TWI528211B - Non-contact palmprint authentication method, device and portable terminal - Google Patents

Description

Non-contact palmprint authentication method, device and portable terminal

The present invention relates to the field of portable terminal identity authentication technologies, and in particular, to a contactless palmprint authentication method and apparatus suitable for a portable terminal.

With the revolution of mobile communication technologies, portable terminals such as smart phones and tablet computers are becoming an important tool for people's daily life and work. For example, in addition to traditional applications such as telephony and text messaging, people can already use smartphones for social networking, online shopping, and online payment. A large amount of valuable work data or private data may be stored on the portable terminal. Therefore, the user is paying more and more attention to the information security on the portable terminal, and it is hoped that the data to be protected cannot be accessed without being authenticated.

In the conventional manner, the portable terminal uses a password or a combination of a username and a password to authenticate the user. The problem with this approach is that there is a natural contradiction between its security and convenience. First of all, if users want to improve security, they need to set up complex passwords. For example, passwords are combinations of letters, numbers and special symbols. It may even require partial letters to be capitalized. Secondly, users may need different authentication portals. Use a password that is not associated; for example, the user's email password is preferably not associated with the QQ password, otherwise another password is easily guessed once one of the passwords is known to others.

Extremely demanding applications such as online payment and mobile banking In the middle, multiple authentication methods will be adopted. In addition to user login authentication, a dual authentication of payment passwords will be introduced. At present, many online payments also need to be authenticated by sending a verification code via SMS. In this case, users must accept these strict but inconvenient security measures in order to have a safe experience.

At present, some developers and vendors are trying to introduce fingerprint authentication methods on portable terminals to replace traditional username/password authentication methods. This type of authentication is more convenient, but its security is greatly reduced. This is because fingerprint authentication is used on the portable terminal. Once the portable terminal is lost and acquired by others, since the user has previously left a large number of fingerprints when using the portable terminal, these fingerprints are easily collected and utilized by others, resulting in the fingerprint authentication being ineffective. In fact, the public security organs use the characteristics that fingerprints are easy to leave, and establish a fingerprint database to assist in the detection of various cases. In addition, fingerprint authentication has the problem of high implementation cost. In order to support fingerprint authentication, the portable terminal needs to additionally configure a fingerprint recognition hardware, and adjust the overall design of the portable terminal accordingly, which not only contradicts the trend of thinning and thinning of the portable terminal, but also introduces development and design. The problem of rising costs.

Therefore, in general, traditional user authentication technology cannot solve the contradiction between convenience and security.

In view of the above, the present invention provides a non-contact palmprint authentication device applied to a portable terminal including a camera and an illumination lamp, the device comprising: an acquisition control unit, configured to enable the camera when the palmprint authentication process is turned on, and Keeping the working state of the illuminator set to the illumination mode when the external illumination is insufficient, Thereby providing a fill light output for the camera; a screening output unit, configured to select a frame of a new image from the video stream output by the camera as a candidate image, and acquire a current state parameter set of the camera for the candidate image Determining whether each state parameter in the set satisfies a preset criterion corresponding to the parameter, and if satisfied, the candidate image is output as a palmprint matching palmprint image, if any state parameter in the set is not Satisfying the corresponding preset criterion, ignoring the candidate image, and reselecting a new frame of the image as the candidate image; and a palmprint matching unit for using the contrast palmprint image and the pre-recorded one according to a preset algorithm Or matching the plurality of reference palmprint images, if the matching is successful, determining that the authentication passes; if the matching fails, outputting an authentication failure prompt or returning to the screening output unit.

The present invention also provides a non-contact palmprint authentication method for a portable terminal including a camera and an illumination lamp, wherein the method comprises the following steps: Step A, enabling the camera when the palmprint authentication process is turned on, and external illumination When insufficient, the working state of the illuminating light is set to an illumination mode to provide a fill light output for the camera; and step B, a new image of a frame is selected from the video stream output by the camera as a candidate image; C: acquiring, according to the candidate image, a current state parameter set of the camera, determining whether each state parameter in the set meets a preset criterion corresponding to the parameter, and if the two are satisfied, matching the candidate image as a palmprint matching The contrast palm print image output, if any of the state parameters in the set does not meet the corresponding preset criteria, the candidate image is ignored and returned Going back to step B; and step D, matching the contrast palmprint image with the pre-recorded reference palmprint image according to a preset algorithm, and if the matching is successful, determining that the authentication passes; if the matching fails, outputting an authentication failure prompt or Go back to step B.

