Teaching Robots to Recognize People and Faces
Biometrics are unique biological characteristics that can be used to identify individuals. Unlike passwords or ID cards that can be lost or stolen, biometric features are part of who you are and are very difficult to fake or duplicate.
It's important to understand the difference between these two related technologies:
Face recognition systems work through several steps:
The ESP32-S3 has built-in camera support that makes face recognition possible. Here's how to initialize the camera:
#include "esp_camera.h"
#include "esp_face_detect.h"
#include "esp_face_recognition.h"
void setupCamera() {
camera_config_t config;
config.ledc_channel = LEDC_CHANNEL_0;
config.ledc_timer = LEDC_TIMER_0;
config.pin_d0 = Y2_GPIO_NUM;
config.pin_d1 = Y3_GPIO_NUM;
config.pin_d2 = Y4_GPIO_NUM;
config.pin_d3 = Y5_GPIO_NUM;
config.pin_d4 = Y6_GPIO_NUM;
config.pin_d5 = Y7_GPIO_NUM;
config.pin_d6 = Y8_GPIO_NUM;
config.pin_d7 = Y9_GPIO_NUM;
config.pin_xclk = XCLK_GPIO_NUM;
config.pin_pclk = PCLK_GPIO_NUM;
config.pin_vsync = VSYNC_GPIO_NUM;
config.pin_href = HREF_GPIO_NUM;
config.pin_sscb_sda = SIOD_GPIO_NUM;
config.pin_sscb_scl = SIOC_GPIO_NUM;
config.pin_pwdn = PWDN_GPIO_NUM;
config.pin_reset = RESET_GPIO_NUM;
config.xclk_freq_hz = 20000000;
config.pixel_format = PIXFORMAT_JPEG;
config.frame_size = FRAMESIZE_QVGA; // 320x240
config.jpeg_quality = 10;
config.fb_count = 1;
// Initialize camera
esp_err_t err = esp_camera_init(&config);
if (err != ESP_OK) {
Serial.printf("Camera init failed with error 0x%x", err);
return;
}
Serial.println("Camera initialized successfully!");
} Let's start with detecting faces in the camera image:
void detectFaces() {
// Capture image from camera
camera_fb_t * fb = esp_camera_fb_get();
if (!fb) {
Serial.println("Camera capture failed");
return;
}
// Convert image format for face detection
dl_matrix3du_t *image_matrix = dl_matrix3du_alloc(1, fb->width, fb->height, 3);
if (!image_matrix) {
esp_camera_fb_return(fb);
Serial.println("Memory allocation failed");
return;
}
// Convert JPEG to RGB
bool converted = fmt2rgb888(fb->buf, fb->len, fb->format, image_matrix->item);
esp_camera_fb_return(fb);
if (!converted) {
dl_matrix3du_free(image_matrix);
Serial.println("Image conversion failed");
return;
}
// Detect faces
box_array_t *net_boxes = face_detect(image_matrix);
if (net_boxes) {
Serial.printf("Found %d faces\n", net_boxes->len);
// Print information about each detected face
for (int i = 0; i < net_boxes->len; i++) {
box_t *box = &(net_boxes->box[i]);
Serial.printf("Face %d: x=%d, y=%d, w=%d, h=%d\n",
i+1, box->box_p[0], box->box_p[1],
box->box_p[2] - box->box_p[0],
box->box_p[3] - box->box_p[1]);
}
free(net_boxes->box);
free(net_boxes);
} else {
Serial.println("No faces detected");
}
dl_matrix3du_free(image_matrix);
} Now let's add face recognition to identify specific people:
// Face recognition variables
face_id_list id_list = {0};
String knownNames[10]; // Store names for recognized faces
int enrolledFaces = 0;
void enrollNewFace(String name) {
camera_fb_t * fb = esp_camera_fb_get();
if (!fb) return;
dl_matrix3du_t *image_matrix = dl_matrix3du_alloc(1, fb->width, fb->height, 3);
fmt2rgb888(fb->buf, fb->len, fb->format, image_matrix->item);
esp_camera_fb_return(fb);
// Detect face for enrollment
box_array_t *net_boxes = face_detect(image_matrix);
if (net_boxes && net_boxes->len > 0) {
// Use the first detected face for enrollment
int8_t left_sample_face = enroll_face(&id_list, image_matrix, &(net_boxes->box[0]));
if (left_sample_face >= 0) {
knownNames[enrolledFaces] = name;
enrolledFaces++;
Serial.println("Face enrolled successfully: " + name);
} else {
Serial.println("Face enrollment failed");
}
free(net_boxes->box);
free(net_boxes);
}
dl_matrix3du_free(image_matrix);
}
void recognizeFaces() {
camera_fb_t * fb = esp_camera_fb_get();
if (!fb) return;
dl_matrix3du_t *image_matrix = dl_matrix3du_alloc(1, fb->width, fb->height, 3);
fmt2rgb888(fb->buf, fb->len, fb->format, image_matrix->item);
esp_camera_fb_return(fb);
// Detect faces
box_array_t *net_boxes = face_detect(image_matrix);
if (net_boxes) {
for (int i = 0; i < net_boxes->len; i++) {
// Try to recognize each detected face
int8_t face_id = recognize_face(&id_list, image_matrix, &(net_boxes->box[i]));
if (face_id >= 0) {
Serial.println("Recognized: " + knownNames[face_id]);
greetPerson(knownNames[face_id]);
} else {
Serial.println("Unknown person detected");
askForIntroduction();
}
}
free(net_boxes->box);
free(net_boxes);
}
dl_matrix3du_free(image_matrix);
}
void greetPerson(String name) {
Serial.println("Hello, " + name + "!");
flashLED(3); // Flash LED 3 times
}
void askForIntroduction() {
Serial.println("I don't recognize you. What's your name?");
flashLED(1); // Single flash for unknown person
} Create a security robot that can recognize family members or classmates and respond differently to known vs. unknown people.
Smart Doorbell System: Design a program for a robot doorbell that can recognize family members and visitors.
Research a real-world application of face recognition technology and write a one-page report covering: