Intel® RealSense™ ID Solution for Facial Authentication

Table of Contents

1. Overview
2. Platforms
3. Building
4. Sample Code
5. RealSenseID API
6. Operation Modes
7. Secure Communication
8. License
9. Intel RealSense ID F450 and F455 Architecure Diagram

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.

Developer kits containing the necessary hardware to use this library are available for purchase at store.intelrealsense.com. See information about the Intel RealSense ID technology at https://www.intelrealsense.com/facial-authentication/

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

Note: Device = Intel RealSense ID F450 / F455

Platforms

• Linux (tested on Ubuntu 18, gcc 7.5+)
• Windows (tested on Windows 10, msvc 2019)

Bindings

• C/C++
• Python
• C#
• Android

Building

Use CMake version 3.14 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

CMake Options

The following possible options are available for the cmake command

Option	Default	Feature
RSID_DEBUG_CONSOLE	ON	Log everything to console
RSID_DEBUG_FILE	OFF	Log everything to rsid_debug.log file
RSID_DEBUG_SERIAL	OFF	Log all serial communication
RSID_DEBUG_PACKETS	OFF	Log packet sent/received over the serial line
RSID_DEBUG_VALUES	OFF	Replace default common values with debug ones
RSID_SAMPLES	OFF	Build samples
RSID_TIDY	OFF	Enable clang-tidy
RSID_PEDANTIC	OFF	Enable extra compiler warnings
RSID_PROTECT_STACK	OFF	Enable stack protection compiler flags
RSID_DOXYGEN	OFF	Build doxygen docs
RSID_SECURE	OFF	Enable secure communication with device
RSID_TOOLS	ON	Build additional tools
RSID_PY	OFF	Build python wrapper
RSID_NETWORK	OFF	Enable networking. Required for update checker.
RSID_PREVIEW	OFF	Enables preview feature.
RSID_INSTALL	OFF	Generate the install target and rsidConfig.cmake

Linux Post Install

In order to install the udev rules for the F450/F455 devices, run the command:

sudo script/udev-setup.sh -i

Note: You can undo the changes/uninstall by using the -u flag.

The capture device will be available to plugdev users while the serial port will be available to dialout users. On Debian/Ubuntu, you can add current user to those groups by issuing the commands:

sudo adduser $USER dialout
sudo adduser $USER plugdev

Note: Changes in group membership will take effect after logout/login (or reboot).

Windows Post Install

In order to be able to capture metadata for RAW format (for enabling frame dumps), open a PowerShell terminal as Administrator and run the command

.\scripts\realsenseid_metadata_win10.ps1

Sample Code

This snippet shows the basic usage of our library.

RealSenseID::FaceAuthenticator authenticator;
connect_status = authenticator.Connect({"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);

For additional languages, build instruction and detailed code please see our code samples and tools.

RealSenseID API

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

• C++ API and samples.
• Other language bindings and samples.

FaceAuthenticator Interface

Connect / Disconnect

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

RealSenseID::FaceAuthenticator authenticator;
RealSenseID::Status connect_status = authenticator.Connect({"COM9"});
authenticator.Disconnect();

Enroll

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 RealSenseID 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.

This operation can be further configured by passing DeviceConfig struct to the FaceAuthenticator::SetDeviceConfig(const DeviceConfig&) function. See the Device Configuration below for details.

class MyAuthClbk : public RealSenseID::AuthenticationCallback
{
public:
    // Called when authentication result is available.
    // If there are multiple faces it will be called for each face detected.
    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);

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);

Device Configuration API

The device operation can be configured by passing the DeviceConfig struct to the FaceAuthenticator::SetDeviceConfig(const DeviceConfig&) function.

The various options and default values are described below:

struct RSID_API DeviceConfig
{
    /**
     * @enum CameraRotation
     * @brief Camera rotation.
     */
    enum class CameraRotation
    {
        Rotation_0_Deg = 0, // default
        Rotation_180_Deg = 1,
        Rotation_90_Deg = 2,
        Rotation_270_Deg = 3
    };

    /**
     * @enum SecurityLevel
     * @brief SecurityLevel to allow. (default is Low)
     */
    enum class SecurityLevel
    {
        High = 0,   // high security level
        Medium = 1, // medium security level
        Low = 2,    // low security level
    };

    /**
     * @enum AlgoFlow
     * @brief Algorithms which will be used during authentication
     */
    enum class AlgoFlow
    {
        All = 0,               // spoof and face detection
        FaceDetectionOnly = 1, // face detection only (default)
        SpoofOnly = 2,         // spoof only
        RecognitionOnly = 3    // recognition only
    };

    enum class DumpMode
    {
        None = 0,        // default
        CroppedFace = 1, // sends snapshot of the detected face (as jpg)
        FullFrame = 2,   // sends left+right raw frames with metadata
    };

    /**
     * @brief Defines three confidence levels used by the Matcher during authentication.
     *
     * Each confidence level corresponds to a different set of thresholds, providing the user with the flexibility to
     * choose between three different False Positive Rates (FPR): Low, Medium, and High. Currently, all sets use the
     * thresholds associated with the "Low" confidence level by default.
     */
    enum class MatcherConfidenceLevel
    {
        High = 0,
        Medium = 1,
        Low = 2 // default
    };

    /**
     * @brief Defines the policy for frontal face orientation.
     *
     * - None: No restriction on face angle (default).
     * - Moderate: Allow some deviation from a forward-facing orientation.
     * - Strict: The face should be directly oriented toward the camera.
     */
    enum class FrontalFacePolicy
    {
        None = 0, // default
        Moderate = 1,
        Strict = 2
    };