The invention can effectively improve the output quality of the contrast palmprint image in the non-contact palmprint authentication, thereby improving the performance of the non-contact palmprint authentication technology.

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1 is a typical application scenario diagram of the present invention.

2 is a schematic diagram showing the logical structure of a non-contact palmprint authentication apparatus and its basic hardware environment in an embodiment of the present invention.

3 is a flow chart of a non-contact palmprint authentication method in an embodiment of the present invention.

4 is a flow chart of a non-contact palmprint authentication method in another embodiment of the present invention.

In order to solve the problems of the prior art, the industry is currently studying technologies such as face recognition to implement user identity authentication. But this technology still does not substantially improve the natural contradiction between convenience and security. Taking face recognition as an example, the security problem is that the acquisition of user face images is relatively easy. Users may store a large number of their own photos on the Internet or other terminals. These photos may be easily taken by others. Get it so that illegal users can use these photos to camouflage through face authentication.

Compared to fingerprints and faces, the possibility that palm prints are acquired by others is very small. This is because, first of all, in the process of using a portable terminal, most of the hand operations depend on the finger. Secondly, in daily life, when people use their hands, the palms are usually in a certain degree of collapse. Even if the palm prints are left, the palm prints are completely different from the palm prints when the palms are open. It is difficult to use for identity authentication. In addition, users generally do not save clear palm photos, so there is no drawback that photos are taken and used by others.

However, the current palmprint authentication implementation technology still relies on dedicated hardware devices, which also causes high cost and insufficient convenience. For example, Chinese Patent Application Publication No. CN101833647A discloses a palmprint acquisition device and a corresponding processing method. In this solution, although the disadvantages of the need to shield ambient light in the conventional technology are improved, it is still necessary to introduce dedicated hardware, using a flash lamp or an external infrared LED to complete the palmprint authentication process, and still be a contact palmprint authentication implementation. In the contact palmprint authentication technology, the user's palm needs to be fixed at a predetermined distance from the camera by a specific positioning component (such as a hand placement table), and the user's palm cannot move freely. Obviously, this technology is very inconvenient and cannot be applied to portable terminals. In addition, Chinese Patent Application Publication No. CN1972186A discloses a mobile identity authentication system and an authentication method thereof, in which a mobile device camera function is used to assist a flash to obtain a palm print for palmprint authentication, which brings certain convenience. However, the quality of the palmprint image is low, so the built-in palmprint matching algorithm is very demanding, and the scheme is still far from the actual commercial.

In view of the shortcomings of the current technologies, the present invention proposes a non-contact palmprint authentication solution to substantially improve the technical basis of non-contact palmprint authentication. Contact palmprint authentication technology provides technical support for breakthroughs in convenience. The so-called non-contact palmprint authentication means that the authenticated palm does not need to be fixed on a certain positioning component.

In a preferred embodiment, the present invention provides a contactless palmprint authentication device based on a computer program, which is applied to a portable terminal (hereinafter, only a smartphone is taken as an example). As shown in FIG. 2, the smartphone typically includes a CPU, a memory, a camera 12, a non-volatile memory, an illumination lamp 11, and various input and output hardware including a touch display screen.

In a preferred manner, the camera 12 and the illumination 11, for example made of LEDs, are typically located on the same side of the smartphone, such as the back of the handset. Considering the deformation of the structure and the design, in the implementation of the present invention, the positional relationship between the camera 12 and the illumination lamp 11 can be further relaxed, as long as the path range of the image captured by the camera 12 intersects with the illumination output range of the illumination lamp 11. Just fine. In fact, as long as the smart phone capable of flashing photos has the basic hardware environment for implementing the present invention. As shown in FIG. 1, the thicker dashed line indicates the illumination output range of the illumination lamp 11, and the thinner dashed line indicates the path range in which the camera 12 captures the image.

In terms of implementation, the device can be installed as a stand-alone mobile application (APP) on the mobile phone, or integrated as a feature in other mobile applications.

