JP2022160861A - Digital hologram signal processing device and digital hologram imaging and reproducing device - Google Patents

Abstract

To correctly obtain a feeling of depth such as the depth position, depth order, etc., of a subject and to compose an image of the subject together with an image picked up with a normal camera.SOLUTION: A digital hologram signal processing device comprises: in-focus/depth position information acquisition means 18A which acquires an in-focus image of a subject and depth position information on the in-focus image from a recomposed image of a digital hologram; reference image acquisition means 18B which adds respective obtained in-focus images to acquire a reference image B through computation for specifying an in-region in-focus image set at a desired depth position in a depth-of-field region; defocus image group acquisition means 18C which acquires a defocus image group Dd through computation for specifying an out-region in-focus image arranged at the desired depth position outside the depth-of-field region; and reference image/defocus image group addition means 18D which adds the obtained reference image B and the obtained defocus image group Dd to each other to obtain an incoherent response image.SELECTED DRAWING: Figure 4

Description

The present invention relates to a digital hologram signal processing device and a digital hologram imaging/reproducing device, and to a digital hologram signal processing device and a digital hologram signal processing device capable of creating a desired reconstructed image using either coherent light or incoherent light. The present invention relates to a hologram imaging/reproducing device.

In digital holography technology, a hologram that reflects the three-dimensional information of a subject is captured by an optoelectronic device such as an image sensor or a photodetector by utilizing the interference of light. Save to By displaying the digital hologram stored in this memory with a spatial light modulator, a three-dimensional image of an object observable with the naked eye can be reproduced. In addition, by performing diffraction propagation calculations on the digital hologram in the signal processing unit, it is possible to reconstruct a two-dimensional image at an arbitrary depth position. It is possible (see Non-Patent Document 1 below).

By using digital holography technology, it is possible to realize the above-mentioned useful functions such as stereoscopic imaging/display and refocusing. was essential. However, with the progress of incoherent digital holography technology, the problem of spatial coherence required for the light source has been alleviated, and it is now possible to capture digital holograms using incoherent light such as sunlight, fluorescence, and LEDs. , it has been shown that the above-described stereoscopic imaging/display and refocusing can be realized, and the application range of digital holography is steadily expanding (see Patent Documents 1 and 2 below).

Digital holography using a laser light (coherent light) as a light source (see Non-Patent Document 1 below) and incoherent digital holography using an incoherent light as a light source (see Patent Documents 1 and 2 below) are based on the coherence of the light source used. Although the length and configuration of the interference optical system for digital hologram production are different, the calculation of diffraction propagation used to reconstruct a two-dimensional image is common.In this case, Fresnel diffraction integration and angular spectrum method (or plane wave expansion) ) are commonly used. These diffraction calculations implicitly assume that the light has high temporal and spatial coherence, and the blurriness of the reconstructed image indicates the coherent light response.
Also in incoherent digital holography, although incoherent light is targeted at the time of imaging, the image at the time of reconstruction exhibits properties related to coherent light.
This coherent light response is essential for reconstructing three-dimensional information using wavefront information of light, and poses no problem when reproducing three-dimensional images.

Therefore, the blurred state of an image obtained by reconstructing a two-dimensional image in digital holography is completely different from the blurred state of a normal camera such as a single-lens reflex camera or a smartphone based on incoherent light. In other words, if a two-dimensional image is output by the above-described normal method using digital holography, which is a technology for capturing three-dimensional images, the user who has used a normal camera will experience blurring of the two-dimensional image in digital holography. The situation feels unnatural.

Furthermore, it is known that humans normally judge the depth of an object, the order of perspective in the depth direction, etc., based on the degree of blurring (magnitude of defocus) (see Non-Patent Documents 2 and 3 below). A conventional digital hologram imaging/reproducing apparatus cannot provide a correct sense of depth from a two-dimensional image. Further, inconsistency occurs when an image material is composed by synthesizing an image picked up by a digital hologram imaging/reproducing device with an image picked up by a normal camera, not a digital hologram imaging/reproducing device.

Japanese Patent Publication No. 2016-533542 Japanese Patent Application Laid-Open No. 2020-060709

Georges Nehmetallah and Partha P. Banerjee, "Applications of digital and analog holography in three-dimensional imaging", Advances in Optics and Photonics, (2012), vol. 4, pp. 472-553. Alex Paul Pentland, "A new sense for depth of field," IEEE Transactions on pattern analysis and machine intelligence, (1987), vol. 4, pp. 523-531. George Mather and David R R Smith, "Blur discrimination and its relation to blur-mediated depth perception," Perception, (2002), vol. 31, pp. 1211-1219.

