WO2017161520A1

WO2017161520A1 - Composite imaging system and mobile terminal supporting near-infrared light and visible-light imaging

Info

Publication number: WO2017161520A1
Application number: PCT/CN2016/077101
Authority: WO
Inventors: 徐鹤菲
Original assignee: 徐鹤菲
Priority date: 2016-03-23
Filing date: 2016-03-23
Publication date: 2017-09-28
Also published as: CN109076147A; CN109076147B

Abstract

Provided is a composite imaging system (100) supporting a visible-light imaging mode and a near-infrared light imaging mode, comprising a lens assembly (130), light filter assembly (130), and image sensor (110) arranged along the incident-light path. The lens assembly comprises a fixed focal-length optical lens. The light filter assembly comprises a visible-light bandpass filter (121) that allows light of a visible-light wave band to pass therethrough and a near-infrared light bandpass filter (122) that allows a near-infrared light wave band to pass therethrough. The image sensor comprises a visible-light imaging region (B), a near-infrared light imaging region (A), and a transitional region (C) between the former two regions. The image sensor operates in visible-light imaging mode and/or in near-infrared light imaging mode; in visible-light imaging mode, the visible-light imaging region images the visible light passing through the visible-light bandpass filter; in near-infrared light imaging mode, the near-infrared light imaging region images the near-infrared light passing through the near-infrared light bandpass filter. A mobile terminal is also disclosed.

Description

Composite imaging system and mobile terminal supporting near-infrared light and visible light imaging

Technical field

The present invention relates to the field of image processing, biometrics, and optical imaging technologies, and more particularly to a composite imaging system that supports a visible light imaging mode and a near infrared light imaging mode.

Background technique

At present, the mobile terminal is used as a means of identity confirmation mainly relying on passwords and cards, and has problems such as difficulty in memory, easy to be stolen, and low security. Among many identification technologies, iris recognition has the highest security and accuracy, and has the advantages of being unique, not requiring memory, being able to be stolen, and having a high level of security.

In the current technology, an iris recognition function is added to a mobile terminal (such as a mobile phone), and a near-infrared camera module needs to be added to the front of the mobile phone, and the front visible light camera module for self-photographing is independent. That is, the front panel of the mobile phone needs to open two holes, one for self-timer and one for iris imaging, which is complicated in industrial design and has an unattractive appearance.

In the prior art, for people of yellow, brown or black eyes, the iris imaging design implemented by the near-infrared camera module generally uses near-infrared light imaging of the 760 nm-880 nm spectrum band. This requires an additional near-infrared source (between 760 nm and 880 nm) for fill-light illumination, and the near-infrared camera module needs to be able to receive this infrared band of energy.

The iris recognition on the mobile phone is mainly used for the user's own identity recognition, and the user experience generally needs to be used in advance. However, the existing front-mounted self-photographing head of the mobile phone cannot accept the infrared light source or receive a large attenuation due to the coating filtration itself. Therefore, the prior art iris recognition requires a separate near-infrared camera for imaging the iris, and cannot be multiplexed with the existing visible light imaging (spectral frequency of 380-760 nm) camera (such as the existing front color camera of the smartphone). ). These all lead to a significant increase in the volume of the iris imaging system, The cost is increased, the design is complicated, and the user experience is poor, and it is impossible to miniaturize the integration application to a mobile terminal with a wider demand.

Therefore, how to use a camera to make a two-in-one, which can meet the normal front-view self-timer visible light imaging function of the mobile phone, and can satisfy the biometric function of near-infrared light imaging, is a current technical bottleneck.

At present, the use of a single camera in near-infrared and visible-light dual-band imaging mainly has the following implementation methods: adding a mechanical switchable near-infrared optical filter (see CN203838720U) in the imaging system, using dual-band infrared and visible light A transmission spectrum filter (see U.S. Patent No. 8,408,821, Chinese Patent Publication No. CN104394306A), and an image sensor using both visible and near-infrared light detecting pixels (see U.S. Patent No. 7,915, 562, Chinese Patent Publication No. CN104284179A).