Referring to FIG. 2, in a software implementation manner (other embodiments are not excluded), the device functions as a logic level virtual device, and mainly includes an acquisition control unit, a screening output unit, and a palmprint matching unit.

Referring to Figure 3, the use and operation of the device includes the following steps.

Step 101: The acquisition control unit starts the palmprint authentication process according to the specific instruction; in step 102, the acquisition control unit enables the camera when the palmprint authentication process is started, and keeps the illumination light set to the illumination mode at least when the external illumination is insufficient; The output unit acquires a frame of a new image as a candidate image from the video stream currently output by the camera; in step 104, the filter output unit acquires a current state parameter set of the camera for the candidate image, and determines each state in the set. Whether the parameter satisfies the preset criterion corresponding to the parameter, and if yes, the candidate image is output as a palmprint matching contrast palm print image, if not, the candidate image is ignored, and the process returns to step 103; step 105 The palmprint matching unit determines whether the contrast palmprint image matches the reference palmprint image, and if so, the authenticated user identity is legal.

Palmprint authentication can be used as an authentication mechanism for various mobile applications. To perform certain operations, such as accessing important data, users need to verify their identity through palmprint authentication. In order to achieve palmprint authentication, it is usually necessary to first enter one or more user palmprint images as a reference palmprint image. The reference palmprint image is the basis of the palmprint authentication, and the subsequent acquired palmprint image is matched with the reference palmprint image, and the matching is successful.

The entry of the reference palmprint image can be done in a variety of ways. One way is for the user to upload a frame of image as a reference palm print image, such as a palm print image taken with other camera equipment as a reference palm print image. In a possible implementation manner, a method similar to the above-described method for collecting a palmprint image may be used to collect a reference palmprint image from the smartphone and save it inside the smartphone.

That is to say, a mobile phone APP can be set with a reference entry process for the user to collect and save the reference palm print image. In this manner, the acquisition control unit enables the camera correspondingly when the reference entry process is turned on, and maintains the illumination operation state when the external illumination is insufficient, and is set to the illumination mode to provide the fill light output for the camera; the filter output unit follows the steps. 103 and screen 104 filter the image, except that in the benchmark entry process, the saved contrast palm image is saved as a reference palmprint image.

The present invention also incorporates these existing implementations in the process of product implementation, but the process of entering the reference palmprint image and determining whether the contrast palmprint image matches the reference palmprint image can be implemented with reference to the prior art. The present invention does not focus on the advantages and disadvantages of the matching algorithm itself. The object of the present invention is to reduce the development difficulty and development cost of the palmprint authentication software product by improving the process of comparing palmprint image acquisition and palmprint authentication.

After the user's palmprint entry as the reference palmprint image is completed, the user may trigger the opening of the palmprint authentication process through a specific interactive interface. For example, the user may click a specific touch button on the screen to trigger the palmprint authentication process to be turned on; of course, the triggering of the palmprint authentication process may also be triggered by a specific application, such as a mobile phone application may trigger when certain conditions are met. The palmprint certification process is open.

In the present invention, after the palmprint authentication process is turned on, the acquisition control unit will enable the camera and set the illumination in the illumination mode. On a smartphone, after the camera is turned on, it automatically captures images through the built-in sensor chip and outputs a video stream of a certain frame rate, such as a 30-frame/second video stream. This video stream is usually displayed on the screen of the phone, allowing the user to intuitively see the direction or target that the camera is aimed at.

To get a frame to compare the palmprint image with the reference palmprint image, the direct idea is to refer to the camera application of the smartphone. In the camera application, when the user clicks on the camera application icon on the screen of the mobile phone, the camera will turn on and output and save the currently acquired image of one frame according to the user operation. If a particular application needs to take a frame of image, the usual practice is to implement the functionality of a simulated camera application.