When reconstructing a two-dimensional image by diffraction propagation calculation with conventional digital holography, the blurred state of the light distribution on the defocused plane, which is out of focus, shows the response of coherent light, and ringing and light singularities occur. There is a problem that it is not possible to obtain smooth blurring as in the case of using a normal camera.

In this way, in addition to the fact that the depth position of the subject and the depth sense of the depth order cannot be obtained correctly, it is not possible to synthesize the images captured by a normal camera. Furthermore, the amount of image blur in digital holography is determined by the distance between the imaging and reproducing device and the subject.

The present invention has been made to solve such a problem, and it is possible to obtain a correct sense of depth such as the depth position and depth order of a subject, and to synthesize it with an image captured by a normal camera. Further, it is an object of the present invention to provide a digital hologram signal processing device and a digital hologram imaging/reproducing device capable of easily adjusting the amount of image blur in digital holography.

The digital hologram signal processing device of the present invention is
A digital hologram signal processing device that performs signal processing for a digital hologram imaging and reproducing device that captures three-dimensional information of an object using light interference,
A focused image/depth for acquiring a desired number of focused images of a subject and information on the depth position of the focused images from the digital hologram reconstructed image obtained by the interference optical system of the digital hologram imaging/reproducing device. location information acquisition means;
The depth of field, the focal length of the lens, the focal length of the lens, and the depth of field are adjusted according to the depth position so that an in-focus image set at the desired depth position within the depth of field can be specified. a reference image obtaining means for obtaining a reference image by setting each element of the aperture diameter and the distance from the lens to the image plane, and adding together the obtained predetermined number of in-region focused images;
the focal length of the lens, the aperture diameter of the lens, the aperture diameter of the lens, and and each element of the distance from the lens to the image plane, and calculate the convolution integral of the intensity distribution of each out-of-area in-focus image obtained and the intensity distribution of the point spread function of the incoherent imaging system defocused image group obtaining means for obtaining a defocused image group by
Reference image/defocused image for obtaining an incoherent response image by adding the reference image obtained by the reference image obtaining means and the defocused image group obtained by the defocused image group obtaining means group addition means;
It is characterized by having

Further, the arithmetic processing for obtaining the reference image in the reference image obtaining means includes a total intensity distribution obtained by adding the intensity distribution of each of the focused images in the region obtained by changing the depth position. , and a convolution integral with the intensity distribution of the point spread function of the incoherent imaging system.

但し、前記レンズから被写体の合焦像までの距離をｚ_１、該レンズから像面までの距離をｚ_２、該レンズの焦点距離をｆとする。 Further, when performing the arithmetic processing related to the convolution integration of the combined intensity distribution and the intensity distribution of the point spread function of the incoherent imaging system, the following formula (A) is satisfied so that the It is preferable to set the parameters of the point spread function of the incoherent imaging system.

However, the distance from the lens to the in-focus image of the object is z ₁ , the distance from the lens to the image plane is z ₂ , and the focal length of the lens is f.

Further, the process of obtaining a desired number of focused images of the subject and the information on the depth position of the focused images in the focused image/depth position information acquisition means may be used to sharpen the reconstructed image of the digital hologram. It is preferable that the processing be performed based on the evaluation result of degree.

Further, the digital hologram imaging/reproducing apparatus of the present invention comprises: an imaging device; and an imaging optical system for forming a hologram image on the imaging device by causing interference between two systems of light, at least one of which carries object information. and the digital hologram signal processing device.

Further, the digital hologram imaging and reproducing apparatus has a coherent light source and an optical system of an interferometer for obtaining a digital hologram from the coherent light from the light source, and the optical system of the interferometer is provided in the digital hologram signal processing apparatus. Preferably, a memory for storing depth resolution is provided, and an optical system of a self-interferometer for obtaining a digital hologram by receiving incoherent light from an object is provided, and the self-interferometer is provided in the digital hologram signal processing device. It is also preferable to have a memory for storing the depth resolution of the optical system.

