---
id: wiki-2026-0508-computer-vision
title: Computer Vision
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [CV, computer vision, image classification, object detection, segmentation, ViT, CLIP, SAM, depth estimation]
duplicate_of: none
source_trust_level: A
confidence_score: 0.95
verification_status: applied
tags: [computer-vision, deep-learning, cnn, vit, segmentation, detection, sam, clip, dino, image-classification]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: Python
  framework: PyTorch / Transformers / Detectron2 / Ultralytics / SAM
---

# Computer Vision

## 매 한 줄
> **"매 pixel 의 meaning"**. 매 classification → 매 detection → 매 segmentation → 매 depth → 매 generation. 매 modern: 매 ViT 의 dominant + 매 foundation model (CLIP, SAM, DINOv2). 매 multi-modal LLM 의 vision encoder 의 base.

## 매 핵심 task

### Classification
- 매 image → 매 class.
- 매 ImageNet, 매 ResNet, 매 ViT.

### Detection
- 매 image → 매 bbox + class.
- 매 [[Bounding-Box-Regression]] 참조.
- 매 YOLO, DETR.

### Segmentation
- **Semantic**: 매 pixel → 매 class.
- **Instance**: 매 pixel → 매 instance.
- **Panoptic**: 매 결합.
- 매 SAM (Segment Anything).

### Depth estimation
- **Monocular**: 매 single image → 매 depth.
- **Stereo**: 매 두 camera.
- 매 MiDaS, Depth Anything.

### Pose estimation
- **2D / 3D**.
- 매 OpenPose, MediaPipe, ViTPose.

### Tracking
- 매 video 의 across frames.
- 매 ByteTrack, BoT-SORT.

### Generation
- 매 GAN, Diffusion, Stable Diffusion.
- 매 [[AI 이미지 생성 및 편집 워크플로우 (AI Image Generation & Editing Workflow)]] 참조.

### OCR
- 매 text from image.
- 매 PaddleOCR, Tesseract, GPT-4V.

### Action recognition
- 매 video understanding.

### Re-Identification
- 매 person / vehicle re-id.

### 3D vision
- 매 NeRF, Gaussian Splatting.
- 매 [[Automated_Mapping]] 참조.

## 매 architecture history

### CNN era (2012-2020)
- AlexNet (2012) → 매 ImageNet revolution.
- VGG, ResNet (skip connection), DenseNet, EfficientNet.
- 매 inductive bias: locality + translation invariance.

### ViT era (2020+)
- ViT (Dosovitskiy 2020).
- 매 patch + transformer.
- 매 large data 의 dominate.
- Swin, DeiT, MAE pretrain.

### Foundation model (2021+)
- **CLIP**: 매 image-text contrastive.
- **DINO / DINOv2**: 매 self-supervised.
- **MAE**: 매 masked autoencoder.
- **SAM**: 매 segment anything.
- **Depth Anything**: 매 universal depth.

### Multi-modal (2023+)
- **GPT-4V, Claude vision, Gemini**: 매 LLM + vision.
- **LLaVA, Qwen-VL**: 매 open.
- **Sora, Veo**: 매 video generation.

## 💻 패턴

### Image classification (ViT, HuggingFace)
```python
from transformers import ViTImageProcessor, ViTForImageClassification
from PIL import Image

processor = ViTImageProcessor.from_pretrained('google/vit-large-patch16-384')
model = ViTForImageClassification.from_pretrained('google/vit-large-patch16-384')

image = Image.open('cat.jpg')
inputs = processor(images=image, return_tensors='pt')
outputs = model(**inputs)
predicted_idx = outputs.logits.argmax(-1).item()
print(model.config.id2label[predicted_idx])
```

### Object detection (YOLO)
```python
from ultralytics import YOLO

model = YOLO('yolov8x.pt')
results = model('image.jpg', conf=0.5)

for r in results:
    for box in r.boxes:
        print(f'{model.names[int(box.cls)]}: {box.conf.item():.2f} at {box.xyxy[0].tolist()}')
```

### Segmentation (SAM)
```python
from segment_anything import sam_model_registry, SamPredictor
import cv2

sam = sam_model_registry['vit_h'](checkpoint='sam_vit_h.pth').to('cuda')
predictor = SamPredictor(sam)
predictor.set_image(image)

# 매 prompt: bbox or point
masks, scores, _ = predictor.predict(
    box=np.array([100, 100, 400, 400]),
    multimask_output=False,
)
```

### Depth estimation (Depth Anything)
```python
from transformers import pipeline

pipe = pipeline('depth-estimation', model='depth-anything/Depth-Anything-V2-Large-hf')
depth = pipe(image)['depth']
depth.save('depth.png')
```

