CN117234017A - Polarized image acquisition depth camera - Google Patents

Abstract

A polarized image acquisition depth camera, comprising: an EEL emission end for emitting infrared light; the first receiving end is used for receiving the first reflected light of the infrared light; a third polarizing plate positioned on an incident light path of the first reflected light; wherein the polarization direction of the third polarizer is different from the polarization direction of the infrared light. The application can improve and reduce the power consumption and improve the efficiency by utilizing the polarization property of the EEL transmitting end.

Description

Polarized image acquisition depth camera

Technical Field

The application relates to the technical field of depth cameras, in particular to a polarized image acquisition depth camera.

Background

In some 2D and 3D payment and identification fields, image quality and overall low power consumption are increasingly pursued, and polarization technology is increasingly applied to this field due to its unique light field processing capability. Part of the noise can be effectively suppressed by differential imaging, but the synchronization also attenuates the effective energy. In the current polarization scheme, the requirement on power consumption is high, and some breakthroughs need to be made in the technology to remedy the disadvantages in the aspect.

The application discloses a polarized high-power laser, which comprises at least two groups of light beam output devices, wherein each group of light beam output devices forms a light path, one light path reaches a polarized beam combining prism through one group of light beam output devices, a light beam compression lens group and a half-wave plate, the second light path reaches the polarized beam combining prism through the other group of light beam output devices and the light beam compression lens group, when the light beam of the first light path enters the polarized beam combining prism, the light beam of the second light path enters the polarized beam combining prism, the light beam of the first light path and the light beam of the second light path are mutually perpendicular, after being converged by the polarized beam combining prism, the light beam of the first light path enters a coupling lens, and then reaches the input end of an optical fiber. The application breaks down a unidirectional light path into two light paths, the light path travel difference in the light beam output device of each light path is smaller, the long-distance light path travel is shortened, the light spot consistency is improved, and the working accuracy of the laser is improved.

The application relates to a reflection eliminating device for a palm vein recognition system, which comprises the following components: the first polaroids are correspondingly arranged above the corresponding near-infrared light sources, so that near-infrared light rays emitted by the near-infrared light sources pass through the corresponding first polaroids; and the second polaroid is arranged above the image sensor, so that light passes through the second polaroid before entering the image sensor, and the light intensity is attenuated to eliminate the reflection of the palm surface. By adopting the anti-reflection device, the light irradiated to each position of the palm area is near infrared polarized light, and the near infrared polarized light passes through the polaroid above the image sensor before entering the image sensor, so that the effect of eliminating the reflection of the palm surface is achieved, palm print information is filtered, only palm vein information is reserved, the contrast ratio of the palm vein area and the non-palm vein area is improved, clear non-reflection palm vein images are obtained, the difficulty of an image processing algorithm is reduced, and the palm vein recognition precision is improved.

In the prior art, a common vertical cavity surface emitting laser is adopted to emit uniform light beams or floodlights, so that human body characteristics are obtained. When the vein feature of the human body is obtained, only polarized light information capable of obtaining the vein feature is reserved by arranging the polarizing plates at the projector end and the receiver end, so that the clear vein feature is obtained. However, the energy of the laser is greatly lost by the application of the polaroid in the prior art.

The foregoing background is only for the purpose of providing an understanding of the inventive concepts and technical aspects of the present application and is not necessarily prior art to the present application and is not intended to be used as an aid in the evaluation of the novelty and creativity of the present application in the event that no clear evidence indicates that such is already disclosed at the date of filing of the present application.

Disclosure of Invention

Therefore, the application utilizes the polarization characteristic of the infrared light emitted by the EEL emission end, and can realize the effect of distributing the polaroids at the receiving end and the emission end in the prior art without arranging the polaroids at the emission end and arranging the polaroids with different polarization directions with the infrared light at the receiving end, thereby not only reducing the energy loss, but also reducing the quantity of the polaroids and saving the cost.

