KR101594309B1 - 3D distance measuring system and 3D distance measuring method - Google Patents

Abstract

The present invention relates to a three-dimensional distance measurement system and a three-dimensional distance measurement method using the same, wherein the three-dimensional distance measurement system estimates a distance using a simple algorithm and estimates the distance from a conductive subject with a flat wall surface without using an additional light source. The three-dimensional distance measurement system comprises: a lens enabling light to pass through at least a part of the conductive subject; an image sensor including a plurality of pixels arranged in a distance farther than a focus distance determined by the lens and the conductive subject; a rotation plate arranged on the focus distance, including at least a pin hole and a multi-band pass filter; and a control unit calculating a distance value between the conductive subject and the lens from the distance value between the rotation plate and the image sensor when a near-field diffraction pattern forms a predetermined pattern by analyzing the near-field diffraction pattern of light passing through the at least pin hole.

Description

[0001] The present invention relates to a three-dimensional distance measuring system and a three-dimensional distance measuring method using the same,

The present invention relates to a three-dimensional distance measuring system and a three-dimensional distance measuring method using the same, and more particularly, to a three-dimensional distance measuring system for estimating a distance between each part of a subject having conductivity, And a 3D distance measurement method using the 3D distance measurement system.

Distance recognition of objects is a technique applied in automobiles and games. It uses a method of creating a three-dimensional distance map by measuring the distance of each object appearing in the camera. An example of the application of the distance recognition of an object is a technique which is installed in the front of a car, for example, to estimate the distance to the front car or to estimate the distance of a sudden pedestrian to warn of the risk of collision. Microsoft is launching a game that responds to the user's movements in close proximity, using a system that recognizes the distance between the user and the surrounding environment in the X-box.

The three-dimensional distance estimation method can be classified into an active method using a light source and a passive method using no light source. In the active mode, a time-of-flight (ToF) method is used in which the laser is momentarily irradiated and the time at which the reflected light reaches the camera is mainly used. It is recognized as the best way to estimate the distance of all the points on the image where the reflection of the laser occurs but it is difficult to apply to human body like a human because it requires a strong laser light source and is mainly used for limited use such as military or geographical measurement. As an alternative to this, in the case of using a method of irradiating a certain pattern light to a subject and obtaining a distance from the pattern of light that is deformed according to the distance of the subject (for example, a keynote employed in MS's X-box) same. For example, a method of estimating the distance of a nearby object by estimating the position of a deformed laser pointer by irradiating several IR laser pointers to the object, is used. Therefore, there is an advantage that a relatively simple system configuration and a distance estimation algorithm are used. On the other hand, although it is possible to operate in a room where the external light intensity is not strong, a precise operation can not be recognized because only a limited number of points can be estimated in the indoor environment. In addition, it is difficult to apply in an outdoor environment in which strong infrared rays due to the sun are being irradiated.

In the passive method, a stereo camera is most commonly used as a method of using light reflected from an object by a usual light source such as illumination or sunlight without using a separate light source. Stereo cameras use the fact that when the light from one object is projected onto two or more cameras that maintain a certain distance from each other, parallax occurs according to the distance of the object. Distance estimation of one and the same object appearing on two images with parallax uses pattern matching to calculate how much of the same object has moved on another image based on one image. Finding the same object in two different images requires highly intelligent algorithms, computationally intensive, and it is difficult to align both cameras correctly, so mis-aligning the camera, Rotation, lens distortion, etc.), which is difficult to commercialize. In order to improve this, various methods have been proposed which can perform the same operation as a stereo camera using one camera. One of the realized techniques is a method of disposing a plurality of intermediate lenses under one lens. In this method, the image of the subject appears at various positions by the intermediate lens, and the distance between the same objects appearing in each intermediate lens is estimated by pattern matching. This method has a simple optical system configuration and does not require correction for the alignment of the lens or image sensor. It has the advantage of easy pattern matching because of the small number of patterns appearing in each intermediate lens, so that the amount of calculation is reduced. However, It is necessary to perform an operation that overlaps the calculation of the pattern matching. In addition, there is a fundamental problem that it is impossible to estimate the distance of a flat object (for example, a wall of the same spike) because it contains only the distance information of an edge of an image which is a fundamental problem of a method of using pattern matching.

