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yair
2025-11-18 01:12:52 +02:00
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gst/intervalometer/README.md
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@@ -66,6 +66,13 @@ make install
| Property | Type | Values | Default | Description |
|----------|------|--------|---------|-------------|
| `ramp-rate` | enum | VSlow, Slow, Medium, Fast, VFast | Medium | Speed of parameter changes |
| `update-interval` | int | 10-10000 | 100 | Time between exposure updates (ms) |
### Brightness Filtering
| Property | Type | Range | Default | Description |
|----------|------|-------|---------|-------------|
| `brightness-smoothing` | double | 0.0-1.0 | 0.1 | Temporal smoothing factor (EMA alpha) |
### Logging
@@ -119,7 +126,28 @@ gst-launch-1.0 idsueyesrc name=cam ! \
videoconvert ! autovideosink
```
### Complete Time-Lapse Pipeline
### Dawn/Dusk Time-Lapse (Recommended)
Optimized settings for smooth sunrise/sunset time-lapse:
```bash
gst-launch-1.0 \
idsueyesrc config-file=ini/whole-presacler64_autoexp-binningx2.ini \
exposure=0.85 framerate=50 gain=0 name=cam device-id=2 ! \
intervalometer enabled=true camera-element=cam \
ramp-rate=vslow \
update-interval=1000 \
brightness-smoothing=0.1 \
log-file=timelapse.csv ! \
videocrop bottom=3 ! queue ! videoconvert ! autovideosink
```
**Key settings:**
- `ramp-rate=vslow`: 5% exposure steps per update (smooth transitions)
- `update-interval=1000`: Updates every 1 second (not too aggressive)
- `brightness-smoothing=0.1`: Filters out moving objects (cars, people, birds)
### Complete Time-Lapse Recording
Record a time-lapse with auto-exposure:
@@ -174,33 +202,77 @@ The filter finds and controls the upstream `idsueyesrc` element using the `camer
Ensure your camera source is named and the name matches the `camera-element` property.
## Ramp Rates
## Configuration Reference
| Rate | Multiplier | Best For |
|------|------------|----------|
| VSlow | 0.5x | Very slow light changes, maximum smoothness |
| Slow | 1.0x | Gradual sunset/sunrise over hours |
| Medium | 2.0x | Normal time-lapse scenarios |
| Fast | 4.0x | Faster light changes, clouds passing |
| VFast | 8.0x | Quick adaptation, testing |
### Ramp Rates
| Rate | Multiplier | Step Size | Best For |
|------|------------|-----------|----------|
| VSlow | 0.5x | 5% per update | Dawn/dusk time-lapse (recommended) |
| Slow | 1.0x | 10% per update | Gradual sunset/sunrise over hours |
| Medium | 2.0x | 20% per update | Normal time-lapse scenarios |
| Fast | 4.0x | 40% per update | Faster light changes, clouds passing |
| VFast | 8.0x | 80% per update | Quick adaptation, testing |
**Note:** The base ramping rate is 10% of the delta between current and target values, multiplied by the ramp rate setting.
### Update Intervals
| Interval | Updates/sec | Best For |
|----------|-------------|----------|
| 100ms | 10 Hz | Fast-changing scenes (clouds, indoor) |
| 500ms | 2 Hz | Moderate changes |
| **1000ms** | **1 Hz** | **Dawn/dusk time-lapse (recommended)** |
| 2000ms | 0.5 Hz | Very slow lighting changes |
| 5000ms | 0.2 Hz | Extremely slow changes |
**Important:** At high frame rates (50fps), avoid very short update intervals (< 500ms) to prevent oscillation and flickering.
### Brightness Smoothing
The `brightness-smoothing` property uses Exponential Moving Average (EMA) to filter out transient brightness changes from moving objects:
```
smoothed_brightness = (alpha × current_brightness) + ((1 - alpha) × previous_smoothed)
```
| Value | Behavior | Best For |
|-------|----------|----------|
| 0.05 | Very heavy smoothing | High traffic scenes |
| **0.1** | **Heavy smoothing (default)** | **Time-lapse with moving objects** |
| 0.3 | Moderate smoothing | Some filtering needed |
| 0.5 | Light smoothing | Quick response |
| 1.0 | No smoothing | Instant response to changes |
**Effect:** With `brightness-smoothing=0.1`, the algorithm effectively averages brightness over ~10 frames, filtering out cars, people, and birds while still tracking slow lighting trends.
