WO2016206002A1 - Catadioptric lens assembly and panoramic image acquisition device - Google Patents

Abstract

A catadioptric lens assembly (210) comprising one or two or more lens elements, having a first reflection surface (212), a second reflection surface (213) and at least one refraction surface (214, 215, 216) for converging incident light. The first reflection surface (212) is provided after all of the refraction surfaces (214, 215, 216) in a light incidence direction, and is not present in a region surrounding an optical axis (201). The second reflection surface (213) is opposite the first reflection surface (212) and is provided at the region surrounding the optical axis. Further provided is a panoramic image acquisition device comprising the catadioptric lens assembly (210) and a photosensitive module (220). The photosensitive module (220) can be installed facing a photographic field in the normal manner.

Description

 Folding lens group and panoramic image capturing device

Technical field

The present invention relates to the field of image technology, and in particular, to a catadioptric lens group and a corresponding panoramic image capturing device.

Background technique

A device that is capable of acquiring an image of an annular region around 360 degrees is generally referred to as a panoramic image capture device. With the development of digital imaging technology, especially the increasing number of pixels and image processing capabilities, the use of panoramic image acquisition devices is becoming more and more common.

The existing panoramic image technologies include the following:

1. Rotate the image around the axis using an ordinary image capture device, and then seamlessly stitch the images to obtain a panoramic image. This method requires a large amount of image stitching calculation, it is difficult to ensure real-time performance, and continuous shooting is impossible for the same position, and it is difficult to record a continuous video.

2. A fisheye lens is attached to the front end of the photosensitive device, and the super wide angle is used for panoramic imaging. Due to the large distortion of the fisheye lens, it is difficult to obtain a high quality image restoration effect.

3. The panoramic image is obtained by using a mirror. As shown in FIG. 1, the light from the shooting area AA is reflected by the rotationally symmetrical curved mirrors BB and CC, and then enters the photosensitive module DD for imaging. This technique has less distortion, but requires discrete reflective elements, the mounting accuracy is not easy to control, and the amount of light actually entering the photosensitive module is small, making it difficult to obtain a clear image.

To provide a more efficient panoramic image acquisition device. The present inventors have proposed a panoramic image capturing device using a catadioptric lens group in the Chinese invention patent application entitled "panoramic image capturing device" on the application date of CN201510183168.5, filed on April 17, 2015. For one embodiment, reference may be made to FIG. 2, which includes a catadioptric lens group and a photosensitive module. The catadioptric lens group is composed of three lens elements L01, and the light is incident from the frontmost refractive surface S02, and is reflected by the reflecting surface R03 to enter the photosensitive state. The photosensitive module includes a photosensitive device C04 and a second lens group L05, and a line channel P06 of the photosensitive module is formed by drilling holes in the lens. This new technology can reduce the size of the system and improve the sharpness of the image. However, since the mounting direction of the photosensitive module is opposite to that of the conventional image capturing device, that is, facing the captured image, if used for handheld Equipment will give users the trouble of framing. And the holes in the lens will also create gaps in the captured image.

Summary of the invention

According to an aspect of the present invention, there is provided a catadioptric lens assembly comprising one or more lens elements having a first reflecting surface, a second reflecting surface and at least one refractive surface for collecting incident light. The first reflecting surface is disposed in the direction in which the light is incident on all of the refracting surfaces for concentrating the incident light and is vacant in the area around the optical axis. The second reflecting surface is opposite to the first reflecting surface and disposed in a region around the optical axis such that the incident light is reflected by the first reflecting surface after passing through the at least one lens element, and then reflected by the second reflecting surface after passing through at least one lens element, and then After passing through at least one lens element or gap, it exits from the area around the optical axis.

According to another aspect of the present invention, a panoramic image capture device includes the above-described catadioptric lens group and a photosensitive module, and the photosensitive module is fixedly or detachably connected to the catadioptric lens group. The photosensitive module includes a photosensitive device for sensing light concentrated by the catadioptric lens group.

According to the catadioptric lens group and the panoramic image capturing device of the present invention, the incident light is collected by combining refraction and double reflection, the light is concentrated once before the reflection, and the second convergence is performed after the first reflection, and It is also possible to perform a third convergence after the second reflection (in this case, the optical paths after the second reflecting surface are not all located in the gap), which not only can double the convergence effect, but also help to obtain a clear image. This makes the device design more compact, and thanks to the use of two reflections, the photosensitive module can be mounted facing the scene in a conventional manner, which also avoids the difficulty of drilling and threading in the lens.

