Intel® RealSense™ Developer Documentation

Code Samples for Intel RealSense ID Solution

Overview

Intel RealSense ID is your trusted facial authentication on-device solution.

Intel RealSense ID combines an active depth sensor with a specialized neural network designed to deliver an intuitive, secure and accurate facial authentication solution that adapts over time. This solution offers user privacy and is activated by user awareness. Built-in anti spoofing technology protects against attacks using photographs, videos or masks.

Intel RealSense ID is a natural solution simplifying secure entry for everyone, everywhere. Supports children to tall adults and designed for Smart Locks, Access Control, PoS, ATMs, and Kiosks.

For high-level architecture, see Intel RealSense ID F450 / F455 Architecture Diagram.

Note: Device = Intel RealSense ID F450 / F455

Platforms Supported

Linux (tested on ubuntu 18, gcc 7.5+)
Windows (tested on windows 10, msvc 2019)
Android (tested on Android 6.0 but should also work on newer versions)

Architecture

Intel RealSense ID F450 and F455 SW Architecture

Building

Use CMake version 3.10.2 or above:

$ cd <project_dir>
$ mkdir build && cd build
$ cmake .. //in case preview is required run: cmake .. -DRSID_PREVIEW=1 //in case secure is required run: cmake .. -DRSID_SECURE=1
$ make -j

Sample Code

This snippet shows the basic usage of our library. It shows how to enroll a user, authenticate a user, and remove a user from the device's storage:

// Start preview
PreviewRender image_clbk;
Preview preview;
bool success = preview.StartPreview(image_clbk);

// Create device controller instance and connect to the device on COM9 which is of type USB
RealSenseID::DeviceController deviceController;
auto connect_status = deviceController.Connect({RealSenseID::SerialType::USB, "COM9"});

// Pair with host
auto pair_status = deviceController.Pair(host_pubkey, host_pubkey_signature, device_pubkey);

// Disconnect from the device
deviceController.Disconnect();

// Create face authenticator instance and connect to the device on COM9 which is of type USB
MySigClbk sig_clbk;
RealSenseID::FaceAuthenticator authenticator {&sig_clbk};
connect_status = authenticator.Connect({RealSenseID::SerialType::USB, "COM9"});

// Enroll a user
const char* user_id = "John";
MyEnrollClbk enroll_clbk;
auto status = authenticator.Enroll(enroll_clbk, user_id);

// Authenticate a user
MyAuthClbk auth_clbk;
status = authenticator.Authenticate(auth_clbk);

// Remove the user from device
success = authenticator.RemoveUser(user_id);

// Disconnect from the device
authenticator.Disconnect();

// Stop preview
success = preview.StopPreview();

For additional languages, build instruction and detailed code, please see examples.

Secure Communication

The communication with the device is encrypted using the Elliptic-curve Diffie–Hellman key exchange (ECDH).

To enable secure communication, the host should perform the following steps:

  • Generate a set of ECDSA public and private keys. The host is responsible for keeping his private key safe.
  • Pair with the device to enable secure communication. Pairing is performed once using the FaceAuthenticator API.
  • Implement a SignatureCallback. Signing and verifying is done with the ECDSA keys. Please see the signature callback example.

Each request (a call to one of the main API functions listed below) from the host to the device starts a new encrypted session, which performs an ECDH key exchange to create the shared secret for encrypting the current session.

class MySigClbk : public RealSenseID::SignatureCallback
{
public:
    bool Sign(const unsigned char* buffer, const unsigned int buffer_len, unsigned char* out_sig) override
    {
      // Sign buffer with host ECDSA private key
    }

    bool Verify(const unsigned char* buffer, const unsigned int buffer_len, const unsigned char* sig,const unsigned int sign_len) override
    {
      // Verify buffer with device ECDSA public key
    }
};

MySigClbk sig_clbk;
RealSenseID::FaceAuthenticator authenticator {&sig_clbk};
Status connect_status = authenticator.Connect({RealSenseID::SerialType::USB, "COM9"});
authenticator.Disconnect();
char* hostPubKey = getHostPubKey(); // 64 bytes ECDSA public key of the host
char host_pubkey_signature[64];
if (!sig_clbk.Sign((unsigned char*)hostPubKey, 64, host_pubkey_signature))
{
    printf("Failed to sign host ECDSA key\n");
    return;
}
char device_pubkey[64]; // Save this key after getting it to use it for verification
Status pair_status = authenticator.Pair(host_pubkey, host_pubkey_signature, device_pubkey);

Host and Device APIs

Device Mode

Device Mode is a set of APIs enable the user to enroll and authenticate on the device itself, including database management and matching on the device.

Host Mode

Host Mode is a set of APIs for users who wish to manage a faceprints database
on the host or the server. In this mode F450 is used as a Faceprints-Extraction device only.

The API provides a 'matching' function which predicts whether two faceprints belong to the same person,
thus enabling the user to scan their database for similar users.

Project Structure

RealSenseID API

The RealSenseID is the main API to the communication with the device.
C, C++ and C# API wrappers are provided as part of the library.
Java and python API is under development.
All APIs are synchronous and assuming a new operation will not be activated till previous is completed.

