JP2014215406A - Imaging device, illuminating device, and microscope device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the resolution of a stereoscopic photographed image with a simple configuration.SOLUTION: An imaging device includes: a pair of aperture stops through which light beams with the light intensity according to the aperture pass; a lens on which a pair of light beams each passed through the pair of aperture stops and then reflected on an observation target object or passed through the observation target object made incident, and collects the pair of light beams; and a pair of light receiving elements that receive each of the collected pair of light beams, where one light receiving element of the pair of light receiving elements outputs pixel signals constituting one of a pair of photographed images having parallax to display a stereoscopic photographed image of the observation target object, and the other light receiving element of the pair of light receiving elements in the row direction outputs pixel signals constituting the other of the pair of photographed images, and thereby the lens has deeper focal depth, and the pair of photographed images have the improved resolution.

Description

  The present invention relates to an imaging device that captures a pair of captured images for displaying a stereoscopic image of an object to be observed, an illumination device that outputs a light beam that irradiates or transmits the object, and a microscope apparatus that includes these devices.

  There is known a microscope apparatus that displays a magnified image of an observation object as a three-dimensional image. Such a microscope apparatus captures an enlarged image of an object to be observed by an objective lens with an image sensor, and displays a stereoscopic image on a display screen. The imaging device used here has a configuration for capturing a pair of captured images having parallax for displaying a stereoscopic captured image. Specifically, the imaging device includes a pair of light receiving elements that form a pair on the left and right for each microlens arranged in a matrix. The light from the observation object that has passed through the microlens forms an image on the light receiving surface of the light receiving element pair. The light receiving element pair corresponds to a pixel pair constituting a picked-up image pair, and a pixel signal that forms a picked-up image for the left eye from the light receiving element for the left eye and a right eye from the light receiving element for the right eye. Is output.

  By the way, the microscope apparatus has an illumination device as an illumination system and an imaging optical system. The illuminating device generates and outputs a light beam that irradiates or transmits the surface of the object to be observed by a light source or an aperture stop. The imaging optical system includes an imaging lens that collects a light beam reflected on the surface of the object to be observed or transmitted through the object to be observed, and an imaging element as described above that images an image formed by the condensed light beam. . As a means for improving the resolution of the stereoscopic image displayed by the captured image pair and improving the accuracy of the stereoscopic measurement, the light beam reflected by the observation object or transmitted through the observation object is entered in the imaging optical system. An example of providing an aperture stop for narrowing is described in Patent Document 1.

JP 11-133309 A

  The objective of this invention is providing the imaging device etc. which can improve the precision of three-dimensional measurement with a simple structure.

  In order to solve the above problems, an imaging apparatus according to one aspect of the present invention is configured to pass an aperture stop pair that transmits a light beam having a light amount corresponding to an opening, and then reflected by the object to be observed after passing through the aperture stop pair. Alternatively, a pair of light beams that have passed through the object to be observed are incident and a lens that collects each light beam and a light receiving element pair that receives each of the collected light beam pairs, and one of the light receiving element pairs. Outputs a pixel signal that constitutes one of a pair of captured images having parallax for displaying a stereoscopic image of the object to be observed, and the other light receiving element in the row direction of the light receiving element pair is It has the light receiving element pair which outputs the pixel signal which comprises the other of the captured image pairs.

In a preferred aspect, when the width of each aperture stop in the direction in which the aperture stop pairs are arranged is d1 and the distance between the aperture stop pairs is d2, d1 and d2 satisfy the following relationship.
1/8 (d1 + d2) ≤d1≤1 / 2 (d1 + d2)
Further, it is preferable that the aperture stop pair and the entrance pupil of the lens have a conjugate relationship. The direction in which the aperture stop pairs are arranged and the direction in which the light receiving element pairs are arranged preferably coincide with each other.

  Another aspect of the present invention is an illumination device that includes an aperture stop pair and a light source that generates a light beam that passes through the aperture stop pair, and outputs the light beam pair that is incident on the imaging device.

