KR20220134356A - Lightfield measuring device for 3d display - Google Patents

Abstract

A light field measuring instrument comprises: a head comprising a pin hole and light-receiving the light rays passing through the pin hole; an imaging element that image-forms the light-received light rays at an upper part of the head; a fixing device that fixes the head and enabling a position of the pin hole to be calculated, wherein the head comprises a parabolic screen having a pin hole formed in a center part and having a predetermined curvature. Accordingly, the present invention enables to supplement a limitation for which is difficult to find a lens having a large numerical aperture, and to increase a range of a measurable wave number vector. Therefore, the present invention is capable of enabling an optical system to be simply designed.

Description

Lightfield Measuring Instrument for 3D Display

The present invention relates to a device for measuring a light field of a three-dimensional display, and more particularly, to a device for measuring a light field of a light wave.

Since the voxel, which is the smallest unit in 3D space, plays an important role in evaluating the quality of a 3D image, an optical system that receives the maximum amount of light from the voxel is required to measure the voxel. One of the methods is to measure a wavenumber vector for one viewpoint of a 3D image.

As shown in FIG. 1, the conventional wavenumber vector measurement forms a frequency domain through several Fourier lenses and is recorded in a CCD (Charge Coupled Device) through a lens and an aperture. Because of this method, the measurement range of the wavenumber vector is determined according to the numerical aperture (NA) of the lens used.

However, in general, an optical system based on a refraction phenomenon such as a lens has a problem that geometric aberration and chromatic aberration increase when the numerical aperture is high.

Therefore, the optical system is composed of several lenses, but in this case, the optical system becomes long and complicated.

Accordingly, there is a need for a method capable of expanding the measurement range of the wave number vector without being limited to the numerical aperture and the number of lenses.

Republic of Korea No. 10-0986044

The present invention has been devised to solve the above problems, and an object of the present invention is to compensate for the limitation that it is difficult to find a lens with a large numerical aperture and to increase the range of measurable wavenumber vectors. To provide a measuring instrument.

A light field measuring device according to an embodiment of the present invention for achieving the above object includes a head including a pin hole for receiving a light beam passing through the pin hole; an imaging device that forms an image of the received light beam from an upper portion of the head; and a fixing device for fixing the head and calculating the position of the pinhole, wherein the head includes: a parabolic screen having the pinhole formed in the center and having a predetermined curvature; includes

And the head, located above the parabolic screen may further include a parabolic mirror for reflecting the light beam passing through the pinhole in a predetermined path.

In addition, the head may further include a wide-angle lens for receiving the light rays scattered by the parabolic screen after being reflected by the parabolic mirror.

And the parabolic mirror is formed to have the same curvature as the curvature of the parabolic screen, and a hole into which a part of the wide-angle lens is inserted may be formed in the center.

In addition, the fixing device, a frame provided in a predetermined shape; a height adjustment unit fixed to the upper and lower part of the frame to adjust the height; and a two-axis stage positioned below the height adjustment unit to fix the head but move in a predetermined direction.

Here, the two-axis stage includes: a first rail positioned under the height adjustment unit and provided with a rail groove formed in a predetermined longitudinal direction at the lower end; a second rail coupled to the rail groove of the first rail and moving along the rail groove of the first rail, formed at a lower end in a longitudinal direction perpendicular to the longitudinal direction of the first rail and provided with a rail groove at the lower end; and a head fixing part that fixes the head and is coupled to the rail groove of the second rail and moves along the rail groove of the second rail.

In addition, the head fixing part, a fixing member coupled to the rail groove of the second rail; a first disk coupled to the fixing member and into which a lower portion of the wide-angle lens is inserted; A pair of second discs positioned below the first disc to couple and fix the parabolic screen and the parabolic mirror so that a portion of the parabolic screen and an outer surface of the parabolic mirror are exposed; and a spacer member positioned between the first disc and the second disc so that the first disc and the second disc are spaced apart by a predetermined distance and coupled thereto.

The head fixing unit may further include a lens fixing member coupled to the upper surface of the first disk and provided to surround a portion of an outer circumferential surface of the wide-angle lens to prevent separation of the wide-angle lens.

According to the above-described aspect of the present invention, by providing an optical system having a high numerical aperture, the optical system can be simply designed and a measurement range of the voxel wavenumber vector can be expanded.

