TWI594628B - Light-field capturing apparatus - Google Patents

Description

Light field camera

The present invention relates to an image pickup apparatus, and more particularly to a light field image pickup apparatus having a fiber bundle and a microlens array.

A conventional optical fiber bundle imaging device has the principle of capturing light of an object through one end of a fiber bundle, and the light is transmitted from the inside to the other end of the fiber bundle, and the light detecting device disposed at the other end of the fiber bundle receives the light. The light emitted by the fiber bundle is processed to obtain an image of the object. The advantage of using a fiber bundle is that it has a small beam diameter and can be applied to a small wound from a tiny wound into a patient's body, but the image resolution of the camera with the fiber bundle is limited to the fiber bundle. The fiber diameter, the arrangement density and the arrangement mode of the fiber, and the fiber diameter and the arrangement density are limited by the machining precision, and it is difficult to further miniaturize, so that the current image pickup device with the fiber bundle often uses the conjugate focal multiple image scanning. After the image reconstruction, the image resolution is improved. Because the method requires the axial displacement component to perform multi-plane scanning, the cost of the camera device is greatly improved, and the dynamics is insufficient, so that the image resolution is improved. limited.

The main object of the present invention is to enable the microlens array to receive the light emitted by the object through the fiber bundle of the equivalent two-dimensional planar pixels by the cooperation of the microlens array and the fiber bundle, thereby restoring the global light field information of the object. Can effectively improve the image resolution of the camera.

A light field imaging device of the present invention is configured to capture an image of an object, the light field imaging device comprising a fiber bundle, a microlens array and a photosensor array, the fiber bundle having a plurality of optical fibers, each of the optical fiber bundles The optical fiber has a first end and a second end, each of the first ends is for receiving light of the object, and the light of the object is transmitted from the first end of each optical fiber to the second end, the micro a lens array is disposed at the second end of the optical fibers, and the microlens array receives light emitted by the second ends, the photo sensor array is optically coupled to the microlens array, and the microlens array is disposed on Between the fiber bundle and the photosensor array, light emitted by the second end of each of the optical fibers is received by the photosensor array after passing through the microlens array.

According to the configuration of the fiber bundle and the microlens array, the depth of field range of the microlens array is equivalently extended to the front of the fiber bundle to record the global light field information of the object, and can be two-dimensionally The light sensor array senses the four-dimensional light field information of the object, thereby improving the image resolution of the object recorded by the original fiber bundle and the light sensor array.

1 is a cross-sectional view of a light field imaging device 100 for capturing an image of an object O. The light field imaging device 100 includes a fiber bundle 110 (FIG. 1). An optical fiber bundle, a microlens array 120, a light sensor array 130, and a processing device 140, refer to FIG. 2, which is a schematic structural diagram of the fiber bundle 110. In this embodiment, The fiber bundle 110 has a plurality of optical fibers 111, a first cladding layer 112, and a plurality of second cladding layers 113. Each of the second cladding layers 113 covers each of the optical fibers 111 to form a plurality of optical fibers F. The second cladding layer 113 is configured to transmit light in the optical fibers 111 for total reflection, and may prevent the light transmitted in the two optical fibers 111 from interfering with each other. The first cladding layer 112 includes The optical fibers F are covered to protect and restrain the optical fibers F.

Referring to FIGS. 1 and 2, each of the optical fibers 111 has a first end 111a and a second end 111b. The first end 111a of each of the optical fibers 111 is adjacent to the object O to receive the light of the object O. The light of the object O is transmitted from the first end 111a of each of the optical fibers 111 to the second end 111b and is permeable by the second ends 111b. For example, if the transmission distance is not long, for example, the length of the optical fiber bundle 110 2 meters, when the light received by the first end 111a of the optical fiber 111 is transmitted to the second end 111b via the optical fiber 111, the light intensity of the light transmitted through the second end 111b is visible. For no attenuation.

Referring to FIGS. 1 and 3, the microlens array 120 is located at the second end 111b of the optical fiber 111 and spaced apart from the second end 111b. The microlens array 120 has an equivalent focal length, preferably The second ends 111b of the optical fibers 111 are disposed at twice the equivalent focal length to obtain a 1:1 image ratio, thereby avoiding distortion. The microlens array 120 has a plurality of microlenses 121, and the microlenses 121 The lens 121 receives the light emitted by the second ends 111b, and since the microlens array 120 is composed of the microlenses 121, the light beams of different angles of view emitted by the optical fibers 111 of the optical fiber bundle 110 are The global lens field information of the object O can be obtained by the microlens array 120.