Among them, the mechanically switchable near-infrared light filter is difficult to be widely used in mobile devices due to its relatively large volume. The use of filters with infrared and visible light-band transmission spectra causes the visible portion and the near-infrared portion to interfere with each other, thereby affecting the quality of the photograph and the accuracy of the recognition. For the design of image sensor, US7915652 only involves the image sensor design of dual-spectrum imaging, but does not provide the entire imaging system design; the sub-region multi-spectral filter used in CN104284179A is the color filter matrix attached to the surface of the image sensor (Color) Filter Array) instead of a separate optical filter.

Summary of the invention

The present invention provides a design of a biometric composite imaging system that achieves multiplexing of near-infrared light and visible light imaging functions by using a fixed focal length lens assembly, a filter assembly, and an image sensor, and a mobile terminal design including the composite imaging system. Therefore, the visible light imaging function of the front-end self-timer of the mobile terminal can be satisfied, and the biometric function of the near-infrared light imaging can be satisfied.

DRAWINGS

A detailed description of non-limiting embodiments made by reading the following figures Other features, objects, and advantages of the invention will become apparent.

1 is a schematic illustration of a composite imaging system 100 for biometrics in accordance with the present invention;

2 is a schematic diagram showing the depth of field of the visible light and near-infrared light of the lens assembly 130;

Figure 3 is a schematic illustration of a composite imaging system with a near infrared source in accordance with the present invention;

4 is a schematic diagram showing the internal structure of an image sensor according to an embodiment of the present invention;

5A to 5D illustrate an embodiment of a mobile terminal including a composite imaging system, in which FIGS. 5A and 5B illustrate a structural configuration of the mobile terminal, and FIGS. 5C and 5D illustrate the mobile terminal in use. User experience map;

6A to 6D illustrate another embodiment of a mobile terminal including a composite imaging system, in which FIGS. 6A and 6B illustrate a structural configuration of the mobile terminal, and FIGS. 6C and 6D illustrate the mobile terminal in use User experience graph.

In the drawings, the same or similar reference numerals indicate the same or similar components.

detailed description

Those skilled in the art will appreciate that the present invention can be implemented in other implementations without departing from the specific details. Also, unnecessary details of known functions and constructions are omitted in the present description in order not to obscure the invention.

The invention is further described in detail below with reference to the accompanying drawings. It should be noted that the size and position of the various components in the drawings are for illustrative purposes only and are not to scale.

1 is a schematic illustration of a composite imaging system for biometrics in accordance with the present invention. As shown in FIG. 1, the composite imaging system 100 includes an image sensor 110, a filter assembly 120, and a lens assembly 130. Wherein, the filter assembly 120 includes a visible light band pass filter 121 and a near infrared light band pass filter 122 (shown as being filled with a backslash), and the image sensor 110 includes an area for near infrared light imaging. A (shown in the figure as filled with backslashes), region B for visible light imaging, and transition region C between A and B regions (shown as filled with horizontal lines).

As shown in FIG. 1, the lens assembly 130, the filter assembly 120, and the image sensor 110 are sequentially disposed along the incident light path. It should be noted that between the three components shown in Figure 1. The distance is only exemplary. The full spectrum of light is incident through the lens assembly 130 and reaches the filter assembly 120, wherein the visible bandpass filter 121 allows visible light (eg, wavelengths of 380-760 nm) to pass, while the near infrared bandpass filter 122 allows near Infrared light (for example, having a wavelength of 780-880 nm) passes. The visible light band pass filter 121 and the near infrared light band pass filter 122 can be realized by plating. The visible light passing through the visible light band pass filter 121 is substantially imaged in the area B of the image sensor, while the near infrared light passing through the near infrared light band pass filter 122 is substantially imaged in the area A of the image sensor. The imaging of the regions B and A of the image sensor can be separately distinguished by image processing software, wherein the imaging of the region B corresponds to normal visible light imaging, for example, the user performs imaging during daily self-timer using a mobile terminal such as a mobile phone, and the area A The imaging corresponds to imaging in the near-infrared mode, such as imaging when the user uses the mobile phone for iris recognition. In this way, switching between visible light and near-infrared light imaging can be conveniently performed without the need to equip moving parts to switch the filter, which greatly improves stability.