  Still another aspect of the present invention is a microscope apparatus including the imaging device, the illumination device, and a display device that displays the stereoscopic captured image.

  According to the present invention, it is possible to improve the accuracy of three-dimensional measurement with a simple configuration.

It is a figure explaining the schematic structure of the imaging device in this embodiment. It is a block diagram which shows the structure of a process part. It is a figure which shows the example of an aperture stop pair. It is a block diagram of an image pick-up element principal part. It is a figure explaining the light beam pair which passes an aperture stop pair. It is a figure which shows the structure of 1st Example. It is a figure which shows the structure of 2nd Example. It is a figure which shows the aperture stop pair of 3rd Example. It is a figure which shows the example of an aperture stop pair.

  Embodiments of the present invention will be described below.

  FIG. 1 is a diagram illustrating a schematic configuration of an imaging apparatus according to the present embodiment. The imaging device 1 includes an illumination device 10 and an imaging optical system 12.

  The illumination device 10 includes a light source 102, a pair of aperture stops 104L and 104R, and a condenser lens 106. The light source 102 is composed of, for example, an LED (Light Emitting Diode), a halogen fiber, or the like. The light source 102 can be in the form of a surface light source, a point light source, a line light source, or the like. The aperture stop pairs 104L and 104R are provided to be separated from each other in the left-right direction with respect to the object to be observed 108, and allow a light flux having a light amount corresponding to each opening to pass therethrough. The light emitted from the light source 102 has a light beam 120L on the left side of the optical axis 100 in the Z-axis direction and a light beam 120R on the right side of the optical axis 100 in FIG. The left and right light beam pairs 120L and 120R are narrowed down to the light beam pairs 122L and 122R by the aperture stop pairs 104L and 104R, respectively. Then, the light flux pairs 122L and 122R are condensed by the condenser lens 106 and irradiate the object 108 to be observed. Here, the light beam pairs 122L and 122R pass through the object to be observed 108 and enter the imaging optical system 12. Note that the light beam pairs 120L and 120R may be reflected by the observation surface of the observation object 108, and the reflected light beam pairs 122L and 122R may be bent and incident on the imaging optical system 12.

  The imaging optical system 12 includes an imaging lens 110 and an imaging element 112. The imaging lens 110 collects the light flux pairs 122L and 122R and makes the light flux pairs 122L and 122R enter the imaging element 112.

  The image sensor 112 captures a captured image pair having parallax of the observation object 108. Each pair of captured images consists of pixels arranged in a matrix (in FIG. 1, the X-axis direction is the row direction and the Y-axis direction is the column direction). The number of pixels constituting one frame of the captured image is, for example, 640 × 480 pixels to 4000 × 11000 pixels (however, the number of pixels and the aspect ratio of one frame may not be limited to this numerical range). As a configuration for capturing such a captured image pair, the image sensor 112 includes a microlens 114 and light receiving element pairs 116L and 116R.

  The microlens 114 is, for example, a spherical lens having a pointed bent surface. The microlenses 114 are arranged in a matrix to form a lens array. The microlens 114 corresponds to each pixel of the captured image.

  The light receiving element pairs 116L and 116R are arranged adjacent to each other in the row direction for each microlens 114. That is, the direction in which the aperture stop pairs 104L and 104R are aligned with the direction in which the light receiving element pairs 116L and 116R are aligned. By doing so, the light receiving element 116L receives the light beam 120L and outputs a pixel signal forming a left-eye captured image, and the light receiving element 116R receives the light beam 120R and forms a right-eye captured image. The pixel signal to be output is output. The pixel signal is taken into the processing unit 113.

  In a preferred embodiment, the aperture stop pairs 104L and 104R and the entrance pupil of the imaging lens 110 are in a conjugate relationship.

