CN111866316B

CN111866316B - Multifunctional imaging equipment

Info

Publication number: CN111866316B
Application number: CN201910346393.4A
Authority: CN
Inventors: 曹毓
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-04-26
Filing date: 2019-04-26
Publication date: 2021-11-12
Anticipated expiration: 2039-04-26
Also published as: CN111866316A

Abstract

The invention provides high-dynamic and multispectral imaging equipment, which comprises a lens, a focusing light field camera body with a micro-lens array, a light modulation array optical filter and an aperture insert. Wherein the shape and focal length of each microlens unit of the microlens array are the same; the micro lens units are arranged sparsely; gaps between adjacent microlens units are light-tight; the light modulation array optical filter is an optical filter with different light intensity attenuation degrees or light passing spectral characteristics in different areas; the diaphragm insert is positioned at the lens diaphragm, and one or more light modulation array filters are fixed on the diaphragm insert. Through adjusting the diaphragm insert, any one light modulation array filter fixed on the diaphragm insert can be positioned on the optical axis of the lens, and the plane of the light modulation array filter is perpendicular to the optical axis of the lens. The invention has simple structure and small volume. In addition, the high-dynamic or multispectral imaging can be realized only by adjusting or replacing the diaphragm insert without replacing a lens, and the use is convenient.

Description

Multifunctional imaging equipment

Technical Field

The invention relates to the technical field of image data generation and processing, in particular to a multifunctional imaging device capable of being conveniently switched between a high dynamic imaging mode and a multispectral imaging mode, and specifically relates to a high resolution real-time imaging device with an adjustable dynamic range and an adjustable spectral band.

Background

In the existing imaging device, the special camera is an imaging device with a special function, and for example, both the high-dynamic camera and the multispectral camera belong to the special camera. The high-dynamic camera is capable of simultaneously recording the ratio of the brightest light intensity to the darkest light intensity of an object to be more than 10⁵1. A multispectral camera refers to an imaging device that can obtain its images under multiple different spectra for the same target scene.

Considering that in many practical applications, the photographed target is not still, and the result obtained by the non-real-time camera will generate "artifacts" to significantly reduce the imaging effect, the real-time high-dynamic camera and the real-time multispectral camera are the main research directions of people. Todor Georgiev et alHuman based focused light field imaging structure^[1](i.e., "Focused Plenoptic Camera") realizes a real-time high-dynamic and real-time multispectral imaging system^[2]And applied for U.S. patent in 2013^[3]The imaging system is to be improved in the following problems:

1) the imaging dynamic range or spectral band is not easily switched.

For high dynamic imaging and multispectral imaging, different lenses are required to be used for realizing the imaging respectively. In addition, if the imaging dynamic range or the spectral band of the system is to be changed, different lenses are required to be used.

2) Only objects at a certain distance can be imaged clearly.

When the distance between the shot object and the imaging system deviates from the preset value, the mosaic effect of the image can occur, and the imaging quality is poor.

3) The resolution of the output image is low.

The elements used by such imaging systems to modulate light are tiled by four small optical elements, the seams of which produce blurred projections in the image that interfere with imaging. To address this problem, the method adopted by Todor Georgiev et al is to reduce the magnification of the secondary imaging of the microlens unit below 1/5^[2]This allows the blurred projected areas of the light modulation element stitched onto the image to be significantly reduced, but the output image resolution is still only 1/30 times the original image resolution.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at a shot target at any distance, the multifunctional imaging equipment is strong in real-time performance, high in resolution, capable of conveniently switching between a high dynamic mode and a multi-spectrum mode, adjustable in imaging dynamic range and adjustable in spectrum band.

The technical scheme of the invention is as follows:

a multifunctional imaging device comprises a lens, a focused light field camera body with a micro lens array; it is characterized in that the preparation method is characterized in that,

the light through hole of the diaphragm is rectangular;

in addition, the device also comprises a light modulation array filter and an aperture insert;

wherein, in the microlens array, the shape and the focal length of each microlens unit are the same; the micro lens units are arranged sparsely; gaps between adjacent microlens units are light-tight;

if the distance between the plane where all the microlens units in the microlens array are located and the imaging surface of the lens is a, and the distance between the plane where all the microlens units in the microlens array are located and the imaging photosensitive surface of the focused light field camera body is b, then:

the light modulation array optical filter is an optical filter with different light intensity attenuation degrees or light passing spectral characteristics in different areas;

the diaphragm insert is positioned at the lens diaphragm, and one or more light modulation array filters are fixed on the diaphragm insert. Through adjusting the diaphragm insert, any one light modulation array filter fixed on the diaphragm insert can be positioned on the optical axis of the lens, and the plane of the light modulation array filter is perpendicular to the optical axis of the lens.