In order to ensure that the image sensor 110 can be completely covered by the filter assembly 120 on the imaging optical path, in the composite imaging system of the present invention, the area of the filter assembly 120 is larger than the area of the image sensor 110. The filter assembly 120 can be a separate component from the image sensor 110 or can be packaged over the surface of the wafer of image sensors by a packaging process. The near-infrared light passing through the near-infrared bandpass filter 122 and the visible light passing through the visible bandpass filter 121 may overlap at the transition region C of the image sensor. In order to minimize or even nearly eliminate the area of the transition region C, the filter assembly 120 should be close to the image sensor 110, for example, less than 2 mm, in which the wide-angle diffusion propagation of light is small and can even be ignored. Even if the image sensor 110 has a transition region C, its area is limited and mainly affects visible light imaging. The pixel region corresponding to the transition region C can be removed from the visible light image by the image processing software to obtain acceptable visible light imaging.

2 is a schematic diagram of the depth of field of the lens assembly 130 for clear imaging of visible light and near-infrared light. In the composite imaging system 100 in accordance with the present invention, the lens assembly 130 has a certain field of view and receives light from the full spectrum. Lens assembly 130 uses a fixed focal length of optical transmission Mirror, the depth of field range d1 of the optical lens for clear imaging of the visible spectrum is overlapped with the depth range d2 of the optical lens for clear imaging of the near-infrared spectrum, so that the system can obtain clear images in both visible and near-infrared bands. ,as shown in picture 2. Alternatively, an achromatic optical lens in which visible light and near-infrared light are confocal may be used.

3 is a schematic diagram of a composite imaging system with a near-infrared light source in accordance with the present invention, in addition to the schematic positional relationship of image sensor 110, filter assembly 120, and lens assembly 130 of FIG. 1A, further A near infrared source 150 is shown. In biometric imaging such as iris, iris information is easily interfered by visible light from the outside environment, for example, visible light reflection spots formed by window reflections on the surface of the eye or reflections of various environmental lights by users wearing glasses. Reflective bright spots can block the iris, which in turn affects recognition rate and user experience. To this end, the near-infrared source 150 can include one or more infrared LEDs having a central spectral range, such as within 780-880 nm, for near-infrared illumination of the biometric features to enhance biometric imaging. The near-infrared source 150 can be independent of the composite imaging system 100, as shown in Figure 3, or as part of a composite imaging system. The near-infrared source 150 has a specific emission tilt angle when installed, and only needs to be illuminated in the near-infrared band of the biometric features within the specific imaging space range α shown in FIG. 3, without having to be within the entire imaging space range β. The object is illuminated. The exiting main optical axis of the near-infrared source 150 is not parallel to the central optical axis of the imaging system to avoid "brightness" effects when imaging biometric features (eg, iris), affecting the performance of the biometric system. The launch tilt of the near-infrared source can be flexibly adjusted based on different object distances and relative placement of the composite imaging system 100. Generally, the range of the launch tilt is set between 0 and 45 degrees, and as the object distance increases, the tilt angle can be correspondingly reduced.

4 is a schematic diagram showing the internal structure of an image sensor according to an embodiment of the present invention.