  FIG. 2 is a block diagram illustrating a configuration of the processing unit 113. The processing unit 113 includes an image processing unit 22, a control unit 24, a storage unit 26, a display unit 28, and a bus 29. The image processing unit 22, the control unit 24, the storage unit 26, the display unit 28, and the image sensor 112 are connected to the bus 29 and configured to be able to transmit and receive various signals to and from each other.

  The image processing unit 22 performs predetermined image processing such as color, luminance correction, and distortion correction, and compression / decompression of data on captured image data including pixel signals for one frame sent from the image sensor 112. For example, the image processing unit 22 performs image processing on captured image data for each frame. The image processing unit 22 is a processor such as a DSP (Digital Signal Processor) or an ASIC (Application Specific Integrated Circuit).

  The storage unit 26 is a frame memory that stores captured image data before and / or after image processing. The storage unit 26 is, for example, an SRAM (Static Random Access Memory) or a DRAM (Dynamic RAM). Alternatively, the storage unit 26 may include a device for reading and writing data to various storage media such as a hard disk and a portable flash memory.

  The display unit 28 is a display device that displays a stereoscopic image based on the captured image data. The display unit 28 includes, for example, an LCD (Liquid Crystal Display) including a polarizing filter corresponding to the parallax between the left and right eyes and a control circuit thereof. The display unit 28 displays left and right captured image data having parallax, and displays a stereoscopic image that allows the user to perceive a stereoscopic effect.

  The control unit 24 sends control signals to the image sensor 112, the image processing unit 22, the storage unit 26, and the display unit 28, and integrally controls these operations. The control unit 24 is a microcomputer, for example.

  FIG. 3 is a diagram illustrating the aperture stop pair 104L and 104R.

  In FIG. 3A, a pair of circular aperture stops 104L and 104R is, for example, on one stop plate 104B in the X-axis direction (that is, in the left-right direction of the object 18 in FIG. And in the row direction in the arrangement of the light receiving element pairs 116L and 116R). The sizes of the aperture stop pairs 104L and 104R (diameters d1 and d3 of the opening) are set according to the aperture value of the imaging lens 110. By switching the plurality of aperture plates 104B having the aperture diaphragm pairs 104L and 104R having different sizes in a turret manner, the sizes of the aperture diaphragm pairs 104L and 104R can be switched in stages.

  In FIG. 3B, elliptic aperture stop pairs 104L and 104R are provided on the stop plate 104B. The width (minor axis) in the row direction and the length (major axis) in the Y-axis direction of each of the aperture stop pairs 104L and 104R are set according to the aperture value of the imaging lens 110, and the aperture stop pairs 104L having a plurality of sizes. , 104R can be replaced with a turret type.

  The aperture stop can have various shapes other than the circular shape as shown in FIG. 3A and the elliptical shape as shown in FIG.

  In FIG. 3C, circular aperture stop pairs 104L and 104R are provided on the stop plate pairs 114L and 114R, respectively. The diameters of the aperture stop pairs 104L and 104R are set according to the aperture value of the imaging lens 110. In the example of FIG. 3C, the size of the aperture stop pair 104L, 104R can be adjusted by opening and closing the wing stop 32 by operating the adjustment lever pair 30L, 30R. The distance between the diaphragm plate pairs 114L and 114R can also be adjusted by the adjusting screw 33. With such a configuration, the width and interval of the aperture stop pair can be easily adjusted without switching the aperture plate.

  FIG. 4A is a configuration diagram in a plane (XY plane) perpendicular to the direction of the optical axis 100 of the main part of the image sensor 112. For each microlens 114 arranged in a matrix, a pair of light receiving elements 116L and 116R is provided adjacent to the row direction (X-axis direction). The light receiving element 116R outputs, for example, a pixel signal that forms a captured image for the right eye among the pair of captured images having parallax for displaying the stereoscopic image of the damage observation object 18, and the light receiving element 116L on the other side. Outputs a pixel signal that constitutes a captured image for the left eye.

