CN105652413B

CN105652413B - A kind of image-forming objective lens suitable for RGB D cameras

Info

Publication number: CN105652413B
Application number: CN201610115118.8A
Authority: CN
Inventors: 王立强; 刘玥; 袁波
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2016-03-01
Filing date: 2016-03-01
Publication date: 2018-03-16
Anticipated expiration: 2036-03-01
Also published as: CN105652413A

Abstract

A kind of image-forming objective lens suitable for RGB D cameras disclosed by the invention, the first lens, the first spacer ring, the second lens and the 3rd lens for having fitting successively from the object side to the image side in lens barrel form imaging lens.The image-forming objective lens use three-chip type spherical mirror structure, and it is plane that each eyeglass, which has a minute surface, and another side is sphere, and processing cost is low, the second lens and the 3rd lens are brought into close contact simultaneously, compact-sized without spacer ring, compact, and three lens radius are identical, assembly technology is simple.Imaging definition is high in the wide spectrum region from visible ray to near-infrared, and optical property is excellent, can reach 65 ° of big visual field, the distortion less than 3.2%.The Depth Imaging system of infrared floor light is applicable to, realizes friendly, easy-to-use natural man-machine interaction.

Description

A kind of image-forming objective lens suitable for RGB-D cameras

Technical field

The present invention relates to a kind of image-forming objective lens suitable for RGB-D cameras, suitable for Depth Imaging and field of human-computer interaction.

Background technology

With the continuous popularization and development of computer technology, natural man-machine interaction that is friendly and being easily used will turn into man-machine One big main flow of interactive development.Depth imaging technique makes contactless as input technology important in nature human-computer interaction technology Gesture and posture interaction be possibly realized.RGB-D cameras are the key equipments of Depth Imaging, and system obtains scene by it Three-dimensional depth information, therefore the quality of its image quality directly influences the accuracy of Depth Imaging and distinguishable precision, and then Influence man-machine interaction experience.

Existing imaging lens optimize as matter just for visible region, are showed near infrared region poor, it is necessary to scheme The influence for eliminating infrared light as adding cutoff filter before sensor.

For Depth Imaging system, near infrared region is important SPECTRAL REGION, when ambient lighting is poor, generally Using near-infrared light source carry out floor light, meanwhile, in depth imaging technique by active light shine using gradation of image come Realize for the technology of Depth Imaging, near-infrared light source is important lighting source, therefore the image quality of near infrared region Emphasis is answered to consider.Therefore, in order to which adapt to RGB-D cameras applies needs, it is necessary to design a from visible ray to near-infrared Wide spectrum region is respectively provided with the image-forming objective lens of good image quality.

The content of the invention

In view of the shortcomings of the prior art, it is an object of the invention to provide a kind of compact-sized, assembly technology is simple, and from can See that light is high to image definition in the wide spectrum region of near-infrared, visual field is big, and distort the small imaging thing suitable for RGB-D cameras Mirror.

The present invention a kind of image-forming objective lens suitable for RGB-D cameras, include three lens altogether in lens barrel, from object space to The first lens, the first spacer ring, the second lens and the 3rd lens that image space has fitting successively form imaging lens.Wherein the first lens For positive lens, it is convex surface towards object space, is plane towards image space；Second lens are negative lens, its towards object space be plane, face It is concave surface to image space；3rd lens are positive lens, and it is plane towards object space, is convex surface towards image space.Positioned at the first lens and The first spacer ring between second lens plays aperture diaphragm simultaneously.It is trim ring after 3rd lens, is revolved by screw thread and lens barrel Tight fit.The end of lens barrel has external screw thread to coordinate with lens mount.

In above-mentioned technical proposal, the first described lens, the first spacer ring, the lens radius of the second lens and the 3rd lens are equal For 1.1000mm.

The first described lens can use H-ZLAF52 glass materials, and the convex radius of the first lens is 2.9630mm, minute surface distance 0.8100mm, minute surface radius 0.9000mm, the plan radius of curvature of the first lens is infinite, minute surface Distance is 0.3000mm, and minute surface radius is 0.6130mm.

The second described lens can use H-ZF1 glass materials, and the plan radius of curvature of the second lens is infinite, minute surface Distance 0.4000mm, minute surface radius 0.1800mm, the concave curvature radiuses of the second lens are 2.3310mm, minute surface distance 0.1053mm, minute surface radius 0.6927mm.

The 3rd described lens can use H-LAK3 glass materials, and the plan radius of curvature of the 3rd lens is infinite, mirror Identity distance is from 0.9500mm, minute surface radius 1.1000mm, and the convex radius of the 3rd lens is -1.5880mm, minute surface radius 0.9000mm。

A kind of image-forming objective lens suitable for RGB-D cameras of the present invention, it is equal using three-chip type spherical mirror structure, each eyeglass It is plane to have a minute surface, and another side is sphere, and processing cost is low, while the second lens and the 3rd lens are brought into close contact, nothing Spacer ring is needed, compact-sized, compact, and three lens radius are identical, assembly technology is simple.Optical design is easy, from can See that the definition of light to image in the wide spectrum region of near-infrared is high, optical property is excellent, can reach 65 ° of big visual field, be less than 3.2% distortion, very high optical transfer function (MTF).

Brief description of the drawings

Fig. 1 is the general structure schematic diagram of the present invention.