The image sensor 110 is a complete image sensor pixel combination array that transmits digital image pixel data collected by the image sensor to a backend encryption chip or processor through a data transmission interface (such as a MIPI interface). To meet the requirements of both visible-light imaging applications (such as self-timer) for larger imaging ranges (corresponding to larger field of view) and near-infrared imaging applications (such as iris imaging) for image resolution (within unit area) The image sensor 110 in the composite imaging system 100 of the present invention can use an image sensor of a large number of pixels, with the accuracy and minimum resolution requirements of the number of pixels. Taking the iris of an ordinary person with an average diameter of 11 mm as an example, according to the ISO standard, the outer diameter of the monocular iris in the image needs to be 120 pixels. If the iris can be recognized by a lens with a horizontal FOV of 60 degrees at a normal use distance (30 CM), the image sensor needs to have at least 3773 pixels in the horizontal direction, and 2120 pixels in the vertical direction according to the image aspect ratio of 16:9. The pixel, that is, the total number of pixels is 8M. Considering the number of pixels of the actual image sensor in the horizontal and vertical directions, it is preferable to use a CMOS image sensor having a pixel number of 8 M or more, for example, a 13 M pixel CMOS image sensor (4680 (W) x 3456 (H)).

As shown in FIG. 4, in the production process, two components, a microlens 112 and a color filter 114, are generally added to the image sensor silicon substrate 116. In general, it is necessary to provide a corresponding color filter on the pixel area of the image sensor to filter out the color. According to an embodiment of the present invention, unlike the conventional scheme, the color filter 114 does not cover the entire silicon base 116 of the image sensor, but covers the visible light imaging region therein, that is, only the visible light region B of the image sensor has a color filter. 114, then the microlens 112 is attached to the color filter 114; while in the near infrared light imaging area A, the color filter is removed, and the microlens 112 is directly attached to the silicon base of the image sensor. The color filter removal design enhances the corresponding spectral sensitivity of the corresponding image sensor area A for the near-infrared spectral range, and enhances the absorption of light energy in the near-infrared band of 760-880 nm, thereby optimizing the enhancement of the area for iris imaging. Image effect. In this way, the infrared LED light source with smaller energy can also maintain the strong near-infrared spectral energy reception, and can image the richer iris details, thereby reducing the power consumption requirement of the system for the active illumination source, and realizing the Low power consumption design for near-infrared biometric imaging of mobile terminal devices.

The area of the transition region C of the image sensor 110 is small, and the transition region C is omitted in FIG. 4 for the sake of simplicity of description. The color filter corresponding to the transition region C can be retained or removed as needed.

As described above, the composite imaging system of the embodiment of the present invention innovatively employs a dual-band filter design, and can further employ an improved image sensor for sub-area imaging, wherein The visible light imaging area has a color filter and the color filter is removed on the near infrared light imaging area. With such a structural design, the image sensor can output pixel data corresponding to the visible light and near-infrared light bands in different regions, so that it can be conveniently switched between the visible light imaging mode and the near-infrared light imaging mode, for example, the user can click on the mobile terminal touch screen. The button or physical button displayed on the screen switches the imaging mode. In the visible light imaging mode (such as daily self-timer), only the imaging of the visible light imaging region of the image sensor can be output, and the imaging of the transition region of the image sensor can be further removed by the image processing software, and the acquired image is not subject to near-infrared light. The effect is reddish. In the near-infrared light imaging mode for biometric recognition, the image sensor can output only the imaging of the near-infrared light imaging region, and the acquired biometric image is not affected by visible light of various complex environments to generate environmental noise.

Different from the prior art, the present invention does not require physical positional switching of the filter, but can realize switching and multiplexing of the visible light and near-infrared light imaging modes only by software, and does not require movement for the filter. The component is capable of enhancing the stability of the system and structure in the falling environment of the mobile terminal.

In the visible light imaging mode, the software control image signal processor ISP selects the corresponding visible light imaging region to work, and invokes the corresponding visible light imaging ISP parameter setting to optimize the effect of visible light imaging. If in the near-infrared light imaging mode, the ISP selects the corresponding near-infrared light imaging area to work, and the corresponding ISP parameter setting of the near-infrared light imaging is called to optimize the effect of the near-infrared light imaging. In particular, for iris recognition, because of active infrared illumination and stable illumination source, it is necessary to modify the ISP parameters to reduce the signal gain of the image sensor CMOS, increase the contrast of the image sensor CMOS, reduce the noise of the image sensor CMOS, and increase the image sensor CMOS. The signal-to-noise ratio is beneficial to improve the quality of iris imaging.