Specific examples in accordance with the present invention will be described in detail below with reference to the accompanying drawings.

DRAWINGS

1 is a schematic diagram of an optical path of one of the existing panoramic image technologies;

Figure 2 is a schematic diagram of a panoramic image capture device in a prior patent application;

3 is a schematic diagram of a panoramic image capturing device according to Embodiment 1 of the present invention;

4 is a schematic diagram of a panoramic image capturing device according to Embodiment 2 of the present invention;

Figure 5 is a schematic diagram of a panoramic image capture device in accordance with Embodiment 3 of the present invention.

detailed description

The invention relates to a catadioptric lens group and a panoramic image capturing device, wherein the panoramic image capturing device comprises a catadioptric lens group and a photosensitive module. The following embodiments are all described by taking a panoramic image capturing device as an example, wherein the catadioptric lens group can be fixedly or detachably connected to the photosensitive module. If the detachable connection is used, the catadioptric lens group can be regarded as a separate device. In this case, the panoramic image capturing device according to the present invention may be a dual-function device, and the panoramic image may be acquired when the folding lens group is added. When the folding lens group is removed, the photosensitive module can also be used as a normal image. The collection device is used. In other words, the panoramic image capturing device can be realized at low cost by adding a folding reflection lens group to an existing image capturing device (for example, a camera, a video camera, a mobile phone camera, etc.).

Example 1

An embodiment of the panoramic image capture device according to the present invention can refer to FIG. 3, including a catadioptric lens group 110 and a photosensitive module 120 having an optical axis of 101.

In this embodiment, the catadioptric lens group has a simple structure and is composed of a lens element 111 having a back surface and a convex refractive surface 114 for condensing incident light, which is referred to as a lens element on the back surface and light (eg The other side of the incident surface is shown by the arrow in the figure.

The first reflecting surface 112 is provided on the back surface of the lens element 111, and can be formed, for example, by plating a reflective film on the back surface of the lens element. It is worth mentioning that in the prior art device that relies on the reflecting surface to collect the panoramic light, the ability to converge light mainly depends on the curved surface shape of the reflecting surface, and in the present invention, since the reflecting surface is combined with the refractive surface of the lens body, It mainly relies on the refractive surface for convergence. Due to the existence of the reflecting surface, the refractive surface of the lens body can be utilized multiple times, which not only has better effect, but also the reflecting surface can adopt various shapes which are easier to process, such as plane and circumferential symmetry. Convex or concave, etc.

The first reflecting surface is vacant in the area around the optical axis, so that the light can finally be emitted therefrom without interference. In the present embodiment, the central portion of the back surface of the lens element 111 is partially hollowed out, thereby forming a vacant area of the first reflecting surface, which is referred to as a region around the optical axis. In other embodiments, the back surface may be flat, and the vacant area of the first reflecting surface may be formed in such a manner that the central portion is not coated and remains transparent.

The second reflecting surface 113 is opposed to the first reflecting surface, and is disposed in a central region of the convex refractive surface, and can be formed by, for example, plating or placing a mirror. Among them, the coating film may be first flattened and then coated, or directly coated.

In other embodiments, the catadioptric lens set may have a varying configuration depending on the design of the optical path and performance requirements, for example, may have more than two refractive surfaces. In the case of having a plurality of refractive faces, the first reflecting surface should be disposed in the direction in which the light is incident after all of the refractive surfaces for concentrating the incident light. In the case of having a plurality of refractive surfaces, the catadioptric lens group may be composed of two or more lens elements, the first reflecting surface being disposed on the back side of the last lens element, the second reflecting surface being disposed opposite thereto, and the second reflecting surface The light path can then pass through the lens element or it can be completely hollowed out. The incident light is reflected by the first reflecting surface after passing through the at least one lens element, and then reflected by the second reflecting surface after passing through at least one lens element, and then exits from the area around the optical axis through at least one lens element or gap, so that the light can be two One or three times (incident once, one or two reflections) pass through the lens element to enhance the convergence effect. Depending on the design of the optical path and the lateral dimensions of the lens, the light may pass through all of the lens elements three times, or it may only repeat through a portion of the lens unit.

