CN101692447B - Multi-CCD super field of view image mosaic photoelectric system - Google Patents

Abstract

The invention discloses a multi-CCD ultra-large field of view image plane splicing photoelectric system, which comprises an imaging optical system with a lens, a rotatable mirror and an image plane circuit board arranged sequentially on the optical path; A circuit board with M*N CCDs that can rotate around the central axis. The mirror and the circuit board can be rotated to work in four positions, the circuit system works four times, so that each CCD obtains images four times, and the whole system only uses one lens and M×N CCDs, and a total of 4×M×N is obtained After a simple splicing process, the system obtains an image whose size is 2M×2N times the size of a single CCD image surface. The present invention has no blind area of the field of view, truly realizes seamless field of view splicing without violent moving parts, and the size of the field of view is not limited by the CCD device, and is suitable for long-distance imaging systems requiring a large field of view and high resolution.

Description

A multi-CCD ultra-large field of view image plane splicing photoelectric system

technical field

The invention relates to a super-large field of view image plane splicing digital imaging photoelectric system.

Background technique

With the increasing development of digital imaging technology, the digital imaging system with CCD (Charge Coupled Device) as the image sensing receiver is widely used in image acquisition fields and systems such as aerospace earth observation, ordinary digital cameras, and infrared imaging systems. .

However, due to the limitation of the number of pixels of the CCD device, even if the optical imaging lens has a very large field of view and high resolution, it is still difficult for the system to obtain a large amount of information. At present, the visible light CCD that can be purchased in the world has a maximum of about 5k×k pixels. If the image plane stitching technology is not used, the highest image resolution that the imaging system can obtain cannot exceed 35M pixels, which cannot meet the growing various imaging needs. Infrared imaging systems have fewer device pixels. For example, the long-wave infrared CCD imaging system, at present, the highest pixel of the uncooled device that can be supplied to my country in the world is 384×288, and the imaging system can only obtain 110,000 pixels of information for a single CCD imaging, making our infrared detection system The imaging field of view, resolution, and detection distance are limited. The current optical digital imaging system, whether it is a visible light or an infrared system, mainly limits the imaging field of view and resolution of the system by the CCD device.

In order to obtain higher resolution and larger imaging field of view, digital imaging system mainly adopts scanning technology and splicing technology. However, the scanning system requires moving parts, which greatly reduces the reliability of the system and is the biggest obstacle to the application in the aerospace field. Although the splicing technology does not require moving parts, since there is generally an edge that cannot be imaged around the imaging area of the CCD device, the size of the left and right or upper and lower edges is close to the size of the imaging area, so direct CCD splicing will result in a very large Imaging blind spots. There is also a scheme to separate the image plane into different spatial positions by using optical spectroscopic method, and then use multiple CCDs to obtain image information separately, but optical spectroscopic is limited by the back intercept of the system, and the spectroscopic system will still cause a certain loss of field of view or Severe vignetting.

Therefore, it is of great significance to invent a large field of view image plane stitching photoelectric imaging system with no moving parts or only simple movement with small amount of movement, no loss of imaging field of view, no vignetting, and high pixel count.

The invention patent with the application number: 200710069052.4 discloses a photoelectric system for seamless splicing of multiple CCDs. However, this invention requires the use of four imaging lenses, four sets of CCD circuit boards, and the optical and electronic systems are four times that of the present invention. , the hardware is complicated, expensive, and not easy to carry.

Contents of the invention

The invention provides a multi-CCD ultra-large field of view image plane splicing photoelectric system, which has no violently moving parts, no missing field of view, and no vignetting, and can realize the imaging system of multi-CCD seamless splicing. With M*N CCDs, Realize the super large field of view image plane of 2M×N CCDs.

The present invention proposes a multi-CCD ultra-large field of view image surface splicing photoelectric system. The whole system mainly includes three parts: an optical imaging system, a rotatable mirror, and a circuit board equipped with M×N CCDs.

The optical imaging system can generally be an optical lens with a large field of view and high resolution, which can be designed, processed or purchased as required (the present invention has no special requirements).

On a circuit board with M×N CCDs installed, the CCDs can be arranged in M columns and N rows, and the values of M and N are not limited in principle, mainly depending on the needs of the overall system and the performance of the optical imaging lens. The center-to-center distance of each adjacent two columns of CCDs on the circuit board is twice the actual photosensitive width X0 in the width direction of each CCD image plane; the center-to-center distance of each adjacent two rows of CCDs is the actual photosensitive width Y0 of each CCD image plane height direction 2 times.

The circuit board can be rotated by piezoelectric ceramics or other micro-rotation mechanisms, and can be used for pitching and left-right rotation, that is, the vertical symmetry axis of the CCD can be used as the rotation axis for left-right rotation, and the CCD horizontal symmetry axis can be used for pitch rotation. Ensure that the surface of the CCD on the rotated circuit board is perpendicular to the optical axis of the light reflected by the mirror.