In view of the sensitivity of the biometric information, the composite imaging system may further include an image encryption unit to provide a function of encrypting the acquired biometric image. The image encryption unit may be implemented by a processor (not shown) or included in the processor or included in an image sensor or a composite imaging system in a separate modular unit. In the group. After the composite imaging system enters the near-infrared light imaging mode and acquires the infrared image, the image encryption unit activates the image encryption function, encrypts the obtained biometric image, and outputs the encrypted data for further processing. When the composite imaging system enters the visible light imaging mode, the image encryption unit does not activate, and the obtained visible light image is not encrypted, so that the image sensor directly outputs the obtained visible light image.

5A-5D illustrate one embodiment of a mobile terminal 100 that includes a composite imaging system of the present invention. 5A and 5B show the structural configuration of the mobile terminal 100, and FIGS. 5C and 5D respectively show user experience diagrams when the mobile terminal is used in the iris recognition mode and the self-photographing mode, respectively.

As shown in FIG. 5A, the mobile terminal 100 includes a composite imaging system 100, a near-infrared light source 150, and a screen implemented as a camera module. The near-infrared source 150 can include one or more infrared LEDs in the 780-880 nm band. The composite imaging system 100 is disposed on one side of the front side of the screen of the mobile terminal, such as the top of the screen or the bottom of the screen, which is the top in FIG. 5A. In the present embodiment, the near-infrared light source 150 and the composite imaging system 100 are arranged on the same side of the front side of the screen of the mobile terminal, which are shown in the figure as being arranged on the top of the front side of the screen, that is, in the N direction of the screen, wherein the near infrared The horizontal distance of the location of the light source 150 from the center of the composite imaging system 100 is in the range of 2-8 cm, which facilitates the elimination of reflected spots when worn by the user of the glasses.

The near-infrared light source 150 is placed under the touch panel of the mobile terminal. For example, the near-infrared light source 150 can be placed on the bottom layer of the front button of the mobile terminal (below the thickness direction of the mobile terminal), such as the Home button. The bottom layer, so that it is not necessary to specifically open holes in other locations to cause a visual appearance. The surface of the touch panel of the near-infrared light source can be coated with an infrared anti-reflection film, which is consistent with the overall color of the front surface of the mobile terminal, and the color of the coating can be silver white, gold or black.

As shown in FIG. 5A, the composite imaging system 100 is in the N direction of the screen, i.e., above the length of the mobile end, and the screen is in the S direction of the composite imaging system 100. In this case, the filter assembly 120 and the image sensor 110 are configured as shown in FIG. 5B: the visible band pass filter 121 is placed above the near-infrared bandpass filter 122 (ie, In the N direction), the visible light imaging region B of the corresponding image sensor is placed above the near-infrared light imaging region A (N direction). The transition region C is located between the visible light imaging region and the near infrared light imaging region. In this embodiment, the area of the visible light imaging area is greater than 50% of the area of the image sensor, and the area of the near infrared light imaging area is less than 50% of the area of the image sensor, and the transition area C is located in the visible light imaging area and the near infrared light imaging area. The area between them is less than 15% of the area of the image sensor. In the case where the two regions are arranged up and down, it may be preferably designed such that the visible light imaging region height is 80% of the height of the entire image sensor, and the near-infrared light imaging region height is 20% of the height of the entire image sensor.