The application provides a polarized image acquisition depth camera, which is characterized by comprising the following components:

an EEL emission end for emitting infrared light;

the first receiving end is used for receiving the first reflected light of the infrared light;

a third polarizing plate positioned on an incident light path of the first reflected light;

wherein the polarization direction of the third polarizer is different from the polarization direction of the infrared light.

Optionally, the polarized image capturing depth camera is characterized in that the EEL transmitting end includes:

an EEL light source for generating infrared light;

the collimator is positioned on the light path of the infrared light and is used for collimating the infrared light;

and the projection lens is positioned on the light path of the infrared light and is used for projecting the collimated infrared light outwards.

Optionally, the polarized image capturing depth camera is characterized by further comprising a second driving part, wherein the second driving part is connected with the third polarizer and is used for driving the third polarizer to rotate so that an included angle between the polarization direction of the third polarizer and the polarization direction of the infrared light accords with a preset value.

Optionally, the polarized image capturing depth camera further includes:

the second receiving end is used for receiving second reflected light of the infrared light;

and a fourth polarizer located on an incident light path of the second reflected light.

Optionally, the polarized image capturing depth camera is characterized by further comprising a third driving part, which is connected with the fourth polarizer and is used for driving the fourth polarizer to rotate so as to keep a fixed included angle between the polarization directions of the third polarizer and the fourth polarizer.

Optionally, the polarized image capturing depth camera is characterized in that the polarization direction of the fourth polarizer is different from that of the third polarizer.

Optionally, the polarized image capturing depth camera is characterized in that the first receiving end and the second receiving end are equidistantly arranged at two sides of the EEL transmitting end.

Optionally, the polarized image capturing depth camera further includes:

a first polarizer located on the optical path of the infrared light; the infrared light is projected on a target object through the first polarizer.

Optionally, the polarized image capturing depth camera further includes:

and the first driving part is connected with the first polaroid and used for driving the first polaroid to rotate.

Optionally, the polarized image capturing depth camera is characterized in that the first polarizer is rectangular.

Compared with the prior art, the application has the following beneficial effects:

the application discovers that the infrared light projected by the EEL transmitting end has polarization attribute for the first time, saves the polaroid of the transmitting end, and realizes the acquisition of a specific target object, such as the acquisition of human vein information by controlling the polarization direction of the third polaroid and the polarization direction of the infrared light.

The application saves the polaroid at the transmitting end, so that the light intensity loss of the depth camera is smaller when the image is acquired, the power consumption is reduced, the light intensity projected on the target object is increased, and the energy utilization rate is higher.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present application, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art. Other features, objects and advantages of the present application will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:

fig. 1 is a schematic structural diagram of a polarized image capturing depth camera according to an embodiment of the present application;

FIG. 2 is a schematic polarization diagram of an EEL transmitting end according to an embodiment of the present application;

FIG. 3 is a schematic polarization diagram of a VCSEL emission end according to an embodiment of the present application;

FIG. 4 is a schematic diagram of an EEL emitter according to an embodiment of the present application;

FIG. 5 is a schematic diagram of another polarized image capturing depth camera according to an embodiment of the present application;

FIG. 6 is a schematic diagram of another polarized image capturing depth camera according to an embodiment of the present application;

FIG. 7 is a schematic diagram of another polarized image capturing depth camera according to an embodiment of the present application;

FIG. 8 is a schematic diagram of another polarized image capturing depth camera according to an embodiment of the present application; and

fig. 9 is a schematic structural diagram of another polarized image capturing depth camera according to an embodiment of the present application.

1-EEL transmitting end;

2-a first polarizer;

3-a first driving part;

6-a first receiving end;

7-a third polarizer;

8-a second driving part;

9-a second receiving end;

10-a fourth polarizer;

11-EEL light source;

a 12-collimator;

13-a projection lens;

14-a third driving section;

Detailed Description

The present application will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the present application, but are not intended to limit the application in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present application.

The terms "first," "second," "third," "fourth" and the like in the description and in the claims and in the above drawings, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the application described herein may be implemented, for example, in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The embodiment of the application provides a method for improving efficiency of a polarization system, which aims to solve the problems in the prior art.

