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Klaus requires a camera to see the pages you’re reading. These settings control camera device selection, image resolution, and automatic rotation.

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Camera Device

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camera_index
integer
default:"0"
Index of the camera device to use.Default: 0 (first camera detected by the system)If you have multiple cameras, you can select which one Klaus uses:
  • 0 = First camera
  • 1 = Second camera
  • 2 = Third camera, etc.
Use Klaus’s Settings dialog to see a list of available cameras and select the correct one. The index will be saved automatically.

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Resolution

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camera_width
integer
default:"1920"
Camera capture width in pixels.Default: 1920 (Full HD width)
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camera_height
integer
default:"1080"
Camera capture height in pixels.Default: 1080 (Full HD height)
Klaus defaults to 1920×1080 (1080p) for optimal text clarity. Lower resolutions may reduce OCR accuracy for small text.

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Supported Resolutions

Common resolution presets:
ResolutionWidthHeightNotes
1080p (default)19201080Best quality, recommended
720p1280720Good quality, faster
480p640480Low quality, not recommended
Your camera must support the specified resolution. If the camera doesn’t support the configured resolution, OpenCV will fall back to the closest available resolution.

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Rotation

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camera_rotation
string
default:"auto"
How to rotate camera frames before sending to Claude.Options:
  • auto: Automatically rotate portrait frames to landscape (default)
  • none: No rotation, use image as-is
  • 90: Rotate 90° clockwise
  • 180: Rotate 180°
  • 270: Rotate 270° clockwise (same as 90° counter-clockwise)
Auto-rotation behavior:
  • Detects portrait orientation (height > width)
  • Rotates 90° clockwise to landscape
  • Useful for phone cameras in portrait mode

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When to Use Each Setting

SettingUse Case
autoPhone camera or any camera that might be in portrait orientation
noneDocument camera or webcam that’s always landscape
90Image is rotated 90° and auto-detection fails
180Camera is upside-down
270Image is rotated 270° and auto-detection fails

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Example Configuration

config.toml
# Use second camera at 720p with auto-rotation
camera_index = 1
camera_width = 1280
camera_height = 720
camera_rotation = "auto"

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Camera Setup Recommendations

USB document cameras (also called visualisers) provide the best experience:
  • Stable mounting
  • Good lighting (many have built-in lights)
  • Clear view of the full page
  • 1080p or higher resolution
Example: PAKOTOO Document Camera (~$50-70)

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Phone as Camera

You can use your phone as a webcam with a gooseneck mount ($10-15):
PlatformAppNotes
macOS + iPhoneContinuity CameraBuilt-in, no install needed (iOS 16+, macOS Ventura+)
macOS + AndroidCamoFree, 1080p, install on phone + Mac
Windows + AndroidDroidCamFree, connect via Wi-Fi or USB
Windows + iPhoneCamoFree, 1080p, install on phone + PC
Point the camera straight down at your reading surface for best results. Klaus auto-rotates portrait orientation.

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Platform-Specific Notes

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macOS

  • Camera names use AVFoundation for friendly display names (e.g., “FaceTime HD Camera” instead of “device 0”)
  • Klaus automatically detects and displays all connected cameras in the Settings dialog

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Windows

  • Uses DirectShow (DSHOW) backend for camera access
  • Camera enumeration may show generic names like “USB Camera” or “Integrated Webcam”

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Camera Preview

Klaus displays a live camera preview in the main window at approximately 30 FPS:
  • The preview helps you position your document correctly
  • Frame capture for Claude happens on-demand when you ask a question
  • Preview and capture use the same resolution settings

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Troubleshooting

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Camera Not Detected

  1. Check physical connection: Ensure the camera is plugged in via USB
  2. Check system permissions:
    • macOS: Grant camera access in System Settings → Privacy & Security → Camera
    • Windows: Grant camera access in Settings → Privacy → Camera
  3. Try a different USB port: Some USB hubs may not provide enough power
  4. Restart Klaus: Camera devices may not be detected if connected after Klaus starts

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Wrong Camera Selected

  1. Open Klaus Settings dialog
  2. Go to Camera tab
  3. Select the correct camera from the dropdown
  4. Settings are applied immediately and saved to config.toml

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Image is Rotated Incorrectly

  1. Try auto mode first: This handles most portrait/landscape cases
  2. If auto fails: Manually set rotation to 90, 180, or 270
  3. Test rotation: Check the camera preview to confirm correct orientation

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Poor Image Quality / Blurry Text

  1. Check resolution: Ensure you’re using at least 1280×720 (720p)
  2. Adjust camera focus: Some document cameras have manual focus rings
  3. Improve lighting: Add more light or use a camera with a built-in light
  4. Clean the lens: Fingerprints or dust can reduce clarity
  5. Check camera distance: Position the camera close enough to read small text

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Camera Settings Not Saved

  • Camera index is saved immediately when changed in the Settings dialog
  • Manual edits to config.toml require a Klaus restart to take effect
  • Check file permissions on ~/.klaus/config.toml

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