According to the digital hologram signal processing apparatus and the digital hologram imaging/reproducing apparatus of the present invention, the reference image obtained by adding together the in-focus images obtained by adjusting the reconstructed image located within the depth of field area, and the depth of field area. By adding a defocused image group consisting of each in-focus image obtained by adjusting the reconstructed image located outside the area, the blur characteristic of the image of the object existing at the defocused position is changed from the coherent response to the incoherent response. It is possible to arbitrarily control the amount of blur by converting and further changing the parameters of the point spread function of the incoherent imaging system.

As a result, it is possible to reconstruct a two-dimensional image showing a blurred state like a normal camera, even from data captured by digital holography technology. Furthermore, it is also possible to synthesize the image with an image captured by a normal camera.

In addition, it is possible to give different amounts of blur according to the depth position of the subject and to freely control the amount of blur, which was not possible with conventional cameras or conventional digital holography. By adding blur, you can also create a dramatic effect.

FIG. 2 is a conceptual diagram mainly for explaining the flow of signal processing related to blur conversion by the digital hologram signal processing device according to the embodiment of the present invention; 1 is a schematic diagram showing the configuration of an incoherent imaging system of a digital hologram imaging/reproducing apparatus according to an embodiment of the present invention; FIG. Schematic diagram showing a configuration example of a digital hologram imaging/reproducing apparatus according to an embodiment of the present invention ((a) when a coherent light source is used as illumination light, and (b) when ambient incoherent light is used as illumination light). be. It is a block diagram showing an example of a digital hologram signal processing unit according to the embodiment of the present invention. 3(a) shows a subject image (a) and a digital hologram (b) obtained by imaging it when using the optical system of the apparatus shown in FIG. 3(a). Two-dimensional images reconstructed based on the digital hologram shown in FIG. ), and 20 mm (e), the reconstructed image). The result of blurring conversion by the technique of this embodiment (F value (focus plane position) is 8.33 for each, and the amount of deviation from the position of the focus plane is -20 mm (a), -10 mm (b), and 0 mm ( c), 10 mm (d), and 20 mm (e)). The result of blurring conversion by the technology of the present embodiment (F value (focus plane position) is 25, and the amount of deviation from the position of the focus plane is -20 mm (a), -10 mm (b), and 0 mm ( c), 10 mm (d), and 20 mm (e)). The result of blurring conversion by the technique of this embodiment (F value (focus plane position) is 83.33 for each, and the amount of deviation from the position of the focus plane is -20 mm (a), -10 mm (b), and 0 mm ( c), 10 mm (d), and 20 mm (e)). In the embodiment technology of the present invention, when imaging a plurality of objects arranged in the depth direction, the arrangement relationship (a) of the three objects and the digital hologram (b) obtained by imaging the three objects are It represents When the reconstructed image based on the digital hologram shown in FIG. The case (c)) of the reconstructed image of "3" is shown. Using the technique of the embodiment of the present invention, the result of converting blur with the depth position of the object "1" as the focal plane for the reconstructed image based on the digital hologram shown in FIG. 11A ((a) is D= 1.0 (F value: 20), (b) for D=0.6 (F value: 33.33), and (c) for D=0.2 (F value: 100). Using the embodiment technique of the present invention, the blur is converted with the depth position of the object "2" as the focal plane for the reconstructed image based on the digital hologram shown in FIG. 1.0 (F value: 20), (b) for D=0.6 (F value: 33.33), and (c) for D=0.2 (F value: 100). Using the technique of the embodiment of the present invention, the blur is converted with the depth position of the object "3" as the focal plane for the reconstructed image based on the digital hologram shown in FIG. 1.0 (F value: 20), (b) for D=0.6 (F value: 33.33), and (c) for D=0.2 (F value: 100).

A digital hologram signal processing device and a digital hologram imaging/reproducing device according to embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows the flow of signal processing according to the present invention. Each step after step 12 (S12) is performed in a digital hologram signal processing device (hereinafter also referred to as signal processing units 18 and 18': see FIGS. 3(a) and 3(b)). It is typically done using a computer program and displayed on a monitor.
First, an interference optical system (to be described later) of a digital hologram imaging/reproducing apparatus takes an image of a digital hologram (S11) and stores it. Based on the acquired digital hologram data, the depth position information and the focused image of each subject (subjects 1 to 4) are acquired by the following procedure ((S12): <1> is the focus image and depth position).

