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# Image Preprocessing

Prepare raw experimental images by removing background noise and enhancing particle contrast.

## 1. Image Source

### Loading Images

1. Set the Num Cameras (e.g., 4).
2. Set the Project Path for output.
3. Click Load Images from Folder and select the parent directory containing your camera subfolders (e.g., `cam1`, `cam2`...).
4. Use the Frame List table to select a specific frame for preview.
5. Click on the image preview to inspect pixel intensity values.

## 2. Processing Steps

### Background Subtraction

Removes static background features.

- Calculate: Computes the average background image from the dataset.
  - Skip Frames: Interval between sampled frames.
  - Avg Count: Total number of frames to average.
- Enable: Check this box to apply the calculated background subtraction to the preview and final export.

### Intensity Adjustment

Enhance particle visibility.

- Input Range: Use the dual-handle slider to clip low intensities (noise) and saturate high intensities.
- Enhanced Denoise: Applies a LaVision-style denoising filter to smooth graininess while preserving particle edges.

## 3. Preview & Export

### View Modes

Toggle the buttons above the image to switch views:

- Original: Raw input image.
- Processed: Result after background subtraction and intensity adjustment.
- Background: The computed static background image.

Tip: Check the intensity difference between particles and background noise. Based on this difference, set an appropriate `Tracer Intensity Threshold` in Settings → Object. This helps Tracking identify and reconstruct particles more efficiently.

### Batch Processing

1. Click Preview to verify settings on the current frame.
2. Click Process Image (Batch Export) to apply these operations to all images in the sequence and save them to the Project directory.