JP2008197540A - Wide-angle imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a panoramic image whose image quality at both ends equals that in the central portion and which is excellent in appearance, in a wide-angle imaging apparatus imaging the panoramic image. <P>SOLUTION: The wide-angle imaging apparatus includes: a center lens 8c receiving light entering from a front area at a field angle of 40°; right and left side lenses 8l and 8r receiving the light entering from right and left areas at a field angle of approximately 40°; right and left 45-degree right-angle prisms 16l and 16r bending the light entering from the right and left areas at a field angle of approximately 40°, to make the light coincide with the optical axis L of the respective side lens 8l or 8r, and guiding the light; diaphragm apertures 13l and 13r limiting the amount of the light entering the right and left side lenses 8l and 8r; and a diaphragm aperture 13c limiting the amount of the light entering the center lens 8c. The wide-angle imaging apparatus is configured so that the diameter of the diaphragm aperture 13c of the center lens 8c is set to be smaller than the diameters of the diaphragm apertures 13l and 13r of the side lenses 8l and 8r and the brightnesses of images formed on a light receiving element 3 by the respective lenses are made almost equal to each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wide-angle imaging device.

  Conventionally, in order to obtain a panoramic image or a stereoscopic image with an angle of view exceeding 120 °, a plurality of imaging optical systems including a lens and a CCD light receiving element are provided, and images are captured by the plurality of imaging optical systems. An imaging device that obtains a panoramic image or a stereoscopic image by synthesizing images is known.

  For example, four captured optical systems, a CCD that captures a subject image formed by the photographed optical system, and filters having different transmittances for each of the four captured optical systems, and four captured images. There is known a multi-lens camera that obtains a subject image with a high dynamic range by combining (see, for example, Patent Document 1).

  In addition, in order to prevent the image size and the focusing state between the plurality of images captured by the plurality of imaging units from being different, a distance measuring unit that measures the distance to the object (subject) is provided, and the distance An image input device that separately adjusts the focus and the like of a plurality of imaging units based on the distance measured by the measuring means is known (see, for example, Patent Document 2).

  On the other hand, a compound-eye imaging device including a compound-eye optical system configured by a plurality of optical blocks and an imaging element that captures a plurality of images formed by the plurality of optical blocks is known (for example, Patent Document 3 and (See Patent Document 4).

Furthermore, an omnidirectional image capture device including a prism used for confirming the rear of an automobile is known (see, for example, Patent Document 5).
JP 2002-281361 A JP 2001-148866 A JP 2005-167443 A JP 2002-171430 A Utility Model Registration No. 3118678

  By the way, in order to pick up a panoramic image by condensing light from a wide-angle object angle exceeding 120 ° by one optical system, a super-wide-angle lens such as a fisheye lens is necessary, and the captured image is large. There is a problem that barrel distortion occurs.

  Therefore, in order to capture a shooting angle of about 120 ° with a small optical system using a normal lens with a small distortion angle of view of about 40 °, the front angle with the shooting angle shifted by about 40 ° is used. It is conceivable that the light is divided into three regions, that is, the left and right regions of the region and the front region (hereinafter referred to as the left and right regions), and the light from each region is collected by separate optical systems.

  In order to construct an optical system in which the condensing angle is shifted by approximately 40 °, a structure in which the directions of the lenses of each optical system are inclined by 40 ° with respect to each other can be considered. Therefore, it is difficult to provide a minute lens with an inclination of exactly 40 °. As a structure including an optical system in which the entire imaging apparatus can be easily designed to be small and the angle of light collection is shifted by approximately 40 °, a prism is added to the compound-eye imaging apparatus described in Patent Document 3 and Patent Document 4. A combined structure is possible.

  Specifically, a prism that bends the condensing path is disposed on the subject side of the optical lens array provided in the compound eye imaging device, and light from the left and right regions passes through the prism, and 2 of the plurality of lenses of the optical lens array. A structure in which light is incident on one lens and light from the front region is incident on another lens without passing through a prism is conceivable.

  However, in the imaging device having the above structure, the left and right region images formed by the light incident on the compound eye imaging device through the prism and the front region formed by the light incident on the compound eye imaging device without passing through the prism are obtained. Since there is a difference in brightness between images, it is necessary to perform brightness correction in the process of digital processing for joining the three images, and to adjust the brightness of the three images substantially equally.

  In other words, the amount of light incident on the prism is reduced due to reflection on the outer peripheral surface of the prism and scattering inside the prism, so the left and right image formed by the light incident on the compound-eye imaging device via the prism is more prismatic. In order to join three images and reproduce them into a series of panoramic images, the brightness of the images in the left and right regions is lower than the image in the front region formed by light incident on the compound-eye imaging device without passing through It is necessary to make corrections to compensate for this.

  Specifically, brightness correction in the course of digital processing is performed by multiplying image brightness data by a preset correction constant (usually a value greater than 1). Is reduced in inverse proportion to the correction constant, the density gradation of the image in the left and right areas to which a larger correction constant is applied is greatly reduced as compared with the image in the front area. When two images are joined, the image quality in the left and right areas may be coarser than the image quality in the front area, resulting in a poor-looking image.