Further, the clear aperture of the rectangular aperture can be adjusted.

The invention has the advantages of

Aiming at the defects of the prior art, the invention provides high-dynamic and multispectral imaging equipment, which has the following specific beneficial effects:

1) the equipment has simple structure and small volume. In addition, the high-dynamic or multispectral imaging can be realized only by adjusting or replacing the diaphragm insert without replacing a lens, and the use is convenient.

2) Due to the design of sparse arrangement of the micro-lens units, the area of fuzzy projection generated in the image by the seam on the light modulation array filter is reduced, and the resolution of the output image is improved.

3) Thanks to the rectangular aperture with adjustable aperture, when the distance between the object to be shot and the imaging device is changed or the imaging field angle is changed by using the zoom lens, the device can obtain high-definition high-dynamic or multi-spectral imaging results.

4) The adjustable design of the aperture insert sheet is also benefited, and different light modulation array filters are arranged on the insert sheet, so that the imaging dynamic range or the spectrum band of the equipment can be easily adjusted and switched according to the brightness characteristic or the spectrum characteristic of the actual scene object to be shot, and the environment object adaptive capacity is stronger.

Drawings

FIG. 1 is a schematic diagram of the apparatus of the present invention;

FIG. 2 is a schematic diagram of two microlens arrangements on a microlens array according to the present invention;

FIG. 3 is a schematic view of a microlens array according to the present invention;

FIG. 4 is a schematic diagram of two implementations of a rectangular aperture in accordance with the present invention;

FIG. 5 is a schematic diagram of two implementations of a light modulating array filter according to the present invention;

FIG. 6 is a schematic diagram of three implementations of an aperture insert according to the present invention;

fig. 7 is a schematic diagram of three implementations of a lens according to the present invention;

FIG. 8 is a schematic diagram of the image mosaic effect;

fig. 9 is an exemplary diagram illustrating the effect of matching the dynamic range of the camera and the scene brightness range.

Detailed description of the preferred embodiment

The device is realized on the basis of a focusing light field camera structure. Is generally accepted in the literature^[1-3]: "focused light field camera" refers to an imaging system that includes a lens, a microlens array, and an imaging photosensitive element. Wherein the Microlens Array has the English name of Microlens Array^[1-3]The present invention relates to a flat optical element having a large number of fine microlens elements arranged on the surface thereof. In the present invention, to distinguish from the above-mentioned concept of "focused light field camera", we refer to a portion of the focused light field camera that does not include a lens as a "focused light field camera body".

Refer to the drawingsStructural features of known existing focused light field cameras^[1-3]Comprises the following steps: a micro lens array 3 is arranged between the lens 1 and an imaging chip 9 of the focusing light field camera body 2, and the micro lens array 3 is positioned in front of or behind an imaging surface 8 of the lens 1, and is positioned behind in the figure. The microlens array 3 performs secondary imaging on the imaging surface 8 of the lens 1: when the microlens array 3 is positioned in front of the imaging surface 8, the imaging surface 8 is a virtual imaging surface; when the microlens array 3 is located behind the imaging surface 8, the imaging surface 8 is a real imaging surface. The imaging chip 9 is located behind the microlens array 3 (i.e. away from the lens 1) and is used for receiving the secondary imaging result of the microlens array 3.

As shown in fig. 1, compared with the existing focused light field camera, the present invention further includes a rectangular aperture 4, a light modulation array filter 5 and an aperture insert 6; the light modulation array filter 5 is fixed on the aperture insert sheet 6, and the aperture insert sheet 6 is positioned at the lens diaphragm.

