Tilt/Pan a 360 image

360_image_remapping.py

import cv2
import numpy as np

# Load input 360 image
img = cv2.imread("my_360_image.png")
h, w = img.shape[:2]


# Select arbitrary rotation angles
d_theta = 0.2 * np.pi
d_phi = 0.1 * np.pi


# Compute the transformation maps
x_grid, y_grid = np.meshgrid(0.5+np.arange(w),
                             0.5+np.arange(h),
                             indexing="xy")
theta_1 = (x_grid / w - 0.5) * 2*np.pi
phi_1 = (y_grid / h - 0.5) * np.pi

px = np.cos(phi_1)*np.sin(theta_1 - d_theta)
py = np.cos(d_phi)*np.sin(phi_1) - np.sin(d_phi)*np.cos(phi_1)*np.cos(theta_1-d_theta)
pz = np.sin(d_phi)*np.sin(phi_1) + np.cos(d_phi)*np.cos(phi_1)*np.cos(theta_1-d_theta)

phi_0 = np.arcsin(py)
theta_0 = np.arctan2(px, pz)

map_x = w * (0.5 + theta_0 / (2*np.pi))
map_y = h * (0.5 + phi_0 / np.pi)


# Generate the transformed image using cv2.remap
map_x -= 0.5  # Opencv shift
map_y -= 0.5
transformed_img = cv2.remap(img,
                            map_x.astype(np.float32),
                            map_y.astype(np.float32),
                            cv2.INTER_CUBIC,
                            borderMode=cv2.BORDER_WRAP)


# Display the results
cv2.imshow("Input image", img)
cv2.imshow("Transformed Image", transformed_img)
cv2.waitKey(0)