  FIG. 4B is a cross-sectional view taken along the optical axis 100 (Z-axis direction) of the main part of the image sensor 112. A pair of light beams 122 </ b> L and 122 </ b> R that are respectively restricted by the aperture stop pairs 104 </ b> L and 104 </ b> R and transmitted through the object 108 or reflected by the object 108 are incident on the image sensor 112 through the image pickup lens 110. The light beam pairs 122L and 122R pass through the objective lens 110 through the entrance pupil 43 and the exit pupil 44. The light beam pairs 122L and 122R are collected by the microlens 114, and light having a wavelength corresponding to the color of the color filter 46 reaches the light receiving element pairs 116L and 116R. Thus, an image of the object to be observed is formed on one of the light receiving element pairs 116L and 116R by any one of R, G, and B light. The light receiving element pairs 116L and 116R are, for example, CMOS or CCD photodiodes.

  FIG. 5 is a diagram for explaining the light beam pairs 122L and 122R passing through the aperture stop pairs 114L and 114R. 5A to 5C schematically show the exit pupil image 110a of the imaging lens 110 for each of the light receiving element pairs 116L and 116R.

FIG. 5A shows light receiving regions 122L ′ and 122R ′ by light beam pairs 122L and 122R in the light receiving element pairs 116L and 116R. The light beam pairs 120L and 120R generated by the light source 102 are stopped by the aperture stop pairs 114L and 114R, so that light receiving regions 122L ′ and 122R ′ are formed in a part of the exit pupil image 110a. Further, FIG. 5A shows the centers of gravity 124L and 124R of the light receiving regions 122L ′ and 122R ′. The centers of gravity 124L and 124R are points g that satisfy the following [Expression 1]. In the following formula, D is the outer diameter of the opening.
[Formula 1]

  FIG. 5B shows, as a comparative example, light receiving regions of the light receiving element pairs 116L and 116R when the aperture stop pairs 104L and 104R are not used, that is, light receiving regions 120L ′ by the light beam pairs 120L and 120R generated by the light source 102, 120R ′ is shown. Then, the centers of gravity 125L and 125R of the light receiving regions 120L ′ and 120R ′ are shown. In FIG. 5B, the light receiving areas 120L ′ and 120R ′ constitute the entire exit pupil image 110a.

  As shown in FIGS. 5A and 5B, the left and right light beam pairs 120L and 120R are narrowed down to the light beam pairs 122L and 122R by using the aperture stop pairs 104L and 104R. By doing so, the distance Δd50 between the centroids 124L and 124R of the light beam pairs 122L and 122R can be made larger than the distance Δd52 between the centroids 125L and 125R of the light beam pairs 120L and 120R. The distance Δd50 between the centroids 124L and 124R of the light beam pairs 122L and 122R is preferably formed to be the farthest in the outer periphery of the exit pupil image 110a.

  The light beam pair 120L, 120R generated by the light source 102 is narrowed down to the light beam pair 122L, 122R by the aperture stop pair 104L, 104R, and the following operational effects are obtained. First, the depth of focus of the imaging lens 110 can be increased by the diffraction phenomenon. When the depth of focus becomes deeper, a larger amount of information before and after the in-focus position can be acquired, so that the stereoscopic effect of the stereoscopic image displayed by the captured image pair increases. Second, the parallax of the captured image pair can be increased. The distance between the centers of gravity of the light beam pairs is proportional to the parallax, and as shown in FIGS. 5A and 5B, the distance between the centers of gravity is larger when the aperture stop pairs 104L and 104R are not used than when they are not used. Since it can, parallax becomes large. By doing so, the stereoscopic effect of the stereoscopic image obtained by the captured image pair is increased.