## Tips for Best Results
### Time-Lapse Settings
### Dawn/Dusk Time-Lapse (Recommended Configuration)
```
exposure-min: 0.85 (or camera-specific minimum)
exposure-max: 1.24 (or 1/framerate to avoid motion blur)
ramp-rate: vslow (5% steps - very gradual)
update-interval: 1000 (1 second between updates)
brightness-smoothing: 0.1 (filter moving objects)
exposure-min: 0.85 (or camera minimum)
exposure-max: 1.24 (or 1/framerate)
gain-min: 0 (cleanest image)
gain-max: 52 (or camera's limit)
ramp-rate: slow or medium
target-brightness: 128-140
gain-max: 52 (or camera limit)
target-brightness: 128
```
**Why these settings:**
- `vslow` ramp rate prevents visible exposure jumps
- 1000ms update interval allows camera hardware to settle
- Brightness smoothing filters transient changes (cars, people)
- Results in smooth, flicker-free time-lapse
### Fast Changing Conditions
```
ramp-rate: fast or vfast
update-interval: 100-500
brightness-smoothing: 0.3-1.0 (more responsive)
compensation: Adjust to preference (-1.0 for darker, +1.0 for brighter)
```
@@ -208,9 +280,18 @@ compensation: Adjust to preference (-1.0 for darker, +1.0 for brighter)
```
gain-max: 20-30 (lower max gain = less noise)
ramp-rate: slow (smoother transitions)
ramp-rate: slow or vslow (smoother transitions)
update-interval: 1000-2000
```
### Avoiding Flickering
If you experience flickering or oscillation:
1. **Increase update-interval**: Start with 1000ms
2. **Decrease ramp-rate**: Use `vslow` or `slow`
3. **Enable brightness-smoothing**: Set to 0.1 or lower
4. **Check your settings**: At 50fps, 100ms updates = every 5 frames (too fast!)
## Troubleshooting
**Filter not adjusting exposure:**
@@ -218,10 +299,22 @@ ramp-rate: slow (smoother transitions)
- Check that camera allows runtime exposure/gain changes
- Ensure `enabled=true` is set
**Flickering or oscillating exposure:**
- **Primary cause:** Update interval too fast for your frame rate
- **Solution:** Increase `update-interval` to 1000ms
- **Also try:** Set `ramp-rate=vslow` and `brightness-smoothing=0.1`
- **At 50fps:** Never use update intervals < 500ms
**Changes too fast/slow:**
- Adjust `ramp-rate` property
- Modify `update-interval` (higher = slower convergence)
- Check `exposure-min`/`exposure-max` range is appropriate
**Brightness oscillates with moving objects:**
- Enable `brightness-smoothing=0.1` to filter transients
- Lower values (0.05) provide even more smoothing
- This filters cars, people, birds while tracking lighting trends
**Brightness not reaching target:**
- Increase `gain-max` to allow more gain
- Increase `exposure-max` if not motion-limited
@@ -241,6 +334,31 @@ ramp-rate: slow (smoother transitions)
| Real-time | Script-based intervals | Frame-by-frame analysis |
| Logging | CSV to SD card | CSV to filesystem |
## Technical Notes
### Flickering Fix (2025)
The original implementation had a critical bug where exposure ramping was not actually implemented - the code would instantly jump to target values instead of gradually ramping. This caused visible flickering, especially with short update intervals.
**Fixed in [`gstintervalometer.c:688-716`](gst/intervalometer/gstintervalometer.c:688-716):**
- Implemented proper gradual ramping using the `ramp_step` variable
- Each update now applies a percentage of the delta (not instant jumps)
- Formula: `current_exposure += (target_exposure - current_exposure) × ramp_step`
### Exposure Range Query Fix
The original implementation used GObject property specs to query exposure limits, which returned incorrect values (0.0 min, DBL_MAX max). This has been fixed to use the IDS uEye SDK directly:
**Changes made:**
- Added IDS SDK header include and camera handle support
- Added `hcam` property to `idsueyesrc` to expose camera handle
- Use `is_Exposure(IS_EXPOSURE_CMD_GET_EXPOSURE_RANGE)` for proper hardware limits
- Result: Proper min/max values (e.g., [0.019 - 19.943] ms) from camera
### Brightness Smoothing
Added Exponential Moving Average (EMA) filtering to handle transient brightness changes from moving objects (cars, people, birds). This prevents exposure oscillation while maintaining responsiveness to actual lighting changes.
## License
This filter is part of gst-plugins-vision and released under the GNU Library General Public License (LGPL).