Korean Patent Laid-Open No. 10-1995-7004670 (November 20, 1995)

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method and apparatus for estimating a distance in a conductive object having a flat wall without using a separate light source, Distance measuring system and a three-dimensional distance measuring method using the same. However, these problems are illustrative and do not limit the scope of the present invention.

According to one aspect of the present invention, a three-dimensional distance measurement system includes: a lens capable of passing light from at least a portion of a conductive object; An image sensor having a plurality of pixels and disposed at a greater distance than the focal distance defined by the conductive object and the lens; A diffraction plate disposed within the focal distance and having at least one pinhole and a multi-band pass filter; And a near-field diffraction pattern of light passing through the at least one pinhole to determine a near field diffraction pattern from a distance value between the diffraction plate and the image sensor when the near- And a controller for calculating a distance value between the conductive object and the lens.

And a driving unit for moving the bifurcation plate.

The control unit may analyze the change of the near field diffraction pattern of light passing through the at least one pin hole of the diffraction plate, which is varied by the driving unit, by controlling the driving unit.

The multi-band pass filter can reduce the interference caused by the light having the adjacent wavelength band.

According to another aspect of the present invention, there is provided a three-dimensional distance measuring method using the above-described three-dimensional distance measuring system, wherein light emitted from at least a part of the conductive object passes through the lens through the at least one pin hole, Reaching the sensor; And analyzing a near field diffraction pattern of light passing through the at least one pinhole from the distance value between the diffraction plate and the image sensor when the near field diffraction pattern forms a constant pattern, And calculating a distance value between the object and the lens.

The distance value between the conductive object calculated by the control unit and the lens can be calculated by analyzing the near field diffraction pattern by a focus formed on the upper portion of the center of the pin hole.

The distance value between the conductive object and the lens may correspond to the distance of the center point of the pin hole on the image obtained by the image sensor.

A color value of the light can be obtained from the pixel value sensed by light passing through the at least one pinhole.

According to another aspect of the present invention, there is provided a three-dimensional distance measuring method using the three-dimensional distance measuring system, wherein light emitted from at least a part of the conductive object passes through the lens through the at least one pin hole, Reaching an image sensor; And a control unit for analyzing a change in the near field diffraction pattern of light passing through the at least one pinhole of the diffraction plate which is varied by the driving unit, And computing a distance value between the conductive object and the lens from the distance value between the image sensor and the out-of-plane image.

The distance value between the conductive object calculated by the control unit and the lens can be calculated by analyzing the near field diffraction pattern by a focus formed on the upper portion of the center of the pin hole.

The distance value between the conductive object and the lens may correspond to the distance of the center point of the pin hole on the image obtained by the image sensor.

A color value of the light can be obtained from the pixel value sensed by light passing through the at least one pinhole.

According to an embodiment of the present invention as described above, according to the three-dimensional distance measuring system of the conductive surface using the near-field diffraction of pinholes and the three-dimensional distance measuring method using the same, distance information and color information of the object can be simultaneously obtained have. Of course, the scope of the present invention is not limited by these effects.

1 is a view schematically showing an example of focus according to the distance of an object by a lens in a three-dimensional distance measuring system according to a comparative example of the present invention.
FIGS. 2A and 2B are schematic diagrams illustrating a three-dimensional distance measurement system according to an embodiment of the present invention.
FIG. 2C is a flowchart schematically illustrating a three-dimensional distance measuring method according to an embodiment of the present invention.
Figure 3 is a schematic diagram of a baffle according to one embodiment of the present invention.
4A and 4B are schematic views illustrating a three-dimensional distance measurement system according to another embodiment of the present invention.
FIG. 4C is a flowchart schematically illustrating a three-dimensional distance measurement method according to another embodiment of the present invention.
FIG. 5 is a view showing a diffraction pattern of light due to focus formed at different distances in the center of a pinhole in a three-dimensional distance measuring system using near-field diffraction of pinholes according to an embodiment of the present invention.
6 is a view showing diffraction of parallel light by far-field diffraction of a pinhole.
FIG. 7 is a diagram showing a diffraction pattern of parallel light by near-field diffraction of a pinhole. FIG.
FIG. 8 is a graph showing the transmittance of a multi-band pass filter used in a three-dimensional distance measurement system using near-field diffraction of a pinhole according to another embodiment of the present invention.
FIG. 9 is a diagram illustrating a three-dimensional distance measurement system using a near-field diffraction of a pinhole according to another embodiment of the present invention. FIG. 9 is a view showing a case where a focus formed at a predetermined distance from the pinhole is located at the center of the pinhole, Fig.
10 is a view schematically showing a shape when light is reflected or scattered according to the type of a subject in a three-dimensional distance measuring system according to a comparative example of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, Is provided to fully inform the user. Also, for convenience of explanation, the components may be exaggerated or reduced in size.