### CLIP zero-shot
```python
import open_clip

model, _, preprocess = open_clip.create_model_and_transforms('ViT-L-14', pretrained='openai')
tokenizer = open_clip.get_tokenizer('ViT-L-14')

candidates = ['a cat', 'a dog', 'a bird']
text = tokenizer(candidates)
img = preprocess(image).unsqueeze(0)

with torch.no_grad():
    img_feat = model.encode_image(img) / ...
    text_feat = model.encode_text(text) / ...
    similarity = (100 * img_feat @ text_feat.T).softmax(-1)
```

### Pose estimation (MediaPipe)
```python
import mediapipe as mp

mp_pose = mp.solutions.pose
with mp_pose.Pose() as pose:
    results = pose.process(cv2.cvtColor(image, cv2.COLOR_BGR2RGB))
    if results.pose_landmarks:
        for lm in results.pose_landmarks.landmark:
            print(lm.x, lm.y, lm.z, lm.visibility)
```

### Tracking (ByteTrack)
```python
from yolox.tracker.byte_tracker import BYTETracker

tracker = BYTETracker(args)
for frame in video:
    detections = detector(frame)  # 매 (N, 5): xyxy + conf
    tracked = tracker.update(detections, frame_size, frame_size)
    for t in tracked:
        print(t.track_id, t.tlbr, t.score)
```

### OCR (PaddleOCR)
```python
from paddleocr import PaddleOCR

ocr = PaddleOCR(use_angle_cls=True, lang='en')
result = ocr.ocr('document.jpg', cls=True)
for line in result[0]:
    bbox, (text, conf) = line
    print(text, conf)
```

### Multi-modal (GPT-4V via API)
```python
from openai import OpenAI
client = OpenAI()

response = client.chat.completions.create(
    model='gpt-4o',
    messages=[{
        'role': 'user',
        'content': [
            {'type': 'text', 'text': 'What objects do you see, and where are they?'},
            {'type': 'image_url', 'image_url': {'url': image_url}},
        ],
    }],
)
print(response.choices[0].message.content)
```

### Self-supervised pre-train (MAE, simplified)
```python
def mae_pretrain(model, image, mask_ratio=0.75):
    patches = patchify(image, patch_size=16)
    n_visible = int(len(patches) * (1 - mask_ratio))
    visible_idx = torch.randperm(len(patches))[:n_visible]
    
    encoded = encoder(patches[visible_idx])
    full = insert_mask_tokens(encoded, visible_idx, total=len(patches))
    reconstructed = decoder(full)
    
    loss = ((reconstructed[masked_idx] - patches[masked_idx]) ** 2).mean()
    return loss
```

### NeRF (volumetric 3D)
```python
# 매 [[Automated_Mapping]] 참조 — 매 NeRF / Gaussian Splatting code
```

## 🤔 결정 기준
| Task | Tool |
|---|---|
| Classify | ViT / EfficientNet |
| Detect | YOLOv8 / DETR / Grounding DINO |
| Segment | SAM (open-vocab) / Mask2Former |
| Depth | Depth Anything V2 |
| Pose | MediaPipe / ViTPose |
| Track | ByteTrack |
| OCR | PaddleOCR / GPT-4V |
| Zero-shot | CLIP / SigLIP |
| Generate | Stable Diffusion / Flux |
| Edge | YOLOv8n / MobileNetV4 |
| Foundation feature | DINOv2 |

**기본값**: 매 task-specific SOTA + 매 CLIP / SAM 의 zero-shot fallback.

## 🔗 Graph
- 부모: [[AI]] · [[Deep Learning]]
- 변형: [[CNN]] · [[ViT]] · [[CLIP]] · [[SAM]] · [[MAE]]
- 응용: [[Object-Detection]] · [[Bounding-Box-Regression]] · [[Automated_Mapping]] · [[Autonomous Vehicles]] · [[Algorithmic-Biology]]
- Adjacent: [[Diffusion-Models]] · [[CV_Synthesis]]

## 🤖 LLM 활용
**언제**: 매 vision task. 매 multimodal product. 매 image search. 매 autonomous system.
**언제 X**: 매 audio / pure text. 매 1D signal.

## ❌ 안티패턴
- **Custom CNN from scratch (small data)**: 매 pretrain 의 use.
- **No augmentation**: 매 generalization X.
- **ImageNet only eval**: 매 distribution shift.
- **No domain adapt**: 매 medical / satellite 의 weak.
- **Single model for all task**: 매 specialized 의 better.

## 🧪 검증 / 중복
- Verified (ImageNet, ViT, CLIP, SAM papers).
- 신뢰도 A.
- Related: [[CLIP]] · [[Bounding-Box-Regression]] · [[Automated_Mapping]] · [[Autonomous Vehicles]] · [[CV_Synthesis]] · [[Algorithmic-Biology]].

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — task taxonomy + history + 매 ViT / YOLO / SAM / Depth / CLIP / GPT-4V code |