When the external light is insufficient, the camera application will automatically fill the light with the flash. This method may meet user requirements in other application scenarios where one frame of image is required, but there is a problem in the palmprint authentication process. First, when a user uses a smartphone to align the palm of his hand, the distance is usually relatively close, typically in the range of tens of centimeters. If you choose the automatic flash mode, in many cases, especially when the external light is not enough, it is easy to cause the image to be overexposed. However, if you choose to manually start the flash, it is not only convenient, but also high on the user. Secondly, since the flash is completed in an instant, if the user's palm is moving while the flash is being fired, the movement of the palm will cause motion blur, which eventually results in a poor quality of the currently shot image. The relative distance between the palm of the user and the mobile phone may change at any time. The constant change of this distance has a direct and significant influence on the focus state and the exposure state. The movement of the palm of the user is impossible to control, and the flashing time of the flash is instantaneous. Completed, therefore, there is an insurmountable contradiction between using the flash mode and the way the mobile terminal is used, resulting in it being generally unable to obtain a palm print image that satisfies the quality requirements of palmprint authentication.

Therefore, when palmprint authentication is performed, if a conventional photographic application method is used to collect contrast palmographic images according to the general technical realization of the art, it is basically difficult to collect contrast palmprint images with better image quality. In this case, developers need to open More powerful algorithms are used to compensate for the lack of quality of the palmprint image, but in this case, the development cost and difficulty will undoubtedly increase, but the overall effect may still be poor.

In addition, from the practical application, the user may perform palmprint authentication in various occasions, and obtaining the contrast palmprint image in the flash mode will undoubtedly cause light pollution and affect the surrounding crowds, and such products are not convenient for use in public places.

In fact, the idea of the flash mode is mainly influenced by the traditional photographic technology ideas, and it is hoped to output a high-powered light to compensate for the lack of illumination. Also, due to the uncertainty of the target distance in most photographic applications, the illumination mode is not suitable for conventional photographic needs. For example, when the subject is far away, the lighting mode is usually meaningless. However, in particular for palmprint authentication applications, since the palm print is usually closer to the camera, it is entirely possible to use the illumination mode to fill the light when imaging.

In other words, the present invention is directed to the practice of palmprint authentication, considering that the palm print is usually closer to the camera, and the illumination mode is used to fill the light. Although the fill light intensity is much smaller than the flash mode, since the distance between the illumination lamp and the palm is relatively close, A good fill-in effect is achieved, and it is basically guaranteed that it will not be overexposed due to the opening of the light.

It is particularly worth noting that since the position of the external light source is uncertain, the present invention can effectively improve the backlighting, the smoothing, and the illumination from different angles in the external illumination by performing the image filling light by using the illumination mode of the mobile phone. The negative impact, that is, the elimination of the negative effects of ambient light, can ensure that the image output quality interval becomes more convergent. For example, compared with taking pictures in the lighting mode, when the flash function is turned on, if the other conditions are the same, the image quality of the smartphone camera output changes more. It means that the image quality output is not stable enough.

Moreover, the output power of the illumination lamp in the flash mode is high, and the illumination cannot be continuously provided. If the illumination is continuously provided, it will easily cause the illumination to burn.

On the basis of improving the quality of the contrast palmprint image by using the illumination mode, the present invention also filters the multi-frame images continuously output by the camera. After the camera is enabled, the operating system may set the camera to continuous autofocus mode by default. The present invention further optimizes the process of acquiring contrast palmographic images, considering that the operating system does not necessarily set the camera to a continuous autofocus mode by default. For example, in the iOS operating system, the operating system allows the application to control the camera to work in either one of the auto focus mode, the continuous auto focus mode, and the manual focus mode. In the iOS 6.0 operating system, the expressions of these three modes are as follows: AVCaptureFocusModeLocked=0, / / lock the focal length, that is, not focus

AVCaptureFocusModeAutoFocus=1, / / focus once, then lock the focus

AVCaptureFocusModeContinuousAutoFocus=2,//Continuous AF

Similarly, for exposure adjustments, iOS also has three modes for users to choose from: fixed exposure mode, one automatic exposure mode, and continuous auto exposure mode. In the iOS 6.0 operating system, the expressions of these three modes are as follows: AVCaptureExposureModeLocked=0, / / lock the aperture, that is, no exposure adjustment

AVCaptureExposureModeAutoExpose=1, / / make an exposure adjustment Whole, then lock the aperture

AVCaptureExposureModeContinuousAutoExposure=2, / / continuous automatic exposure adjustment

In order to continuously obtain high quality image output, the acquisition control unit further controls the camera through the interface provided by the operating system when the camera is enabled, so that the camera operates in continuous autofocus mode and continuous auto exposure mode. Similarly, it can be inferred that if the white balance state parameter is involved in the implementation process, the acquisition control unit needs to make similar settings for the white balance adjustment mode.

