Simple Python script to create a heatmap from a video file

video_heatmap.py

import sys

import cv2
import numpy as np

def preprocess_frame(frame):
    # Convert to grayscale and apply Gaussian blur
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    blurred = cv2.GaussianBlur(gray, (21, 21), 0)
    return blurred

movie_path = 'video.mp4'
vidcap = cv2.VideoCapture(movie_path)
success, frame = vidcap.read()

if not success:
    print('ERROR: Could not read video file', file=sys.stderr)
    sys.exit(1)

total_frames = int(vidcap.get(cv2.CAP_PROP_FRAME_COUNT))
processed_frames = 0

prev_frame = preprocess_frame(frame)
activity_map = np.zeros(prev_frame.shape, dtype=np.float32)

while success:
    # Preprocess current frame
    curr_frame = preprocess_frame(frame)

    # Calculate difference and update activity map
    frame_diff = cv2.absdiff(prev_frame, curr_frame)
    activity_map += frame_diff.astype(np.float32)

    prev_frame = curr_frame
    success, frame = vidcap.read()

    # Update and print progress
    processed_frames += 1
    progress = (processed_frames / total_frames) * 100
    print(f"Progress: {progress:.2f}%")

# Normalize the activity map
activity_map = cv2.normalize(activity_map, None, 0, 255, cv2.NORM_MINMAX)

# Convert to heatmap using a colormap
heatmap = cv2.applyColorMap(activity_map.astype(np.uint8), cv2.COLORMAP_JET)

# Save or display the heatmap
cv2.imwrite('activity_heatmap.jpg', heatmap)
cv2.imshow('Activity Heatmap', heatmap)
cv2.waitKey(0)
cv2.destroyAllWindows()