The following describes the technical scheme of the present application and how the technical scheme of the present application solves the above technical problems in detail with specific embodiments. The following embodiments may be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.

According to the application, by utilizing the polarization characteristic of the infrared light emitted by the EEL emission end, the effect that the polarizers are distributed on the receiving end and the emission end in the prior art can be realized without arranging the polarizers on the emission end and only arranging the polarizers with different polarization directions from the infrared light on the receiving end, so that the energy loss is reduced, the number of the polarizers is reduced, and the cost is saved.

Fig. 1 is a schematic structural diagram of a polarized image capturing depth camera according to an embodiment of the present application. As shown in fig. 1, a polarized image capturing depth camera according to an embodiment of the present application includes:

the EEL transmitting terminal 1 is used for transmitting infrared light.

Specifically, due to the emission characteristics of the EEL emission end, the emitted infrared light has polarization properties. As shown in fig. 2, the polarization degree of the polarized light emitted by the EEL emission end is 3 after detection by the polarization analyzer. As shown in fig. 3, the polarization degree of the polarized light emitted by the VCSEL emission end is 1 after detection by the polarization analyzer. Comparing fig. 2 and fig. 3, it can be found that both the VCSEL emission end and the EEL emission end have certain polarization characteristics, but the polarization characteristics of the EEL emission end are more obvious. This is also the reason for the application to choose the EEL transmitting end. The polarization properties of the EEL transmitting end itself are not known in the prior art, but the present embodiment uses the polarization properties to improve efficiency.

A first receiving end 6 for receiving the first reflected light of the infrared light.

Specifically, the first receiving end and the EEL transmitting end work synchronously and are used for receiving the reflected signal of the target object. The type of light received by the first receiving end is the same as that of the EEL transmitting end, for example, the EEL transmitting end is a structured light projector, and the receiving end is a structured light receiver; the EEL transmitting end is a floodlight projector, and the receiving end is a floodlight receiver.

A third polarizing plate 7 positioned on an incident light path of the first reflected light;

specifically, the polarization direction of the third polarizer is different from the polarization direction of the infrared light. The light reflected by the target object passes through the third polaroid and is received by the receiving end. Preferably, the polarization direction of the third polarizer is perpendicular to the polarization direction of the infrared light.

Since the infrared light has a polarization characteristic, the light irradiated on the target object is light having a polarization characteristic, and the light reflected by the target object is light having an increased polarization characteristic, the signal received by the first receiving terminal 6 is a mixed signal having a polarization characteristic. The image obtained in this embodiment is an image with more pronounced polarization characteristics than a single polarization image, so that more characteristic processing can be performed. For example, for face recognition scenes, a superposition graph of face features and vein features can be obtained, and more information can be obtained than a single face feature graph and a single vein feature graph, so that comprehensive comparison can be performed, and the method has more stability and safety than the method of simply utilizing the face features or the vein features, and particularly has a good recognition effect on prosthesis attack.

In the prior art, the emitting end emits unpolarized light with energy of I, and after passing through the first polarizer, the energy is attenuated by 50%, so that the emitted energy is 50% I. In this embodiment, the transmitting end does not need to be provided with a polarizer, so that there is no attenuation at the transmitting end, and therefore, the energy emitted by the embodiment is I, and the efficiency is improved by 100%.

After passing through the target object, the optical efficiency of the present embodiment is determined by the emission end, i.e. the efficiency is improved by 100%, because the optical efficiency is proportionally distributed to the surface reflection, the internal scattering and the reflection according to the inherent characteristics of the object.

Fig. 4 is a schematic structural diagram of an EEL transmitting end according to an embodiment of the application. As shown in fig. 4, an EEL transmitting end in an embodiment of the present application includes:

an EEL light source 11 for generating infrared light.

Specifically, the EEL light source may be a structured light source or a floodlight source.

A collimator 12 is located on the optical path of the infrared light for collimating the infrared light.

Specifically, a collimator collimates the infrared light.

And the projection lens 13 is positioned on the light path of the infrared light and is used for projecting the collimated infrared light outwards.

