### BlendedMVS Directory Structure Example

Source: https://context7.com/yoyo000/blendedmvs/llms.txt

This illustrates the expected directory layout after extracting the BlendedMVS dataset. Each scene is organized by its Project ID (PID) and contains blended images, camera parameters, and depth maps.

```tree
DATA_ROOT
├── BlendedMVG_list.txt        # 502 scene IDs for the full BlendedMVG superset
├── BlendedMVS_list.txt        # 113 scene IDs for the core BlendedMVS subset
├── BlendedMVS+_list.txt       # scene IDs for the BlendedMVS+ subset
├── BlendedMVS++_list.txt      # scene IDs for the BlendedMVS++ subset
├── 5bfe5ae0fe0ea555e6a969ca/  # example scene directory (PID)
│   ├── blended_images/
│   │   ├── 00000000.jpg           # rendered + blended color image
│   │   ├── 00000000_masked.jpg    # same image with foreground mask applied
│   │   ├── 00000001.jpg
│   │   ├── 00000001_masked.jpg
│   │   └── ...
│   ├── cams/
│   │   ├── pair.txt               # view selection: reference → source image pairs
│   │   ├── 00000000_cam.txt       # camera intrinsics + extrinsics for view 0
│   │   ├── 00000001_cam.txt
│   │   └── ...
│   └── rendered_depth_maps/
│       ├── 00000000.pfm           # ground-truth depth map in PFM format
│       ├── 00000001.pfm
│       └── ...
├── 58eaf1513353456af3a1682a/
└── ...                            # up to PID501 for BlendedMVG
```

--------------------------------

### Download BlendedMVS (Low-Res)

Source: https://context7.com/yoyo000/blendedmvs/llms.txt

Use this command to download the original BlendedMVS subset (low-resolution). Unzip the archive into your desired data root directory.

```bash
# Download BlendedMVS low-resolution set (768x576, 27.5 GB)
wget https://github.com/YoYo000/BlendedMVS/releases/download/v1.0.0/BlendedMVS.zip

# Unzip into your data root
unzip BlendedMVS.zip -d /path/to/DATA_ROOT
```

--------------------------------

### Download BlendedMVS++ (Split Archives)

Source: https://context7.com/yoyo000/blendedmvs/llms.txt

This script downloads all 42 split archive parts for BlendedMVS++ and the final zip descriptor. Ensure all parts are downloaded before extraction using p7zip.

```bash
#!/bin/bash

BASE_URL="https://github.com/YoYo000/BlendedMVS/releases/download/v1.0.2"

# Download split parts BlendedMVS2.z01 through BlendedMVS2.z42
for i in $(seq -w 1 42); do
    FILE="BlendedMVS2.z$i"
    echo "Downloading $FILE..."
    wget -c "${BASE_URL}/${FILE}"
done

# Download the final zip descriptor
wget -c "${BASE_URL}/BlendedMVS2.zip"

echo "All parts downloaded. Extracting..."
7z x BlendedMVS2.zip -o/path/to/DATA_ROOT
```

--------------------------------

### Download BlendedMVS Dataset

Source: https://github.com/yoyo000/blendedmvs/blob/master/README.md

Use this command to download the main BlendedMVS dataset archive.

```bash
wget https://github.com/YoYo000/BlendedMVS/releases/download/v1.0.0/BlendedMVS.zip
```

--------------------------------

### Download BlendedMVS+ (Split Archives)

Source: https://context7.com/yoyo000/blendedmvs/llms.txt

This script downloads all 42 split archive parts for BlendedMVS+ and the final zip descriptor. Ensure all parts are downloaded before extraction using p7zip.

```bash
#!/bin/bash

BASE_URL="https://github.com/YoYo000/BlendedMVS/releases/download/v1.0.1"

# Download split parts BlendedMVS1.z01 through BlendedMVS1.z42
for i in $(seq -w 1 42); do
    FILE="BlendedMVS1.z$i"
    echo "Downloading $FILE..."
    wget -c "${BASE_URL}/${FILE}"
done

# Download the final zip descriptor
wget -c "${BASE_URL}/BlendedMVS1.zip"

echo "All parts downloaded. Extracting..."
# On Linux: use p7zip
7z x BlendedMVS1.zip -o/path/to/DATA_ROOT
```