The light radiation 7 emitted by the shot object enters the lens 1 along the direction indicated by the arrow in the figure, then passes through the rectangular aperture 4 and the light modulation array filter 5 in sequence, is focused and imaged on an imaging surface 8, then further diverges and carries out secondary imaging through the micro-lens array 3, and the imaging result falls on an imaging chip 9 in the focusing light field camera body 2 and is finally output in the form of an image. It should be noted that: the order in which the optical radiation 7 passes through the rectangular aperture 4 and the light modulating array filter 5 need not be specified, but may be first passed through the light modulating array filter 5 and then through the rectangular aperture 4.

In fig. 1, the rectangular aperture 4 and the light modulation array filter 5 both need to be placed as close as possible to the aperture surface of the lens 1, and the plane where the rectangular aperture 4 and the light modulation array filter 5 are located needs to be parallel to the aperture surface of the lens 1. For all the lenses, incident light of a scene to be shot in any direction in the field of view of the lens needs to pass through a narrowest traffic critical path, the plane where the traffic critical path is located is the diaphragm surface of the lens, and the diaphragm surface of the lens is perpendicular to the optical axis of the lens. The invention can obtain the best imaging effect only if the rectangular aperture 4 and the light modulation array filter 5 are arranged close to the diaphragm surface of the lens 1 as much as possible.

Fig. 2 is a schematic diagram of two microlens arrangements on the microlens array according to the present invention. The existing focusing light field camera is generally used for three-dimensional imaging, in order to improve the space utilization rate of a lens imaging surface, the arrangement mode between the microlens units 10 in the microlens array is compact, that is, the adjacent microlens units 10 are seamlessly connected, and meanwhile, the shapes and focal lengths of the microlens units 10 are usually different, and the different purposes are to improve the depth of field of imaging. The microlens units 10 provided by the present invention have the same shape and focal length, the arrangement mode between the microlens units 10 is sparse, and the gaps between the adjacent microlens units 10 are opaque. Fig. 2 shows two sparse arrangements: respectively a square sparse arrangement (A) and a staggered sparse arrangement (B). When sparsely populated in squares: the arrangement pitches of the centers of the microlens units 10 in the horizontal direction and the vertical direction are equal to each other, D in the figure, and the arrangement pitch D is larger than the diameter D of the microlens unit 10. When sparsely populated in a staggered fashion: the microlens units 10 are divided into two groups, each group is sparsely arranged in a square shape, as shown in the right diagram of fig. 2, the dark microlens units 10-1 are one group, and the light microlens units 10-2 are the other group; in addition, the spacing of the square sparse arrangement of the two groups of microlens units is also the same, and is D in the figure, but the two groups of microlens units have the same dislocation in the horizontal and vertical directions, and the dislocation distance is half of the spacing of the square sparse arrangement, and is D/2 as shown in the figure. Regardless of the sparse arrangement, it is necessary to ensure that the areas between the microlens elements 10 on the microlens array are opaque. There are various means for light-proof, for example, black chrome plating or black light-absorbing flocking may be performed. Of course, the way of sparse arrangement is not limited to the above two, as long as the arrangement between the microlens cells 10 is such that the blurred region of the seam of the light modulation array filter 5 on the imaging plane is as small as possible.

Fig. 3 is a schematic structural diagram of a microlens array according to the present invention, in which the plane of all the microlens units 10 in the microlens array 3 is parallel to the plane of the imaging chip 9, and there is a gap between all the microlens units 10, and the gap area is covered by a black chrome film 11. On the other side of the microlens array 3 (i.e., the side without the microlens unit 10), an antireflection film 12 is coated for the purpose of suppressing light reflected from the black chrome film 11 in the microlens array 3 from entering the microlens unit 10 through secondary reflection, thereby avoiding the problem of image ghosting as much as possible.