1 is a view for explaining a method of measuring a light field using a conventional Fourier lens,
2 is a view for explaining a light field measuring mechanism according to an embodiment of the present invention,
3 is a view for explaining a state of measuring a light field through a head according to an embodiment of the present invention;
4 is a view for explaining a head according to an embodiment of the present invention,
5 and 6 are views for explaining a parabolic screen and a parabolic mirror according to an embodiment of the present invention,
7 is a view for explaining a result measured by a light field measuring device according to an embodiment of the present invention,
8 is a view for explaining a method of converting a result value measured by a light field measuring device into data according to an embodiment of the present invention;
9 is a graph for explaining a result measured by a light field measuring device according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0016] Reference is made to the accompanying drawings, which show by way of illustration specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein with respect to one embodiment may be implemented in other embodiments without departing from the spirit and scope of the invention. In addition, it should be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the present invention. Accordingly, the detailed description set forth below is not intended to be taken in a limiting sense, and the scope of the present invention, if properly described, is limited only by the appended claims, along with all scope equivalents to those claimed. Like reference numerals in the drawings refer to the same or similar functions throughout the various aspects.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings.

2 is a view for explaining a light field measuring mechanism according to an embodiment of the present invention.

The light field measuring device according to the present embodiment is provided to have a simple optical structure while widening the wavenumber measurement range of voxels through a high numerical aperture to measure the light field of a 3D display. The head 100 and the image pickup device 200 ), and a fixing device 300 .

The head 100 is for specifying the light quantity distribution according to the wavenumber vector of the light beam propagating from the voxel. The head 100 receives the light beam so that the received light beam is imaged on the image pickup device 200. Parabolic screen 110, parabolic mirror (120), has a structure including a wide-angle lens (130).

First, the parabolic screen 110 passes the light beam, causes the passed light beam to be scattered, and allows the scattered light beam to be received by the wide-angle lens 130 . To this end, the parabolic screen 110 is formed with a pin hole (Pin hole) 111 for passing the light beam in the center.

And the parabolic screen 110 has a predetermined curvature for scattering of light, which will be described later in more detail with reference to FIGS. 3 to 6 .

On the other hand, the parabolic mirror 120 is provided to reflect the light beam passing through the pinhole to a predetermined path, that is, the parabolic screen 110 and is located on the parabolic screen 110 . The curvature of the parabolic mirror 120 is formed to be the same as the curvature of the parabolic screen 110 , and a hole of a certain size is provided in the center so that a part of the wide-angle lens 130 is inserted.

The wide-angle lens 130 receives the light scattered by the parabolic screen 110 after being reflected by the parabolic mirror 120, and the lens portion located at the lowest end is inserted into the hole of the parabolic mirror 120, so that the parabolic mirror 120. can be combined with In addition, the wide-angle lens 130 is provided to adjust the brightness including the aperture 135 .

On the other hand, the imaging device 200 is to image the light beam received by the wide-angle lens 130 to measure a light quantity distribution different from the wavenumber vector of the light beam passing through the pinhole 111 . The imaging device 200 may be coupled to an upper portion of the head 100 , that is, a part of the wide-angle lens 130 .

In the present embodiment, it is assumed that the head 100 and the imaging device 200 are provided, respectively, but this is only an example for convenience of description, and the head 100 may be provided including the imaging device 200 . have.

On the other hand, the fixing device 300 allows the positions of the head 100 and the imaging device 200 to move while fixing the head 100 and the imaging device 200 so that they are positioned on the same line, and the position of the pinhole 111 is fixed. Calculate. The fixing device 300 is provided to include a frame 310 , a height adjustment unit 320 , and a two-axis stage 330 .

The frame 310 is to fix the height adjustment unit 320 and the two-axis stage 330, and has a predetermined shape through a combination of a plurality of supports as shown in FIG. 2, and the frame 310 is the head 100 ) and the height adjustment unit 320 and the two-axis stage 330 for fixing and moving the image pickup device 200 may be fixed to the ground through bolt coupling in order to prevent shaking or separation due to an external shock or the like. Accordingly, the frame 310 may be provided with a plurality of fasteners 311 for bolt coupling to the support in contact with the ground among the plurality of supports.

On the other hand, the height adjustment unit 320 is fixed to the upper lower portion of the frame 310 , and the lower portion is coupled with the second axis stage 330 to adjust the height of the second axis stage, such a height adjustment unit 320 . may be provided with a lab jack (Laboratory jack) as shown in FIG. 2 to adjust the height, that is, the Z-axis.