--------------------------------

### Download BlendedMVS+ Dataset

Source: https://github.com/yoyo000/blendedmvs/blob/master/README.md

This script downloads the BlendedMVS+ dataset, which is split into multiple .z files and a final .zip file. It uses wget with the -c option to allow resuming interrupted downloads.

```bash
#!/bin/bash

# Base URL
BASE_URL="https://github.com/YoYo000/BlendedMVS/releases/download/v1.0.1"

# Download split files BlendedMVS1.z01 to BlendedMVS1.z42
for i in $(seq -w 1 42); do
    FILE="BlendedMVS1.z$i"
    echo "Downloading $FILE..."
    wget -c "${BASE_URL}/${FILE}"
done

# Download the final .zip descriptor
ZIP_FILE="BlendedMVS1.zip"
echo "Downloading $ZIP_FILE..."
wget -c "${BASE_URL}/${ZIP_FILE}"

echo "All files downloaded."
```

--------------------------------

### Parse BlendedMVS Pair File (Python)

Source: https://context7.com/yoyo000/blendedmvs/llms.txt

Parses a pair.txt file to create a dictionary mapping reference view indices to lists of source view indices and their associated scores. The source views are pre-sorted by score in descending order.

```python
def parse_pair_file(pair_path):
    """
    Parse pair.txt into a dict mapping reference view index to
    a list of (source_idx, score) tuples, sorted by score descending.
    """
    pairs = {}
    with open(pair_path, 'r') as f:
        num_views = int(f.readline().strip())
        for _ in range(num_views):
            ref_idx = int(f.readline().strip())
            tokens = f.readline().strip().split()
            num_src = int(tokens[0])
            sources = []
            for i in range(num_src):
                src_idx = int(tokens[1 + i * 2])
                score   = float(tokens[2 + i * 2])
                sources.append((src_idx, score))
            pairs[ref_idx] = sources  # already sorted by score
    return pairs

# Example usage
pairs = parse_pair_file('5bfe5ae0fe0ea555e6a969ca/cams/pair.txt')
ref = 0
print(f"Reference view {ref} → source views: {pairs[ref][:5]}")
# Reference view 0 → source views: [(1, 2.345), (2, 2.101), (3, 1.987), (4, 1.876), (5, 1.654)]
```

--------------------------------

### Download BlendedMVS++ Dataset

Source: https://github.com/yoyo000/blendedmvs/blob/master/README.md

This script downloads the BlendedMVS++ dataset, which is also split into multiple .z files and a final .zip file. It supports resuming interrupted downloads using wget -c.

```bash
#!/bin/bash

# Base URL
BASE_URL="https://github.com/YoYo000/BlendedMVS/releases/download/v1.0.2"

# Download split files BlendedMVS2.z01 to BlendedMVS2.z42
for i in $(seq -w 1 42); do
    FILE="BlendedMVS2.z$i"
    echo "Downloading $FILE..."
    wget -c "${BASE_URL}/${FILE}"
done

# Download the final .zip descriptor
ZIP_FILE="BlendedMVS2.zip"
echo "Downloading $ZIP_FILE..."
wget -c "${BASE_URL}/${ZIP_FILE}"

echo "All files downloaded."
```

--------------------------------

### Parse BlendedMVS Camera File (Python)

Source: https://context7.com/yoyo000/blendedmvs/llms.txt

Parses a *_cam.txt file to extract extrinsic and intrinsic camera matrices, along with depth range parameters. Ensure the file path is correct.

```python
import numpy as np

def parse_cam_file(cam_path):
    """Parse a BlendedMVS *_cam.txt file into extrinsic, intrinsic, and depth range."""
    with open(cam_path, 'r') as f:
        lines = [l.strip() for l in f if l.strip()]

    # Extrinsic matrix (4x4): lines 1–4 after 'extrinsic' header
    extrinsic = np.array([
        list(map(float, lines[1].split()))
        list(map(float, lines[2].split()))
        list(map(float, lines[3].split()))
        list(map(float, lines[4].split()))
    ])  # shape (4, 4)

    # Intrinsic matrix (3x3): lines after 'intrinsic' header
    intrinsic = np.array([
        list(map(float, lines[6].split()))
        list(map(float, lines[7].split()))
        list(map(float, lines[8].split()))
    ])  # shape (3, 3)

    # Depth range
    depth_params = lines[9].split()
    depth_min = float(depth_params[0])
    depth_max = float(depth_params[1])

    # Guard against degenerate depth values (documented edge case)
    if depth_min <= 0 or depth_max <= 0:
        print(f"Warning: non-positive depth range in {cam_path}: [{depth_min}, {depth_max}]")

    return extrinsic, intrinsic, depth_min, depth_max

# Example usage
extrinsic, intrinsic, d_min, d_max = parse_cam_file('5bfe5ae0fe0ea555e6a969ca/cams/00000000_cam.txt')
print("Extrinsic:\n", extrinsic)
print("Intrinsic:\n", intrinsic)
print(f"Depth range: [{d_min}, {d_max}]")
```