  The shape of the aperture stop is not limited to a circle, and various shapes are possible. For example, when the aperture is elliptical as shown in FIG. 3B, the light receiving regions 122L ′ and 122R ′ of the light beam pairs 120L and 120R are shown in FIG. 5C. Also in this case, the distance Δd53 between the centroids 124L and 124R of the light beam pairs 122L and 122R can be made larger than the distance Δd52 between the centroids 125L and 125R of the light beam pairs 120L and 120R, and the above-described effects can be obtained. .

Next, examples of the present embodiment will be shown.
[First embodiment]
The first embodiment relates to a case where the imaging apparatus is used in a transmission microscope. FIG. 6 shows the configuration of the first embodiment. The same reference numerals are given to the same components as those in FIG. The imaging device 6 used in the transmission microscope includes an illumination device 10 ′, an imaging optical system 12 ′, and a processing unit 113.

  The illumination device 10 ′ includes a light source 102, a window lens 62 that guides light generated by the light source 102 to the aperture stop pairs 104L and 104R, aperture stop pairs 104L and 104R that pass the light beam pairs 122L and 122R, and a light beam pair 122L, And condenser lens 64 for condensing and outputting 122R.

  The light beam pairs 122L and 122R output from the illumination device 10 ′ are transmitted through the object to be observed 108 and enter the objective lens 66 of the imaging optical system 12 ′. The imaging optical system 12 'includes an objective lens 66, an imaging lens 110 that refracts a pair of light beams 122L and 122R that has passed through the objective lens, a microlens 114, and a pair of light receiving elements 116L and 116R. And an image sensor 112 that captures a pair of captured images with the light flux pairs 122L and 122R that have passed.

  In the first embodiment, the imaging device 6 can be configured by additionally providing a pair of aperture stops 104L and 104R in a normal transmission microscope illumination device. For example, when an aperture stop is provided in the imaging scholarly system 12a, it is necessary to disassemble and reconfigure the objective lens and the like. However, the transmission microscope 6 of the first embodiment can be configured more easily. Therefore, it is possible to improve the resolution of the stereoscopic image with a simple configuration.

[Second Embodiment]
The second embodiment relates to a case where the imaging apparatus is used for a reflection microscope. FIG. 7 shows the configuration of the second embodiment. The same components as those in FIGS. 1 and 6 are denoted by the same reference numerals. The imaging device 7 used for the reflection microscope includes an illumination device 10 ″, an imaging optical system 12 ″, and a processing unit 113. The illuminating device 10 ″ includes a light source 102, a window lens 62 that guides light generated by the light source 102 to the aperture stop pairs 104L and 104R, an aperture stop pair 104L and 104R that passes the light beam pairs 122L and 122R, and a light beam pair 122L. , 122R, the condenser lens 64 for condensing the light beam pairs 122L and 122R, and the mirror 70 for guiding the condensed light beam pairs 122L and 122R to the objective lens.

  The light beam pairs 122L and 122R output from the illuminating device 10 ″ irradiate the object 108 through the objective lens 66 of the imaging optical system 12 ″, and are reflected on the object lens 66 reflected by the object 108. Incident.

  The imaging optical system 12b includes an objective lens 66, an imaging lens 110 that refracts a pair of light beams 122L and 122R that has passed through the objective lens 66, a microlens 114, and a pair of light receiving elements 116L and 116R. And an image sensor 112 that captures a pair of captured images with the light flux pairs 122L and 122R that have passed.

  The image pickup apparatus 7 of the second embodiment can also be configured by additionally providing a pair of aperture stops 104L and 104R in a normal reflection microscope illumination device. In particular, by providing the aperture stop pair 104L, 104R between the light source 102 and the mirror 70, it can be configured more easily than the case where it is provided in other parts. Therefore, it is possible to improve the resolution of the stereoscopic image with a simple configuration.