When in the near infrared light imaging mode, an eye image preview window 160 can be provided in the screen. The eye image preview window 160 only outputs an image of the corresponding near-infrared light imaging region (ie, biometric imaging) for guiding the user to cooperate to acquire the biometric image. In use, the position of the eye image preview window 160 may be placed on the upper or lower side of the screen on the screen of the mobile terminal. In the present embodiment, as shown in FIGS. 5A and 5C, the eye image preview window 160 is located on the upper side of the screen, that is, near the side of the composite imaging system 100, which facilitates the user's eyes when in use. Naturally, the direction of the composite imaging system 100 is gaze, thereby reducing the occlusion of the iris texture features on the eyelids and eyelashes of the human eye, so as to obtain a better and richer iris image, which is advantageous for recognition. At this time, the user can tilt the upper portion of the mobile terminal (ie, the side including the composite imaging system 100) toward the user side as shown in FIG. 5C, so that the user's eyes are gazing at the eye image preview window 160. An image can be output in the eye image preview window 160 so that a biometric image (eg, an iris image) can be acquired for subsequent pre-processing or encryption recognition processes. In particular, composite imaging system 100 captures visible and near-infrared light from biometrics. Due to the principle of lens imaging inversion, near-infrared light from biometrics enters the interior of the mobile terminal through the composite imaging system 100, and passes through the near-infrared (S) near-infrared bandpass filter 122 to the image sensor. S) Near-infrared light imaging area to perform near-infrared light imaging of biometric features. Placing the near-infrared source 150 above the mobile terminal helps to more fully illuminate the biometric features (e.g., the iris) as the upper portion of the mobile terminal is tilted toward the user. In order to ensure sufficient illumination of the biometric features by the near-infrared light source, in this embodiment, The direction of emission of the infrared source 150 can be appropriately tilted toward the system 100 or the upper portion of the screen of the mobile terminal by a certain angle, as shown in FIG. 5C. The divergence angle of the near-infrared light source 150 can be flexibly adjusted according to different object distances and the placement positions of different systems. In the visible light imaging mode, such as the user's daily self-timer, as shown in FIG. 5D, the upper portion of the mobile terminal does not need to be tilted toward the user side as in FIG. 5C, and the near-infrared light source 150 does not operate. The user looks at the middle of the screen. Compared with the near-infrared light imaging mode, the light of the self-timer region of interest mainly passes through the visible (N) visible light bandpass filter 121 and reaches the upper (N) visible light imaging region of the image sensor. , get a self-portrait image.

6A-6D illustrate another embodiment of a mobile terminal 100 that includes a composite imaging system of the present invention. 6A and 6B show the structural configuration of the mobile terminal 100, and FIGS. 6C and 6D respectively show user experience diagrams when the mobile terminal is used in the iris recognition mode and the self-photographing mode, respectively. In contrast to the embodiment of Figures 5A through 5D, in the embodiment of Figures 6A through 6D, the near-infrared source 150 is located in the lower portion of the screen (i.e., the S-direction), and the composite imaging system 100 is located in the upper portion of the screen (i.e., the N-direction). . The filter assembly 120 and the image sensor 110 are configured as shown in FIG. 6B: the visible band pass filter 121 is placed below the near-infrared bandpass filter 122 (S); and the visible light image of the image sensor The area B is placed below the near-infrared light imaging area A (S), and the transition area C is located between the visible light imaging area B and the near-infrared light imaging area A.

Similar to the embodiment of FIGS. 5A to 5D, when used, when the mobile terminal enters the near-infrared light imaging mode to perform near-infrared light imaging of the biometric feature (eg, into the iris recognition mode), it may be provided in an area above the screen. The eye image preview window 160 is used to guide the user to cooperate to collect the biometric image. This is advantageous for the user's eyes to naturally look at the direction of the composite imaging system 100, thereby reducing the occlusion of the iris texture features on the eyelids and eyelashes of the human eye, so as to obtain a better and richer iris image, which is advantageous for recognition. At this time, the user can tilt the upper portion of the mobile terminal (ie, the side including the composite imaging system 100) toward the direction away from the user side as shown in FIG. 6C, so that the user pans through the image while looking at the eye image preview window 160. A unit (not shown) performs translation control to ensure that the preview image in the eye image preview window 160 is a preview of the near-infrared light imaging area of the image sensor, An image of the user's eyes can be outputted in the eye image preview window 160 so that a biometric image (eg, an iris image) can be acquired for subsequent pre-processing or encryption recognition processes. If the preview window is placed in the lower portion of the screen area of the mobile terminal, the iris texture is blocked by the upper eyelids and the eyelashes during use by the user, so the present invention does not favor this configuration. In the configuration of the present embodiment, the near-infrared light source 150 is placed under the mobile terminal such that the biometric features (e.g., the iris) can be more fully illuminated when the upper portion of the mobile terminal is tilted away from the user. In order to ensure sufficient illumination of the biometric features by the near-infrared light source, in the present embodiment, the emission direction of the near-infrared light source 150 may be inclined at a certain angle toward the upper direction of the system 100 or the screen of the mobile terminal. The tilt angle of the near-infrared light source 150 can be flexibly adjusted according to different object distances and placement positions of different systems. In the visible light imaging mode, such as the user's daily self-timer, as shown in FIG. 6D, the upper portion of the mobile terminal can be tilted toward the user side, and the near-infrared light source 150 does not operate.

