the color measuring device 40, In the same manner as in Example 1, the lightness L ^* of each measurement point of the measurement object 2 is obtained, and the average (△ L ^* ) of the difference between the obtained lightness L ^* and the lightness obtained by the spectral colorimeter is obtained. (Comparative Example 1). The result is shown in FIG.

FIG. 4 shows that the brightness obtained by performing the illuminance correction based on the three-dimensional shape of the measurement object 2 matches well with the brightness obtained by the spectrocolorimeter.

Example 2 As a sample of the skin color area, 60 color patches (Hue H = 2YR to 8YR, lightness V = 5 to 7, color saturation C of Munsell color system)
= 2 to 5) were prepared and attached to a cylinder to obtain a measurement object 2.

Using the same measuring device 1A as in the first embodiment,
The output value RGB of each color chart by the light receiver 43 was obtained, and the output value RGB was subjected to illuminance correction based on a three-dimensional shape to obtain corrected R'G'B '. On the other hand, the tristimulus value X of each color chart was measured using a spectrophotometer (CM1000, manufactured by Minolta).
YZ was determined. Then, R'G'B 'obtained by the measuring device 1A
From the tristimulus values XYZ obtained by the spectral colorimeter and the
, A conversion matrix M between R′G′B ′ and XYZ is obtained, and using the obtained conversion matrix M, R′G ′ of each color chart is obtained.
The corresponding XYZ is obtained from B ′, and each L ^* a ^* b ^* is obtained from XYZ of each color chart thus obtained and XYZ of each color chart obtained by the spectrophotometer, and the color difference (△ E ^* ab) )
I asked.

FIG. 5 shows the result. Here, the average color difference (ΔE ^* ab) is 0.60, and this measuring device 1A
According to the graph, it can be seen that a colorimetric result very close to that of a spectral colorimeter can be obtained.

Example 3 and Comparative Example 2 Using a measuring device 1A similar to that of Example 1, a human face was used as a colorimetric object 2, and the internal diffused light was cut off to obtain a full-color cylindrical projection image from only the surface reflected light. Was prepared (Example 3). In addition, the polarization filter 45 of the polarization irradiating section 41 and the polarization filter 4
2, a full-color cylindrical projection image of a person's face was created in the same manner as in Example 3 except that an image consisting of both the internal diffused light and the surface reflected light of the measurement object was formed using the object from which the object 2 was removed. Comparative Example 2).

The obtained full-color cylindrical projection images were compared with each other for glossiness, pores, and wrinkles. Table 1 shows the results.

[0050]

[Table 1]

From Table 1, according to the image created by blocking the internal diffused light of the object to be measured and only the reflected light from the surface, gloss, pores, and wrinkles, which are the appearance of unevenness on the surface of the object to be measured, are clearly observed. We can see that we can do it.

[0052]

According to the present invention, in a measuring apparatus for measuring the shape and color of a three-dimensional object in synchronization with each other, measurement is performed by distinguishing surface reflected light and internal diffused light. And the color can be measured accurately. Further, it is possible to obtain the color value and the spectral reflectance of the three-dimensional object, and to evaluate the glossiness.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an optical system of a three-dimensional object measuring apparatus according to the present invention.

FIG. 2 is an external view of a three-dimensional object measuring apparatus according to the present invention.

FIG. 3 is an explanatory diagram of an image formed by the three-dimensional object measuring device of the present invention.

FIG. 4 is a diagram showing a difference between the brightness measured in the example and the comparative example and the brightness measured by the spectrocolorimeter.

FIG. 5 is a diagram showing a color difference between the embodiment and a color chart for a spectrocolorimeter.

FIG. 6 is an explanatory diagram of an optical system of a conventional three-dimensional object measuring device.

FIG. 7 is an external view of a conventional three-dimensional object measuring device.

FIG. 8 is an explanatory diagram of an image formed by a conventional three-dimensional object measuring device.

FIG. 9 is an explanatory diagram of surface reflection and internal reflection when natural light enters the skin S.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Conventional three-dimensional object measuring apparatus 1A Three-dimensional object measuring apparatus of the present invention 2 Object to be measured 3 Center table 10, 10A digitizer unit 20 Range finder 21 Light source 22 Lens system 23 Monochrome CCD camera 30 Colorimeter 31 Colorimetry Light source 32 Color CCD camera (color TV camera) 40 Colorimeter 41 Polarization irradiator 42 Polarization filter 43 Light receiver 44 Light source 45 Polarization filter A Rotating direction of digitizer unit L Light L ₁ Surface reflected light L ₂ Internal diffused light

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI G06T 7/00 A61B 5/10 300B 1/00 300Q G06F 15/62 415 15/64 M 320C 15/66 310 15/70 310

Claims (5)

[Claims] 1. A method for measuring a three-dimensional object in which a measurement of a three-dimensional shape of a measurement object and a color measurement are performed in synchronization with each other. A method for measuring a three-dimensional object, wherein colorimetry of an object to be measured is performed based on internal diffused light or surface reflected light by receiving reflected light through a polarizing filter. 2. A light source for use in measurement and colorimetry of a three-dimensional shape of a measurement object and a light receiving device for receiving reflected light from the measurement object are simultaneously moved with respect to the measurement object,
The method for measuring a three-dimensional object according to claim 1, wherein the measurement of the three-dimensional shape and the colorimetry are synchronized by simultaneously scanning the measurement part and the colorimetry part of the three-dimensional shape of the measurement object. 3. A method of receiving reflected light from a measurement object of polarized light through a polarizing filter by a color CCD camera and outputting RGB values as colorimetric values of internal diffused light.
The RGB values are corrected for illuminance based on the three-dimensional shape of the measurement object, and the tristimulus values XY are calculated based on the corrected RGB values.
2. The method according to claim 1, further comprising: outputting Z, a color value L ^* a ^* b ^* or a color value L ^* u ^* v ^* , or outputting a spectral reflectance calculated by a principal component analysis method based on the RGB values after illuminance correction. Or 2
The method for measuring a three-dimensional object according to the description. 4. A three-dimensional object measuring device comprising a three-dimensional shape measuring device and a color measuring device and outputting the measured values in synchronization with each other, wherein the color measuring device irradiates polarized light to the object to be measured. An irradiating unit, comprising a light receiver that receives reflected light of the polarized light from the object to be measured through a polarizing filter, and based on the detected value of the polarized light detected by the light receiver, the internal diffused light or the surface reflected light of the object to be measured. An apparatus for measuring a three-dimensional object, which outputs a measured value. 5. A light source forming a three-dimensional shape measuring device and a colorimetric device, and a light receiver for receiving reflected light from the measuring object are simultaneously moved with respect to the measuring object, and a third order of the measuring object is measured. The three-dimensional object measurement apparatus according to claim 4, wherein the measurement of the three-dimensional object and the colorimetry are synchronized by simultaneously scanning the measurement part and the colorimetry part of the original shape.