  Accordingly, the present invention provides a wide-angle imaging device for capturing a panoramic image, which can be configured with as few optical systems as possible without using a wide-angle lens, and separate images formed by light incident from different shooting angles. In the image after the correction for adjusting the brightness, a large difference in density gradation does not occur, and a good-looking panoramic image can be obtained without conspicuous joint portions, and the entire apparatus is not bulky. It is an object to provide a wide-angle imaging device that can be configured to be thin.

  In order to achieve the above object, a first aspect of the present invention is a lens optical system that collects light incident from a wide angle of view for each predetermined angle of view to form a plurality of images on a focal plane. Imaging means for converting a plurality of images formed on the focal plane and formed by the lens optical system into electronic image information, and performing brightness correction on the image information of the plurality of images converted by the imaging means. And a center lens that receives light incident from a region of approximately 40 ° in front of the object angle. The left and right side lenses, which are disposed on both the left and right sides of the center lens and receive the light incident from approximately 40 ° on the left and right sides of the subject angle, are parallel to the center lens. Formed on The optical lens array is arranged on the light incident side of the left and right side lenses so that light incident from a region of about 40 ° on the left and right sides of the subject angle coincides with the optical axis of each side lens. Left and right 45 ° right-angle prism or 60 ° -30 ° right-angle prism bent and guided to each side lens and the left and right side lenses via the left-right 45 ° right-angle prism or 60 ° -30 ° right-angle prism A side lens aperture that limits the amount of light incident on the center lens, and a center lens aperture that limits the amount of light incident on the center lens larger than the side lens aperture, and the imaging means includes the optical lens. A light receiving device that is arranged in parallel to the optical lens array at a predetermined distance from the array and that captures images formed by the center lens and the left and right side lenses, respectively. The image reproducing means includes an image of a region of approximately 40 ° in front of the shooting angle converted into image information by the light receiving element array, and a region of approximately 40 ° to the left and right of the shooting angle. Each image is subjected to brightness correction, and the images subjected to brightness correction are combined and reproduced as a panoramic image having an angle of view of 120 ° or more.

  According to a second aspect of the present invention, there is provided a lens optical system that collects light incident from a wide angle of field for each predetermined field angle to form a plurality of images on a focal plane, and is disposed on the focal plane. A panoramic image obtained by joining a plurality of images formed by the lens optical system to electronic image information and image information of the plurality of images converted by the imaging unit after performing brightness correction. In the wide-angle imaging device, the lens optical system is disposed on both the left and right sides of the center lens, and a center lens that receives light incident from a front area at the object angle. An optical lens array in which a lens and an optical axis are parallel, and left and right side lenses that receive light incident from the left and right regions within the angle of field are formed on one plane, and the light of the left and right side lenses Enter And a prism that guides the light incident from the left and right regions within the field angle to the side lenses by bending the light to coincide with the optical axis of the side lenses, and guided by the prisms. Side light quantity limiting means for limiting the amount of light condensed on the imaging means through the side lens, and the amount of light that is directly incident on the center lens and condensed on the imaging means without passing through the prism A center light amount limiting unit that limits the amount of light more than the side light amount limiting unit, and the imaging unit is disposed in parallel to the optical lens array at a predetermined distance from the optical lens array, and A light receiving element array for picking up images formed by the side lenses, and the image reproducing means converts image information into image information by the light receiving element array. Brightness correction is performed on the converted image of the front area at the shooting angle and the image of the left and right areas at the shooting angle, and the images subjected to the brightness correction are combined and reproduced as a panoramic image. Features.

  According to a third aspect of the present invention, in the second aspect of the invention, the side light amount limiting unit and the center light amount limiting unit are diaphragm apertures disposed close to the side lens and the center lens, respectively. To do.

  According to a fourth aspect of the present invention, in the second aspect of the invention, the side light amount limiting unit and the center light amount limiting unit are filters coated on the surfaces of the side lens and the center lens, respectively.

  According to the first aspect of the present invention, light incident from a region of approximately 40 ° in front of the shooting angle is received by the center lens, and light incident from approximately 40 ° left and right of the shooting angle is Since the light is received by the side lens, the apparatus can be configured with as few optical systems as possible without using a wide-angle lens. In addition, a side lens aperture that limits the amount of light that enters the left and right side lenses via the left and right 45 ° right angle prisms or 60 ° -30 ° right angle prisms, and the amount of light that is directly incident on the center lens, Since it has a center lens aperture that restricts more than the aperture, the value of the correction constant for adjusting the brightness of the image in the front area and the image in the left and right areas in the process of digital processing can be made a value that does not differ greatly. A large difference in density gradation does not occur between the image of the front area and the left and right areas after the brightness correction is performed, and a panoramic image having a good appearance can be obtained without conspicuous joint portions.

  According to the second aspect of the present invention, the light incident from the front area of the shooting angle is received by the center lens, and the light incident from the left and right areas of the shooting angle is received by the left and right side lenses. The apparatus can be configured with as few optical systems as possible without using it. Further, the side light quantity limiting means for limiting the amount of light condensed on the imaging means via the prism, and the amount of light directly incident on the center lens and condensed on the imaging means are larger than those of the side light quantity limiting means. Since the center light quantity limiting means for limiting is provided, the value of the correction constant for adjusting the brightness of the image in the front area and the image in the left and right areas in the process of digital processing can be set to a value that does not differ greatly. A large difference in density gradation does not occur between the image of the front area and the left and right areas after the correction, and a panoramic image having a good appearance can be obtained without conspicuous joint portions.