FaceAuthenticator

Connect / Disconnect

Connects host to device using USB
(RealSenseID::serialtype::USB) or UART interfaces
(RealSenseID::serialtype::UART).

class MySigClbk : public RealSenseID::SignatureCallback
{
public:
    bool Sign(const unsigned char* buffer, const unsigned int buffer_len, unsigned char* out_sig) override
    {
      // Sign buffer with host ECDSA private key
    }

    bool Verify(const unsigned char* buffer, const unsigned int buffer_len, const unsigned char* sig,const unsigned int sign_len) override
    {
      // Verify buffer with device ECDSA public key
    }
};

MySigClbk sig_clbk;
RealSenseID::FaceAuthenticator authenticator {&sig_clbk};
Status connect_status = authenticator.Connect({RealSenseID::SerialType::USB, "COM9"});
authenticator.Disconnect();

Pair
Perform an ECDSA key exchange. In pairing, the host sends the following:

  • ECDSA public key.
  • ECDSA public key signature with the previous ECDSA private key. If this is the first pairing, the signature is ignored.
Status pair_status = authenticator.Pair(host_pubkey, host_pubkey_signature, device_pubkey);

The Host will receive the device's ECDSA public key, and should save it for verification in the implementation of SignatureCallback::Verify.

Enrollment
Starts device, runs neural network algorithm and stores encrypted faceprints on database. A faceprint is a set number of points which is represented as mathematical transformation of the user’s face. saves encrypted facial features to secured flash on Intel RealSense ID F450 / F455. Stored encrypted faceprints are matched with enrolled faceprints later during authentication. For best performance, enroll under normal lighting conditions and look directly at the device. During the enrollment process, device will send a status hint to the callback provided by application. Full list of the hint can be found in EnrollStatus.h.

class MyEnrollClbk : public RealSenseID::EnrollmentCallback
{
public:
    void OnResult(const RealSenseID::EnrollStatus status) override
    {
        std::cout << "on_result: status: " << status << std::endl;
    }

    void OnProgress(const RealSenseID::FacePose pose) override
    {
        std::cout << "on_progress: pose: " << pose << std::endl;
    }

    void OnHint(const RealSenseID::EnrollStatus hint) override
    {
        std::cout << "on_hint: hint: " << hint << std::endl;
    }
};

const char* user_id = "John";
MyEnrollClbk enroll_clbk;
Status status = authenticator.Enroll(enroll_clbk, user_id);

Authenticate
Single authentication attempt: Starts device, runs neural network algorithm, generates faceprints and compares them to all enrolled faceprints in database. Finally, returns whether the authentication was forbidden or allowed with enrolled user id. During the authentication process, device will send a status hint to the callback provided by application. Full list of the hint can be found in AuthenticationStatus.h.

class MyAuthClbk : public RealSenseID::AuthenticationCallback
{
public:
    void OnResult(const RealSenseID::AuthenticateStatus status, const char* user_id) override
    {
        if (status == RealSenseID::AuthenticateStatus::Success)
        {
            std::cout << "******* Authenticate success.  user_id: " << user_id << " *******" << std::endl;
        }
        else
        {
            std::cout << "on_result: status: " << status << std::endl;
        }
    }

    void OnHint(const RealSenseID::AuthenticateStatus hint) override
    {
        std::cout << "on_hint: hint: " << hint << std::endl;
    }
};

MyAuthClbk auth_clbk;
Status status = authenticator.Authenticate(auth_clbk);

AuthenticateLoop
Starts device, runs authentication in a loop until Cancel() API is invoked. Starts camera and running loop of

  • NN algo(s) pipeline
  • Facial features extraction
  • Matches them to all previously stored features in database.
  • Returns result whether the authentication was forbidden or allowed with pre-enrolled user id. During the authentication process hint statuses might be sent to the callback provided by application. Full list of the hints can be found in AuthenticationStatus.h.
class MyAuthClbk : public RealSenseID::AuthenticationCallback
{
public:
    void OnResult(const RealSenseID::AuthenticateStatus status, const char* user_id) override
    {
        if (status == RealSenseID::AuthenticateStatus::Success)
        {
            std::cout << "******* Authenticate success.  user_id: " << user_id << " *******" << std::endl;
        }
        else
        {
            std::cout << "on_result: status: " << status << std::endl;
        }
    }

    void OnHint(const RealSenseID::AuthenticateStatus hint) override
    {
        std::cout << "on_hint: hint: " << hint << std::endl;
    }
};

MyAuthClbk auth_clbk;
Status status = authenticator.AuthenticateLoop(auth_clbk);

Cancel
Stops current operation (Enrollment/Authenticate/AuthenticateLoop).

authenticator.Cancel();

RemoveAll
Removes all enrolled users in the device database.

bool success = authenticator.RemoveAll();

RemoveUser
Removes a specific user from the device database.

const char* user_id = "John";
bool success = authenticator.RemoveUser(user_id);
DeviceController

Connect / Disconnect
Connects host to device using USB
(RealSenseID::serialtype::USB) or UART interfaces
(RealSenseID::serialtype::UART).