That is, in this step 12 (S12), the diffraction propagation calculation is applied to the intensity distribution of the digital hologram or the complex amplitude distribution extracted from the digital hologram by the phase shift method or the Fourier fringe analysis method. For calculation of diffraction propagation, methods such as Fresnel diffraction integration and angular spectrum method (plane wave expansion) can be used. When calculating the diffraction propagation, the propagation distance is changed stepwise and successively to obtain a two-dimensional reconstructed image at each propagation distance. These two-dimensional reconstructed images are focused or blurred according to changes in the depth position of the subject, that is, according to the propagation distance. When a focused image is formed, the propagation distance at that time corresponds to the depth position of the object. Therefore, the depth position of the subject can be obtained by searching for the most focused image from the two-dimensional reconstructed images at each propagation distance. Also, to search for the most focused image, the sharpness of the two-dimensional reconstructed image may be evaluated. As a method for evaluating the sharpness, differentiation of each image or comparison of magnitudes of spatial frequency components of each image may be used. These techniques are known as autofocus techniques in the field of digital holography.

The sharpness of each of the obtained two-dimensional reconstructed images is evaluated, and the propagation distance with the highest sharpness is taken as the depth position of the subject. This depth position information and the focused image of the subject are obtained, and signal processing Stored in unit 18, 18' (see FIG. 3). It should be noted that a device such as a lidar may be used in combination to obtain the depth position of the subject.

Next, the signal processors 18 and 18' (see FIG. 3) are supplied with information on the depth position to be focused, desired depth of field information centered on the depth position, and information corresponding to the amount of blurring to be realized. The parameters of the coherent imaging system are specified (S13). The depth of field is set to a value larger than the depth resolution of the optical system in the digital hologram imaging/reproducing device 19, 19'.
As a result, the response of the imaging system can be physically correctly calculated, and unnecessary arithmetic processing can be omitted. Information on the depth resolution of the optical system is stored in the memories of the signal processing units 18 and 18', reflecting information on the configuration of the optical system.

ここで，P(x,y)はレンズの開口関数であり、ｘ、ｙは瞳面の空間領域の座標系である。
本実施形態においては、通常のカメラレンズを想定して、レンズの開口関数を直径Ｄの円形開口とするが、アポダイゼーション、矩形開口やランダムな開口をはじめ、付与したいぼやけ状態に応じて自由に設定してもよい。λは光源の波長であり、ｆ_ｘ、ｆ_ｙは空間周波数領域の座標系の変数である。 As the parameters of the incoherent imaging system, as shown in FIG. and a distance z ₂ from the virtual lens ₆ to the image plane 7 . Based on these four parameters, the point spread function of the incoherent imaging system is formed as shown in Equation (1) below.

where P(x,y) is the aperture function of the lens, and x,y are the coordinates of the spatial domain of the pupil plane.
In this embodiment, assuming a normal camera lens, the aperture function of the lens is a circular aperture with a diameter of D, but it can be freely set according to the blurring state to be imparted, including apodization, rectangular aperture, and random aperture. You may λ is the wavelength of the light source, and f _x , f _y are the variables of the coordinate system in the spatial frequency domain.

Using the parameters set as described above, a two-dimensional image whose blur has been converted is generated in the following procedure.
As shown in FIG. 2, the in-focus images of the subjects 2 and 3 existing within the set depth position information and depth of field area are added to obtain an added image I ((S14): <2> shows the added image I of the in-focus image within the depth of field).
After that, using the following formula (2), the addition image I and the point spread function (PSF) of the incoherent imaging system are convoluted to obtain the reference image B ((S15): <3> to the reference image B ).

When performing the arithmetic processing of the above equation (2), by setting the parameters of the point spread function of the above equation (1) so as to satisfy the relationship of the following equation (3), the subject 2 , 3 can be obtained.

On the other hand, the effect of P(x, y) in the above equation (1), that is, the limit of the finite aperture diameter of the lens, also includes the effect of lowering the resolution. may be calculated using the PSF of the above equation (2) as a delta function, or this calculation itself may be omitted and B=I.
It should be noted that in calculating the above equations (1) and (2), it is common to use a Fourier transform algorithm. , and keep the intensity constant.

