mirror of
https://github.com/azaion/gps-denied-desktop.git
synced 2026-04-22 08:56:36 +00:00
Eg0Ri4
129 lines
5.0 KiB
Python
129 lines
5.0 KiB
Python
import numpy as np
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import math
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class GeoTracker:
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def __init__(self, focal_length_mm, sensor_width_mm, image_width_px, image_height_px):
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# Intrinsics
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self.fx = (focal_length_mm / sensor_width_mm) * image_width_px
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self.fy = self.fx
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self.cx = image_width_px / 2.0
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self.cy = image_height_px / 2.0
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self.image_w = image_width_px
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self.image_h = image_height_px
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# Standard Camera Matrix
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self.K = np.array([
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[self.fx, 0, self.cx],
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[0, self.fy, self.cy],
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[0, 0, 1]
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])
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self.K_inv = np.linalg.inv(self.K)
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def _get_rotation_matrix(self, yaw, pitch, roll):
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# Converts NED Euler angles to Rotation Matrix (Body to NED)
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# Using ZYX convention
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y, p, r = np.radians(yaw), np.radians(pitch), np.radians(roll)
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Rz = np.array([[np.cos(y), -np.sin(y), 0], [np.sin(y), np.cos(y), 0], [0, 0, 1]])
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Ry = np.array([[np.cos(p), 0, np.sin(p)], [0, 1, 0], [-np.sin(p), 0, np.cos(p)]])
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Rx = np.array([[1, 0, 0], [0, np.cos(r), -np.sin(r)], [0, np.sin(r), np.cos(r)]])
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R_body_to_ned = Rz @ Ry @ Rx
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# Camera Frame Alignment (Camera Z is Forward, NED X is North)
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# Standard assumption: Camera is mounted Forward-Right-Down relative to Body
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# But usually for drones, Camera Z (Optical) aligns with Body X (Forward) or Body Z (Down)
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# Assuming standard "Forward Looking" camera:
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# Cam Z -> Body X, Cam X -> Body Y, Cam Y -> Body Z
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T_cam_to_body = np.array([
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[0, 0, 1],
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[1, 0, 0],
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[0, 1, 0]
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])
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return R_body_to_ned @ T_cam_to_body
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def pixel_to_ned_ground(self, u, v, altitude, R_cam_to_ned):
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"""
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Ray-plane intersection.
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Projects pixel (u,v) to the ground plane (z=0) in NED frame.
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"""
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# 1. Pixel to Normalized Camera Ray
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pixel_homo = np.array([u, v, 1.0])
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ray_cam = self.K_inv @ pixel_homo
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# 2. Rotate Ray to NED Frame
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ray_ned = R_cam_to_ned @ ray_cam
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# 3. Intersect with Ground (Z = 0)
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# Camera is at [0, 0, -altitude] in NED
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# Ray equation: P = O + t * D
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# We want P.z = 0
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# 0 = -altitude + t * ray_ned.z
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# t = altitude / ray_ned.z
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if ray_ned[2] <= 0: # Ray pointing up or parallel to horizon
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return None
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t = altitude / ray_ned[2]
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# P_ground relative to camera position (which is 0,0 in horizontal)
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north = t * ray_ned[0]
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east = t * ray_ned[1]
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return np.array([north, east])
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def calculate_movement(self, kpts0, kpts1, altitude, yaw, start_lat, start_lon):
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"""
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Calculates the drone's movement based on optical flow on the ground.
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Returns dictionary with shift in meters and new lat/lon.
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"""
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# Rotation Matrix (Assuming simplified Pitch=-90 for Nadir or 0 for Forward)
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# For a downward facing drone, Pitch is usually -90.
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# For this example, we assume the camera is stabilized or we use the passed yaw.
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# We will assume a gimbal pitch of -90 (looking down) if not specified,
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# or -45 if looking forward.
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# Let's assume standard Nadir view for mapping (Pitch = -90).
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R = self._get_rotation_matrix(yaw, -90, 0)
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shifts_n = []
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shifts_e = []
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# Process a subset of points to save time
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step = max(1, len(kpts0) // 50)
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for i in range(0, len(kpts0), step):
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p0 = self.pixel_to_ned_ground(kpts0[i][0], kpts0[i][1], altitude, R)
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p1 = self.pixel_to_ned_ground(kpts1[i][0], kpts1[i][1], altitude, R)
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if p0 is not None and p1 is not None:
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# If the image moved LEFT, the drone moved RIGHT.
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# If pixel 0 is at (10,10) and pixel 1 is at (5,5), the world moved "back" relative to camera.
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# Drone movement = P1_world - P0_world?
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# NO. If we are tracking static ground, P0 and P1 correspond to the SAME physical point.
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# So the Ground Point relative to Camera 0 is X.
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# The Ground Point relative to Camera 1 is Y.
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# Camera Movement = X - Y.
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diff = p0 - p1
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shifts_n.append(diff[0])
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shifts_e.append(diff[1])
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if not shifts_n:
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return None
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# Robust average (Median) to reject outliers
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avg_n = np.median(shifts_n)
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avg_e = np.median(shifts_e)
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# Convert Meters to Lat/Lon
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# Earth Radius approx 6,378,137m
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d_lat = (avg_n / 6378137.0) * (180 / math.pi)
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d_lon = (avg_e / (6378137.0 * math.cos(math.radians(start_lat)))) * (180 / math.pi)
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return {
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'move_north_m': avg_n,
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'move_east_m': avg_e,
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'new_lat': start_lat + d_lat,
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'new_lon': start_lon + d_lon,
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'ground_points': len(shifts_n)
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} |