# Technical Document Extraction: Mel-spectrogram Analysis
## Header Section
- **Title**: Input Mel-spectrogram
- **Axes**:
- **Y-axis**: Time (s)
- **X-axis**: Frequency (Hz)
- **Color Gradient**: Purple (low intensity) → Green (high intensity)
## Main Chart
### Section 1: `l = 1`
- **Structure**:
- Vertical bars grouped in columns (frequency bins)
- Annotations: Yellow dots with black outlines
- Connections: Yellow lines between annotations
- **Trends**:
- Sparse connections between annotations
- Vertical bars show consistent intensity across time
### Section 2: `l = 4`
- **Structure**:
- Vertical bars with increased density of annotations
- Connections: Yellow lines with red lines overlaying
- **Trends**:
- More complex inter-annotation relationships
- Red lines suggest secondary relationships or emphasis
### Section 3: `l = 8`
- **Structure**:
- Vertical bars with dense annotations
- Connections: Yellow lines with red lines forming loops
- **Trends**:
- Highly interconnected annotations
- Red loops indicate cyclical or feedback relationships
## Footer Section
- **Legend** (bottom-right corner):
- **Yellow**: Primary connections (annotations)
- **Red**: Secondary/emphasized connections
- **Spatial Grounding**:
- Legend color matches line colors in diagrams
- Yellow lines connect annotations; red lines highlight critical paths
## Cross-Reference Verification
1. **Legend Consistency**:
- Yellow lines in all sections match legend's yellow
- Red lines in `l = 4` and `l = 8` match legend's red
2. **Trend Validation**:
- `l = 1`: Simple linear connections
- `l = 4`: Emerging complexity with red lines
- `l = 8`: Fully interconnected network with red loops
## Component Isolation
1. **Header**: Pure heatmap with no annotations
2. **Main Chart**: Three independent sections (`l = 1`, `l = 4`, `l = 8`)
3. **Footer**: Legend exclusively in bottom-right
## Data Extraction
- **No numerical data tables present**
- **Key Observations**:
- Increasing `l` values correlate with denser annotations and connections
- Red lines appear only in `l ≥ 4`, suggesting threshold-based highlighting
## Language Notes
- **Primary Language**: English
- **No non-English text detected**
