File size: 5,568 Bytes
49bc52e
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
from functools import partial

import torch

from .prope import _rope_precompute_coeffs


def intrinsics_to_K(intrinsics):
    batch_size, num_frames, _ = intrinsics.shape
    K = torch.zeros((batch_size, num_frames, 3, 3), dtype=intrinsics.dtype, device=intrinsics.device)
    K[..., 0, 0] = intrinsics[..., 0]
    K[..., 1, 1] = intrinsics[..., 1]
    K[..., 0, 2] = intrinsics[..., 2]
    K[..., 1, 2] = intrinsics[..., 3]
    K[..., 2, 2] = 1.0
    return K


def get_recammaster_embedding(cam_c2w, height, width):
    batch_size, num_frames, _, _ = cam_c2w.shape
    cam_emb = cam_c2w[:, :, :3, :].reshape(batch_size, num_frames, 1, 1, 12)  # b f 4 4 -> b f 3 4 -> b f 1 1 12
    cam_emb = cam_emb.repeat(1, 1, height, width, 1)  # b f 1 1 12 -> b f h w 12
    return cam_emb


def get_plucker_embedding(intrinsics, cam_c2w, height, width, height_dit=None, width_dit=None, flip_flag=None):
    """
    Computes the Plucker embedding given camera intrinsics and extrinsics

    Params:
        intrinsics (torch.Tensor): Camera intrinsics, shape b f 4 -> b f [ fx fy cx cy ]
        cam_c2w (torch.Tensor): Camera extrinsics, shape b f 4 4
        ...

    Returns:
        plucker (torch.Tensor): Plucker embedding, shape b f h w 6

    From AC3D: https://github.com/snap-research/ac3d/blob/3c1e29e688f4a6d0f0ad41f1bf75d2eab709dac2/training/controlnet_datasets_camera.py#L111
    """

    custom_meshgrid = partial(torch.meshgrid, indexing="ij")

    batch_size, num_frames = intrinsics.shape[:2]

    use_dit_hw = True
    if height_dit is None or width_dit is None:
        use_dit_hw = False
        height_dit = height
        width_dit = width
    else:
        patch_height = height / height_dit
        patch_width = width / width_dit

    j, i = custom_meshgrid(
        torch.linspace(0, height_dit - 1, height_dit, device=cam_c2w.device, dtype=cam_c2w.dtype),
        torch.linspace(0, width_dit - 1, width_dit, device=cam_c2w.device, dtype=cam_c2w.dtype),
    )
    # b f (h w)
    i = i.reshape([1, 1, height_dit * width_dit]).expand([batch_size, num_frames, height_dit * width_dit]) + 0.5
    j = j.reshape([1, 1, height_dit * width_dit]).expand([batch_size, num_frames, height_dit * width_dit]) + 0.5

    if use_dit_hw:
        i = i * patch_width + (patch_width / 2)
        j = j * patch_height + (patch_height / 2)

    n_flip = torch.sum(flip_flag).item() if flip_flag is not None else 0
    if n_flip > 0:
        j_flip, i_flip = custom_meshgrid(
            torch.linspace(0, height_dit - 1, height_dit, device=cam_c2w.device, dtype=cam_c2w.dtype),
            torch.linspace(width_dit - 1, 0, width_dit, device=cam_c2w.device, dtype=cam_c2w.dtype)
        )
        i_flip = i_flip.reshape([1, 1, height_dit * width_dit]).expand(batch_size, 1, height_dit * width_dit) + 0.5
        j_flip = j_flip.reshape([1, 1, height_dit * width_dit]).expand(batch_size, 1, height_dit * width_dit) + 0.5
        if use_dit_hw:
            i_flip = i_flip * patch_width + (patch_width / 2)
            j_flip = j_flip * patch_height + (patch_height / 2)

        i[:, flip_flag, ...] = i_flip
        j[:, flip_flag, ...] = j_flip

    fx, fy, cx, cy = intrinsics.chunk(4, dim=-1)  # b f 1

    zs = torch.ones_like(i)  # b f (h w)
    xs = (i - cx) / fx * zs
    ys = (j - cy) / fy * zs
    zs = zs.expand_as(ys)

    directions = torch.stack((xs, ys, zs), dim=-1)  # b f (h w) 3
    directions = directions / directions.norm(dim=-1, keepdim=True)  # b f (h w) 3

    rays_d = directions @ cam_c2w[..., :3, :3].transpose(-1, -2)  # b f (h w) 3
    rays_o = cam_c2w[..., :3, 3]  # b f 3
    rays_o = rays_o[:, :, None].expand_as(rays_d)  # b f (h w) 3
    # cam_c2w @ directions
    rays_dxo = torch.cross(rays_o, rays_d, dim=-1)  # b f (h w) 3
    plucker = torch.cat([rays_dxo, rays_d], dim=-1)
    plucker = plucker.reshape(batch_size, cam_c2w.shape[1], height_dit, width_dit, 6)  # b f h w 6
    return plucker


def get_prope_dict(
    cam_c2w, intrinsics, height, width, height_dit, width_dit, time_division_factor=4,
    precompute_coeffs=False, coeffs_x=None, coeffs_y=None, head_dim=None, num_frames_multiplier=2,
):
    cam_c2w = cam_c2w[:, ::time_division_factor]
    K = intrinsics_to_K(intrinsics)[:, ::time_division_factor]

    dtype = cam_c2w.dtype
    device = cam_c2w.device

    batch_size, num_frames, _, _ = cam_c2w.shape
    num_frames = num_frames * num_frames_multiplier  # For ReCamMaster-type training
    if precompute_coeffs:
        if coeffs_x is None:
            assert head_dim is not None
            coeffs_x = _rope_precompute_coeffs(
                torch.tile(torch.arange(width_dit, dtype=dtype, device=device), (height_dit * num_frames,)),
                freq_base=100.0,
                freq_scale=1.0,
                feat_dim=head_dim // 4,
            )
        if coeffs_y is None:
            assert head_dim is not None
            coeffs_y = _rope_precompute_coeffs(
                torch.tile(
                    torch.repeat_interleave(
                        torch.arange(height_dit, dtype=dtype, device=device), width_dit
                    ),
                    (num_frames,),
                ),
                freq_base=100.0,
                freq_scale=1.0,
                feat_dim=head_dim // 4,
            )

    prope_dict = {
        "viewmats": cam_c2w,
        "Ks": K,
        "patches_x": width_dit,
        "patches_y": height_dit,
        "image_width": width,
        "image_height": height,
        "coeffs_x": coeffs_x,
        "coeffs_y": coeffs_y,
    }
    return prope_dict