The principle of screening is whether each state parameter in the current state parameter set of the camera satisfies the preset standard corresponding to the parameter. If all the preset criteria are met, the current frame image is an acceptable contrast palm image. The set of state parameters includes at least one state parameter. In a possible implementation manner, the collection state set may include any one or more of a focus state parameter, an exposure state parameter, and a white balance state parameter. Of course, if the operating system can provide more state parameters, it can be selected according to the needs of the application.

In a possible implementation manner, when the screening output unit obtains one frame of image from the camera, it needs to make a selection according to the current focus state parameter of the camera and the exposure state parameter. Generally, the focus state parameter can respectively represent the two states of focus completion and focus progress, and the exposure state parameter can also characterize both the exposure parameter adjustment and the exposure adjustment completion. Of course, with the development of technology, the focus state parameters and the exposure state parameters recorded in the operating system may have more states, and it is even possible to combine multiple state parameters together. In the actual implementation process of the present invention, those skilled in the art may Make adaptations based on these changes.

In the actual implementation of the present invention, the desired focus state parameters and exposure state parameters can be saved as acceptable preset criteria. In addition, the preset criteria for each parameter may vary from operating system to operating system. Once the screening output unit finds that the two state parameters respectively satisfy the corresponding preset criteria, it can be determined that the current frame image is an acceptable contrast palm image. For example, in the embodiment of the present invention, it is assumed that the focus state parameter is 1 when the focus is completed, and when it is 0, the focus is in progress; the exposure state of 1 indicates that the exposure adjustment is completed, and the value of 0 indicates that the exposure adjustment is in progress. Then, when the set of state parameters acquired by the screening output unit is 11, it is determined that the candidate image is an acceptable contrast palm print image, and when the state parameter set is 00, 01 or 10, the candidate image can be ignored.

Take the implementation of the iOS 6.0 operating system as an example. For the focus state parameter to meet the preset standard, the corresponding interface provided by the system can be used to determine whether the camera is performing focus adjustment. Specifically, it can be judged based on the return value obtained by calling the following interface, @property(nonatomic, readonly, getter=isAdjustingFocus)BOOL adjustingFocus. If it returns YES, it indicates that it is currently in the focus adjustment state; if it returns NO, it indicates that it is not currently focusing, which can be understood as the focus completion status.

Whether the exposure state parameter satisfies the preset standard can determine whether the camera is performing exposure adjustment by determining whether the camera is performing exposure adjustment. Specifically, it can be judged based on the return value obtained by calling the following interface, @property(nonatomic, readonly, getter=isAdjustingExposure)BOOL adjustingExposure. If YES is returned, it indicates that the exposure adjustment is currently in progress; return NO Indicates that the exposure adjustment is not currently being performed, that is, the exposure adjustment is completed.

After the one-frame contrast palm print image is acquired, the contrast palm print image can be output to the palmprint matching unit inside the device. The palm print matching unit can match the contrast palm print image with a pre-recorded reference palm print image using, for example, a preset matching algorithm. If the match is successful, the user identity is authenticated. If the matching is unsuccessful, it indicates that the current contrast palm print image may not be from the palm of the legitimate user, or it may be that the quality of the current contrast palmprint image still does not meet the requirements of the matching algorithm, and the authentication failure prompt may be output to the user. Referring to FIG. 4, in a possible implementation manner, if the candidate image is returned after the matching is unsuccessful, the reliability of the authentication result may be improved.

Considering that a legitimate user may acquire images in any lighting environment, if some lighting environment is extremely bad, the contrast palmprint image obtained by this screening may still not meet the requirements of the matching algorithm. One way is that the authentication fails immediately. Another way to output the authentication failure prompt to the user is to try to filter and output the contrast palm print image to improve the reliability of the authentication result. Further, in order to further improve the user experience and avoid repeated loops such as repeated unsuccessful attempts, the acquisition control unit may start a timer having a predetermined duration, such as a 10-second timer, after the palmprint authentication process is started. When the timer expires but the palm print matching is still unsuccessful, the palmprint authentication process is ended, and the authentication failure prompt is output to the user.