In addition, an auxiliary near-infrared light source (not shown) may be incorporated in the displayed screen in front of the mobile terminal. When the mobile terminal is in the near-infrared light imaging mode, the auxiliary near-infrared light source can assist the near-infrared light illumination of the biometric feature, thereby saving power of the near-infrared light source disposed on the mobile terminal. The iris of the human eye can be illuminated by the infrared screen portion of the screen that is illuminated by the control of the software, and the screen can be illuminated with the OLED light source in the normal mode.

The composite imaging system and mobile terminal of the present invention have at least the following advantages:

1) The single camera module works in visible light and near-infrared light imaging mode, which simplifies the hardware design, has no moving parts to switch the filter, greatly improves the stability, and realizes the visible light and near-infrared light imaging mode by software. Switch between.

2) Ensure the normal use of the front camera of the mobile device, such as self-timer, and collect infrared biometric images that meet the biometric (eg, iris) recognition requirements at the user's normal distance (eg, 20-50 cm). Affect the user experience.

3) Sub-regional near-infrared light imaging requires only a portion of the image sensor to receive illumination from the near-infrared source, rather than the entire image sensor, thereby reducing the total power consumption of the image sensor for the infrared illumination source, ie, using less energy and Smaller emission angle of infrared The LED light source can also maintain sufficient absorption of near-infrared spectral energy in the infrared region to obtain a biometric image rich in texture details.

4) The composite imaging system of the present invention can encrypt the acquired biometric image to ensure the security of the user's personal sensitive information.

The present invention takes iris recognition as an example to illustrate the imaging function multiplexing composite imaging system of the present invention. However, aspects of the present invention are not limited to the recognition of the iris of the human eye, but can also be applied to other biological features that can be used for identification, such as whitening, fingerprints, retina, nose, face (two-dimensional or three-dimensional), Eye lines, lip lines and veins.

The terminology used herein is for the purpose of the description of the embodiments and As used herein, the singular "," It is also to be understood that the term "comprising", when used herein, is intended to refer to the features, the whole, the steps, the operation, the elements, and / , operations, components, components, and/or groups thereof.

Terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs, unless otherwise defined. Terms used herein are to be interpreted as having a meaning consistent with their meaning in the context of the specification and the related art, and are not to be interpreted in an ideal or overly formal sense unless specifically defined herein.

A8. The composite imaging system of A1, wherein the area of the filter assembly is greater than the area of the image sensor. A9. The composite imaging system of A1, wherein the image sensor has an image resolution greater than 2400 pixels in the horizontal direction of both eyes of the human eye. A10. The composite imaging system of A1, wherein the image sensor comprises a color filter, wherein the color filter covers only the visible light imaging region of the image sensor. A11. The composite imaging system of A1, wherein the filter assembly is less than 2 mm from the image sensor.