In addition, the two-axis stage 330 enables the fixed head 100 and the imaging device 200 to move left and right or up and down at a predetermined height while fixing the head 100 and the imaging device 200 . To this end, the two-axis stage 330 is positioned below the height adjustment unit 320 and includes a first rail 331 , a second rail 333 and a head fixing unit 335 .

First, the first rail 331 is coupled to the lower portion of the height adjustment unit 320 , and allows the second rail 333 to move in a predetermined longitudinal direction. To this end, a rail groove is formed in a predetermined longitudinal direction at the lower end of the first rail 331 . Here, the preset longitudinal direction refers to the horizontal, y-axis direction on a virtual plane parallel to the ground including the Z-axis coordinates of the pinhole 111 located at a predetermined height by the height adjustment unit 320 . indicates the direction in which the

On the other hand, the second rail 333 is coupled to the rail groove formed in the lower portion of the first rail 331 and moves along the longitudinal direction of the second rail 333, but the head fixing part 335 can move in a predetermined direction. let it be To this end, the lower end of the second rail 333 is formed in a longitudinal direction perpendicular to the longitudinal direction of the first rail 331, and a rail groove is formed at the lower end. Here, the orthogonal longitudinal direction refers to a direction in which the head 100 is moved vertically, that is, in the x-axis direction on an imaginary plane parallel to the ground including the Z-axis coordinate of the pinhole 111 located at a certain height.

On the other hand, the head fixing part 335 fixes the head 100 and the imaging device 200, and the second rail 333 in order to allow the fixed head 100 and the imaging device 200 to move in a predetermined direction. It is coupled to the rail groove and can move along the rail groove of the second rail 333 . In addition, the head fixing unit 335 is fixed to the fixing member 3351, the first disk 3353, the second disk 3355, the spacer member 3357 and the lens for fixing the head 100 and the imaging device 200. member 3351 is included.

The fixing member 3351 fixes the first disk 3353, the second disk 3355 and the spacer 3357, and the upper end is coupled to the rail groove of the second rail 333 as shown in the second rail ( 333) along the rail groove.

The first disk 3353 has a hole formed in the center so that a part of the lower part of the wide-angle lens 130 is inserted so that the head 100 can be fixed to the head fixing unit 335 . And the first disk 3353 is coupled to the lower end of the fixing member (3351).

And the second disk 3355 is located at the lower portion of the first disk 3353, but is fixed to the first disk 3353 in a state spaced apart from the first disk 3353 by a spacer member 3357 by a predetermined distance. And the second disc 3355 is provided as a pair for the parabolic screen 110 and the parabolic mirror 120 to be coupled and fixed, for this purpose. One second disk 3355 is in contact with a portion of the outer surface of the parabolic mirror 120, and the other second disk 3355 is in contact with a portion of the outer surface of the parabolic screen 110, so that the parabolic screen 110 and the parabolic mirror ( 120) to be interlocked with each other.

More specifically, as shown in Fig. 4, the parabolic screen 110 and the parabolic mirror 120 according to this embodiment are formed with a portion protruding from the periphery by a certain width, and each of the pair of second disks 3355 is By pressing the extended protruding part from the top and bottom, the parabolic screen 110 and the parabolic mirror 120 are combined to form a parabolic mirror.

And each of the pair of second disks 3355 has a hole formed in the center so that a part of the outer surface of the parabolic screen 110 and the parabolic mirror 120 is exposed, through which the center height of the parabolic mirror 120 is deformed or curvatured This change can be prevented.

On the other hand, the spacer member 3357 is positioned between the first disk 3353 and the second disk 3355 so that the first disk 3353 and the second disk 3355 are fixed in a state spaced apart by a predetermined distance.

At this time, the fixing member 3351, the first disc 3353, a pair of the second disc 3355 and the spacer 3357 may be coupled by various coupling methods including bolt coupling.

In addition, the head fixing unit 335 according to the present embodiment may further include a lens fixing member 3351 as shown. The lens fixing member 3351 is coupled to the upper surface of the first circular plate 3353 and is provided to surround a portion of the outer peripheral surface of the wide-angle lens 130 , thereby preventing the wide-angle lens 130 from being separated.