The photosensitive module 120 includes a photosensitive device 121 and a PCB substrate 122 for fixing and providing a circuit for sensing light concentrated by the catadioptric lens group 110. Preferably, the photosensitive module further includes a second lens group 123 disposed in front of the photosensitive device, and the light is sensed by the photosensitive device after passing through the second lens group. The addition of the second lens group on the one hand further enhances the concentrating ability, and on the other hand, expands the freedom of optical design. In other embodiments, the photosensitive module can also have a simple structure without the use of an additional lens set.

In the present embodiment, a part of the photosensitive module, that is, the second lens group, is housed in the hollowed-back portion of the lens element 111 to achieve a more compact arrangement. In other embodiments, the photosensitive module may also be integrally disposed behind the catadioptric lens group, so that it is not necessary to provide a recess for accommodating in the lens of the catadioptric lens group.

In order to provide more abundant and excellent functions, the present embodiment further includes the following additional components. In other embodiments, one or more of the additional components may be selectively included according to the needs of the application, and details are not described herein.

The movable infrared filter 130 is fixed on the motor-driven rotating support 131 and movably disposed between the folding reflection lens group 110 and the photosensitive device 121. In this embodiment, the second embodiment is further disposed in the second lens group. 123 is between the photosensor 121. When color images need to be acquired, such as during the day or with other externally visible illumination sources, the mobile infrared filter can be moved to the optical path of the photosensitive device to filter out the infrared light for better color. When it is necessary to take an infrared photograph, such as at night or when the external light is weak, the moving infrared filter is removed from the optical path of the photosensitive device to improve the sensing capability of the photosensitive device to infrared light.

An image processor (not shown) for reducing a pie-shaped panoramic image captured by the photosensitive device into a cylindrical image. For example, a pie-shaped image captured by a photosensitive device can be reduced to a continuous cylindrical image by means of coordinate transformation and interpolation calculation.

A display (not shown) for displaying images captured by the sensor, for example, displaying the original image captured by the sensor or displaying the image restored by the image processor (segmentable display). Depending on the needs of the application, the normal to the display can be perpendicular to the optical axis of the device or parallel to the optical axis of the device. Alternatively, the display can be set separately from the image capture device, only via a data connection.

A storage unit (not shown) for storing images captured by the photosensitive device and other related data.

The communication unit (not shown) is configured to transmit the image processed by the image processor in a wireless or wired manner, for example, to a receiving end designated by the user.

With the panoramic image capturing device of the embodiment, the photosensitive device can be installed in the same manner as in the conventional video camera, and the difference is that the light from the image will be concentrated after three stages. The catadioptric lens group is emitted to the photosensitive module.

Example 2

Another embodiment of the panoramic image capture device according to the present invention can be referred to FIG. 4, including a catadioptric lens set 210 and a photosensitive module 220 having an optical axis of 201.

The main difference between this embodiment and the embodiment 1 is that the catadioptric lens group 210 is composed of two lens elements (ie, the front lens element and the succeeding lens element) which are sequentially placed in the direction in which the light is incident, the first reflection. The face 212 is disposed on the back side of the rear lens element, and thus has three refractive faces 214, 215, 216. The second reflecting surface 213 is disposed in a central region of the front surface (i.e., the refractive surface 214) of the preceding lens element. To facilitate the placement of the second reflecting surface, the central region may be flattened.

The photosensitive module 220 also includes a photosensitive device 221, a PCB substrate 222, and a second lens group 223. The mobile infrared filter is omitted in this embodiment.

The central area of the rear lens element in the catadioptric lens group is completely hollowed out, and the photosensitive device of the photosensitive module and the second lens group are accommodated therein.

In this embodiment, since the central region of the rear lens element is completely hollowed out, the light from the image passes through the preceding lens element three times, and only passes through the subsequent lens element twice.

In other embodiments, the central region of the preceding lens element may also be completely hollowed out. In other words, the area of each lens element in the catadioptric lens group around the optical axis may be all hollowed out, which will facilitate optical design and machining. When the central area after the second reflecting surface is completely hollowed out, the incident light passes through the gap and passes through the gap instead of the lens body to enter the photosensitive module. At this time, the image can be corrected by setting the second lens group in the photosensitive module.