ここで、ｄは被写界深度の領域外の被写体の奥行距離である。
なお、上式（１）に対して上式（４）が相違するのは、ｚ_１がｄに置き換わっている点である。この演算を、被写界深度の領域外の被写体１、４毎にｄの値を変化させて適用する。 Separately from the creation of the reference image B described above, defocused images Dd of the subjects 1 and 4 outside the depth of field area are created. When creating the defocused image Dd, the calculations of the following equations (4) and (5) are applied.
That is, a defocused image Dd is obtained by convoluting the focused images of the subjects 1 and 4 outside the area of the depth of field and the point spread function of the imaging system ((S16): <4> defocused image Dd outside the region of depth of field).

where d is the depth distance of the subject outside the depth of field region.
Note that the above equation (4) differs from the above equation ( ₁ ) in that z1 is replaced with d. This calculation is applied by changing the value of d for each of the subjects 1 and 4 outside the region of depth of field.

Finally, by performing addition of the reference image B and all defocused images (a group of defocused images Dd), a two-dimensional image in which the state of blur has been converted can be obtained ((S17): 2D image obtained as a result of signal processing (adding all images together).

Note that in the above calculations, the values of f and z2 _are fixed in order to give a blurred state when a common lens (virtual lens) 6 is used for all subjects 1 to 4. However, any of them may be changed according to subjects 1-4.
Also, the depth position information of each of the subjects 1 to 4 may be changed to any value. By the above operation, a blurred two-dimensional image that cannot be captured by a normal camera can be obtained, and depth position information can be arbitrarily exchanged, so that the range of video expression can be expanded.

As a digital hologram imaging/reproducing apparatus that realizes the signal processing of the above-described blur conversion, for example, those shown in FIGS. 3(a) and 3(b) can be employed.
The optical system of the imaging/reproducing apparatus shown in FIGS. 3(a) and (b) has a general configuration in the field of digital holography. In addition to the fact that the units 18 and 18' are installed, the information of the depth resolution of the optical system, which is necessary for improving the efficiency of calculation of the signal processing of the blur conversion, is stored in the signal processing units 18 and 18'. is set and set.

FIG. 3(a) shows a digital hologram imaging/reproducing apparatus 19 using coherent light as a light source. A laser beam from a laser light source 16 in a digital hologram imaging/reproducing device 19 is made into a plane wave by a spatial filter 15 and a lens 11 and split by a beam splitter 13 . One of the split beams is irradiated onto the object 12, and the other split beam is reflected by the plane mirror 14.例文帳に追加The former light is used as object light, and the latter light as reference light. This is imaged as a digital hologram and stored in a memory section (not shown) of the signal processing section 18 .

On the other hand, FIG. 3(b) shows a digital hologram imaging/reproducing apparatus 19' in which ambient incoherent light is used as a light source. Reflected light from an object 12' illuminated by ambient incoherent light is condensed by a lens 11' and split by a beam splitter 13'. The split incoherent light is reflected by the plane mirror 14' and the concave mirror 20, returned to the beam splitter 13' again, combined, and interfered on the surface of the imaging device 17'. This is imaged as a digital hologram by the imaging element 17' and stored in a memory (not shown) of the signal processing section 18'.

Further, FIG. 4 is a block diagram showing the internal configuration of the signal processing section 18 (the same applies to the signal processing section 18'). That is, the signal processing unit 18 includes a focused image/depth position information acquisition unit 18A, a reference image acquisition unit 18B, a defocused image group acquisition unit 18C, and a reference image/defocused image group addition unit 18D. ing.

First, the in-focus image/depth position information acquisition means 18A extracts in-focus images of the subject 12 (subject images 1 to 4) and the depth position information of the in-focus image.

In addition, the reference image acquiring means 18B determines the depth of field, The focal length f of the lens 6, the aperture diameter D of the lens 6, and the distance z2 from the lens 6 to the image plane ₇ are set, and the intensity distributions of the obtained in-focus images in a predetermined number of areas are added together. Then, the reference image B is acquired.

Further, the arithmetic processing for obtaining the reference image B in the reference image obtaining means 18B is performed by the intensity It is desirable to perform calculation by convolution integration of the combined intensity distribution obtained by adding the distributions and the intensity distribution of the point spread function of the incoherent imaging system.