(First embodiment)
A first embodiment according to the present invention will be described below with reference to FIGS. As shown in FIGS. 1 and 2, the wide-angle imaging device 1 of this embodiment includes a lens optical system 2 that collects light incident from a shooting angle of 120 ° and forms an image on a predetermined focal plane, A light receiving element array (imaging means) 3 that is arranged on the focal plane of the lens optical system 2 and converts an image formed by the lens optical system 2 into electronic image information, and image information converted by the light receiving element array 3 A DSP (Digital Signal Processor) 5 that is captured as a digital signal via the AD converter 4, and a microprocessor that performs image processing such as distortion removal and brightness correction on the image information captured by the DSP 5 to reproduce a panoramic image ( An image reproducing means) 6 and a display device 7 such as a liquid crystal panel for displaying an image reproduced by the microprocessor 6.

  As shown in FIGS. 1 and 3, the lens optical system 2 of the present embodiment includes nine optical lenses 8 in three rows and three columns whose optical axes L are parallel to each other on one plane of one transparent substrate 9. The optical lens array 11, the support frame 12 of the optical lens array 11, the aperture openings 13l, 13c, 13r formed on the upper surface of the support frame 12, and the light emitted from the optical lenses 8 do not interfere with each other. The light shielding frame 14 partitioned in this way, the optical filter 15 disposed above the light receiving element array 3, and the light incident side of the optical lens array 11 are disposed to face the left and right optical lenses 8 l and 8 r, respectively. And 45 ° right-angle prisms 16l and 16r. The nine optical lenses 8 all have an angle of view of 40 °.

  The 45 ° right-angle prisms 16l and 16r have a right-angled isosceles triangle, and are inclined with respect to the optical lens array 11 as shown in FIG. The specific arrangement will be described in detail later.

  Three optical lenses (hereinafter referred to as a center lens) 8c in the center row of the optical lens array 11 directly receive light incident from a region of approximately 40 ° in front of the object angle, and each of the three lenses in the left and right rows. The optical lenses (hereinafter referred to as side lenses) 8l and 8r receive light incident from the regions of approximately 40 ° on the left and right of the object angle via 45 ° right-angle prisms 16l and 16r, respectively.

  The 45 ° right-angle prisms 16l and 16r receive light from one side 16la and 16ra facing outward from the two sides 16la, 16lb, 16ra and 16rb across the right angle, and the incident light is reflected by the oblique sides 16lc and 16rc. It arrange | positions so that it may radiate | emit from one side 16lb and 16rb. In the present specification, for convenience of describing the light incident surface, the light emitting surface, and the like of the prism in comparison with the side view (FIG. 2) showing the light traveling path, “one side”, “ This is indicated using terms such as “slope side”.

  Specifically, as shown in FIG. 2, the 45 ° right-angle prisms 16l and 16r are arranged such that the sides 16lb and 16rb facing the side lenses 8l and 8r are inclined at an angle of 25 ° with respect to the optical lens array 11. The oblique sides 16 lc and 16 rc are arranged so as to be inclined at an angle of 70 ° with respect to the optical lens array 11. Accordingly, the 45 ° right-angle prisms 16l and 16r do not exist in a range of approximately 40 ° in the front direction from the center lens 8c, and the light incident on the center lens 8c is configured not to be blocked.

  Among the two sides 16la, 16lb, 16ra, 16rb sandwiching the right angle of the 45 ° right-angle prisms 16l, 16r, light in an angle range of about 40 ° is incident on the side lens 8l. , 8r and focused on the light receiving element array 3.

  The diaphragm aperture 13c (center light amount limiting means) of the center lens 8c into which the light from the subject directly enters without being blocked by the 45 ° right-angle prisms 16l and 16r allows the light from the subject to pass through the 45 ° right-angle prisms 16l and 16r. Are formed with a smaller diameter than the apertures 13l and 13r (side light quantity limiting means) of the side lenses 8l and 8r that are incident on the side lenses 8l and 8r, so that the quantity of light reaching the light receiving element array 3 is more restricted (see FIG. (See FIG. 3).

  Specifically, the diameters of the apertures 13c, 13l, and 13r are set so that the amount of light emitted from the center lens 8c and the side lenses 8l and 8r and reaching the light receiving element array 3 is substantially equal. .

  Next, the light receiving element array 3 will be described. The light receiving element array 3 is a solid-state image sensor that is parallel to the optical lens array 11 and is disposed on the focal plane of each optical lens 8 of the optical lens array 11, and is a CMOS (Complementary) formed on the substrate. (Metal Oxide Semiconductor) image sensor. The solid-state imaging device may be a CCD (Charge Coupled Device).

  On the light receiving element array 3, an individual image of 3 rows and 3 columns is formed by the optical lens 8 of 3 rows and 3 columns. A mode of the monocular image 17 formed on the light receiving element array 3 will be described in detail with reference to FIG. Now, in front of the wide-angle imaging device 1, subjects B displayed as “L”, “C”, and “R” are arranged at equal intervals of 40 ° over a 120 ° field angle as shown in FIG. It is assumed that In this case, the center “C” (region of 40 ° in the center) is inverted vertically and horizontally by the center lens 8 c and is formed as three single-eye images 17 on the center row of the light receiving element array 3.