Fig. 4 is a schematic diagram of two implementations of a rectangular aperture according to the present invention. The reason why the rectangular aperture is adopted in the present invention is that: the point spread function of incident light after passing through the rectangular aperture is rectangular, and then the seamless close arrangement of all light beams can be realized only by the sparse arrangement microlens array to the imaging plane, at the moment, the loss of pixels on the imaging chip in the focusing light field camera body is minimum, so that the imaging chip can be utilized most fully, and the resolution of the finally output image is also highest. When the microlens units 10 in the microlens array are sparsely arranged in a square, the through hole 13 in the middle of the rectangular aperture is square, as shown in fig. 4 (a); when the microlens units 10 in the microlens array are sparsely arranged in a staggered shape, the through hole 13 in the middle of the rectangular aperture is rectangular with an aspect ratio of 2:1, as shown in fig. 4 (B). In addition, the aperture of the through hole 13 of the rectangular diaphragm is adjustable, and the aperture of the through hole 13 is gradually reduced from left to right in fig. 4(a) and (B). In the process of adjusting the aperture of the through hole 13, the rectangular aperture needs to ensure that the length-width ratio of the rectangular through hole 13 is unchanged, and two right-angle sides of the rectangular through hole are respectively kept parallel to two right-angle sides of the light-sensitive chip of the focusing light field camera body. In the best use state, the center of the through hole 13 holding the rectangular diaphragm is always located on the lens optical axis, while the plane of the through hole 13 is perpendicular to the lens optical axis. The way of realizing the aperture-adjustable rectangular aperture may be that two "L" shaped opaque sheets are stacked on each other, or that 4 "I" shaped sheets are stacked on each other, where the "L" shaped or "I" shaped sheets can move toward or away from each other at the same time relative to the center of the optical axis, and fig. 4 only depicts the case where two "L" shaped sheets are stacked on each other to form the rectangular aperture, that is, the "L" shaped sheet with a dark color and the "L" shaped sheet with a light color in the figure. The opaque sheet may be made of a material used for an existing diaphragm.

The light modulation array filter has two types, namely a light intensity modulation array filter and a spectrum modulation array filter. When the light modulation array filter is the light intensity modulation array filter, the light intensity modulation is realized, and at the moment, the device can realize the function of high dynamic imaging; when the light modulation array filter is a spectrum modulation array filter, the function of the light modulation array filter is to realize the spectrum modulation of light, and at the moment, the device can realize the function of multispectral imaging.

The arrangement of the light modulation array filter can be various, as long as the light intensity attenuation degree (corresponding to the light intensity modulation array filter) or the light passing spectrum characteristic (corresponding to the spectrum modulation array filter) of different areas on the light modulation array filter are different. Fig. 5 shows two implementations of a light modulating array filter. The left image of fig. 5 is a light modulation array filter shaped like a Chinese character 'ri', two light intensity attenuation pieces or two spectrum filters are closely arranged, when the light modulation array filter is used, areas with different depths represent the light intensity attenuation pieces with different attenuation degrees, and when the light modulation array filter is used, areas with different depths represent the spectrum filters with different spectrum characteristics. The right diagram of fig. 5 is a light modulation array filter shaped like a Chinese character tian, and four light intensity attenuation pieces or four spectrum filters are closely arranged, when the light modulation array filter is used, areas with different depths represent the light intensity attenuation pieces with different attenuation degrees, and when the light modulation array filter is used, areas with different depths represent the spectrum filters with different spectrum characteristics. The optimal implementation scheme is that the light intensity modulation array filter or the spectrum modulation array filter is formed by tightly splicing two or four square light intensity attenuation sheets or square spectrum filters which are made of the same material and have the same size, and the light intensity attenuation characteristics or the spectrum filtering characteristics of different areas are determined according to actual requirements.

Fig. 6 is schematic diagrams of three implementation manners of the aperture insert according to the present invention, which are respectively: a replaceable diaphragm insert 6-1, a push-pull diaphragm insert 6-2 and a runner diaphragm insert 6-3. The shape and size of the diaphragm insert sheet are different corresponding to each implementation mode, wherein only one light modulation array light filter 5 is fixed on the replaceable diaphragm insert sheet 6-1, and when the diaphragm insert sheet is used, the replaceable diaphragm insert sheet 6-1 inserted into a lens is replaced by different light modulation array light filters 5, so that the function of switching between two functions of high dynamic imaging and multispectral imaging is achieved, or the function of adjusting the imaging dynamic range or the spectral band is achieved. Two or more light modulation array filters 5 are fixed on the push-pull type aperture inserting sheet 6-2 and the rotary wheel type aperture inserting sheet 6-3, and the structural design of the push-pull type aperture inserting sheet and the rotary wheel type aperture inserting sheet ensures that any one light modulation array filter 5 can be easily adjusted to a proper position and can be kept fixed. The diaphragm insert is usually a thin sheet, and the shape, size and lens size are matched, and the diaphragm insert can be made of non-deformable materials, such as metal materials and carbon fiber materials.