Terms such as "top" or "bottom" referred to in the process of describing the present embodiment may be used to describe the relative relationship of certain elements to other elements, as illustrated in the figures. That is, relative terms may be understood to include different directions of the structure apart from the directions depicted in the figures. For example, if the top and bottom of the structure are inverted in the figures, the elements depicted as being on the top surface of the other elements may be on the bottom surface of the other elements. Thus, by way of example, the term "tops" may include both "top" and "bottom" directions, relative to a particular direction in the figures.

Further, in the course of describing the present embodiment, when it is mentioned that an element is located on another element, or "connected" to another element, the element is positioned directly on the other element Or directly connected to the other component, but may also mean that one or more intervening components may be present therebetween. However, when an element is referred to as being "directly on" another element, "directly connected" to another element, or "directly in contact" with another element, Which means that there are no intervening components.

In the following embodiments, the x-axis, the y-axis, and the z-axis are not limited to three axes on the orthogonal coordinate system, but can be interpreted in a broad sense including the three axes. For example, the x-axis, y-axis, and z-axis may be orthogonal to each other, but may refer to different directions that are not orthogonal to each other.

1 is a view schematically showing an example of focus according to the distance of an object by a lens in a three-dimensional distance measuring system according to a comparative example of the present invention.

Referring to FIG. 1, in a three-dimensional distance measuring system according to a comparative example of the present invention, focusing on the distance of the object 100 by the lens 10, two points at different distances from the lens 10 The light beams 105a and 105b are collected at two different points by the lens 10. A focus 110a is positioned between the image plane 110 of the image sensor (not shown) and the lens 10 so that the surface shape of the object 100 is displayed on the focus surface 110a in an inverted manner.

In the case of a generally used lens 10, when the distance between the object 100 and the lens 10 is close (near object), the focus is located a long distance from the lens 10, (Distance subject) is farther from the lens 10, the focal point is located at a distance from the lens 10. In an ordinary camera, the image sensor is arranged so that the focus coincides with an object at a specific distance, and this area is called depth of field (DoF). That is, if the object is in the DoF, the image will appear clearly, and if it is outside the DoF, the image of the object will appear to be spread. Therefore, if the distance between the lens and the image sensor is moved to find a position where the object appears clearly, the distance of the object appearing clearly can be obtained.

FIGS. 2A and 2B are schematic diagrams showing a three-dimensional distance measurement system according to an embodiment of the present invention, and FIG. 2C is a flowchart schematically showing a three-dimensional distance measurement method according to an embodiment of the present invention And Figure 3 is a schematic diagram of a baffle according to one embodiment of the present invention.

Referring to FIG. 2C, a method for measuring three-dimensional distance using a diffraction plate and an image sensor according to an embodiment of the present invention includes a step of passing light from at least a part of a conductive object through at least one pin hole through a lens A step (S100) of reaching the image sensor, and a step of, in the control section, analyzing the near field diffraction pattern of light passing through the at least one pinhole to determine a distance between the diffraction plate and the image sensor And calculating a distance value between the conductive object and the lens from the value (S200).

Referring to FIGS. 2A and 2B, the image sensor 30 may be located at a distance farther than the focal point of the object 100 to be estimated. This means that the distance between the lens 10 and the image sensor 30 is larger than between the lens 10 and the focal distance. Where the focal distance refers to the distance between the object 100 and the three-dimensional distance measurement system. The image sensor 30 is composed of a plurality of pixels 35 and the surface of the image sensor 30 can be matched with the image plane 110 shown in Fig. A plurality of pinholes 20a are disposed between the image sensor 30 and the focal point of the object 100. 3, the baffle plate 20 may be a glass substrate 25 and may be formed of a metal or a black polymer material on a glass substrate 25 to form a plurality of And pinholes 20a can be formed. In addition, a multi-band pass filter or a multi-band pass filter may be formed on the glass substrate 25 so as to transmit only selected light of a certain number of bands.