  The left “L” (left 40 ° region) and the right “R” (right 40 ° region) are vertically reversed by the 45 ° right-angle prisms 16r and 16l and then vertically moved by the side lenses 8r and 8l, respectively. In addition, the left and right sides are inverted, and three individual images 17 are formed on the left and right columns of the light receiving element array 3.

  After these nine single-eye images 17 are converted into image information by the light receiving element array 3, the microprocessor 6 sequentially reads out the image information, and the image in which the top, bottom, left and right are inverted as described above is correctly oriented. The image “C” in the front area and the images “L” and “R” in the left and right areas are joined and the brightness is corrected.

  Next, the reproduction of the image information to the panoramic image P and the correction of the brightness of the image performed by the microprocessor 6 will be described with reference to FIGS. 5, 6A, and 6B. 5 represents an image viewed from the object B side in FIG. 4, and the image on the left side of FIG. 5 shows a state of being formed on the light receiving element array 3, and the image at the center and the right side of FIG. The image is captured by the microprocessor 6 and shows a state in the middle of being processed in the microprocessor 6.

  As shown in the center of FIG. 5, the image information sequentially read by the microprocessor 6 has the left and right columns in opposite positions and the left and right column images 17 themselves are left and right as shown in the center of FIG. 5. Inverted. This image information is interchanged by the microprocessor 6 in the positions of the left and right rows of images 17, and the image itself is horizontally reversed and reproduced as a panoramic image P with an angle of view of 120 ° as shown on the right side of FIG. Is done.

  Specifically, the microprocessor 6 performs image processing on image information of three single-eye images (portions indicated by thick frames 18 in the center of FIG. 5) in the center row. The microprocessor 6 first mirror-inverts the left-right inverted “L” (left 40 ° region image) and “R” (right 40 ° region image) single-eye image 17 to return it to a normal image. The restored images “L” and “R” are combined with the image “C” in the central 40 ° region and reproduced as a 120 ° panoramic image P.

  Further, the microprocessor 6 performs brightness correction in the following order when joining the images “L”, “C”, and “R” whose positions and orientations have been returned to normal as described above.

  The microprocessor 6 stores in advance a correction constant C (x, y) for brightness correction, which is a function of the position (x, y) on the image, in the ROM 6a of the microprocessor 6 itself.

  As shown in FIG. 6B, the correction constant C (x, y) in the present embodiment is assigned an x coordinate in the horizontal direction of the image and a y coordinate in the vertical direction. A constant is uniquely determined for the plane position (x, y) to be corrected. The image shown in FIG. 6B corresponds to the image on the right side of FIG.

  Now, the correction constant C (x, y1) when the y coordinate is y1 (vertical center position in the image of FIG. 6B) is shown in FIG. 6A.

  That is, as shown in FIGS. 6A and 6B, the correction constant indicated by the curve Cl is applied to the middle line portion (y = y1) of the image “L” in the left region, and the front surface The correction constant indicated by the curve Cc is applied to the middle line portion (y = y1) of the image “C” in the region, and the middle line portion (y = y1) of the image “R” in the right region. Is applied with the correction constant indicated by the curve Cr, and the brightness constant of the pixel in each image is multiplied by the correction constant.

  For example, the correction constant = 2 is applied to the pixel p1 at the left end of the middle line portion (y = y1) of the image “L”, and the brightness is corrected by a factor of 2, and the pixel p2 at the center is corrected. , The correction constant = 1 is applied and the brightness is left as it is, and the correction constant = 1.5 is applied to the leftmost pixel p3 of the middle line portion (y = y1) of the image “C”. Is corrected to 1.5 times, and the correction constant = 1 is applied to the pixel p4 at the center position, and the brightness is left unchanged.

  It should be noted that the correction constants for the images “L”, “C”, and “R” are all drawn in a quadratic curve having downwards because the images “L”, “C”, and “R” are all of the optical lens 8. This is because it is formed by the light collecting action. That is, the peripheral portion of each image is less bright than the central portion, so a relatively large correction constant is applied.

  As described above, when the microprocessor 6 performs the brightness correction on each of the images “L”, “C”, and “R”, the pixel position is included in the brightness data for all the pixels in each image. A corrected constant C (x, y) corresponding to (x, y) is multiplied as a digital value to generate a corrected image.

  In the wide-angle imaging device 1 of the present embodiment, the aperture 13c of the center lens 8c into which light from the subject B directly enters is a side lens through which light from the subject B enters through 45 ° right-angle prisms 16l and 16r. Since the light amount reaching the light receiving element array 3 is more greatly limited by being formed in a smaller diameter than the aperture openings 13l and 13r of 8l and 8r, the front area formed on the light receiving element array 3 and the left and right areas The image 17 itself is formed into an image having no large brightness difference, and the correction constant (curve Cc) for the image “C” in the front area and the correction constants (curves Cl, Cr for the images “L” and “R” in the left and right areas. ) Does not have a big difference.

