# Image_SDF
**Automatic Diagram Generation for Analytic Geometry Problems using Signed Distance Fields**
---
## Introduction
**Image_SDF** is an automatic system that converts mathematical geometry problem text into accurate visualizations. By leveraging **Signed Distance Fields (SDF)** combined with differentiable optimization, the system can automatically generate precise conic section diagrams from symbolic geometric expressions.
Traditional geometry diagram generation often relies on manual drawing or rule-based methods. This system takes a different approach: it models geometric constraints as differentiable loss functions and uses gradient-based optimization to find curve parameters that satisfy all constraints, ultimately rendering high-quality geometric diagrams.
### Key Features
- **Fully Automated**: Generate PNG diagrams directly from JSON-formatted geometry problems without manual intervention
- **High Accuracy**: Achieves **96.7%** validation pass rate on parseable problems
- **Large-Scale Validation**: Tested on **10,861** geometry problems across 3 datasets
- **Rigorous Verification**: Multi-dimensional geometric property validation including focus position, eccentricity, and asymptote slope
---
## Supported Curve Types
The system supports four classical conic sections, each with complete SDF representation and constraint validation:
| Curve Type | Standard Form | Validated Properties |
|------------|---------------|---------------------|
| **Ellipse** | x²/a² + y²/b² = 1 | Focus distance c²=a²-b², eccentricity, points on curve |
| **Hyperbola** | x²/a² - y²/b² = 1 | Focus distance c²=a²+b², asymptote slope, eccentricity |
| **Parabola** | y² = 4px | Focus position, directrix equation, points on curve |
| **Circle** | (x-h)² + (y-k)² = r² | Center position, radius, points on curve |
---
## How It Works
The system follows a four-stage pipeline:
```
Text Parsing → SDF Construction → Constraint Optimization → Diagram Rendering
```
### 1. Text Parsing
Extract geometric parameters from mathematical expressions. For example:
```
Input: "ellipse x²/4 + y²/9 = 1"
Output: Ellipse(a=2, b=3, center=(0,0))
```
The parser supports various expression formats including fractions, radicals, and LaTeX-formatted mathematical expressions.
### 2. SDF Construction
Build a signed distance field function for each curve type. The SDF value represents the signed distance from any point in space to the curve boundary:
- Positive: point is outside the curve
- Negative: point is inside the curve
- Zero: point is exactly on the curve
### 3. Constraint Optimization
Optimize curve parameters via gradient descent to satisfy all geometric constraints:
```python
# Total loss = point constraint + focus constraint + eccentricity constraint + crowd penalty
L_total = λ₁·L_point + λ₂·L_focus + λ₃·L_ecc + λ₄·L_crowd
```
Using the AdamW optimizer, convergence typically occurs within 100-200 iterations.
### 4. Diagram Rendering
Extract the zero-level set of the SDF (i.e., the curve itself), overlay coordinate axes, focus annotations, problem information, and other elements to generate the final PNG diagram.
---
## Datasets and Results
The system has been fully tested on three datasets:
| Dataset | Total Problems | Parseable | Successful | Parseable Accuracy |
|---------|----------------|-----------|------------|-------------------|
| dev | 1,035 | 809 | 788 | **97.4%** |
| test | 2,069 | 1,649 | 1,595 | **96.7%** |
| train | 7,757 | 6,052 | 5,844 | **96.6%** |
| **Total** | **10,861** | **8,510** | **8,227** | **96.7%** |
> **Note**: "Parseable" refers to problems with explicit geometric expressions (e.g., x²/4 + y²/9 = 1) rather than implicit or parametric forms. Approximately 22% of problems cannot be parsed due to overly complex or incomplete expressions.
### Curve Type Distribution
| Type | Dev | Test | Train | Total |
|------|-----|------|-------|-------|
| Ellipse | 220 | 467 | 1,730 | 2,417 |
| Hyperbola | 293 | 564 | 2,025 | 2,882 |
| Parabola | 262 | 532 | 1,999 | 2,793 |
| Circle | 13 | 32 | 90 | 135 |
---
## Installation and Usage
### Requirements
- Python >= 3.9
- PyTorch >= 2.0.0
- NumPy >= 1.24.0
- Matplotlib >= 3.7.0
- tqdm >= 4.65.0
### Install Dependencies
```bash
pip install -r requirements.txt
```
### Running Examples
```bash
# Process test dataset
python src/main.py --input data/test_en.json --output results/test/
# Process dev dataset
python src/main.py --input data/dev_en.json --output results/dev/
# Process train dataset (~30 minutes)
python src/main.py --input data/train_en.json --output results/train/
# Process only first 100 problems with verbose output
python src/main.py -i data/test_en.json -o results/test/ -m 100 -v
```
### Command Line Arguments
| Argument | Description | Default |
|----------|-------------|---------|
| `-i, --input` | Input JSON file path | `data/test_en.json` |
| `-o, --output` | Output directory | `results/` |
| `-m, --max` | Maximum number of problems to process | All |
| `-v, --verbose` | Enable verbose output | False |
### Python API
```python
from src.sdf_geo import SDFBatchProcessor
# Create processor
processor = SDFBatchProcessor(output_dir='results/')
# Batch processing
results = processor.process_batch('data/test_en.json', max_problems=100)
# Calculate success rate
success_rate = sum(r['success'] for r in results) / len(results)
print(f"Success rate: {success_rate:.1%}")
```
---
## Project Structure
```
Image_SDF/
├── data/
│ ├── dev_en.json # Dev set (1,035 problems)
│ ├── test_en.json # Test set (2,069 problems)
│ └── train_en.json # Train set (7,757 problems)
├── results/
│ ├── dev/ # Dev set results
│ ├── test/ # Test set results
│ └── train/ # Train set results
├── src/
│ ├── main.py # CLI entry point
│ └── sdf_geo/ # Core modules
│ ├── primitives.py # SDF geometric primitives
│ ├── constraints.py # Differentiable constraint functions
│ ├── parser.py # Expression parser
│ ├── optimizer.py # Gradient optimizer
│ ├── processor.py # Batch processing & validation
│ └── renderer.py # Diagram renderer
├── requirements.txt
└── README.md
```
---
## Output Format
Each problem generates a PNG image containing:
- **Geometric Curve**: Rendered from the SDF zero-level set
- **Feature Point Annotations**: Foci (F₁, F₂), vertices, center, etc.
- **Coordinate System**: Cartesian coordinate system with grid
- **Problem Information**: Original problem, equation parameters, expected answer
Results are organized by curve type:
```
results/test/
├── summary.json # Statistics summary
├── circle/ # Circle diagrams
├── ellipse/ # Ellipse diagrams
├── hyperbola/ # Hyperbola diagrams
└── parabola/ # Parabola diagrams
```
---
## Validation Standards
The system employs multi-dimensional geometric property validation to ensure mathematical correctness of generated diagrams:
| Validation Item | Tolerance | Description |
|-----------------|-----------|-------------|
| Point on curve | 0.03 | SDF(p) ≈ 0 |
| Eccentricity | 0.05 | \|e_calculated - e_target\| < tol |
| Focus position | 0.05 | \|c_calculated - c_given\| < tol |
| Asymptote slope | 0.05 | \|b/a - slope\| < tol |
---
## Methodology
This implementation is based on the methodology described in:
> **GeoSDF: Plane Geometry Diagram Synthesis via Signed Distance Field**
The core ideas of using signed distance fields for geometric representation and differentiable optimization for constraint satisfaction are derived from this work.
---
## License
MIT License