    CameraRotation camera_rotation = CameraRotation::Rotation_0_Deg;
    SecurityLevel security_level = SecurityLevel::Low;
    AlgoFlow algo_flow = AlgoFlow::FaceDetectionOnly;
    DumpMode dump_mode = DumpMode::None;
    MatcherConfidenceLevel matcher_confidence_level = MatcherConfidenceLevel::Low;
    FrontalFacePolicy frontal_face_policy = FrontalFacePolicy::None;

    /**
     * @brief Specifies the maximum number of consecutive spoofing attempts allowed before the device rejects further
     * authentication requests.
     *
     * Setting this value to 0 disables the check, which is the default behavior. If the number of consecutive spoofing
     * attempts reaches max_spoofs, the device will reject any subsequent authentication requests. To reset this
     * behavior and allow further authentication attempts, the device must be unlocked using the Unlock() API call.
     */
    unsigned char max_spoofs = 0;

    /**
     * @brief Controls whether GPIO toggling is enabled(1) or disabled(0, default) after successful authentication.
     *
     * Set this value to 1 to enable toggling of GPIO pin #1 after each successful authentication.
     * Set this value to 0 to disable GPIO toggling (default).
     *
     * @note Only GPIO pin #1 can be toggled. Other values are not supported.
     */
    int gpio_auth_toggling = 0;
};

Notes:

• If SetDeviceConfig() never called, the device will use the default values described above.
• CameraRotation enable the algorithm to work with a rotated device. For preview rotation to match, you'll need to define previewConfig.portraitMode accordingly (see Preview section).

The following example configures the device to only detect spoofs (instead of the default full authentication):

...
using namespace RealSenseID;
// config with default options except for the algo flow which is set to spoof only
DeviceConfig device_config;
device_config.algo_flow = AlgoFlow::SpoofOnly;
auto status = authenticator->SetDeviceConfig(device_config);

DeviceController Interface

Connect / Disconnect

RealSenseID::DeviceController deviceController;
Status connect_status = deviceController.Connect({"COM4"});
deviceController.Disconnect();

Reboot

Resets and reboots device.

bool success = deviceController.Reboot();

Preview Interface

Currently 704x1280 or 1056x1920 RGB formats is available.

Preview Configuration

/**
 * Preview modes
 */
enum class PreviewMode
{
    MJPEG_1080P = 0, // default
    MJPEG_720P = 1,
    RAW10_1080P = 2,
};

/**
 * Preview configuration
 */
struct RSID_API PreviewConfig
{
    DeviceType deviceType = DeviceType::F45x;           // device type
    int cameraNumber = -1;                              // attempt to auto detect by default
    PreviewMode previewMode = PreviewMode::MJPEG_1080P; // RAW10 requires custom fw support
    bool portraitMode = true; // change Preview to get portrait or landscape images. Algo process is defined separately in DeviceConfig::CameraRotation
    bool rotateRaw = false;   // enables rotation of raw data in portraitMode == true
};

Notes:

• The rotation used by algorithm is based only on DeviceConfig.camera_rotation attribute.
• Indepedently, you can choose each preview mode (except raw) to be portrait or non-portrait.
• Keep in mind that if you want preview to match algo: CameraRotation::Rotation_0_Deg and CameraRotation::Rotation_180_Deg is for portraitMode == true.(default) CameraRotation::Rotation_90_Deg and CameraRotation::Rotation_270_Deg is for portraitMode == false.

Sensor Timestamps

Access to the sensor timestamps (in milliseconds). To enable it on Windows please turn on the Metadata option in when using the SDK installer. The installer create specific dedicated registry entry to be present for each unique RealSenseID device. For Linux, Metadata is supported on kernels 4.16 + only.

The timestamps can be acquired in OnPreviewImageReady under image.metadata.timestamp . Other metadata isn't valid.

more information about metadata on Windows can be found in microsoft uvc documetnation

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)
	{
		// Callback will be used to provide RGB preview image (for RAW10_1080P PreviewMode - raw converted to RGB).
	}

    	void OnSnapshotImageReady(const Image& image) // Not mandatory. To enable it, see Device Configuration API.
	{
		// Callback will be used to provide images destined to be dumped (cropped/full). See DeviceConfig::DumpMode attribute.
		// Raw formatted images will be raised by this function.
	}
};

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();

Operation Modes

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 the RealSenseID camera is used as a Feature-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.

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);

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;
    }
}

Secure Communication

The library can be compiled in secure mode. Once paired with the device, all communications will be protected. If you wish to get back to non-secure communcations, you must first unpair your device.

Cryptographic algorithms that are used for session protection:

• Message signing - ECDSA P-256 (secp256-r1).
• Shared session key generation - ECDH P-256 (secp256-r1)
• Message encryption - AES-256, CTR mode.
• Message integrity - HKDF-256.

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

• Compile the library with RSID_SECURE enabled.
• Generate a set of ECDSA P-256 (secp256-r1) 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 P-256 (secp256-r1) keys. Please see the pairing sample on how to pair the device and use keys.

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 P-256 (secp256-r1) 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({"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);

Python API

Starting with version 0.22.0 we provide python API:

"""
Authenticate example
"""
import rsid_py

def on_result(result, user_id):
    if result == rsid_py.AuthenticateStatus.Success:
        print('Authenticated user:', user_id)

with rsid_py.FaceAuthenticator("COM4") as f:
    f.authenticate(on_result=on_result)

Please visit the python samples page for details and samples.

License

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

Intel RealSense ID F450 and F455 Architecture Diagram