--------------------------------

### Load BlendedMVS Scene List

Source: https://context7.com/yoyo000/blendedmvs/llms.txt

Loads scene IDs from a text file and returns valid scene paths within the specified data root. It warns if scene directories are not found.

```python
import os

def load_scene_list(list_path, data_root):
    """
    Load a BlendedMVS scene list and return valid scene paths.
    Skips IDs whose directories do not exist under data_root.
    """
    scenes = []
    with open(list_path, 'r') as f:
        for line in f:
            pid = line.strip()
            if not pid:
                continue
            scene_dir = os.path.join(data_root, pid)
            if os.path.isdir(scene_dir):
                scenes.append(scene_dir)
            else:
                print(f"Warning: scene directory not found: {scene_dir}")
    return scenes

DATA_ROOT = '/path/to/DATA_ROOT'

# Load the core BlendedMVS training split (113 scenes)
train_scenes = load_scene_list('project_lists/BlendedMVS_training.txt', DATA_ROOT)

# Load the validation split (7 scenes)
val_scenes = load_scene_list('project_lists/validation_list.txt', DATA_ROOT)

print(f"Training scenes: {len(train_scenes)}")   # up to 113
print(f"Validation scenes: {len(val_scenes)}")   # 7

# Example: iterate over all images in training scenes
for scene in train_scenes[:2]:
    img_dir = os.path.join(scene, 'blended_images')
    images = sorted(f for f in os.listdir(img_dir) if f.endswith('.jpg') and '_masked' not in f)
    print(f"{os.path.basename(scene)}: {len(images)} images")
```

--------------------------------

### PyTorch Dataset for BlendedMVS

Source: https://context7.com/yoyo000/blendedmvs/llms.txt

A PyTorch Dataset that loads reference images, source images, camera parameters, and depth maps for MVS training. It requires helper functions like `parse_pair_file`, `read_pfm`, and `parse_cam_file` to be defined elsewhere.

```python
import os, cv2, numpy as np
from torch.utils.data import Dataset, DataLoader

class BlendedMVSDataset(Dataset):
    def __init__(self, list_path, data_root, num_src=4, img_wh=(768, 576)):
        self.data_root = data_root
        self.num_src   = num_src
        self.img_wh    = img_wh
        self.metas     = []

        with open(list_path) as f:
            scene_ids = [l.strip() for l in f if l.strip()]

        for sid in scene_ids:
            scene_dir  = os.path.join(data_root, sid)
            pair_path  = os.path.join(scene_dir, 'cams', 'pair.txt')
            if not os.path.exists(pair_path):
                continue
            pairs = parse_pair_file(pair_path)   # reuse function defined above
            for ref_idx, sources in pairs.items():
                src_indices = [s[0] for s in sources[:num_src]]
                if len(src_indices) < num_src:
                    continue  # skip if not enough source views
                self.metas.append((scene_dir, ref_idx, src_indices))

    def __len__(self):
        return len(self.metas)

    def __getitem__(self, idx):
        scene_dir, ref_idx, src_indices = self.metas[idx]

        def load_img(i):
            path = os.path.join(scene_dir, 'blended_images', f'{i:08d}.jpg')
            img  = cv2.imread(path)
            img  = cv2.resize(img, self.img_wh)
            return img.astype(np.float32) / 255.0  # normalize to [0, 1]

        ref_img  = load_img(ref_idx)
        src_imgs = [load_img(i) for i in src_indices]

        # Load reference depth map
        depth_path = os.path.join(scene_dir, 'rendered_depth_maps', f'{ref_idx:08d}.pfm')
        depth, _   = read_pfm(depth_path)   # reuse function defined above
        depth      = cv2.resize(depth, self.img_wh, interpolation=cv2.INTER_NEAREST)

        # Load cameras
        ref_ext, ref_int, d_min, d_max = parse_cam_file(
            os.path.join(scene_dir, 'cams', f'{ref_idx:08d}_cam.txt'))

        return {
            'ref_img':  ref_img,          # (H, W, 3)
            'src_imgs': src_imgs,         # list of (H, W, 3)
            'ref_extrinsic': ref_ext,     # (4, 4)
            'ref_intrinsic': ref_int,     # (3, 3)
            'depth': depth,               # (H, W)
            'depth_min': d_min,
            'depth_max': d_max,
        }

# Usage
dataset = BlendedMVSDataset(
    list_path='project_lists/BlendedMVS_training.txt',
    data_root='/path/to/DATA_ROOT',
    num_src=4,
)
loader = DataLoader(dataset, batch_size=2, shuffle=True, num_workers=4)
sample = next(iter(loader))
print("Batch ref_img shape:", sample['ref_img'].shape)  # (2, 576, 768, 3)
print("Depth shape:", sample['depth'].shape)             # (2, 576, 768)
```