Considering the popularity of networked applications, the contrast palm print image can be output not only to the local palmprint matching unit, but also to the remote server via the network. The remote server can also have a palm print matching unit, which can also use the preset contrast algorithm to Compare the palm print image with the pre-recorded palm print image on the server. In this case, the palmprint authentication process can be controlled by the remote server.

As can be seen from the above description, the method for collecting a frame image of the present invention is completely different from the manner of conventionally collecting a frame image. The present invention checks the current camera state for a candidate image, and the camera state meets a preset standard before the candidate is selected. The image is acquired as a contrast palmprint image, otherwise the candidate image is ignored and the next frame image is acquired.

In summary, the present invention improves the image quality of the video stream in the whole process, and filters the image with better image quality in the video stream, which is completely different from the traditional camera application. The image is acquired only at a certain time according to the user or the software instruction, and the image is not filtered in combination with the current state parameters such as the focus state, the exposure state, and the like of the camera itself.

In the above implementation manner, the whole process is without user intervention, and the present invention refers to this mode as an automatic scanning mode. As mentioned earlier, the smartphone may be set by default or by the acquisition control unit in continuous autofocus mode, so it will automatically focus when the camera is turned on. On this basis, in order to provide users with different experiences, the present invention provides a manual click implementation in another possible implementation manner. This approach allows the user to click to determine when to start filtering the image.

In a manual click implementation, the apparatus further includes a screening enable unit. The screening enabling unit is further configured to wait for the user to filter and compare the instructions after the palmprint authentication process is started, and enable the screening output unit after receiving the screening comparison instruction sent by the user. The camera will automatically focus after it is turned on, but the filter output unit will not filter any images at this time. When the user issues a screening comparison command by clicking the touch display screen, the screening output unit starts to perform the screening processing of the contrast palmprint image at step 103.

In this way, since the user can visually observe the sharpness of the screen on the screen, when the screen is clear, the screen is triggered to compare the palmprint image screening processing, and the time from screening to certification passing will be greatly shortened. It is worth noting that in this embodiment, the screening output unit still obtains a contrast palm print image through a certain screening operation, but the screening process may be greatly shortened.

Whether it is an automatic scanning method or a manual clicking method, it does not require the movement of the user's authenticated palm, or there is no guiding measure to guide the user to place the palm in a distance range suitable for obtaining a high quality picture. In order to speed up the palmprint authentication, the present invention, in a possible embodiment, provides a guiding measure to guide the user to place the palm.

In an embodiment in which the user is guided to place the palm, the acquisition control unit may also set the focus parameter (usually the focal length) of the camera and the exposure parameter (such as the aperture) to a preset fixed value when the camera is enabled. Of course, as the hardware capabilities of mainstream cameras change, this fixed value may change. In addition, different models of mobile phones, the corresponding fixed values may not be the same. In this embodiment, if the user does not move the palm to enter a collection distance interval corresponding to the fixed value set, the screening output unit will not be able to filter the contrast palm print image that meets the preset standard, because the focal length is already a fixed value, It looks like a fixed focus camera. That is to say, in step 104, the user's palm does not enter a better collection distance, which may result in unclear focus or underexposure of the candidate palmprint image. The image is ignored because the camera state parameter obtained based on the candidate palmprint image does not meet the preset criteria. Therefore, in order to let the user move the palm or the smart phone as soon as possible to change the distance between the palm and the camera, when any of the focus state parameter and the exposure state parameter in the state parameter set does not satisfy the corresponding preset standard, the acquisition control The unit may further output a prompt message with a wrong distance to the user. This kind of prompt information can be implemented in many ways, possibly text, or image or sound; even through the change of the background color of the screen. For example, when the user's palm is not in the preferred collection distance interval, the screen background is different from the normal default color. If the user's palm is in the preferred collection distance interval, the screen background is restored to normal because there is no need to output the distance error prompt information. The default color.

In a possible implementation manner, the acquisition control unit can disable the camera and the illumination after the authentication is passed. For the case of authentication failure, the processing of the acquisition control unit can be more flexible. For example, you can either enable the camera and the illuminator; you can also disable the illuminator only; you can keep the camera and the illuminator enabled without processing, and wait for the user to trigger a new palmprint authentication again. The process or the user's exit indication, if the user exits, the camera and lights need to be enabled.