Therefore, in the light field measuring device according to this embodiment, the head 100 and the imaging device 200 are fixed to be positioned on the same line through the head fixing unit 335, and the head fixing unit ( 335) can be moved, and the coordinates of the pinhole 111 through which the light beam passes can be scanned because the movement coordinates can be calculated through the two-axis stage 330.

Meanwhile, FIG. 3 is a view for explaining a state of measuring a light field through the head 100 according to an embodiment of the present invention, and FIG. 4 is a view for explaining the head 100 according to an embodiment of the present invention 5 and 6 are views for explaining a parabolic screen 110 and a parabolic mirror 120 according to an embodiment of the present invention, and FIG. 7 is a light field measuring instrument according to an embodiment of the present invention. is a view for explaining a result measured through , and FIG. 8 is a view for explaining a method of converting a result value measured through a light field measuring device into data according to an embodiment of the present invention, and FIG. 9 is , is a graph for explaining the results measured by the light field measuring device according to an embodiment of the present invention.

As described above, the head 100 according to the present embodiment is for specifying a light quantity distribution according to a wavenumber vector of a light beam traveling from a voxel, and receives the light beam so that the received light beam is imaged on the imaging device 200 . In this regard, the same or overlapping content as described above in FIG. 2 will be omitted.

A voxel is a minimum unit in a 3D space, and plays an important role in evaluating the quality of a 3D image. Since the head 100 according to the present embodiment includes the parabolic screen 110 and the parabolic mirror 120 , it is possible to have a wider measurement range than the wavenumber vector measurement range of the conventional voxel.

As shown in FIG. 3 , the exaggeration in which light propagating from the voxel is received and formed is described. The light propagating from the voxel, that is, the light beam passes through the pinhole 111 , and the light beam passing through the pinhole 111 is a parabolic mirror 120 . ) by the parabolic screen 110 is reflected. Then, the reflected light beam is scattered by the parabolic screen 110 and then received by the wide-angle lens 130 , and the received light beam is imaged on the imaging device 200 . The measuring device according to the present embodiment can measure the amount of light according to the wavenumber vector of the light beam passing through the pinhole 111 through this process. To this end, the measuring device according to the present embodiment may communicate with a separate terminal in which a program for measuring the amount of light according to the wavenumber vector is stored.

는 포물면 거울(120)의 초점거리인

의 1/2가 된다. Meanwhile, since the curvature of the parabolic screen 110 and the parabolic mirror 120 according to this embodiment is formed to have the same curvature as shown in FIGS. 5 and 6 , the height of the center of the parabolic mirror 120 .

is the focal length of the parabolic mirror 120

becomes 1/2 of

을 이용하면 중심 높이인

가 일 때의 포물면 거울(120)의 반지름

은

로 산출될 수 있다. Therefore, the parabolic graph formula below is

Using , the center height is

The radius of the parabolic mirror 120 when is

silver

can be calculated as

At this time, the F-number (F/#) of the parabolic mirror 120, which is the ratio between the focal length and the diameter D of the parabolic mirror 120, has 0.3535 as shown below.

Therefore, it can be seen that the numerical aperture (NA) of the parabolic mirror 120 according to this embodiment has a high numerical aperture as follows.

That is, the parabolic mirror 120 according to the present embodiment provides the effect that the wavenumber vector measurement range of voxels can be wider through the high numerical aperture as described above.

은 K-벡터의 방향각인

(theta)와 아래와 같은 관계를 갖게 되며, 이를 통해 광각렌즈(130)에 대해 이미지 매핑을 할 수 있다. And with reference to FIGS. 7 and 8 , in the measuring device according to the present embodiment, a wavenumber vector of a voxel, that is, a K-vector is incident and is a position in an image obtained from the image pickup device 200 .

is the direction angle of the K-vector

(theta) has the following relationship, and through this, image mapping can be performed with respect to the wide-angle lens 130 .

은 number of pixels로 정의되고

는 pixel pitch로 정의된다. here

is defined as the number of pixels and

is defined as the pixel pitch.

As the incident angle of the wavenumber vector, that is, the K-vector, of the light beam passing through the pinhole 111 increases, it moves away from the center of the parabolic screen 110, and the imaging position on the image pickup device 200 also moves away from the center of the image pickup device 200. it can be seen that

As described above, in the measuring device according to the present embodiment, since a voxel having a specific wavenumber vector progressed from the voxel is located at a specific point on the parabolic screen 110, the obtained information is 2 containing the wavenumber vector information as shown in FIG. It can be plotted in a dimensional coordinate system. Through this, coordinate information of the voxel and the wavenumber vector constituting the voxel may be derived. In addition, by scanning a 3D image with the designed optical system, it can be utilized as a system for determining and evaluating the quality of the entire image.