Fig. 2 is the optical transfer function of the present invention.

Fig. 3 is the distortion of the present invention.

Embodiment

The present invention is further illustrated below in conjunction with accompanying drawing.

Shown in Fig. 1, a kind of image-forming objective lens suitable for RGB-D cameras of the invention include three lens 1,2,3, lens barrel altogether There are the first lens 1, the first spacer ring 4, the second lens 2 and the fitting of the 3rd lens 3 to form imaging lens in 6 successively from the object side to the image side Head.Wherein the first lens 1 are positive lens, and it is convex surface towards object space, is plane towards image space；Second lens 2 are negative lens, its It is plane towards object space, is concave surface towards image space；3rd lens 3 are positive lens, and it is plane towards object space, is convex towards image space Face.The first spacer ring 4 between the first lens 1 and the second lens 2 plays aperture diaphragm simultaneously.It is after 3rd lens 3 Trim ring 5, cooperation is screwed by screw thread and lens barrel 6.The end of lens barrel 6 has external screw thread to coordinate with lens mount.

When applied to RGB-D cameras, image-forming objective lens of the invention can obtain blur-free imaging from visible ray to near-infrared, After coordinating with illuminator and image variants software systems, the scene depth of high-accuracy and resolving accuracy will be obtained Figure.It is applied to share three lens 1,2,3 in the lens barrel 6 of the image-forming objective lens of RGB-D cameras in this example, altogether 6 minute surfaces, from Object space is defined as successively to image space：The convex surface of first lens 1 is the first minute surface, and the plane of the first lens 1 is the second minute surface；Second The plane of lens 2 is the 3rd minute surface, and the concave surface of the second lens 2 is the 4th minute surface；The plane of 3rd lens 3 is the 5th minute surface, the The convex surface of three lens 3 is the 6th minute surface.The structural parameters of 6 minute surfaces are shown in Table 1：

Table 1

Fig. 2 and Fig. 3 illustrates the optical imagery performance of the present invention.

Fig. 2 calculates the angle of visual field 0 ° (central visual field) in normalization coordinate, 22.75 ° of the angle of visual field (0.7 visual field), the angle of visual field The optical transfer function value of 32.5 ° (peripheral field) three visual fields.From Figure 2 it can be seen that it is of the invention when transmission function is 0.3, depending on The transfer function values of rink corner 32.5 ° (peripheral field) can reach 70lp/mm, the transmission function of 22.75 ° of the angle of visual field (0.7 visual field) Value can reach 91lp/mm, and the transfer function values of the angle of visual field 0 ° (central visual field) can reach 105lp/mm.Show one kind of the present invention It can reach 65 ° suitable for the maximum field of view of the image-forming objective lens of RGB-D cameras, and blur-free imaging can be obtained.Fig. 3 is the present invention A kind of distortion curve suitable for the image-forming objective lens of RGB-D cameras in the case of 470nm, 535nm, 640nm and 850nm.Tool For body, maximum distortion of the image-forming objective lens under 470nm wavelength is 3.08143%, and the maximum distortion under 535nm wavelength is 3.06866%, the maximum distortion under 640nm wavelength is 3.07992%, and maximum distortion at a wavelength of 850 nm is 3.12895%, control below 3.2%.Fig. 2 and Fig. 3 shows a kind of image-forming objective lens suitable for RGB-D cameras of the present invention There is the advantages of visual field is big, and distortion is small, high resolution in the wide spectrum region from visible ray to near-infrared.

Claims

A kind of 1. image-forming objective lens suitable for RGB-D cameras, it is characterised in that：Including lens barrel（6）, in lens barrel（6）It is interior from object space It is fitted with the first lens successively to image space（1）, the first spacer ring（4）, the second lens（2）With the 3rd lens（3）, form imaging lens Head；Wherein the first lens（1）For positive lens, it is convex surface towards object space, is plane towards image space；Second lens（2）It is saturating to bear Mirror, it is plane towards object space, is concave surface towards image space；3rd lens（3）For positive lens, its towards object space be plane, towards Image space is convex surface；First spacer ring（4）Play aperture diaphragm simultaneously, in the 3rd lens（3）Trim ring is provided with afterwards（5）, trim ring（5） Pass through screw thread and lens barrel（6）Screw cooperation；Lens barrel（6）End there is external screw thread and lens mount to coordinate；The first described lens （1）, the second lens（2）With the 3rd lens（3）Lens radius be 1.1000mm；

The first described lens（1）Using H-ZLAF52 glass materials, the convex radius of the first lens is 2.9630mm, mirror Identity distance is from 0.8100mm, and minute surface radius 0.9000mm, the plan radius of curvature of the first lens is infinite, and minute surface distance is 0.3000mm, minute surface radius are 0.6130mm；The second described lens（2）Using H-ZF1 glass materials, the plane of the second lens Radius of curvature is infinite, minute surface distance 0.4000mm, minute surface radius 0.1800mm, and the concave curvature radius of the second lens is 2.3310mm, minute surface distance 0.1053mm, minute surface radius 0.6927mm；The 3rd described lens（3）Using H-LAK3 glass materials Material, the plans radius of curvature of the 3rd lens are infinite, minute surface distance 0.9500mm, minute surface radius 1.1000mm, the 3rd lens Convex radius is -1.5880mm, minute surface radius 0.9000mm.