On the other hand, the defocused image group acquisition means 18C is configured to specify an out-of-area focused image (focused images of subjects 1 and 4) arranged at a desired depth position outside the depth-of-field area. Depending on the depth position, the focal length f of the lens 6, the aperture diameter D of the lens 6, and the distance z2 from the lens ₆ to the image plane are set, and the obtained out-of-area focused image (subject 1 , 4) and the intensity distribution of the point spread function of the incoherent imaging system to obtain a defocused image group Dd.
In other words, the defocused image group acquiring means 18C converts the blurring state of the image of the subject 12 existing at the defocused position from coherent response to incoherent response, and furthermore, converts the point spread of the incoherent imaging system. The amount of blurring is adjusted by changing the parameters of the function.

Further, the reference image/defocused image group addition means 18D adds the reference image B obtained by the reference image acquisition means 18B and the defocused image group Dd obtained by the defocused image group acquisition means 18C. to obtain an incoherent response image.
Although not shown in FIG. 4, the signal processing section 18 is provided with a memory section for storing the depth resolution of the optical system of the interferometer.

The optical systems of the digital hologram imaging/reproducing devices 19 and 19' shown in FIGS. Various other configurations can be employed as long as they can be used to capture a digital hologram and derive depth position information of the optical system.

In the following, the reconstruction results obtained by the examples of the present invention will be described, and the details and results of the simulation according to the prior art as a comparative example will also be described.
In the simulations according to the present embodiment and the above-described comparative example, diffraction calculation of light waves by the angular spectrum method is used, and the propagation of light can be accurately calculated.
As a digital hologram imaging/reproducing apparatus, the one using coherent light shown in FIG. 3(a) was adopted. The wavelength of the coherent light is 633 nm, the subject 12 is a two-dimensional image shown in FIG. 5A, and the depth position of the subject 12 is 100 mm. A plane wave having a plane phase was used as the reference light. As the imaging device 17, one having 256×256 pixels, a pixel pitch of 10 μm, and a gradation number of 8 bits was used. Here, the hologram image acquired by the imaging device in the comparative example was the same as that shown in FIG. 5(b).

FIG. 6 shows a reconstructed image obtained by extracting a complex amplitude distribution from the hologram obtained by the imaging device by the phase shift method. A two-dimensional image is obtained at each position while changing the propagation distance at intervals of 10 mm within a range of ±20 mm around the focus position of the subject. That is, the reconstruction result when the set propagation distance is 0 mm (focus position of the subject) is shown in (c), and the set propagation distances are -20 mm, -10 mm, 10 mm and 20 mm, respectively. The reconstruction results when , are shown in (a), (b), (d), and (e), respectively.
From the reconstruction results in FIG. 6, it is clear that ringing occurs in the defocused image in the reconstruction calculation of ordinary digital holography, and the state of blur differs from that of the ordinary camera.

Next, FIG. 7 shows the result of reconstruction by applying the technique of this embodiment. The parameters of the incoherent imaging system and virtual lens 6 are z ₁ = 100 mm, z ₂ = 100 mm, f = 50 mm, D = 6 mm (F value 8.33), and the length of the depth of field region is 8 mm. and By applying the technique of this embodiment, it is clear that the defocused image is smoother than in the case of FIG.
8 and 9 show the processing results when D=2 mm (F value 25) and D=0.6 mm (F value 83.33) (the propagation distance for (a) to (e) is same as in Fig. 6). As the F number increases, the amount of blurring of the defocused image is reduced, and it is clear that the amount of blurring can be well controlled.

Next, as shown in FIG. 10A, the result of application when three subjects 12 are arranged with a distance of 60 mm from each other in the depth direction will be described below. When these three subjects 12 are imaged, the digital hologram shown in FIG. 10(b) is obtained. Hereinafter, the three subjects 12 are referred to as "object 1," "object 2," and "object 3" in the depth direction in FIG. 10(a) for convenience.

11(a) to 11(c) show the results of applying the phase shift method and the diffraction propagation calculation to the digital hologram of FIG. 10(b). When each subject 12 is focused and reconstructed, it is clear that a defocused image with a blurry state (having a striped pattern) peculiar to coherent light is obtained.
12, 13, and 14 show reconstruction results obtained by applying the technique of the present embodiment to the reconstruction results shown in FIGS. 11(a) to 11(c).