In one possible implementation, the illuminator can be fixedly held in the illumination mode. In this way, when the external illumination is insufficient, the illumination lamp maintains the fill light output, which can significantly improve the image quality; while the external illumination is good, the fill light output is maintained, and the image quality can be improved to some extent, for example, the improvement is smooth. The effects of light and backlighting. This embodiment is effective for improving image quality, but its energy saving effect is slightly inferior.

In another possible implementation manner, the acquisition control unit first reads The light sensor provided by the smart phone obtains the current illumination parameter, and according to the illumination parameter, the illumination lamp is controlled to perform the fill light output under the corresponding illumination level. This embodiment can achieve a lower intensity fill light output with better illumination, and may even not turn on the illumination. When the external illumination is poor, the illumination can be controlled to achieve a higher intensity fill light output.

That is to say, in this embodiment, the control of the illumination control by the acquisition control unit is divided into a plurality of situations, which respectively correspond to different illumination levels. For example, in the first illumination level, the acquisition control unit does not enable the illumination lamp; when the external illumination level drops to the second illumination level, the acquisition control unit sets the illumination and the like in the illumination mode, and sets the fill light output intensity of the illumination lamp to The first fill light intensity; at the third illumination level, the acquisition control unit sets the illumination light in the illumination mode, and sets the fill light output level of the illumination light to a higher second fill light intensity.

Both of the above embodiments can improve the image quality under the condition of insufficient illumination. When the illumination is good, one embodiment tends to consider image quality, and the other prefers energy saving.

As can be seen from the description of the previous paragraph, the present invention refers to keeping the illumination lamp set to the illumination mode when the external illumination is insufficient, and does not specifically refer to a trigger relationship. That is to say, in the present invention, insufficient external illumination may trigger the illumination lamp to be enabled by the acquisition control unit and perform a corresponding level of fill light output. However, in a possible implementation, the illuminator operates in the illumination mode when the camera is enabled, and is not directly related to the lack of external illumination. Therefore, keeping the illumination light set to the illumination mode when the external illumination conditions are insufficient is an expression of a state relationship, rather than an expression of a trigger relationship.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. All modifications, equivalents, improvements, etc., made within the spirit and scope of the invention are intended to be included within the scope of the invention.

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Claims (21)