10 is a view schematically showing a shape when light is reflected or scattered according to the type of a subject in a three-dimensional distance measuring system according to a comparative example of the present invention.

Referring to FIGS. 2A, 2B, and 10, the three-dimensional distance measurement system 1 according to the comparative example of the present invention schematically shows a shape when light is reflected or scattered according to the type of a subject. As shown in FIG. 10 (a), when light is incident on the surface of the conductive object 100a, the electrons e existing on the surface move simultaneously due to the electric field of the incident light, With a phase having < RTI ID = 0.0 > When the light is gathered at one focal point by the lens 10 and passes through the pinhole 20a, an interference fringe is formed. In this case, since the diffraction by the pinhole 20a changes in phase, the interference fringe can be explained by the wave-optical analysis.

Also, the color value of the light may be obtained from the value of the pixel 35 sensed by the light passing through the at least one pinhole 20a.

10 (b), when light is incident on the surface of a nonconductive object 100b such as a polymer or a ceramic such as a fiber, the light passes through each of the constrained electrons e (e) constituting the nonconductive object 100b ) Or holes, the scattered light is scattered with a random-phase that is not correlated with each other, so that the light collected at one focus by the lens 10 is interpreted geometrically, regardless of the phase . That is, the intensity of total light is expressed as the sum of the intensity of each light irrespective of the phase of each light.

FIGS. 4A and 4B are schematic diagrams showing a three-dimensional distance measurement system according to another embodiment of the present invention, and FIG. 4C is a flowchart schematically showing a three-dimensional distance measurement method according to another embodiment of the present invention to be.

Referring to FIG. 4C, a method of measuring three-dimensional distance according to another embodiment of the present invention includes a step S110 in which light emitted from at least a portion of a conductive object passes through a lens through at least one pin hole to reach an image sensor, And a control unit for analyzing a change in the near field diffraction pattern of light passing through at least one pinhole that changes as the diffraction plate moves, so that when the near field diffraction pattern forms a constant pattern, the distance between the diffraction plate and the image sensor And calculating a distance value between the conductive object and the lens from the value (S210).

4A and 4B, the image sensor 30 is located at a distance farther than the focal point of the object 100 to be distance-estimated, and the image sensor 30 is composed of a plurality of pixels 35 A plurality of pinholes 20a having a plurality of pinholes 20a are arranged at a fixed height between the focus of the image sensor 30 and the object 100. A movable lens 20 is disposed above the lenshole 20, And the height h between the lens 10 and the baffle plate 20 can be varied by the driving unit 40. [

The light gathered in at least one focus is diffracted through at least one pinhole 20a and the diffracted light is sensitized by the plurality of pixels 35 and the diffracted pattern is transmitted between the conductive object and the lens 10 And the distance between the image sensor 30 and the baffle plate 20. It is also possible to obtain the color value of the light from the value of the pixel 35 sensed by the light passing through the at least one pinhole 20a. A detailed description thereof will be described later with reference to Figs. 5 to 9. Fig.

Near-field diffraction and far-field diffraction are used to distinguish diffraction by pinholes. Near-field diffraction and far-field diffraction are the distances between the pinhole and the image sensor or screen And can be expressed by the following Equation (1).

[Equation 1]

(Where D is the diameter of the pinhole, Y is the distance between the pinhole and the image sensor,? Is the wavelength of the light, and Yc is the distance limit that distinguishes between near field diffraction and far field diffraction)

That is, near-field diffraction occurs when the distance Y between the pinhole and the image sensor is smaller than Yc. This region is referred to as a Fresnel Region, and when Y is larger than Yc, far-field diffraction appears, This region is called the Fraunhofer Region.

FIG. 5 is a view showing a diffraction pattern of light due to focus formed at different distances in the center of a pinhole in a three-dimensional distance measuring system using near-field diffraction of pinholes according to an embodiment of the present invention.