  Here, for comparison, a correction constant Ct (x, y1) when the apertures 13c of the center lens 8c and the apertures 13l and 13r of the side lenses 8l and 8r have the same diameter (hereinafter referred to as a comparative example) is used. In FIG. 6A, curves Ct and Crt (two-dot chain lines) are shown. In the case of the comparative example, the brightness of the images “L” and “R” in the left and right regions is relatively decreased with respect to the image “C” in the front region. The correction constants (curves Clt, Crt) for the images “L” and “R” in the region are larger than the correction constants (curves Cl, Cr) in the present embodiment.

  Specifically, the correction constant Ct (x, y1) in the comparative example for the images “L” and “R” is a value ranging from 1.5 to 3. (For example, the correction constant for the pixel p1 in the image “L” ≈3, the correction constant for the pixel p2≈1.5)

  Here, since the number of gradations displayed on the display device 7 is given by density gradation / correction constant value, when the density gradation is 256, the area around the pixel p1 of the image “L” in the comparative example is The number of gradations decreases to about 256 / 3≈85.

  On the other hand, the number of gradations displayed on the display device 7 in the wide-angle imaging device 1 of the present embodiment is such that the magnitude of the correction constant ranges from 1 to 2 for each of the images “L”, “C”, and “R”. Therefore, a value of about 256 to 128 is obtained. Accordingly, it is possible to prevent the panoramic image P that is reproduced by joining the images “L”, “C”, and “R” from being greatly deteriorated in the panoramic image P on both sides and thus becoming a poor-looking panoramic image P. The

  Note that each of the images “L”, “C”, and “R” is an image of a region of approximately 40 °, and therefore, three images are joined together with almost no overlapping portion of the joined portions. Further, since the center lens 8c and the side lenses 8l and 8r are lenses having an angle of view of 40 °, unlike the so-called wide-angle lens, the distortion of the outer peripheral portion of each image hardly occurs, and the complex distortion with respect to each image at the time of joining the images. No correction process is required.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. The wide-angle imaging device 1 of the second embodiment has almost the same configuration as that of the first embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted.

  The second embodiment is different from the first embodiment in that a 60 ° -30 ° right-angle prism 26l is used instead of 45 ° right-angle prisms 16l, 16r as prisms arranged on the light incident side of the optical lens array 11. , 26r are arranged. As shown in FIG. 7, the 60 ° -30 ° right-angle prisms 26l and 26r are prisms having a cross section of a right triangle and two angles facing at right angles formed at 60 ° and 30 °.

  The 60 ° -30 ° right-angle prisms 26l, 26r have long sides that sandwich the right angle, with the short sides 26lb, 26rb of the two sides 26la, 26lb, 26ra, 26rb sandwiching the right angle parallel to the optical lens array 11. 26la and 26ra are arranged so as to be perpendicular to the outside. Therefore, the oblique sides 26 lc and 26 rc have an inclination of 60 ° with respect to the optical lens array 11.

  Then, light from a region of 40 ° left and right with an object angle of 120 ° is incident from the long sides 26la and 26ra of the 60 ° -30 ° right-angle prisms 26l and 26r, reflected by the oblique sides 26lc and 26rc, and the short sides 26lb and 26rb. And is condensed by the side lenses 8l and 8r and formed on the light receiving element array 3 as an image of a region of approximately 40 ° on the left and right.

  Also in the second embodiment, the diaphragm aperture 13c of the center lens 8c is formed with a smaller diameter than the diaphragm apertures 13l and 13r of the side lenses 8l and 8r, and the brightness of each image formed on the light receiving element array 3 is increased. The panorama image is configured to be almost the same, and does not cause a large difference in density gradation between the image of the front area and the left and right areas after brightness correction, and the appearance of the panoramic image is excellent without any conspicuous joints. P can be obtained.

(Third embodiment)
Next, a third embodiment capable of capturing a panoramic image having an angle of view of approximately 180 ° will be described with reference to FIG. The wide-angle imaging device 1 of the third embodiment has substantially the same configuration as that of the first embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted.

  The third embodiment is different from the first embodiment in that each optical lens 8l, 8c, 8r is configured with a lens having an angle of view of 60 ° in order to widen the viewable angle of view. Instead of the 45 ° right-angle prism as the prism on the light incident side of the optical lens array 11, regular triangle prisms 36l and 36r are arranged. As shown in FIG. 8, the equilateral triangular prisms 36l and 36r are prisms having a regular triangular cross section.

  The equilateral triangular prisms 36 l and 36 r are arranged so that the sides 36 lb and 36 rb are parallel to the optical lens array 11. Therefore, the oblique sides 36 lc and 36 rc facing inward have an inclination of 60 ° with respect to the optical lens array 11. Then, light from a region of 60 ° left and right with a field angle of approximately 180 ° is incident from the outer oblique sides 36la and 36ra of the equilateral triangular prisms 36l and 36r, reflected by the inner oblique sides 36lc and 36rc, and the optical lens array. 11 is emitted from the sides 36 lb and 36 rb parallel to 11 and condensed by the side lenses 8 l and 8 r, and is formed on the light receiving element array 3 as an image of a region of approximately 60 ° on the left and right.

  Also in the third embodiment, the diaphragm aperture 13c of the center lens 8c is formed with a smaller diameter than the diaphragm apertures 13l and 13r of the side lenses 8l and 8r, and the brightness of each image formed on the light receiving element array 3 is increased. The panorama image is configured to be almost the same, and does not cause a large difference in density gradation between the image of the front area and the left and right areas after brightness correction, and the appearance of the panoramic image is excellent without any conspicuous joints. P can be obtained.