Fig. 7 is a schematic diagram of three implementation manners of the lens according to the present invention. The lens 1 in fig. 7(a) has a replaceable diaphragm insert 6-1. In the figure, 14 is a locking knob of the replaceable diaphragm insert 6-1 for locking the replaceable diaphragm insert 6-1 to thereby lock the light modulation array filter 5 to a prescribed position, and 15 is a lifting knob of the replaceable diaphragm insert 6-1 for easy insertion and extraction from the lens side. In addition, in order to enhance the sealability of the lens, the bottom of the handle 15 is widened and a rubber gasket is added to the contact area with the lens, thereby preventing dust from entering the inside of the lens. The reference numeral 16 denotes a rotary ring for adjusting the aperture of the rectangular aperture, and the aperture of the rectangular aperture can be adjusted by rotating the rotary ring 16. The lens 1 in fig. 7(B) is provided with a push-pull type aperture insertion sheet 6-2, which is a schematic view from the rear part of the lens 1 viewed from the back incident ray view angle, and when the push-pull type aperture insertion sheet 6-2 is used, the insertion depth of the push-pull type aperture insertion sheet in the lens is controlled by pushing and pulling, so that the switching of different light modulation array filters 5 is realized. Fig. 7(C) shows the lens 1 with the turret type iris insert 6-3, which is a schematic view from the rear of the lens 1 viewed against the incident light. The center of the rotating shaft of the rotating wheel type aperture inserting sheet 6-3 is fixed on the lens 1, when in use, the switching of different light modulation array filters 5 is realized by a rotating method, and the rotating mode can be manual or automatic electric control.

The aperture insert 6 may be a sheet made of a metal material or a carbon fiber material, and when the light modulation array filter 5 is fixed to the aperture insert 6, a corresponding position of the aperture insert 6 may be partially hollowed and fixed by being inserted into the groove. Of course, other means of attachment, such as adhesive attachment, are also possible.

The invention is mainly embodied in the following four aspects:

1) the target at any distance can be clearly imaged.

Todor Georgiev^[2-3]A square light modulation optical element with a fixed light transmission aperture is arranged in a camera lens, so that the structure can only clearly image a certain specific plane of an object. As shown in fig. 8, assuming that the clear aperture of the square light modulation optical element is set to image for a specific object plane, and at this time, the image of the scene object of the object plane on the imaging chip is as shown in fig. 8(a), in the figure, each microlens unit corresponds to a square imaging region (including 4 small blocks with different depths) in a shape of "tian", which is called a sub-image 17, and the adjacent sub-images 17 are closely arranged, which means that the space on the imaging surface of the camera is fully utilized and no pixel is wasted. However, when the distance between the shooting target and the camera deviates from the preset object plane, the imaging effect after the lens finishes focusing is as shown in fig. 8(B), and it can be seen that the size of the sub-image 17 corresponding to each microlens unit changes, resulting in a gap between the corresponding adjacent sub-images 17. The space on the imaging surface of the camera is not fully utilized, and the phenomenon is the image mosaic effect caused by mismatching of the clear aperture of the lens. Fig. 8(B) shows only the case where there is a gap in the sub-image 17, but aliasing may occur in the sub-image 17, which is determined according to whether the object is far from or near the set object plane. However, in both the far and near regions, the larger the deviation distance is, the more serious the image mosaic effect is, and the poorer the imaging quality is. In order to solve the problem, the aperture of the lens in the device is made into a rectangle with adjustable aperture, so that the object at any distance can be adjusted by adjusting the momentThe aperture of the circular aperture realizes the close arrangement of the sub-images corresponding to each micro lens, thereby eliminating the mosaic effect of the image and finally obviously improving the imaging effect.

Note that, for Todor Georgiev^[2-3]In the scheme, if a zoom lens is used, a certain degree of image mosaic effect is generally brought when the focal length is changed, so that the function of adjusting the aperture of the rectangular aperture can also improve the imaging effect on the occasion of adjusting the angle of the imaging field of view.