The mirror installed on the image-side optical path of the optical imaging system can be rotated by piezoelectric ceramics or other micro-rotating mechanisms, so that the image-side field of view of the imaging optical system can be displaced relative to the circuit board on which the CCD is installed. The reflector should have at least four working positions with different reflection angles. The first working position makes the center of the optical axis of the imaging optical system be located at (-X0/2, Y0/2) above the center of the circuit board, and the second The working position makes the center of the optical axis of the imaging optical system be located at (X0/2, Y0/2) above the center of the circuit board. (-X0/2, -Y0/2) position, the fourth working position makes the optical axis center of the imaging optical system be located at the (X0/2, -Y0/2) position below the center right of the circuit board.

When the reflector is in each working position, the CCD and the circuit system work once, four times in total, so that each CCD obtains images four times, and the whole system obtains 4×M×N images in total. According to the relative positional relationship of the four working positions of the mirror and the layout of the CCD on the circuit board, the field of view of the four imaging is exactly the complementary position, and the optical conjugate just fills the entire field of view of the image plane. After simple splicing, the system Obtain an image whose size is 2M×2N times the size of a single CCD image surface, and realize the seamless splicing of CCD.

The present invention does not have a blind area of the field of view, and truly realizes seamless and vignetting-free field of view splicing, and the size of the field of view is not limited by the CCD device. As long as the optical imaging lens allows it, the theoretical imaging field of view of the system is infinite. The amount of movement of the moving parts is very small and can be rotated under the control of controllers such as piezoelectric ceramics.

The present invention only needs one imaging lens and M*N blocks of CCD in total, so that the system can obtain a large field of view image of 2M*2N times that of the CCD, and the M and N values are not limited, completely solving the problem of optical imaging due to the insufficient size of the CCD device Due to the limited field of view of the system, it is very suitable for long-distance imaging systems that require a large field of view and high resolution, such as satellite remote sensing, aircraft aerial photography, infrared reconnaissance and air defense and other fields.

Description of drawings

Fig. 1a is a diagram showing the relative positions of an optical imaging lens, a mirror, and a circuit board.

Figure 1b is a front view of the reflector.

Figure 1c is a front view of the circuit board.

Figures 2a-2d are diagrams showing the relationship between the center position of the image plane of the optical system and the circuit board in the four working positions of the reflector, respectively.

Figures 3a-3d are the images obtained by the CCD in the four working positions of the mirror respectively.

Fig. 3e is an effect diagram after combining the images acquired four times.

Detailed ways

As shown in Figure 1a, a multi-CCD ultra-large field of view image plane splicing photoelectric system includes three parts: an optical imaging system, a rotatable mirror, and a circuit board equipped with M×N CCDs. The optical imaging system can be an optical lens with a large field of view and high resolution, which can be designed, processed or purchased as required. Figure 1b is a front view of the reflector, where O1 is the center of the reflector, u-axis is the horizontal symmetry axis of the reflector, and v is the vertical symmetry axis of the reflector. Figure 1c is a front view of the circuit board, O is the center of the circuit board (the center of the CCD imaging area), the x-axis is the horizontal symmetry axis of the circuit board, and the y-axis is the vertical symmetry axis of the circuit board. The photosensitive area of each CCD is X0 in the horizontal direction and Y0 in the vertical direction. The center-to-center distance of each adjacent two columns of CCDs on the circuit board is twice the actual photosensitive width X0 in the width direction of each CCD image plane; the center-to-center distance of each adjacent two rows of CCDs is the actual photosensitive width Y0 of each CCD image plane height direction 2 times.

2a-2d are the positions of M×N CCDs on the circuit board of the present invention and the image-side field of view of the optical system. Figure 2a is the positional relationship between the center of the image plane of the optical system and the circuit board when the mirror is in the first position; Figure 2b is the positional relationship between the center of the image plane of the optical system and the circuit board when the mirror is in the second position; Figure 2c is the positional relationship between the center position of the image plane of the optical system and the circuit board when the reflector is in the third position; Figure 2d is the positional relationship between the center position of the image plane of the optical system and the circuit board when the reflector is in the fourth position. The outer circle in Fig. 2a, 2b, 2c, and 2d is the imaging range of the optical imaging lens, and the geometric center o of the outer circle is the center of the field of view of the image square, that is, the intersection point of the optical axis and the image plane. The small squares in the figure are CCD devices, and the CCDs can be arranged in M columns and N rows (3 columns × 3 rows in the figure), and the values of M and N are not limited in principle.