(Fourth embodiment)
Next, a fourth embodiment capable of capturing a panoramic image with an angle of view of approximately 180 ° will be described with reference to FIGS. 9 and 10. The wide-angle imaging device 1 of the fourth embodiment has substantially the same configuration as that of the first embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted.

  The difference of the fourth embodiment from the first embodiment is that each optical lens 8l, 8c, 8r is composed of a lens having an angle of view of 60 ° in order to widen the viewable angle of view, Instead of a 45 ° right-angle prism as a prism on the light incident side of the optical lens array 11, one large regular triangular prism 46 is arranged. The size of one side of the equilateral triangular prism 46 is configured to be a length extending over three optical lenses 8 l, 8 c, 8 r in one row of the optical lens array 11.

  The equilateral triangular prism 46 is arranged so that one side 46 c is parallel to the optical lens array 11. Therefore, the other two sides 46 a and 46 b have an inclination of 60 ° with respect to the optical lens array 11. Then, light from a region of 60 ° on the left and right sides of the field angle of about 180 ° is incident from the two oblique sides 46a and 46b of the regular triangle prism 46, reflected by the opposite oblique sides 46b and 46a, and emitted from the side 46c. The light is condensed by the side lenses 8 l and 8 r and formed on the light receiving element array 3 as an image of a region of about 60 ° on the left and right.

  On the other hand, the light from the region of approximately 60 ° facing the front is collected by the center lens 8cd (FIG. 10) in the center of the lower row of the optical lens array 11, and on the light receiving element array 3 in the region of approximately 60 ° of the center. It is imaged as an image.

  As in the first embodiment, the left and right 60 ° region images and the central 60 ° region image are reproduced by the microprocessor 6 into a panoramic image P having a field angle of about 180 °. In the case of the fourth embodiment, since it is not necessary to replace the single-eye images in the left and right columns, the procedure of reproduction processing by the microprocessor 6 is simplified accordingly.

  In the fourth embodiment, the aperture opening 13c of the center lens 8cd at the center of the lower row of the optical lens array 11 is formed to have a smaller diameter than the aperture apertures 13l and 13r of the side lenses 8l and 8r. The brightness of each image formed on the array 3 is configured to be substantially equal, and there is no significant difference in density gradation between the front area and the left and right area images after the brightness correction is performed. It is possible to obtain a panoramic image P having a good appearance without conspicuous joint portions.

(Fifth embodiment)
Next, a fifth embodiment that can capture a substantially hemispherical panoramic image in front of the wide-angle imaging device 1 will be described with reference to FIGS. 11 and 12. The wide-angle imaging device 1 according to the fifth embodiment is similar to the panoramic imaging device 1 according to the first embodiment, and includes an optical lens array 11 having nine optical lenses 8 in three rows and three columns, and a predetermined distance from the optical lens array 11. The light receiving element array 3 is provided at a position separated by a distance. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The fifth embodiment is different from the first embodiment in that the prism provided on the light incident side of the optical lens array 11 can collect light from all directions of a substantially hemisphere in 3 rows and 3 columns. The center optical lens 8ce is arranged to face all the remaining eight optical lenses 8f except for the central optical lens 8ce.

  Specifically, as shown in FIG. 11, except for the center optical lens 8ce in the 3 rows and 3 columns, it is radially centered on the center optical lens 8ce at the position facing the remaining eight optical lenses 8f. A 45 ° right angle prism 56 is arranged. The 45 ° right-angle prism 56 is tilted with respect to the optical lens array 11 so that one side facing the optical lens array 11 is inclined at an angle of 25 ° with respect to the optical lens array 11 as in the first embodiment. The oblique side is arranged so as to be inclined at an angle of 70 ° with respect to the optical lens array 11. As a result, the 45 ° right-angle prism 56 does not exist in a range of approximately 40 ° in the front direction from the central optical lens 8ce, and the light from the subject is not blocked by the prism 56, and the central optical lens 8ce. Incident to

  In the fifth embodiment, only one optical lens 8ce at the center of 3 rows and 3 columns is a center lens, and the remaining eight optical lenses 8f correspond to side lenses.

  On the light receiving element array 3, an image of a region of approximately 40 ° in the front is formed as a single-eye image by the center lens 8ce, and regions B1 to B8 (approximately 40 ° of the peripheral side of the approximately hemisphere on the peripheral side are formed by eight side lenses 8f. The images in FIG. 12) are formed as individual images. These nine images (single-eye images) are reproduced by the microprocessor 6 into a substantially hemispherical panoramic image. Each region B1 to B8 has a vertical field angle of 40 ° and a horizontal field angle of 45 °, as shown in FIG.

  In the fifth embodiment, the diaphragm aperture of one central optical lens 8ce is formed with a smaller diameter than the aperture apertures of the remaining eight optical lenses 8f, and each image formed on the light receiving element array 3 is formed. The brightness is almost the same, and there is no significant difference in density gradation between the front and left and right area images after the brightness correction is applied. A panoramic image P can be obtained.