2) The method can be used for rapidly switching between a high dynamic imaging mode and a multispectral imaging mode.

Under the structural scheme of the invention, if the light modulation array light filter is a light filter with different light intensity attenuation degrees in different regions, the imaging equipment realizes the function of high dynamic imaging, and if the light modulation array light filter is a light filter with different light-passing spectral characteristics in different regions, the imaging equipment realizes the function of multispectral imaging. Due to the design of the flexibly adjustable aperture insert, the fast switching between the high dynamic imaging mode and the multispectral imaging mode can be realized only by simply switching the type of the light modulation array filter carried on the aperture insert.

3) The imaging dynamic range and the imaging spectral band are easy to adjust.

The design of flexibly adjustable aperture insert pieces is benefited, and the light intensity modulation array filters with different light intensity attenuation degrees borne by the aperture insert pieces are switched, so that the imaging dynamic range can be rapidly changed; the spectral modulation array optical filter with different light-passing spectral characteristics borne on the aperture inserting sheet is switched, so that the imaging spectral band combination can be rapidly changed. The above functions have important value in practical application. For example, in the field of high dynamic imaging technology, the luminance range in a shooting scene is varied, and if the dynamic range of a camera cannot be flexibly adjusted according to the luminance range of the shooting scene, image information is easily lost due to overexposure or underexposure, as shown in fig. 9. In the upper graph of fig. 9, there are three different exposure intensity images for the same scene, with the areas indicated by arrows indicating good exposure. Therefore, for the whole shooting scene, any target area is well exposed, the synthesized high-dynamic image has a good effect, and information loss basically cannot occur. In the lower diagram of fig. 9, the same imaging device is used, and there are three different exposure intensity images for another scene, and the area inside the oval frame in the diagram is all over-exposed in the three images, and at this time, information loss still occurs in the synthesized high-dynamic image at the area. Therefore, if the dynamic range of the camera is constantly non-adjustable, the dynamic range of the camera cannot match with the brightness range of the shot scene, and the final high-dynamic imaging effect is not good.

In addition, the invention is an imaging system capable of realizing the rapid change of the imaging spectral band combination, and has important application value in the fields of agricultural remote sensing, ore sorting and the like. In the field of agricultural remote sensing application, solar spectrums reflected by blades of different crops and the same crop in different growth periods are different, so that the multispectral camera for agricultural remote sensing is required to have a specific spectrum combination for each crop, and the conventional multispectral camera is difficult to customize and replace the spectrum. In the field of ore sorting, multispectral cameras help to improve sorting accuracy, but spectral characteristics are different for different ore types, which also requires the capability of spectral customization of multispectral cameras. The multispectral imaging device can easily change the imaging spectral band by switching the spectral array filter, thereby being particularly suitable for the application field.

Particularly, aiming at multispectral imaging, the device can realize the function of laser interference imaging resistance by reasonably selecting a proper spectral band in the spectral modulation array optical filter and avoiding the wavelength of a common laser. For example, for a spectral modulation optical element having a "checkerboard" distribution, the four spectral filters are set as different bandpass filters, and their pass spectral bands do not intersect or overlap with each other. If the pass spectral bands are respectively as follows: 415-, 505-, 545-, 625-, 680-, 770-, and 780-, 1100-nanometers. At this time, the apparatus can resist irradiation attack of most of the semiconductor lasers which are readily available on the market.

4) The imaging resolution is high.

In the Todor Georgiev [2-3] device, the light modulating elements placed within the lens are tiled by multiple small optical elements, the seams of which produce blurred projections in the image, thereby interfering with the imaging. To address this problem, Todor Georgiev et al have adopted a method of reducing the magnification of the secondary imaging of the microlens unit to below 1/5, which can limit the blurred projection area of the light modulation element seam on the image to a small range, but significantly sacrifice the resolution of the output image. In the system of Todor Georgiev et al, the output image resolution is reduced to 1/30 the original image resolution of the imaging chip.