Referring to FIGS. 2 and 3, each of the optical fibers 111 of the bundle 110 has a central axis 111c, and a central pitch 111c between adjacent optical fibers 111 has a first pitch P1 (Pitch), and each of the microlenses 121 Having a center point 121a, a second pitch P2 is formed between the center points 121a of the adjacent two microlenses 121. In the embodiment, the first pitch P1 is not less than the second pitch P2, so that the optical fibers 111 are The light rays emitted from different viewing angles may be completely captured by the microlenses 121 on the microlens array 120. Preferably, the first pitch P1 of the adjacent optical fibers 111 is equal to the adjacent microlenses 121. The second pitch P2, but since the mechanical limitation of producing the optical fiber 111 is larger than that of the microlens array 120, the first pitch P1 can be set to a positive integer multiple of the second pitch P2, and the same The light beams of different angles of view emitted by the optical fibers 111 are captured by the microlens array 120 to avoid interference of each pixel of the two-dimensional image to obtain the global light field information of the object O.

Referring to FIG. 1 , in the embodiment, the microlens array 120 has a Depth of field range, and the depth of field range D covers at least the second end 111 b of the optical fibers 111 to the light. The range of the sensor array 130, the second end 111b of each of the optical fibers 111 is located in the depth of field range D of the microlens array 120, thereby enabling the optical fiber to transmit light completely by total reflection. The depth of field range D of the microlens array 120 is equivalently extended to the front of the first end 111a of the optical fibers 111, so that the object O is located in front of the first end 111a of the optical fibers 111. When the lens array 120 has an equivalent depth of field, the microlens array 120 can capture the global light field information of the object O through the fiber bundle 110.

Referring to FIG. 1 , the photo sensor array 130 is optically coupled to the microlens array 120 , and the microlens array 120 is disposed between the fiber bundle 110 and the photo sensor array 130 . The light emitted by the second end 111b of the 111 is received by the photosensor array 130 through the microlens array 120 to generate a two-dimensional image signal, wherein the microlens array 120 captures the whole domain of the object O. Preferably, the photo sensor array 130 is selected from a CCD or CMOS image sensor, and the image sensor having a high effective pixel can be calculated by light field imaging to perform image sensing. Test to facilitate the reconstruction of subsequent images.

Referring to FIG. 1 , the processing device 140 is electrically connected to the photo sensor array 130 to receive the image signal generated by the photo sensor array 130. The image signal carries the four dimensions of the object O. The three dimensions plus time) light field information, therefore, the processing device 140 performs global domain calculation by the correlation between the pixels of the image signal to reconstruct the image, and generates an image of the object O.

Since the light field imaging device 100 can be used as an endoscope, generally operating in a region of low brightness such as a human body or an object, illumination of the auxiliary light source is required to provide light to illuminate the object O, and then the object O can be reflected. Light is delivered to the bundle 110 and received by the first end 111a of the filaments 111. Preferably, the light field camera device 100 further includes a lighting device 150, a tube body 160 and a cover 170. The lighting device 150 has a light emitting portion 151, a transmission portion 152, and a light source 153, the transmission section 152 is connected to the light emitting part 151 and the light source 153. In the embodiment, the transmission section 152 is a light conductor, such as an optical fiber, to transmit the light emitted by the light source 153 to the light emitting part. 151 is emitted by the light emitting portion 151. In other implementations, the light source 153 is a light emitting diode chip, and the light source 153 is disposed on the light emitting portion 151. The transmission segment 152 is a conductor, such as a copper wire, and conducts a power source (not shown) to The light source 153 of the light-emitting portion 151 causes the light source 153 to emit light.

Referring to FIGS. 1 and 4, since the illumination device 150 is configured to provide light to illuminate the object O such that the object O can reflect light to the fiber bundle 110, in the present embodiment, the illumination device 150 The transmitting section 152, the light emitting part 151 and the fiber bundle 110 are covered in the tube body 160, and the light emitting part 151 is adjacent to the first end 111a of the optical fiber wires 111, and the tube body 160 can be used on the one hand. The illuminating device 150 can be moved synchronously with the fiber bundle 110, and the fiber bundle 110 and the illuminating device 150 can be protected on the other hand. The tube body 160 has a detecting end 161, and the first of the optical fibers 111 The end portion 111a and the light emitting portion 151 of the illuminating device 150 are disposed on the detecting end 161 of the tube body 160. Preferably, the tube body 160, the fiber bundle 110 and the transmitting portion 152 of the illuminating device 150 have The flexible body is bent, so that the detecting body 161 is adjacent to the object O, so that the first end 111a of the optical fiber 111 and the light emitting portion 151 of the illumination device 150 can Adjacent to the object O, wherein the illumination device 150 illuminates the object O, and the object O reflects light to the light The first end 111a of the wire 111, the light reflected by the object O is transmitted to the plurality of optical fiber yarn 111 of the second end 111b, the microlens array 120 by capturing light field to obtain the gamut information of the object O. The cover 170 covers the detecting end 161 to seal the detecting end 161 of the tube 160 to protect the bundle 110 and the illumination device 150. The material of the cover body 170 is made of a transparent material to facilitate the penetration of the illumination light of the illumination device 150 with the reflected light of the object O.