RealSenseID::DeviceController deviceController;
Status connect_status = deviceController.Connect({RealSenseID::SerialType::USB, "COM9"});
deviceController.Disconnect();

Reboot
Resets and reboots device.

bool success = deviceController.Reboot();

FW Upgrade (Not supported yet)


Preview API

Host needs to have OpenCV installed. Currently 640x352 YUV format is available.

StartPreview
Starts preview. Callback function that is provided as parameter will be invoked for a newly arrived image and can be rendered by your application.

class PreviewRender : public RealSenseID::PreviewImageReadyCallback
{
public:
    void OnPreviewImageReady(const Image image){
    {
        // render image
    }
};

PreviewRender image_clbk;
Preview preview;
bool success = preview.StartPreview(image_clbk);

PausePreview
Pause preview.

bool success = preview.PausePreview();

ResumePreview
Resumes the preview.

bool success = preview.ResumePreview();

StopPreview
Stops preview.

bool success = preview.StopPreview();
Host Mode Methods

ExtractFaceprintsForAuth
Extracts faceprints from a face, in the device, and sends them to the host.
Uses 'Authentication Flow' to eliminate spoof attempts and verify a face was detected.

// extract faceprints using authentication flow
class FaceprintsAuthClbk : public RealSenseID::AuthFaceprintsExtractionCallback
{
public:
    void OnResult(const RealSenseID::AuthenticateStatus status, const Faceprints* faceprints) override
    {
        std::cout << "result: " << status << std::endl;
        s_extraction_status = status;
        // if status was success pass '_faceprints' to user 
    }

    void OnHint(const RealSenseID::AuthenticateStatus hint) override
    {
        std::cout << "hint: " << hint << std::endl;
    }
};

FaceprintsAuthClbk clbk;
auto status = authenticator->ExtractFaceprintsForAuth(clbk);

ExtractFaceprintsForEnroll
Extracts faceprints from a face, in the device, and sends them to the host.
Uses 'Enrollment Flow' to verify face-pose is correct and that a face was detected.

// extract faceprints using enrollment flow
class MyEnrollServerClbk : public RealSenseID::EnrollmentCallback
{
    const char* _user_id = nullptr;

public:
    explicit MyEnrollServerClbk(const char* user_id) : _user_id {user_id}
    {        
    }

    void OnResult(const RealSenseID::EnrollStatus status, const Faceprints* faceprints) override
    {
        std::cout << "result: " << status << "for user: " << _user_id << std::endl;
        s_extraction_status = status;    
        // if status was success pass '_faceprints' to user            
    }

    void OnProgress(const RealSenseID::FacePose pose) override
    {
        std::cout << "pose: " << pose << std::endl;
    }

    void OnHint(const RealSenseID::EnrollStatus hint) override
    {
        std::cout << "hint: " << hint << std::endl;
    }
};

MyEnrollServerClbk enroll_clbk {user_id.c_str()};
auto status = authenticator->ExtractFaceprintsForEnroll(enroll_clbk);

ExtractFaceprintsForAuthLoop
Extracts faceprints in a loop, each iteration extracts from a single face and sends it to the host.
Uses 'Authentication Flow' to eliminate spoof attempts and verify a face was detected.

// extract faceprints in a loop using authentication flow
class AuthLoopExtrClbk : public RealSenseID::AuthFaceprintsExtractionCallback
{    
public:
    void OnResult(const RealSenseID::AuthenticateStatus status, const Faceprints* faceprints) override
    {        
        std::cout << "result: " << status << std::endl;
        s_extraction_status = status;
        // if status was success pass '_faceprints' to user 
    }

    void OnHint(const RealSenseID::AuthenticateStatus hint) override
    {
        std::cout << "hint: " << hint << std::endl;
    }
};

AuthLoopExtrClbk clbk;
auto status = authenticator->ExtractFaceprintsForAuthLoop(clbk);

MatchFaceprints
Matches two faceprints to each other and calculates a prediction of whether they belong to
the same person.

// match extracted faceprints to the ones in the user-managed database
for (auto& db_item : db)
{
    auto match_result = authenticator->MatchFaceprints(scanned_faceprints, db_item.faceprints, updated_faceprints);    
    if (match_result.success)
    {
        std::cout << "Match succeeded with user id: " << db_item.id << std::endl;
        break;
    }
}
Packet Manager

The PacketManager is the communication protocol implementation.
Communication is encrypted and managed by PacketManager::SecureSessionManager.

SecureSessionManager
Manages the secure session. Sends packets using PacketManager::PacketSender.

PacketSender
Responsible for sending and receiving serial packets over a serial port using PacketManager::SerialConnection interface.

SerialConnection
Interface for communication over a serial port. Implemented over supported platforms (WindowsSerial/LinuxSerial/Android).
For new platform, implement this interface.

SerialPacket
Packet structure base. We have 2 types of packets:

DataPacket - Payload contains data buffer.
FaPacket - Payload contains user id and status.

License

This project is licensed under Apache 2.0 license. Relevant license info can be found in "License Notices" folder

Updated 6 months ago

Code Samples for Intel RealSense ID Solution


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