Unlike the Todor Georgiev approach, we solve the above problem by making the arrangement of the microlens units sparse, while controlling the magnification of the secondary imaging of the microlens units between 1/2 and 1/5. Doing so better guarantees the resolution of the output image. Because: the resolution of the output image is approximately equal to the original image resolution of the imaging chip multiplied by the secondary imaging magnification of the microlens unit 2, so the maximum output resolution of the corresponding device of the invention is about 1/4 of the original image resolution of the imaging chip, and the index is obviously better than that of the device of Todor Georgiev.

The sparse arrangement of the microlens units can overcome the problem of blurred projection in the image caused by the seams of optical elements in the lens, but also pay the cost of losing a part of incident light energy. In other words, the sparser the arrangement between the microlens units, the longer the imaging exposure time required by the apparatus of the present invention in the case where the subject scene luminance is constant. Experiments show that the invention can realize better imaging results under the conditions that the distance D between the micro-lens units is larger than the diameter D of the micro-lens units, which is limited by the problem of light diffraction and the limited brightness of the shot scene. But by trade-off we get the best range for the microlens cell diameter D to be 2/3 smaller than the microlens cell pitch D and 1/4 larger than the microlens cell pitch D.

Reference documents:

[1]Todor Georgiev,Andrew Lumsdaine.Focused Plenoptic Camera and Rendering[J].Journal of Electronic Imaging,2010,19(2),021106.

[2]Todor Georgiev,Andrew Lumsdaine，Georgi Chunev.Using Focused Plenoptic Cameras for Rich Image Capture[J].IEEE Computer Graphics and Applications,2011,50-61.

[3]Todor Georgiev,Andrew Lumsdaine.Methods and Apparatus for Rich Image Capture with Focused Plenoptic Cameras[P].US Patent,US-8345144B1,2013.

Claims

1. a multifunctional imaging device comprises a lens, a focused light field camera body with a micro lens array; it is characterized in that the preparation method is characterized in that,

the light through hole of the diaphragm is rectangular;

the aperture insert is positioned at the lens diaphragm, an optical modulation array filter is fixed on the aperture insert, and the plane of the optical modulation array filter is vertical to the optical axis of the lens; the function of switching between high dynamic imaging and multispectral imaging is achieved by replacing the diaphragm insert, or the function of adjusting the imaging dynamic range or the spectral band is achieved.

2. The multifunctional imaging apparatus according to claim 1, wherein a clear aperture of the rectangular aperture is adjustable.

3. The multifunctional imaging apparatus as claimed in claim 1 or 2, wherein the microlens cell diameter ranges from 2/3 smaller than the microlens cell pitch and 1/4 larger than the microlens cell pitch.

4. A multifunctional imaging device comprises a lens, a focused light field camera body with a micro lens array; it is characterized in that the preparation method is characterized in that,

the light through hole of the diaphragm is rectangular;

the aperture insert is positioned at the lens diaphragm, and at least two light modulation array filters are fixed on the aperture insert; when the light modulation array optical filter is replaced, any one light modulation array optical filter fixed on the aperture inserting sheet can be positioned on the optical axis of the lens by pushing and pulling the aperture inserting sheet, and the plane of the light modulation array optical filter is perpendicular to the optical axis of the lens.

5. The multifunctional imaging apparatus according to claim 4, wherein a clear aperture of the rectangular aperture is adjustable.

6. The multifunctional imaging device as claimed in claim 4 or 5, wherein the diameter of the microlens unit ranges from 2/3 smaller than the pitch of the microlens unit and 1/4 larger than the pitch of the microlens unit.

7. A multifunctional imaging device comprises a lens, a focused light field camera body with a micro lens array; it is characterized in that the preparation method is characterized in that,

the light through hole of the diaphragm is rectangular;

the aperture insert is positioned at the lens diaphragm, and at least two light modulation array filters are fixed on the aperture insert; and replacing the light modulation array filter, and rotating the aperture insert sheet to enable any light modulation array filter fixed on the aperture insert sheet to be positioned on the optical axis of the lens, wherein the plane of the light modulation array filter is perpendicular to the optical axis of the lens.

8. The multifunctional imaging apparatus according to claim 7, wherein a clear aperture of the rectangular aperture is adjustable.

9. The multifunctional imaging apparatus as claimed in claim 7 or 8, wherein the diameter of the microlens unit ranges from 2/3 smaller than the pitch of the microlens unit and 1/4 larger than the pitch of the microlens unit.