Example 3

Another embodiment of the panoramic image capture device according to the present invention can refer to FIG. 5, including a catadioptric lens set 310 and a photosensitive module 320 having an optical axis of 301.

This embodiment is similar to the first embodiment. The catadioptric lens group is composed of a lens element, the back surface of which is a first reflecting surface 312, the front surface thereof is a convex surface refracting surface 314, and the second reflecting surface 313 is disposed at a central area of the convex surface.

The photosensitive module 320 includes a photosensitive device 321, a PCB substrate 322, and a second lens group 323. In this embodiment, the second lens group adopts an autofocus lens group, including a stator 3231 and a mover 3232, and the lens group is disposed on the mover. The drive motor used for the autofocus may be, for example, a polyhedral ultrasonic motor, a voice coil motor, or the like. The quality of the image can be further improved by using an autofocus lens group.

In this embodiment, the back surface of the catadioptric lens group is smooth, and no recess is provided. The first reflecting surface is not coated in the central region and remains transparent, and the photosensitive module is integrally disposed behind the folding reflection lens group, which makes the production easier.

In addition, the panoramic image capturing device of the embodiment further includes an LCD display screen 340 disposed on the other side of the PCB substrate, the normal line of which is parallel to the optical axis of the photosensitive device, so as to display the captured image to the user.

The embodiments of the present invention have been described with reference to the specific embodiments of the present invention. It is understood that the above embodiments are only used to help the understanding of the present invention and are not to be construed as limiting the invention. Variations to the above-described embodiments may be made in accordance with the teachings of the present invention.

Claims (8)

A catadioptric lens assembly comprising one or more lens elements having a first reflecting surface, a second reflecting surface and at least one refractive surface for collecting incident light, The first reflecting surface is disposed in a direction in which the light is incident, after all of the refractive surfaces for concentrating the incident light are vacant, and the area around the optical axis is vacant. The second reflecting surface is opposite to the first reflecting surface and disposed in a region around the optical axis such that the incident light is reflected by the first reflecting surface after passing through the at least one lens element, and then reflected by the second reflecting surface after passing through at least one lens element, and then After passing through at least one lens element or gap, it exits from the area around the optical axis. The lens assembly according to claim 1, wherein said group of the catadioptric lens is composed of a lens member having a convex refractive surface and a back surface, said back surface being a flat surface, a convex surface or a concave surface, first The reflective surface is disposed on the back surface, and the second reflective surface is disposed on a central region of the convex refractive surface. The lens assembly according to claim 1, wherein the group of the catadioptric lens is composed of two lens elements sequentially placed in a direction in which the light is incident, and the first reflecting surface is disposed on the back side of the rear lens element, The two reflecting surfaces are disposed in a central region of the front surface of the preceding lens element. A panoramic image capturing device, characterized in that a catadioptric lens group having the structure according to any one of claims 1-3; The photosensitive module is fixedly or detachably connected to the group of the catadioptric lens, and the photosensitive module comprises a photosensitive device for sensing light concentrated by the group of the catadioptric lens. The device according to claim 4, wherein the photosensitive module further comprises a second lens group disposed before the photosensitive device, and the light is sensed by the photosensitive device after passing through the second lens group. The device of claim 5 wherein the second lens group is an autofocus lens group. The device according to any one of claims 4-6, wherein the photosensitive module is integrally disposed behind the folding reflection lens group, or In the group of the catadioptric lens, the central region of the back surface of the last lens element is at least partially hollowed out in the direction in which the light is incident, and at least a portion of the photosensitive module is housed in the hollowed portion.  A device according to any of claims 4-7, further comprising one or more of the following elements: a display screen for displaying an image captured by the photosensitive device, the normal line of the display screen being perpendicular or parallel to an optical axis of the photosensitive device; An image processor for reducing a circular image of the dome-shaped image collected by the photosensitive device into a cylindrical image; a storage unit, configured to store an image collected by the photosensitive device; a communication unit, configured to transmit the image processed by the image processor in a wireless or wired manner; A mobile infrared filter is movably disposed between the group of the catadioptric lens and the photosensitive device.