B15. The mobile terminal of B14, further comprising an image shifting unit for performing panning control of the eye image in the near infrared imaging mode to ensure that the preview image in the eye image preview window is near infrared light of the image sensor A preview of the imaging area imaging. B16. The mobile terminal of B12, wherein the near-infrared light source is placed under the button on the front side of the mobile terminal. B17. The mobile terminal of B16, wherein the surface of the aperture portion of the near-infrared light source is plated with an infrared anti-reflection film that allows transmission of a light source in the near-infrared band. B18. The mobile terminal of B16, wherein the color of the infrared anti-reflection film is consistent with the color of the front surface of the mobile terminal. B19. The mobile terminal of B12, wherein the screen comprises an auxiliary near-infrared light source, and the auxiliary near-infrared light source of the screen assists the near-infrared light illumination of the biometric feature when in the near-infrared light imaging mode.

Although some embodiments have been described in detail above, other modifications are possible. For example, to achieve a desired result, the logic flow depicted in the figures does not require a particular order, or a sequential order. Other steps may be provided, or some steps may be eliminated from the described flow, and other components may be added to or removed from the described system. Other embodiments are possible within the scope of the following claims.

Claims

A composite imaging system supporting a visible light imaging mode and a near infrared light imaging mode, including a lens assembly, a filter assembly, and an image sensor disposed along an incident optical path, wherein:

The lens assembly includes an optical lens with a fixed focal length;

The filter assembly includes a visible light band pass filter that allows light in the visible light band to pass through and a near infrared light band pass region that allows passage of the near infrared light band;

The image sensor includes a visible light imaging region, a near infrared light imaging region, and a transition region between the two regions, the image sensor operating in one of a visible light imaging mode and/or a near infrared light imaging mode, wherein the image sensor The visible light imaging region images visible light passing through the visible light band pass filter in the visible light imaging mode, and the near infrared light imaging region passes through the near infrared light band in the near infrared light imaging mode The near-infrared light of the filter is imaged.
The composite imaging system of claim 1 wherein the depth of focus of the fixed focal length optical lens for clear imaging of the visible light spectral band overlaps with the depth of field of the optical lens for clear imaging of the near infrared spectral band.
The composite imaging system of claim 1 wherein said fixed focal length optical lens comprises an achromatic optical lens that is confocal with visible light and near infrared light.
The composite imaging system of claim 1 further comprising:

A near-infrared source that illuminates the region of interest in the near-infrared band in near-infrared imaging mode.
The composite imaging system of claim 3 wherein the exiting primary optical axis of the near infrared source and the central optical axis of the imaging system are non-parallel.
The composite imaging system of claim 1 further comprising:

An image encryption unit for encrypting an image generated by the image sensor.
The composite imaging system of claim 5 wherein:

After generating the near-infrared light image by the image sensor in the near-infrared light imaging mode, the image encryption unit encrypts the obtained near-infrared light image of the biometric and outputs the encrypted image;

In the visible light imaging mode, the image encryption unit does not encrypt the visible light image generated by the image sensor.
A mobile terminal supporting a visible light imaging mode and a near infrared light imaging mode, comprising:

A composite imaging system according to any of claims 1-7;

a near-infrared light source for illuminating a region containing a biometric of interest in a near-infrared band in a near-infrared light imaging mode, wherein the near-infrared source is arranged to have a specific emission tilt angle toward an upper portion of the screen of the mobile terminal;

a screen for providing an eye image preview window for guiding a user to cooperate to acquire a biometric image in a near-infrared light imaging mode, the eye image preview window being disposed adjacent to a side of the composite imaging system, The imaging of the near-infrared light imaging area of the image sensor is preview output.
The mobile terminal of claim 8 wherein:

The composite imaging system and the near-infrared light source are both disposed at an upper portion of a screen, and a visible light band pass filter of the filter assembly is disposed above the near-infrared bandpass filter, the image sensor A visible light imaging region is disposed above the near infrared light imaging region.
The mobile terminal of claim 8 wherein:

The composite imaging system is disposed at an upper portion of the screen, the near-infrared light source is disposed at a lower portion of the screen, and the visible light band pass filter of the filter assembly is disposed under the near-infrared light band pass filter, A visible light imaging region of the image sensor is disposed below the near infrared light imaging region.