sphere-snap 1.0.2

A quick and easy to use library for reprojecting various image types

SphereSnap

A quick and easy to use library for reprojecting various image types. (inspired by http://paulbourke.net/panorama/sphere2persp/ )

Examples and usecases

Reprojecting equirectangular image into pinhole-camera images with customizable FoV and resolution

Create equirectangular image using cubemap faces

Create fisheye images from equirectangular or cubemap images

Create top view images from equirectangular/fisheye/planar images

Correct radially distorted images

How to use it

Module sphere_snap.reprojections contains easy to use functions for simple situations:

• equi2cubemap
• cubemap2equi
• cubemap2fisheye
• equi2fisheye
• fisheye2equi
• equi2tv

For more complex situtation SphereSnaper can be used which is more flexible

import sphere_snap.utils as snap_utils
import sphere_snap.sphere_coor_projections as sphere_proj
from sphere_snap.snap_config import SnapConfig, ImageProjectionType
from sphere_snap.sphere_snap import SphereSnap
import sphere_snap.reprojections as rpr

Snap to perspective from equirectangular

snap_config = SnapConfig( [0,0,0,1], (1400,1400),(120,120), equi_photo.shape[:2], source_img_type=ImageProjectionType.EQUI)
snap_test = SphereSnap(snap_config)
persp_img = snap_test.snap_to_perspective(equi_photo)

Reproject equirectangular into 6 planar images of 90 degrees FoV (Cubemap)

def get_cube_map_faces(face_size=1440, source_img_hw=(2000,4000), source_img_type=ImageProjectionType.EQUI):

    snap_configs = [SnapConfig( rot(90*i,0), (face_size,face_size),(90,90), source_img_hw, source_img_type=source_img_type)
                        for i in range(4)]
    # top
    snap_configs.append(SnapConfig( rot(0,90), (face_size,face_size),(90,90), source_img_hw, source_img_type=source_img_type))
    # bottom
    snap_configs.append(SnapConfig( rot(0,-90), (face_size,face_size),(90,90), source_img_hw, source_img_type=source_img_type))
    return snap_configs

cube_configs = get_cube_map_faces(face_size=1440, source_img_hw=equi_img.shape[:2])
cube_faces_snaps = [SphereSnap(c) for c in cube_configs]
cumbe_faces_imgs = [snap.snap_to_perspective(equi_img) for snap in cube_faces_snaps]

or

cube_faces_imgs = rpr.equi2cubemap(equi_img)

Reproject a planar image into equirectangular

reconstructed_equi = SphereSnap.merge_multiple_snaps((1000,2000), 
                                                     cube_faces_snaps, # snap object specifies destination position
                                                     cumbe_faces_imgs[::-1], # snap image contains planar image pixels
                                                     target_type=ImageProjectionType.EQUI, # destination image type
                                                     merge_method="max")

Reproject a planar image into fisheye 180

reconstructed_fisheye = SphereSnap.merge_multiple_snaps((1000,1000), 
                                                    cube_faces_snaps, # snap object specifies destination position
                                                    cumbe_faces_imgs, # snap image contains planar image pixels
                                                    target_type=ImageProjectionType.FISHEYE_180, # destination image type
                                                    merge_method="max")                                                    

Snap to perspective from fisheye 180

snap_config = SnapConfig( rot(45,1), (1400,1400),(100,100), reconstructed_fisheye.shape[:2], source_img_type=ImageProjectionType.FISHEYE_180)
snap_test = SphereSnap(snap_config)
persp_img = snap_test.snap_to_perspective(reconstructed_fisheye)

Reproject fisheye 180 to equirectangular

snap_configs = [SnapConfig( rot(yaw,pitch), (800,800),(90,90), fisheye180_img.shape[:2], source_img_type=ImageProjectionType.FISHEYE_180) 
                    for yaw,pitch in [[-45,-45],[45,-45],[-45,45],[45,45],[0,0]]]
snaps = [SphereSnap(c) for c in snap_configs]
snap_imgs = [snap.snap_to_perspective(fisheye180_img) for snap in snaps]

reconstructed_equi = SphereSnap.merge_multiple_snaps((1000,2000), 
                                                     snaps, # snap object specifies destination position
                                                     snap_imgs, # snap image contains planar image pixels
                                                     target_type=ImageProjectionType.EQUI, # destination image type
                                                     merge_method="max")