[Third embodiment]
The third example is an example in which a Fresnel lens is used as the condenser lens 106 in the configuration of FIG. Further, as shown in FIG. 8, the third embodiment uses elliptical aperture stop pairs 104L and 104R. Here, in the aperture stop pairs 104L and 104R, the minor axis in the row direction (X-axis direction) is d1 and d3, the major axis in the column direction (Y-axis direction) is d4, and the interval between the aperture diaphragm pairs 104L and 104R is d2. Each dimension is as follows.
d1: 8 mm
d2: 4.8 mm
d3: 8 mm
d4: 12 mm
Also,
Focal length of photographic lens 110: 25 mm
F-number of taking lens 110: 1.2
And

At this time, the aperture stop pair 104L and 104R are in a conjugate position with the entrance pupil of the photographing lens. Here, it is preferable that the following [Formula 2] holds.
[Formula 2] 1/8 (d1 + d2) ≦ d1 ≦ 1/2 (d1 + d2)
In the above [Expression 2], if d1 is less than the lower limit of the above [Expression 2], the left and right parallaxes become too small to obtain a stereoscopic effect. On the other hand, if d1 exceeds the upper limit, the image will be dark because it protrudes from the pupil region. Therefore, in a preferred embodiment, when d1 is within the range satisfying the above condition, the light emitted from the light source 100 passes through the aperture stop pair 104L and 104R, and 122L and 122R irradiate the object 108 from different angles, respectively. Is done. Then, the light flux pairs 122L and 122R transmitted through the object 108 are incident on the photographing lens 110. At this time, an image of the observation object 108 is formed by the photographing lens 110 in the vicinity of the light receiving surfaces of the light receiving element pairs 116L and 116R with a sufficient light receiving amount and area.

[Reference example]
FIG. 9 shows an example of an aperture stop pair. Tables 90 and 92 in FIG. 9 show the magnification and aperture value of the objective lens when the widths d1 and d3 in the row direction of the aperture stop pairs 104L and 104R and the distance d2 between the aperture stop pairs 104L and 104R are changed. NA), the correspondence relationship with the focal length.
In the tables 90 and 92, for example, when d1 (d3) = “1.8” and d2 = “2.4”, d1 satisfies the above [Equation 2], and the aperture stop pairs 104L and 104R correspond to the photographing lenses. The position is conjugate with the entrance pupil.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each means, each step, etc. can be rearranged so that there is no logical contradiction, and a plurality of means, steps, etc. can be combined or divided into one. .

1: Imaging device 10: Illuminating device 104: Aperture stop 110: Imaging lens 112: Imaging device 116L, 116R: Light receiving device

Claims (6)

A pair of aperture stops that allow a light flux corresponding to the aperture to pass;
After passing through each of the aperture stop pairs, a light beam pair reflected by the object to be observed or transmitted through the object to be observed is incident, and a lens that collects each light beam,
A pair of light receiving elements that respectively receive the collected light flux pairs, wherein one of the light receiving element pairs has a parallax for displaying a stereoscopic image of the object to be observed. A light receiving element pair that outputs a pixel signal that constitutes one of the light receiving element pairs, and that the other light receiving element in the row direction of the light receiving element pair outputs a pixel signal that constitutes the other of the captured image pairs;
An imaging apparatus having In claim 1,
The width of each aperture stop in the direction in which the aperture stop pairs are arranged is d1,
When the distance between the aperture stop pair is d2,
1/8 (d1 + d2) ≤d1≤1 / 2 (d1 + d2)
An imaging device characterized by being: In claim 1 or 2,
An imaging apparatus, wherein the aperture stop pair and the entrance pupil of the lens are in a conjugate relationship.   4. The imaging apparatus according to claim 1, wherein a direction in which the aperture stop pair is aligned and a direction in which the light receiving element pair is aligned. An aperture stop pair according to claim 1 and a light source that generates a light beam that passes through the aperture stop pair,
An illuminating device that outputs the light flux pair to be incident on the imaging device according to claim 1. An imaging device according to claim 1;
A lighting device according to claim 5;
A microscope apparatus comprising: a display device that displays the stereoscopic image.

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