47 lines
1.7 KiB
Markdown
47 lines
1.7 KiB
Markdown
# Strip Photography / Slit Photography
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A digital implementation of **strip photography** (also called **slit photography**) that captures a two-dimensional image as a sequence of one-dimensional images over time.
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Strip photography records a moving scene over time by extracting the same line position from each video frame and assembling them into a composite image where:
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- One axis represents **space** (the slit/line being observed)
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- The other axis represents **time** (progression through video frames)
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- Moving objects appear as visible shapes, stationary objects as stripes
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- Object width is inversely proportional to speed (faster = narrower, slower = wider)
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## Usage
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**Row Mode** - Extract horizontal lines with threshold filtering:
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```bash
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uv run main.py .\line500fps32pix.mp4 --yrow 16 --output demo.jpg --threshold 0.005
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```
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**Debug Mode** - Analyze changes and generate threshold recommendations:
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```bash
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uv run main.py .\line500fps32pix.mp4 --yrow 16 --output demo.jpg --debug
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```
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## Setup
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Install dependencies with uv:
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```bash
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uv sync
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```
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## Output Modes
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- **Column mode**: Extracts vertical line (`--xcolumn`) → Width = frames, Height = video height
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- **Row mode**: Extracts horizontal line (`--yrow`) → Width = video width, Height = frames
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## Features
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**Change Detection**: Automatically filters frames with minimal changes using configurable thresholds
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- Use `--threshold` (0-1) to control sensitivity
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- `--debug` mode provides threshold recommendations and change analysis
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- Higher thresholds = more compression, fewer frames
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**Threshold Guide**:
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- `0.001-0.005`: High sensitivity (10-30% compression)
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- `0.005-0.02`: Medium sensitivity (30-70% compression)
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- `0.02+`: Low sensitivity (70%+ compression)
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