The configuration of the fiber bundle 110 and the microlens array 120 is such that the depth of field range D of the microlens array 120 is equivalently extended to the front of the fiber bundle 110 to capture the global light field information of the object O, and The four-dimensional light field information of the object O can be sensed by the two-dimensional photosensor array 130, thereby improving the resolution of the image of the object O.

The scope of the present invention is defined by the scope of the appended claims, and any changes and modifications made by those skilled in the art without departing from the spirit and scope of the invention are within the scope of the present invention. .

100‧‧‧Light field camera
110‧‧‧Fiber bundle
111‧‧‧Fiber wire
111a‧‧‧ first end
111b‧‧‧second end
111c‧‧‧ central axis
112‧‧‧First cladding
113‧‧‧Second coating
120‧‧‧Microlens array
121‧‧‧Microlens
121a‧‧‧ center point
130‧‧‧Photosensor array
140‧‧‧Processing device
150‧‧‧Lighting device
151‧‧‧Lighting Department
152‧‧‧Transport segment
153‧‧‧Light source
160‧‧‧ tube body
161‧‧‧Detection
170‧‧‧ cover
F‧‧‧Fiber
O‧‧‧ objects
D‧‧‧Depth of field range
P1‧‧‧ first spacing
P2‧‧‧Second spacing

Figure 1 is a schematic illustration of a light field imaging device in accordance with an embodiment of the present invention. Figure 2 is a schematic illustration of a fiber bundle in accordance with an embodiment of the present invention. Figure 3 is a schematic illustration of a microlens array in accordance with an embodiment of the present invention. 4 is a schematic view showing the arrangement of a tube body, the fiber bundle, and the illumination device according to an embodiment of the present invention.

100‧‧‧Light field camera

110‧‧‧Fiber bundle

111‧‧‧Fiber wire

111a‧‧‧ first end

111b‧‧‧second end

120‧‧‧Microlens array

130‧‧‧Photosensor array

140‧‧‧Processing device

150‧‧‧Lighting device

151‧‧‧Lighting Department

152‧‧‧Transport segment

153‧‧‧Light source

160‧‧‧ tube body

161‧‧‧Detection

170‧‧‧ cover

O‧‧‧ objects

D‧‧‧Depth of field range

Claims (9)

A light field camera device for capturing an image of an object, the light field camera device comprising: an optical fiber bundle having a plurality of optical fibers, each of the optical fibers having a first end and a second end Each of the first ends is configured to receive light of the object, and the light of the object is transmitted from the first end of each of the optical fibers to the second end; a microlens array is located at the second of the optical fibers And disposed at a distance from the second end, and the microlens array receives light emitted by the second ends; and a photo sensor array optically coupled to the microlens array, and the microlens array is disposed on Between the fiber bundle and the photosensor array, light emitted by the second end of each of the optical fibers is received by the photosensor array after passing through the microlens array, wherein the microlens array has a depth of field The Depth of field range covers at least the range from the second end of the fiber optic to the photosensor array. The light field image pickup device of claim 1, wherein the microlens array has an equivalent focal length, and the second end of the optical fibers is disposed at twice the equivalent focal length. The light field image pickup device of claim 1, wherein the microlens array has a plurality of microlenses, each of the optical fiber bundles has a central axis, and a central axis between adjacent two optical fibers has a The first pitch (Pitch), each of the microlenses has a center point, and a center of the adjacent two microlenses has a second pitch, wherein the first pitch is not less than the second pitch. The light field imaging device of claim 1, wherein the microlens array has a plurality of microlenses, each of the optical fiber bundles has a central axis, and a central axis between the adjacent two optical fibers has a first A pitch (Pitch), each of the microlenses has a center point, and a center of the adjacent two microlenses has a second pitch, wherein the first pitch is a positive integer multiple of the second pitch. The light field image capturing device of claim 1, comprising a processing device electrically connected to the light sensor array to receive an image signal generated by the light sensor array, The processing device processes the image signal to generate an image of the object. The light field image capturing device of claim 1, comprising a lighting device, wherein the lighting device has a light emitting portion adjacent to the first end of the optical fibers, the light emitting portion is configured to provide Light illuminates the object such that the object reflects light and is received by the first end of the optical fibers. The light field image capturing device of claim 6, wherein the lighting device has a transmission section, the transmission section is connected to the light emitting section, and the transmission section, the light emitting section and the fiber bundle are wrapped in a tube body. The tube body has a detecting end, the first end of the optical fiber and the light emitting portion of the illumination device are disposed at the detecting end of the tube body, and a cover body covers the detecting end to seal the The detection end of the tube body. The light field image pickup device of claim 7, wherein the tube body, the fiber bundle, and the transmission section of the illumination device are flexible. The light field image pickup device of claim 1, wherein the fiber bundle has a first cladding layer and a plurality of second cladding layers, and each of the second cladding layers covers each of the optical fibers to form A plurality of optical fibers, the first cladding layer coating the optical fibers.