--------------------------------

### Read PFM Depth Map (Python)

Source: https://context7.com/yoyo000/blendedmvs/llms.txt

Reads a depth map from a Portable Float Map (.pfm) file. Returns the depth data as a NumPy array and the scale factor. Handles both color and grayscale PFM formats.

```python
import numpy as np
import re, sys

def read_pfm(filename):
    """Read a PFM depth map. Returns (data: np.ndarray, scale: float)."""
    with open(filename, 'rb') as f:
        header = f.readline().decode('utf-8').rstrip()
        if header == 'PF':
            color = True
        elif header == 'Pf':
            color = False
        else:
            raise ValueError(f"Not a PFM file: {filename}")

        dims = f.readline().decode('utf-8').strip()
        width, height = map(int, dims.split())
        scale = float(f.readline().decode('utf-8').strip())
        endian = '<' if scale < 0 else '>'
        scale = abs(scale)

        data = np.frombuffer(f.read(), endian + 'f')
        shape = (height, width, 3) if color else (height, width)
        data = np.reshape(data, shape)
        data = np.flipud(data)  # PFM is stored bottom-to-top

    return data, scale

# Example: load and inspect a depth map
depth, scale = read_pfm('5bfe5ae0fe0ea555e6a969ca/rendered_depth_maps/00000000.pfm')
print(f"Depth map shape: {depth.shape}")       # e.g. (576, 768)
print(f"Depth range: [{depth.min():.3f}, {depth.max():.3f}]")

# Guard against empty depth maps (documented edge case)
if depth.max() == 0:
    print("Warning: empty depth map — the mesh model may be incomplete for this view.")
```

--------------------------------

### BibTeX Citation for BlendedMVS

Source: https://context7.com/yoyo000/blendedmvs/llms.txt

Use this BibTeX entry when publishing work that utilizes the BlendedMVS or BlendedMVG dataset.

```bibtex
@article{yao2020blendedmvs,
  title={BlendedMVS: A Large-scale Dataset for Generalized Multi-view Stereo Networks},
  author={Yao, Yao and Luo, Zixin and Li, Shiwei and Zhang, Jingyang and Ren, Yufan
          and Zhou, Lei and Fang, Tian and Quan, Long},
  journal={Computer Vision and Pattern Recognition (CVPR)},
  year={2020}
}
```

--------------------------------

### BlendedMVS Dataset Directory Structure

Source: https://github.com/yoyo000/blendedmvs/blob/master/README.md

This outlines the expected directory structure for the BlendedMVS dataset, adhering to the MVSNet input format. Ensure your dataset is organized similarly after downloading.

```text
DATA_ROOT 
├── BlendedMVG_list.txt 
├── BlendedMVS_list.txt 
├── BlendedMVS+_list.txt 
├── BlendedMVS++_list.txt 
├── ...
├── PID0 
│  ├── blended_images 
│  │	├── 00000000.jpg 
│  │	├── 00000000_masked.jpg 
│  │	├── 00000001.jpg 
│  │	├── 00000001_masked.jpg 
│  │	└── ... 
│  ├── cams 
│  │  	├── pair.txt 
│  │  	├── 00000000_cam.txt 
│  │  	├── 00000001_cam.txt 
│  │  	└── ... 
│  └── rendered_depth_maps 
│      	├── 00000000.pfm 
│     	├── 00000001.pfm 
│     	└── ... 
├── PID1 
├── ... 
└── PID501 

```

--------------------------------

### BlendedMVS Citation

Source: https://github.com/yoyo000/blendedmvs/blob/master/README.md

This is the citation information for the BlendedMVS paper, to be used when referencing the dataset in academic work.

```bibtex
@article{yao2020blendedmvs,
  title={BlendedMVS: A Large-scale Dataset for Generalized Multi-view Stereo Networks},
  author={Yao, Yao and Luo, Zixin and Li, Shiwei and Zhang, Jingyang and Ren, Yufan and Zhou, Lei and Fang, Tian and Quan, Long},
  journal={Computer Vision and Pattern Recognition (CVPR)},
  year={2020}
}
```

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