Specifically, the projection lens projects infrared light outwards, so that the infrared light can be projected outwards according to preset parameters, such as a specific FOV, light intensity distribution and the like.

Fig. 5 is a schematic structural diagram of another polarized image capturing depth camera according to an embodiment of the present application. As shown in fig. 5, another polarized image capturing depth camera according to the embodiment of the present application further includes a second driving part 8.

The second driving part 8 is connected with the third polarizer 7 and is used for driving the third polarizer to rotate so that the included angle between the polarization direction of the third polarizer and the polarization direction of the infrared light accords with the preset.

In this embodiment, since the EEL emission end remains stationary, the polarization direction of the infrared light remains stationary. When the second driving part drives the third polaroid to rotate, the included angle alpha between the third polaroid and the polarization direction of infrared light changes. When the included angle alpha is 90 degrees, the polarization direction of the infrared light is perpendicular to the polarization direction of the third polaroid, the best filtering effect is achieved, the clearest vein image can be obtained, and the light intensity is weakest. When the included angle alpha is 0 degree, the polarization direction of the infrared light is parallel to the polarization direction of the third polaroid, the filtered information is the least, the characteristic information of the surface of the human body, such as the face characteristics, the palm print characteristics and the like, can be stored to the greatest extent, and the light intensity is the strongest. When the included angle alpha is between 0 and 90 degrees, the obtained image is positioned between the 90-degree and 0-degree images, the obtained characteristic information of the human body surface is different from the vein information in proportion, and the light intensity is correspondingly changed.

Fig. 6 is a schematic structural diagram of another polarized image capturing depth camera according to an embodiment of the present application. As shown in fig. 6, another polarized image capturing depth camera according to an embodiment of the present application further includes:

a second receiving end 9 for receiving a second reflected light of the infrared light;

and a fourth polarizing plate 10 disposed on an incident light path of the second reflected light.

Specifically, the fourth polarizing plate 10 is located between the second receiving end 9 and the target object, and performs polarization processing on the reflected light, and then enters the second receiving end as second reflected light. The second receiving end 9 and the first receiving end 6 are synchronously exposed to obtain information of different dimensions at the same moment. The fourth polarizer 10 is identical to the third polarizer 7, i.e. has the same model parameters, to achieve the same processing of the reflected light.

In some embodiments, the second receiving end 9 is also identical to the first receiving end 6, and has the same model parameters. When the first receiving end 6 and the second receiving end 9 are synchronously exposed, a first image and a second image are generated, respectively. The first image and the second image can be weighted and subtracted by identifying the image brightness of the surface information and the vein information in the first image and the second image to obtain a third image with only vein characteristics and a fourth image with only surface characteristics, so that various types of processing can be carried out on a human body by using the first image, the second image, the third image and the fourth image, and the range of the human body identification processing is greatly expanded.

In some embodiments, the fourth polarizer and the third polarizer have different polarization directions.

In some embodiments, the first receiving end and the second receiving end are equidistantly disposed on both sides of the EEL transmitting end. The distance between the first receiving end and the second receiving end can be maximized, and the first receiving end and the second receiving end can form a binocular system, so that accuracy of a measurement result is maintained.

Fig. 7 is a schematic structural diagram of another polarized image capturing depth camera according to an embodiment of the present application. As shown in fig. 7, another polarized image capturing depth camera according to an embodiment of the present application further includes:

and a third driving part 14 connected with the fourth polarizer for driving the fourth polarizer to rotate so as to maintain a fixed included angle between the polarization directions of the third polarizer and the fourth polarizer.

Specifically, the third driving section moves according to the movement information of the second driving section. When the second driving part drives the third polaroid, the third driving part synchronously drives the fourth polaroid. The third driving part and the second driving part have the same driving direction and the same speed, so that the polarization directions of the third polaroid and the fourth polaroid keep a fixed included angle.

In this embodiment, the third driving portion follows the second driving portion to rotate synchronously, so that the included angle between the third polarizer and the fourth polarizer is kept fixed, and information such as the angle of the target object can be determined by the difference between the first image and the second image.