12, 13, and 14 respectively show the reproduction when the arrangement positions of the object "1", the object "2", and the object "3" are set as the depth position of the focus, and the depth of field is set to 10 mm. It shows the configuration result.
12 to 14, when the aperture diameter D=1 (F value 20) in each (a) of FIGS. 12 to 14, D=0.6 ( Each (c) of FIGS. 12 to 14 shows the results when D=0.2 (F value 100).
As is clear from the respective reconstruction results described above, by using the technique of the present embodiment, the state of blur can be converted from the state using coherent light to the state using incoherent light, and the amount of blur can be reduced. It is clear that it can be arbitrarily adjusted.

The results of the simulation described above were obtained when the digital hologram imaging/reproducing device 19 using coherent light was used. ', the same effects can be obtained.

It should be noted that the digital hologram signal processing device and the digital hologram imaging/reproducing device of the present invention are not limited to the above embodiments, and other various modifications are possible.

1 to 4, 12, 12' Subject 6 Virtual lens (lens)
7 image planes 11, 11' lenses 13, 13' beam splitters 14, 14' plane mirror 15 spatial filter 16 laser light sources 17, 17' imaging devices 18, 18' signal processing unit 18A focused image/depth position information acquiring means 18B Reference image acquisition means 18C Blur amount adjustment means 18D Reference image/defocused image group addition means 19, 19' Digital hologram imaging/reproducing device 20 Concave mirror B Reference image Dd Defocused image group I Addition image

Claims (7)

A digital hologram signal processing device that performs signal processing for a digital hologram imaging and reproducing device that captures three-dimensional information of an object using light interference,
A focused image/depth for acquiring a desired number of focused images of a subject and information on the depth position of the focused images from the digital hologram reconstructed image obtained by the interference optical system of the digital hologram imaging/reproducing device. location information acquisition means;
The depth of field, the focal length of the lens, the focal length of the lens, and the depth of field are adjusted according to the depth position so that an in-focus image set at the desired depth position within the depth of field can be specified. a reference image obtaining means for obtaining a reference image by setting each element of the aperture diameter and the distance from the lens to the image plane, and adding together the obtained predetermined number of in-region focused images;
the focal length of the lens, the aperture diameter of the lens, the aperture diameter of the lens, and and each element of the distance from the lens to the image plane, and calculate the convolution integral of the intensity distribution of each out-of-area in-focus image obtained and the intensity distribution of the point spread function of the incoherent imaging system defocused image group obtaining means for obtaining a defocused image group by
Reference image/defocused image for obtaining an incoherent response image by adding the reference image obtained by the reference image obtaining means and the defocused image group obtained by the defocused image group obtaining means group addition means;
A digital hologram signal processing device comprising: Arithmetic processing for obtaining the reference image in the reference image obtaining means includes a total intensity distribution obtained by adding the intensity distributions of the in-region focused images obtained by changing the depth position, and the 2. The digital hologram signal processing apparatus according to claim 1, wherein the arithmetic processing is a convolution integral with an intensity distribution of a point spread function of an incoherent imaging system. When performing the arithmetic processing related to the convolution integral of the combined intensity distribution and the intensity distribution of the point spread function of the incoherent imaging system, the incoherent 3. The digital hologram signal processing apparatus according to claim 2, wherein the digital hologram signal processing apparatus is configured to set parameters of a point spread function of an imaging system.

However, the distance from the lens to the in-focus image of the object is z ₁ , the distance from the lens to the image plane is z ₂ , and the focal length of the lens is f. The process of acquiring a desired number of focused images of the subject and information on the depth position of the focused images in the focused image/depth position information acquisition means is performed to improve the sharpness of the reconstructed image of the digital hologram. 4. The digital hologram signal processing apparatus according to any one of claims 1 to 3, wherein the processing is performed based on evaluation results. an imaging optical system that forms a hologram image on the imaging device by causing interference between two systems of light, at least one of which carries subject information, and the digital imaging device according to any one of claims 1 to 4; and a hologram signal processing device. A coherent light source and an interferometer optical system for obtaining a digital hologram from the coherent light from the light source are provided, and a memory for storing the depth resolution of the interferometer optical system is provided in the digital hologram signal processing device. 6. The digital hologram imaging and reproducing apparatus according to claim 5, characterized by: An optical system of a self-interferometer for obtaining a digital hologram by receiving incoherent light from an object is provided, and a memory for storing the depth resolution of the optical system of the self-interferometer is provided in the digital hologram signal processing device. 6. The digital hologram imaging/reproducing apparatus according to claim 5, wherein:

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