The mirror rotates through piezoelectric ceramics or other micro-rotating mechanisms, so that the image-side field of view of the imaging optical system can be displaced relative to the circuit board on which the CCD is installed. The circuit board rotates through piezoelectric ceramics or other micro-rotation mechanisms, and can do pitching and left-right rotation, that is, it can use the CCD vertical symmetry axis as the rotation axis to do left-right rotation, and use the CCD horizontal symmetry axis as the rotation axis to do pitch rotation to ensure rotation The surface of the CCD on the final circuit board is perpendicular to the optical axis of the light reflected by the reflector.

The reflector should have at least four working positions. The first position makes the center of the optical axis of the imaging optical system at the (-X0/2, Y0/2) position above the left of the center of the circuit board, as shown in Figure 2a; the second The first position makes the center of the optical axis of the imaging optical system be located at (X0/2, Y0/2) above the center of the circuit board, as shown in Figure 2b; the third position makes the center of the optical axis of the imaging optical system located on the circuit board The (-X0/2, -Y0/2) position below the center left, as shown in Figure 2c; the fourth position makes the optical axis center of the imaging optical system located at (X0/2, -Y0/2) below the center right of the circuit board. Y0/2) position, as shown in Figure 2d.

When the reflector is in each working position, the CCD and the circuit system work once, four times in total, so that each CCD obtains images four times, and the whole system obtains 4×M×N images in total. Figure 3a is the image obtained by all the CCDs during the first work, Figure 3b is the image obtained by all the CCDs during the second work, Figure 3c is the image obtained by all the CCDs during the third work, and Figure 3d is the image obtained by the fourth work Images obtained by all CCDs.

According to the relative positional relationship of the four working positions of the reflector and the layout of M×N CCDs on the circuit board, the field of view of the four imaging is exactly the complementary position. After a simple splicing process, the system obtains a single CCD image A completely continuous image with a surface size 2M×2N times larger, as shown in Figure 3e.

Claims (2)

1. A multi-CCD super large field of view image plane splicing optoelectronic system, comprising an imaging optical system, a reflective mirror and an image plane circuit board arranged successively on the optical path, is characterized in that: the described image plane circuit board is distributed with M × N CCDs arranged in a matrix, the center-to-center distance of two adjacent CCDs in the width direction of the image plane on the circuit board is twice the actual photosensitive width of each CCD in the width direction of the image plane; the center-to-center distance of two adjacent CCDs in the height direction of the image plane is each 2 times of the actual photosensitive width in the height direction of the CCD image plane; The reflective mirror is rotatable, and the image plane circuit board can also rotate around the center. The reflector can rotate and work in four positions, and the image plane circuit board also rotates four positions accordingly, and the CCD receives the scene reflected by the reflector. Corresponding to a quarter of the imaging field of view of the system, the mirror and the circuit board correspond to the entire imaging field of view after four working positions and four times of imaging. The whole system only uses one lens and M*N CCDs. A total of 4*M*N images are obtained for one imaging, and after splicing processing, the system obtains an image whose size is 2M*2N times the size of a single CCD image surface; The first working position of the reflector makes the center of the optical axis of the imaging optical system be located above the center of the circuit board to the left, that is, the center of the circuit board is the origin, and the width of each CCD image plane is shifted to the left along the direction of the width of the image plane. One-half of the actual photosensitive width in the direction, offset upwards along the height direction of the image surface by one-half of the actual photosensitive width of each CCD in the direction of the image surface height; the second working position makes the center of the optical axis of the imaging optical system on the circuit board The upper right of the center, that is, taking the center of the circuit board as the origin, offset to the right along the image width direction of each CCD by half of the actual photosensitive width of the image width direction, and offset each CCD image upward along the image height direction One-half of the actual photosensitive width in the direction of surface height; the third working position makes the center of the optical axis of the imaging optical system be located below the left of the center of the circuit board, that is, take the center of the circuit board as the origin and shift to the left along the width of the image surface One-half of the actual photosensitive width in the width direction of each CCD image plane, and one-half of the actual photosensitive width in the height direction of each CCD image plane along the height direction of the image plane; the fourth working position makes the imaging optical system The center of the optical axis is located at the lower right of the center of the circuit board, that is, taking the center of the circuit board as the origin, offset to the right along the width direction of the image plane by half of the actual photosensitive width of each CCD in the direction of the width of the image plane, and along the direction of the height of the image plane Offset down by half of the actual photosensitive width in the height direction of each CCD image plane. 2. The image plane splicing photoelectric system according to claim 1, characterized in that: the circuit board is rotated left and right with the vertical symmetry axis of the CCD as the rotation axis or pitched with the horizontal symmetry axis of the CCD as the rotation axis, so that the rotation The surface of the CCD on the final circuit board is perpendicular to the optical axis of the light emitted by the reflector. the

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