Fig. 8 is a schematic structural diagram of another polarized image capturing depth camera according to an embodiment of the present application. As shown in fig. 8, another polarized image capturing depth camera according to an embodiment of the present application further includes:

a first polarizer 2 positioned on the optical path of the infrared light; the infrared light is projected on a target object through the first polarizer.

Specifically, the polarization direction of the infrared light is the same as the polarization direction of the first polarizing plate. After passing through the first polarizer 2, the infrared light has a higher degree of polarization than before, so that the target object characteristics of a specific attribute can be better obtained. The first polarizing plate 2 has a higher polarization characteristic than infrared light. When the polarization direction of the infrared light of the first polaroid is the same as that of the infrared light of the EEL emission end, the most infrared light passes through the first polaroid, and the energy loss is minimum. The shape of the second polarizing plate may be any shape, for example, may be rectangular, circular, or the like.

Fig. 9 is a schematic structural diagram of another polarized image capturing depth camera according to an embodiment of the present application. As shown in fig. 9, another polarized image capturing depth camera according to an embodiment of the present application further includes:

and the first driving part 3 is connected with the first polaroid and is used for driving the first polaroid to rotate.

Specifically, the first driving part may rotate the first polarizer such that the polarization direction of the infrared light is the same as that of the first polarized light, i.e., for placing the EEL emission end and the first polarizer at initial positions. Further, the first driving part can also drive the first polaroid to rotate, so that the polarization direction of the first polaroid is different from that of the infrared light, and the polarization direction and the light intensity of the emergent infrared light are changed, thereby realizing finer adjustment of biological characteristics. The embodiment not only can adjust the polarization direction of the emergent light of the high-efficiency polarized projection light source, but also can adjust the light intensity of the emergent light, thereby realizing the measurement of veins at different parts of a human body and having wider applicable parts.

In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The foregoing describes specific embodiments of the present application. It is to be understood that the application is not limited to the particular embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the claims without affecting the spirit of the application.

Claims (10)

1. A polarized image acquisition depth camera, comprising:

an EEL emission end for emitting infrared light;

the first receiving end is used for receiving the first reflected light of the infrared light;

a third polarizing plate positioned on an incident light path of the first reflected light;

wherein the polarization direction of the third polarizer is different from the polarization direction of the infrared light.

2. The polarized image acquisition depth camera of claim 1 wherein the EEL emission end comprises:

an EEL light source for generating infrared light;

the collimator is positioned on the light path of the infrared light and is used for collimating the infrared light;

and the projection lens is positioned on the light path of the infrared light and is used for projecting the collimated infrared light outwards.

3. The polarized image capturing depth camera of claim 1, further comprising a second driving portion connected to the third polarizer for driving rotation of the third polarizer so that an included angle between a polarization direction of the third polarizer and a polarization direction of the infrared light meets a preset value.

4. The polarized image acquisition depth camera of claim 1, further comprising:

the second receiving end is used for receiving second reflected light of the infrared light;

and a fourth polarizer located on an incident light path of the second reflected light.

5. The polarized image capturing depth camera of claim 4 further comprising a third driving section coupled to the fourth polarizer for driving rotation of the fourth polarizer such that the third polarizer maintains a fixed included angle with the polarization direction of the fourth polarizer.

6. The polarized image capture depth camera of claim 4 wherein the fourth polarizer has a different polarization direction than the third polarizer.

7. The polarized image acquisition depth camera of claim 4 wherein the first receiving end and the second receiving end are equidistantly disposed on either side of the EEL emission end.

8. The polarized image acquisition depth camera of claim 1, further comprising:

a first polarizer located on the optical path of the infrared light; the infrared light is projected on a target object through the first polarizer.

9. The polarized image acquisition depth camera of claim 8, further comprising:

and the first driving part is connected with the first polaroid and used for driving the first polaroid to rotate.

10. The polarized image acquisition depth camera of claim 8 wherein the first polarizer is rectangular.