In particular, as shown in FIG. 9, it can be seen that there are three points where K-vectors are gathered through the measuring device according to this embodiment. and the graph for the x-z plane.

[Table 1] below is a table showing the results measured by the measuring device according to the present embodiment. It is a comparison between the actual location of the LED of FIG. 9 and the coordinates where the K-vectors of the voxel measured through the measuring device are gathered. .

Real value(x,y,z)
(mm) Measured value(x,y,z)
(mm) Error (mm) ① (78, 132, 262) (79.07, 130.71, 260.15) 2.49 ② (150, 150, 235) (147.97, 149.33, 235.93) 2.33 ③ (223,167,251) (222.15, 168.54, 250.17) 1.94

As such, since the measuring device according to this embodiment receives light using the reflection optical system of the parabolic screen 110 and the parabolic mirror 120 instead of the lens, it is possible to implement a system having a simple optical structure while having a high numerical aperture. , has the advantage of being able to measure the light field in a wide wavenumber vector range.

In the above, various embodiments of the present invention have been illustrated and described, but the present invention is not limited to the specific embodiments described above, and it is common in the technical field to which the present invention pertains without departing from the gist of the present invention as claimed in the claims. Various modifications are possible by those having the knowledge of, of course, and these modifications should not be individually understood from the technical spirit or perspective of the present invention.

100: head 110: parabolic screen
111: pinhole 120: parabolic mirror
130: wide-angle lens 135: aperture
200: imaging device 300: fixing device
310: frame 311: fixture
320: height adjustment unit 330: 2-axis stage
331: first rail 333: second rail
335: head fixing part 3351: fixing member
3353: first disk 3355: second disk
3357: spacer member 3359: lens fixing member

Claims (8)

a head including a pin hole for receiving a light beam passing through the pin hole;
an imaging device that forms an image of the received light beam from an upper portion of the head; and
and a fixing device for fixing the head and calculating the position of the pinhole,
The head is
The pinhole is formed in the center, the parabolic screen having a predetermined curvature; A light field measuring instrument comprising a. According to claim 1,
The head is
Light field measuring instrument, which is located on the parabolic screen and further comprises a parabolic mirror for reflecting the light beam passing through the pinhole in a predetermined path. 3. The method of claim 2,
The head is
Light field measuring instrument, characterized in that it further comprises a wide-angle lens for receiving the light rays scattered by the parabolic screen after being reflected by the parabolic mirror. 4. The method of claim 3,
The parabolic mirror is
It is formed to have the same curvature as the curvature of the parabolic screen, and a light field measuring device, characterized in that a hole into which a part of the wide-angle lens is inserted is formed in the center. 4. The method of claim 3,
The fixing device is
a frame provided in a predetermined shape;
a height adjustment unit fixed to the upper and lower part of the frame to adjust the height; and
The light field measuring device, which is located under the height adjusting part and includes a two-axis stage fixed to the head but moving in a predetermined direction. 6. The method of claim 5,
The two-axis stage,
a first rail positioned under the height adjustment unit and provided with a rail groove formed at a lower end in a predetermined longitudinal direction;
a second rail coupled to the rail groove of the first rail and moving along the rail groove of the first rail, formed at a lower end in a longitudinal direction perpendicular to the longitudinal direction of the first rail and provided with a rail groove at the lower end; and
and a head fixing part that fixes the head and is coupled to the rail groove of the second rail and moves along the rail groove of the second rail. 7. The method of claim 6,
The head fixing unit,
a fixing member coupled to the rail groove of the second rail;
a first disk coupled to the fixing member and into which a lower portion of the wide-angle lens is inserted;
A pair of second discs positioned below the first disc to couple and fix the parabolic screen and the parabolic mirror so that a portion of the parabolic screen and an outer surface of the parabolic mirror are exposed; and
and a spacer member positioned between the first disk and the second disk so that the first disk and the second disk are spaced apart by a predetermined distance and coupled thereto. 8. The method of claim 7,
The head fixing unit,
and a lens fixing member coupled to the upper surface of the first disk and provided to surround a portion of an outer peripheral surface of the wide-angle lens to prevent separation of the wide-angle lens.

Images