`charucal preview`¶

The preview command loads a saved calibration file and opens a window showing the real-time top-down view. It is a quick way to verify a calibration result without writing any code.

Usage¶

charucal preview CALIBRATION [OPTIONS]

CALIBRATION is the path to a .json file produced by charucal calibrate.

Input options¶

Option	Description
`--camera SOURCE [SOURCE ...]`	Camera index, video path, or image glob(s). Repeat for each camera (must match the order used during calibration).
`--resolution WIDTHxHEIGHT`	Override resolution for live cameras
`--fps INT`	Override framerate for live cameras

Render options¶

Option	Default	Description
`--output-size WIDTHxHEIGHT`	`720x720`	Maximum output canvas size in pixels
`--front METERS`	`10.0`	Forward render distance in meters
`--lateral METERS`	`5.0`	Lateral render distance in meters (each side)
`--nearest`	off	Use nearest-neighbor interpolation instead of bilinear. Faster but produces blockier edges.

Interactive controls (live mode)¶

Key	Action
`Q` or `Esc`	Close the preview window

Interactive controls (image mode)¶

When you provide image files instead of live cameras, the preview shows one frame set at a time.

Key	Action
`H` or `Left`	Previous frame
`L` or `Right`	Next frame
`Q` or `Esc`	Close the preview window

Examples¶

Live preview with three webcams:

charucal preview calibration.json \
  --camera 0 --camera 1 --camera 2

Custom render distance and output size:

charucal preview calibration.json \
  --camera 0 --camera 1 \
  --front 15 --lateral 7.5 \
  --output-size 1280x720

Preview from recorded images using nearest-neighbor interpolation:

charucal preview calibration.json \
  --camera "frames/cam0/*.jpg" \
  --camera "frames/cam1/*.jpg" \
  --nearest

Notes¶

The camera order passed to --camera must match the order used during calibration. If the output looks misaligned, check that you are not mixing up camera indices. See Troubleshooting for guidance.

charucal preview¶