(Sixth embodiment)
Next, the light from the angle of 180 ° is divided into five regions of approximately 36 ° each, and is condensed by separate condensing paths for each of the five regions, so that the light receiving element array 3 has five individual images. A sixth embodiment in which an image is formed will be described with reference to FIG. The wide-angle imaging device 1 according to the sixth embodiment has substantially the same structure as the wide-angle imaging device 1 according to the first embodiment. However, the right and left prisms provided on the light incident side of the optical lens array 11 are two each. is there.

  In the wide-angle imaging device 1 of the sixth embodiment, 45 ° right-angle prisms 66lu and 66ru are respectively opposed to the side lenses 8l and 8r in the upper row of the optical lens array 11 and are 26 ° with respect to the optical lens array 11. The 45 ° right-angle prisms 66ld and 66rd are arranged with an inclination of 10 ° with respect to the optical lens array 11 so as to face the lower side lenses 8l and 8r, respectively.

  The light from the imaging angle of approximately 36 ° in the front area is collected by the center lens 8c in the center row of the optical lens array 11, and the light from the imaging angle of approximately 36 ° adjacent to the left and right of the front area is , 45 ° right angle prisms 66lu and 66ru, and are collected by the side lenses 8l and 8r in the upper row of the optical lens array 11, and light from an angle of view of approximately 36 ° on the outermost side is 45 ° perpendicular. The light enters the prisms 66 ld and 66 rd and is collected by the side lenses 8 l and 8 r in the lower row of the optical lens array 11.

  In the sixth embodiment, the apertures of the center lenses 8c in the center row of the optical lens array 11 are the apertures of the four side lenses 8l and 8r facing the 45 ° right-angle prisms 66lu, 66ru, 66ld, and 66rd. The brightness of each image formed on the light receiving element array 3 is substantially the same, and the density gradation between the images after the brightness correction is large. It is possible to obtain a panoramic image P that does not cause a difference and has a good appearance without a conspicuous joint portion.

  Note that the 45 ° right-angle prisms 66lu and 66ru arranged in the upper row of the optical lens array 11 and the 45 ° right-angle prisms 66ld and 66rd arranged in the lower row have different inclination angles with respect to the optical lens array 11 ( 26 degrees and 10 degrees), the degree of decrease in the amount of light due to the surface reflection of the prism is different, and in order to make the brightness of the individual images formed on the light receiving element array 3 substantially equal, a right angle of 45 degrees The diameters of the apertures of the two side lenses 8l and 8r facing the prisms 66lu and 66ru may be different from the diameters of the apertures of the two side lenses 8l and 8r facing the 45 ° right angle prisms 66ld and 66rd. desirable.

  In the first to sixth embodiments described above, in order to make the amount of light emitted from each optical lens 8 and reaching the light receiving element array 3 substantially equal, the aperture 13c (center light amount limiting means) of the center lens 8c. ) Is set to be smaller than the aperture diameters of the diaphragm apertures 13l and 13r (side light quantity limiting means) of the side lenses 8l and 8r, but can be configured as follows instead.

  That is, a filter with different light transmittance is coated on the surface of the center lens 8c and the side lenses 8l and 8r, and the light transmittance of the filter coated on the center lens 8c is set to the light transmission of the filter coated on the side lenses 8l and 8r. The light quantity reaching the light receiving element array 3 is set to be substantially the same for each optical lens 8.

  In addition, the optical filter 15 disposed above the light receiving element array 3 is configured as a filter having a different light transmittance for each portion partitioned by the light shielding frame 14, and the light of the portion through which the light emitted from the center lens 8c is transmitted. The transmittance is set to be smaller than the light transmittance of the portion through which the light emitted from the side lenses 8l and 8r is transmitted, and the amount of light reaching the light receiving element array 3 is substantially equal for each optical lens 8. May be.

  As described above, according to the wide-angle imaging device 1 of the present invention, light incident from the front area of the shooting angle is received by the center lens 8c, and light incident from the left and right areas of the shooting angle is received by the left and right side lenses. Since light is received at 8l and 8r, the apparatus can be configured with as few optical systems as possible without using a wide-angle lens, and prisms 16l, 16r, 26l, 26r, 36l, 36r, 46, 56, 66lu, 66ru, 66ld, 66rd Then, the side light quantity limiting means 13l and 13r for limiting the amount of light condensed on the light receiving element 3 and the amount of light directly incident on the center lens 8c and condensed on the light receiving element 3 are set as side light quantity limiting means 13l, Since the center light amount limiting means 13c that restricts larger than 13r is provided, the brightness of the image in the front area and the image in the left and right areas is adjusted in the process of digital processing. Correction constant value can be set to a value that does not differ greatly, and there is no significant difference in density gradation between the front and left and right image after brightness correction, and the joint is not noticeable. It is possible to obtain a panoramic image P having a good appearance.

