app.py

import numpy as np
import cv2
import tensorflow as tf
from tensorflow.keras.applications import ResNet50
from tensorflow.keras.applications.resnet50 import preprocess_input
from sklearn.metrics.pairwise import cosine_similarity
from filterpy.kalman import KalmanFilter
import gradio as gr

# Load the frozen inference graph
frozen_graph_path = "frozen_inference_graph.pb"

# Load the frozen TensorFlow model
with tf.io.gfile.GFile(frozen_graph_path, "rb") as f:
    graph_def = tf.compat.v1.GraphDef()
    graph_def.ParseFromString(f.read())

# Convert the frozen graph to a function
def wrap_frozen_graph(graph_def, inputs, outputs):
    def _imports_graph_def():
        tf.compat.v1.import_graph_def(graph_def, name="")
    wrapped_import = tf.compat.v1.wrap_function(_imports_graph_def, [])
    return wrapped_import.prune(
        tf.nest.map_structure(wrapped_import.graph.as_graph_element, inputs),
        tf.nest.map_structure(wrapped_import.graph.as_graph_element, outputs))

# Define input and output tensors
inputs = ["image_tensor:0"]
outputs = ["detection_boxes:0", "detection_scores:0", "detection_classes:0", "num_detections:0"]

# Get the detection function
detection_fn = wrap_frozen_graph(graph_def, inputs, outputs)

# TensorFlow function for detection
@tf.function(input_signature=[tf.TensorSpec(shape=[None, None, None, 3], dtype=tf.uint8)])
def detect_objects(image):
    return detection_fn(image)

# Load ResNet50 for feature extraction
resnet_model = ResNet50(weights="imagenet", include_top=False, pooling="avg")

# Initialize variables to store features and identities
person_features = []
person_identities = []
person_colors = {}
kalman_filters = {}
next_person_id = 1  # Starting unique ID for persons

# Function to generate unique colors based on person ID
def get_color(person_id):
    np.random.seed(person_id)  # Ensure color is unique for each person_id
    color = tuple(np.random.randint(0, 256, size=3))  # Generates RGB tuple
    return (int(color[0]), int(color[1]), int(color[2]))  # Ensure the color is a tuple of ints

def extract_features(person_roi):
    # Resize and preprocess the ROI for ResNet50 input
    person_roi_resized = cv2.resize(person_roi, (224, 224))
    person_roi_preprocessed = preprocess_input(person_roi_resized)

    # Add batch dimension for ResNet50 input
    input_tensor = np.expand_dims(person_roi_preprocessed, axis=0)

    # Extract features using ResNet50
    features = resnet_model.predict(input_tensor)
    return features

def initialize_kalman_filter(bbox):
    kf = KalmanFilter(dim_x=7, dim_z=4)
    kf.F = np.array([[1, 0, 0, 0, 1, 0, 0],
                     [0, 1, 0, 0, 0, 1, 0],
                     [0, 0, 1, 0, 0, 0, 1],
                     [0, 0, 0, 1, 0, 0, 0],
                     [0, 0, 0, 0, 1, 0, 0],
                     [0, 0, 0, 0, 0, 1, 0],
                     [0, 0, 0, 0, 0, 0, 1]])
    kf.H = np.array([[1, 0, 0, 0, 0, 0, 0],
                     [0, 1, 0, 0, 0, 0, 0],
                     [0, 0, 0, 1, 0, 0, 0],
                     [0, 0, 0, 0, 0, 1, 0]])
    kf.R[2:, 2:] *= 10.
    kf.P[4:, 4:] *= 1000.
    kf.P *= 10.
    kf.Q[-1, -1] *= 0.01
    kf.Q[4:, 4:] *= 0.01
    kf.x[:4] = bbox.reshape((4, 1))
    return kf

def predict_bbox(kf):
    kf.predict()
    return kf.x[:4].reshape((4,))

def update_kalman_filter(kf, bbox):
    kf.update(bbox.reshape((4, 1)))
    return kf

def match_and_identify(features, bbox):
    global next_person_id

    # Flag to check if a match is found
    matched = False

    # Iterate over existing identities to check for matches
    for idx, (feat, identity) in enumerate(zip(person_features, person_identities)):
        # Compute cosine similarity between features
        similarity = cosine_similarity(
            np.array(feat).reshape(1, -1),
            np.array(features).reshape(1, -1)
        )[0][0]

        # If similarity is above threshold, consider them as the same person
        similarity_threshold = 0.7  # Adjust as needed
        if similarity > similarity_threshold:
            # Assign color if not already assigned
            if identity in person_colors:
                color = person_colors[identity]
            else:
                color = get_color(identity)
                person_colors[identity] = color

            # Update Kalman filter
            kalman_filters[identity] = update_kalman_filter(kalman_filters[identity], bbox)

            # Set matched flag to True
            matched = True
            return identity, color

    # If no match found, add new identity
    if not matched:
        person_features.append(features)
        person_identities.append(next_person_id)
        color = get_color(next_person_id)
        person_colors[next_person_id] = color

        # Initialize Kalman filter
        kalman_filters[next_person_id] = initialize_kalman_filter(bbox)

        identity = next_person_id
        next_person_id += 1

        return identity, color

def process_image(image):
    # Prepare the image tensor
    image_np = np.array(image)
    input_tensor = np.expand_dims(image_np, axis=0)

    # Run inference
    detections = detect_objects(input_tensor)

    # Extract output tensors and convert to numpy arrays
    boxes = detections[0].numpy()[0]
    scores = detections[1].numpy()[0]
    classes = detections[2].numpy()[0]
    num_detections = int(detections[3].numpy()[0])

    # Filter detections for 'person' class
    threshold = 0.3  # Adjust this threshold as needed
    for i in range(num_detections):
        class_id = int(classes[i])
        score = scores[i]
        box = boxes[i]

        if class_id == 1 and score > threshold:
            h, w, _ = image.shape
            ymin, xmin, ymax, xmax = box
            left, right, top, bottom = int(xmin * w), int(xmax * w), int(ymin * h), int(ymax * h)
            
            # Extract person ROI
            person_roi = image[top:bottom, left:right]

            # Extract features
            features = extract_features(person_roi)

            # Predict bbox using Kalman filter
            predicted_bbox = np.array([xmin, ymin, xmax, ymax])

            # Match and identify
            identity, color = match_and_identify(features, predicted_bbox)

            # Draw bounding box
            left, top, right, bottom = int(predicted_bbox[0] * w), int(predicted_bbox[1] * h), int(predicted_bbox[2] * w), int(predicted_bbox[3] * h)
            cv2.rectangle(image, (left, top), (right, bottom), color, 2)
            cv2.putText(image, f'Person {identity}', (left, top - 10), cv2.FONT_HERSHEY_SIMPLEX, 0.5, color, 2)

    return image

def gradio_interface(input_image):
    # Process the input image
    output_image = process_image(input_image)
    return output_image

# Create Gradio interface
iface = gr.Interface(
    fn=gradio_interface,
    inputs=gr.Image(),
    outputs=gr.Image(),
    title="Person Detection and Tracking",
    description="Upload an image to detect and track persons."
)

# Launch the interface
iface.launch()