Referring to FIG. 5, in a three-dimensional distance measuring system for a conductive surface using near-field diffraction of a pinhole according to an embodiment of the present invention, it is a focus diffraction pattern formed at different distances in the center of the pinhole 20a. For example, FIG. 5A shows a case where the distance between the pinhole 20a and the focus is about 8 μm, FIG. 5B shows a case where the distance between the pinhole 20a and the focus is about 6 μm to be. Simulation is the result of light with a wavelength of about 0.5 μm. Here, the intensity value of the light is expressed as a relative value. When these two patterns are compared, a pattern of about 8 mu m appears dark in the center, and a pattern of about 6 mu m is divided into different patterns in which the center appears bright. Therefore, by analyzing the shape of the pattern as described above, it is possible to obtain the distance at which the focal point is collected in the pinhole 20a, and from this, the distance of the subject emitting the light of this wavelength band can be obtained.

6 is a view showing diffraction of parallel light by far-field diffraction of a pinhole.

Referring to FIG. 6, the interference fringe by Far-Field Diffraction has a relatively simple pattern, and the intensity of the light with respect to the circular pinhole 20a appears as shown in FIG. That is, there is a strong light core at the center and a small sub-peak at the adjacent position. The intensity ratio between the central core intensity and the first peak is as small as about 100: 1 It is difficult to distinguish whether interference occurs using one pinhole 20a. Therefore, in the usual case, the interference fringe measurement uses a method of measuring the interference of multiple pinholes 20a caused by the plurality of pinholes 20a. On the other hand, the calculation method of the near field diffraction is complicated, and even in the case of the parallel light, the diffracted light varies according to the distance between the pinhole and the image sensor.

FIG. 7 is a diagram showing a diffraction pattern of parallel light by near-field diffraction of a pinhole. FIG.

Referring to FIG. 7, the parallel light diffracted by the pinhole 20a changes into a complex shape according to the distance between the pinhole 20a and the image sensor 30. In this case, the light goes straight in the form of maintaining the size of the pinhole 20a, but is not expressed by a simple expression, and is usually obtained through simulation. Light starting from the subject and collected at a predetermined focus by the lens 10 is diffracted by the pinhole 20a so that the pattern of light diffracted in the region where the distance between the pinhole 20a and the image sensor 30 is closer to Yc Is obtained by computer simulation.

FIG. 8 is a graph showing the transmittance of a multi-band pass filter used in a three-dimensional distance measurement system using near-field diffraction of a pinhole according to another embodiment of the present invention.

Referring to FIG. 8, a multi-band pass filter that transmits only a few bands selected as shown in FIG. 8 may be used to reduce the interference caused by the light of the adjacent wavelength band. When light in adjacent wavelength regions forms a focal point at the same position, the diffraction pattern that appears is expressed as the sum of diffraction patterns of light in each wavelength band. Accordingly, when a large number of adjacent patterns of light are formed in the vicinity of the pinhole 20a, the interference fringe is smear-outed, making it difficult to distinguish the interference fringe pattern. As a solution to this case, a multi-band pass filter may be formed to allow light of only a few selected specific bands to pass through the glass substrate on which the pinhole 20a is formed, or a multi- can do.

FIG. 9 is a diagram illustrating a three-dimensional distance measurement system using a near-field diffraction of a pinhole according to another embodiment of the present invention. FIG. 9 is a view showing a case where a focus formed at a predetermined distance from the pinhole is located at the center of the pinhole, Fig.

9, assuming that a certain point of the object is located at the center of at least one pinhole 20a, the focal point formed by the object in the vicinity of the object in the vicinity of the pinhole 20a is deviated from the center of the pinhole 20a It is necessary to consider the effect of the focus formed at a position deviated from the center. Fig. 9 is a diffraction pattern 9b formed at the center of the pinhole 20a and a diffraction pattern 9b formed at a certain distance (for example, about 3 mu m) from the center. When the two patterns are compared, the ratio of the maximum intensity of the diffraction by the focus formed at the center of the pinhole 20a to the maximum intensity of the diffraction by the focus shifted by about 3 μm is about 1: 0.16, The diffraction due to the focus formed at the upper part of the center of the diffraction grating 20a is mainly shown. Therefore, the distance estimation by the diffraction pattern is obtained from the focus formed at the upper portion of the center of the pinhole 20a, and the distance obtained from this corresponds to the distance of the center point of the pinhole 20a on the image.

According to the above description, the three-dimensional distance image sensor system of the conductive surface using the near-field diffraction of the pinhole is provided with a bifurcated plate having a plurality of pinholes formed thereon at a constant distance from the top of the image sensor, The upper part is composed of a lens arranged to maintain a constant distance and a lens barrel supporting the lens. The light incident on the camera from the subject forms a focal point with a different distance from the diffraction plate depending on the distance between the subject and the camera. The scattered light is diffused by at least one pinhole of the diffraction plate The distance value of the object can be obtained by analyzing the diffraction pattern of light passing through at least one pin hole from a plurality of pixels located under at least one pin hole. It is also possible to obtain a color value of light incident on at least one pinhole from all pixel values of light passing through at least one pinhole.

Also, when a lens and an image sensor are configured, the distance of the conductive object can be recognized in pixels by using a simple configuration such as an actuator capable of forming a baffle on top of the image sensor and moving the baffle. A pinhole may be provided on the upper or lower portion of the glass substrate used in the package of the image sensor. In addition, the 3D distance measurement system according to an embodiment of the present invention does not require a complicated algorithm, and the diffraction pattern of the light starting from the subject changes according to the distance between the diffraction plate and the image sensor, It is possible to estimate the distance of the starting point (subject) of light passing through at least one pin hole from the distance between the diffraction plate and the image sensor when the light passing through one pin hole forms a certain pattern.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

1: 3D distance measurement system
10: Lens
20: Burnout
20a: pin hole
25: substrate
30: Image sensor
35: Pixel
40:
50:
100: object
100a: Conductive object
100b: a nonconductive object
105a and 105b: light
110: Image plane
110a: Focus surface

Claims (12)

A lens capable of passing light from at least some portion of the conductive object;
An image sensor having a plurality of pixels and disposed at a greater distance than the focal distance defined by the conductive object and the lens;
A diffraction plate disposed within the focal distance and having at least one pinhole and a multi-band pass filter; And
A near field diffraction pattern of light passing through the at least one pinhole is analyzed to determine a distance between the diffraction plate and the image sensor when the near field diffraction pattern forms a constant pattern, A control unit operable to calculate a distance value between the conductive object and the lens;
/ RTI >
3D distance measurement system. The method according to claim 1,
And a drive capable of moving the bifurcation plate. 3. The method of claim 2,
Wherein the control unit is capable of analyzing a change in a near field diffraction pattern of light passing through the at least one pinhole of the baffle plate which is variable by the driving unit by controlling the driving unit. The method according to claim 1,
Wherein the multi-band pass filter is capable of reducing the interference caused by the light having the adjacent wavelength band. A three-dimensional distance measuring method using a three-dimensional distance measuring system using the three-dimensional distance measuring system according to any one of claims 1 to 4,
Wherein light from at least a portion of the conductive object passes through the lens through the at least one pin hole to reach the image sensor; And
Wherein the control unit analyzes the near field diffraction pattern of light passing through the at least one pinhole to determine a distance between the diffraction plate and the image sensor when the near field diffraction pattern forms a constant pattern, And calculating a distance value between the lens and the lens,
Three dimensional distance measurement method. 6. The method of claim 5,
Wherein the distance value between the conductive object calculated by the control unit and the lens is calculated by analyzing the near field diffraction pattern by a focus formed on the upper portion of the center of the pin hole. 6. The method of claim 5,
Wherein the distance value between the conductive object and the lens corresponds to the distance of the center point of the pinhole on the image obtained by the image sensor. 6. The method of claim 5,
Wherein a color value of the light is obtained from the pixel value sensed by light passing through the at least one pinhole. A three-dimensional distance measuring method using a three-dimensional distance measuring system according to any one of claims 2 and 3,
Wherein light from at least a portion of the conductive object passes through the lens through the at least one pin hole to reach the image sensor; And
Wherein the control unit analyzes the change of the near field diffraction pattern of light passing through the at least one pinhole of the diffraction plate which is varied by the driving unit so that the diffraction efficiency of the diffraction plate And calculating a distance value between the conductive object and the lens from a distance value between the image sensor and the image sensor.
Three dimensional distance measurement method. 10. The method of claim 9,
Wherein the distance value between the conductive object calculated by the control unit and the lens is calculated by analyzing the near field diffraction pattern by a focus formed on the upper portion of the center of the pin hole. 10. The method of claim 9,
Wherein the distance value between the conductive object and the lens corresponds to the distance of the center point of the pinhole on the image obtained by the image sensor. 10. The method of claim 9,
Wherein a color value of the light is obtained from the pixel value sensed by light passing through the at least one pinhole.

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