A non-contact palmprint authentication device is applied to a portable terminal including a camera and an illumination lamp, characterized in that the device comprises: an acquisition control unit, configured to enable the camera when the palmprint authentication process is turned on, and external illumination When insufficient, the operating state of the illumination lamp is set to an illumination mode to provide a fill light output for the camera; and a screening output unit is configured to select a frame of a new image from the video stream output by the camera as a candidate map For example, acquiring a current state parameter set of the camera for the candidate image, determining whether each state parameter in the set satisfies a preset criterion corresponding to the parameter, and if satisfied, the candidate image is matched as a palmprint. Comparing the palmprint image output, if any of the state parameters in the set does not satisfy the corresponding preset criterion, the candidate image is ignored, and a new frame of image is reselected as a candidate image; and a palmprint matching unit is used for Performing the contrasting palmprint image with one or more reference palmprint images pre-recorded according to a preset algorithm If the match is successful, it is determined by the authentication; if the matching fails screening failure prompt or return the output unit outputs an authentication to the user. The device of claim 1, wherein the state parameter comprises a focus state parameter and an exposure state parameter, wherein the focus state parameter includes focus completion and focus progress; and the exposure state parameter includes exposure adjustment And the exposure adjustment is completed; the preset criterion is that the focus state parameter indicates that the focus is completed, and the exposure state parameter indicates that the exposure adjustment is completed. The device of claim 1, wherein the acquisition control unit is configured to: The focus parameter and the exposure parameter of the camera are set to a fixed value; and when any of the focus state parameter and the exposure state parameter in the state parameter set does not satisfy the corresponding preset criterion, the distance error prompt information is output to the user. The device of claim 1, wherein the acquisition control unit is further configured to disable the camera and the illumination after the authentication is passed. The device of claim 1, wherein the acquisition control unit is further configured to: start a timer having a preset duration when the palmprint authentication process is started, and time out the timer In the case, the palmprint authentication process is ended, and an authentication failure prompt is output to the user. The device of claim 1, further comprising: a screening enabling unit, wherein the screening enabling unit is configured to: after the palmprint authentication process is started, receive a screening comparison instruction issued by the user In the case, the screening output unit is enabled. The device of claim 1, wherein the acquisition control unit is further configured to enable the camera when the reference entry process is turned on, and maintain the working state of the illumination when the external illumination is insufficient. Provided as an illumination mode to provide a fill light output for the camera; the filter output unit is further configured to use the contrast palm print image output by the camera as a reference palmprint when the reference entry flow is turned on Like pre-save. The device of claim 1, wherein the acquisition control unit is further configured to set an operating state of the illumination light to an illumination mode when external illumination is sufficient, thereby providing a fill light output for the camera. . The device of claim 1, wherein the acquisition control unit is further configured to: according to the photosensitive sensor of the portable terminal The supplied external illumination parameter determines an illumination level and determines a fill light output intensity of the illumination light based on the illumination level. The device of claim 1, wherein the acquisition control unit is further configured to set the camera to a continuous autofocus mode and a continuous auto exposure mode when the camera is enabled. A non-contact palmprint authentication method is applied to a portable terminal including a camera and an illumination lamp, wherein the method comprises the following steps: Step A, enabling the camera when the palmprint authentication process is turned on, and insufficient external illumination Maintaining an operating state of the illumination lamp to be set to an illumination mode to provide a fill light output for the camera; and step B, selecting a frame of a new image from the video stream output by the camera as a candidate image; Obtaining, according to the candidate image, a current state parameter set of the camera, determining whether each state parameter in the set meets a preset criterion corresponding to the parameter, and if the two are satisfied, the candidate image is matched as a palmprint. Comparing the palm print image output, if any one of the state parameters in the set does not meet the corresponding preset criterion, the candidate image is ignored and returns to step B; and step D, the contrast palm image is compared according to a preset algorithm The pre-recorded reference palmprint image is matched. If the matching is successful, the authentication is determined to pass; if the matching fails, the user is authenticated. An authentication failure prompt or return to step B. The method of claim 11, wherein the state parameter comprises a focus state parameter and an exposure state parameter, wherein the focus state parameter comprises focus completion and focus in progress; The exposure state parameters include exposure adjustment and exposure adjustment completion; the preset criteria are: the focus state parameter characterizes focus completion, and the exposure state parameter characterizes exposure adjustment completion. The method of claim 11, further comprising: before the step A, further comprising: setting a focus parameter of the camera and an exposure parameter to a fixed value; and the step C specifically includes: in the state parameter set When any of the focus state parameter and the exposure state parameter does not satisfy the corresponding preset standard, the distance error prompt information is output to the user. The method of claim 11, further comprising: step E, disabling the camera and the illumination after the authentication is passed. The method of claim 11, further comprising: step F1, starting a timer having a preset duration when the palmprint authentication process is started; and step F2, in case the timer expires Ending the palmprint authentication process and outputting an authentication failure prompt to the user. The method of claim 11, further comprising: step G1, waiting for a screening comparison instruction of the user after the palmprint authentication process is started; and step G2, receiving the screening comparison sent by the user After the instruction, go to step B. The method of claim 11, wherein before step A, the method further comprises: enabling the camera when the reference entry process is turned on, and maintaining the external light when the external light is insufficient. The working state of the illumination lamp is set to an illumination mode to provide a fill light output for the camera; the step B further includes: saving the output contrast palm print image as a reference palm print image when the reference entry flow is turned on The method of claim 11, wherein the step A further comprises: setting an operating state of the illumination light to an illumination mode when the external illumination is sufficient, thereby providing a fill light output for the camera. The method of claim 11, wherein the step A further comprises: determining a current illumination level according to an external illumination parameter provided by the photosensitive sensor of the portable terminal, and determining a fill light of the illumination light according to the illumination level. Output intensity. The method of claim 11, wherein the step A further comprises: setting the camera to a continuous autofocus mode and a continuous auto exposure mode when the camera is enabled. A portable terminal, comprising a camera and an illumination lamp, characterized by further comprising the non-contact palmprint authentication device according to any one of claims 1 to 10.