1 is a perspective view illustrating a schematic configuration of a wide-angle imaging device according to a first embodiment of the present invention. The side view which shows the lens optical system and the advancing path | route of light in the wide-angle imaging device. FIG. 3 is a side sectional view showing a structure of a lens optical system in the wide-angle imaging device. The perspective view which shows the relationship of the to-be-photographed object over the same wide-angle imaging device and 120 degree of field angles. The figure which shows the process in which the image formed with the lens optical system in the wide-angle imaging device is reproduced | regenerated as a panoramic image. (A) is a figure which shows the example of the correction constant C (x, y1) in the brightness correction | amendment of the same wide-angle imaging device, (b) is a figure which shows the example of the image corresponding to the coordinate of a correction constant. The side view which shows the lens optical system and the advancing path | route of light in the wide angle imaging device which concerns on the 2nd Embodiment of this invention. The side view which shows the lens optical system of the wide-angle imaging device which concerns on the 3rd Embodiment of this invention, and the advancing path | route of light. The side view which shows the lens optical system of the wide-angle imaging device which concerns on the 4th Embodiment of this invention, and the advancing path | route of light. The top view which shows the lens optical system of the same wide angle imaging device. The top view which shows the lens optical system in the wide angle imaging device which concerns on the 5th Embodiment of this invention. The perspective view which shows the relationship between the wide-angle imaging device and a substantially hemispherical subject. The perspective view which shows schematic structure of the wide angle imaging device which concerns on the 6th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wide-angle imaging device 2 Lens optical system 3 Light receiving element array 8c Center lens 8l, 8r Side lens 11 Optical lens array 13c Aperture opening (center lens aperture, center light quantity limiting means)
13l, 13r Aperture aperture (side lens aperture, side light quantity limiting means)
16l, 16r 45 ° right angle prism 17 single eye image (image)
26l, 26r 60 ° -30 ° right angle prism 36l, 36r equilateral triangle prism 46 equilateral triangle prism 56 45 ° right angle prism 66lu, 66ru, 66ld, 66rd 45 ° right angle prism L optical axis P panoramic image

Claims (4)

A lens optical system that collects light incident from a wide angle of view for each predetermined angle of view and forms a plurality of images on a focal plane; and
An imaging means for converting a plurality of images arranged on the focal plane and formed by the lens optical system into electronic image information;
In a wide-angle imaging apparatus, comprising: image reproduction means that reproduces a panoramic image after performing brightness correction on image information of a plurality of images converted by the imaging means,
The lens optical system is
A center lens that receives light incident from an area of approximately 40 ° in front of the shooting angle, and disposed on both left and right sides of the center lens, the center lens and the optical axis are parallel, and the left and right of the shooting angle are An optical lens array in which left and right side lenses each receiving light incident from a region of approximately 40 ° are formed on one plane;
The side lenses arranged on the light incident side of the left and right side lenses are bent so as to coincide with the optical axes of the side lenses by making light incident from a region of approximately 40 ° left and right of the angle of view. Left and right 45 ° right angle prisms or 60 ° -30 ° right angle prisms to guide to
A side lens aperture that limits the amount of light incident on the left and right side lenses via the left and right 45 ° right angle prisms or 60 ° -30 ° right angle prisms;
A center lens aperture that limits the amount of light incident on the center lens to be larger than the side lens aperture, and
The imaging means is
A light receiving element array that is disposed in parallel to the optical lens array at a predetermined distance from the optical lens array and that captures images formed by the center lens and left and right side lenses,
The image reproduction means is
Brightness correction is performed by performing brightness correction on an image in a region of approximately 40 ° in front of the shooting angle converted into image information by the light receiving element array and an image in a region of approximately 40 ° on the left and right of the shooting angle. A wide-angle imaging device, wherein the images subjected to the processing are synthesized and reproduced into a panoramic image having an angle of view of 120 ° or more. A lens optical system that collects light incident from a wide angle of view for each predetermined angle of view and forms a plurality of images on a focal plane; and
An imaging means for converting a plurality of images arranged on the focal plane and formed by the lens optical system into electronic image information;
In a wide-angle imaging apparatus, comprising: image reproduction means that reproduces a panoramic image after performing brightness correction on image information of a plurality of images converted by the imaging means,
The lens optical system is
A center lens that receives light incident from the front area of the shooting angle, and the center lens that is disposed on both the left and right sides of the center lens and is parallel to the optical axis and is incident from the left and right areas within the shooting angle. An optical lens array in which left and right side lenses for receiving light are formed on one plane;
It is arranged on the light incident side of the left and right side lenses, and guides the light incident from the left and right areas within the field angle to the side lenses by bending them so as to coincide with the optical axes of the side lenses. Prism,
Side light quantity limiting means for limiting the amount of light guided by the prism and condensed on the imaging means via the side lens;
A center light quantity limiting unit that limits the amount of light that is directly incident on the center lens without being passed through the prism and is collected on the imaging unit, larger than the side light quantity limiting unit;
The imaging means is
A light receiving element array that is disposed in parallel to the optical lens array at a predetermined distance from the optical lens array and that captures images formed by the center lens and left and right side lenses,
The image reproduction means is
Brightness correction is performed on the image of the front area of the shooting angle converted into image information by the light receiving element array and the image of the left and right area of the shooting angle, and the images subjected to the brightness correction are synthesized. A wide-angle imaging device that reproduces a panoramic image.   3. The wide-angle imaging device according to claim 2, wherein the side light amount limiting unit and the center light amount limiting unit are diaphragm apertures disposed close to the side lens and the center lens, respectively.   The wide-angle imaging device according to claim 2, wherein the side light quantity limiting unit and the center light quantity limiting unit are filters coated on the surfaces of the side lens and the center lens, respectively.

Images