CamRuler - Interactive Camera Measurement Tool

CamRuler is a Python application that uses OpenCV to provide live camera-based measurement capabilities. It allows users to measure objects in real-time, both manually by clicking points and automatically by detecting object contours. The tool supports calibration for converting pixel measurements to real-world units (mm, cm, inches) and offers live adjustments for various image processing parameters.

Inspired by the functionality demonstrated in ClaytonDarwin's YouTube channel video on a similar tool.

Features

• Live Camera Feed: Displays video from your webcam.
• Manual Measurement Mode:
  • Click two points on the live feed to draw a line and a bounding box.
  • Displays X (horizontal), Y (vertical), and L (diagonal) lengths.
  • Shows the area of the drawn bounding box.
  • Measurements are displayed in both pixels and selected real-world units.
• Auto Measurement Mode:
  • Automatically detects objects (e.g., coins) using contour detection.
  • Draws bounding boxes around detected objects.
  • Displays Width, Height, Average Dimension, and Area for each detected object in the selected real-world units.
• Calibration Mode:
  • Step-by-step process to calibrate pixel-to-unit conversion.
  • Place a ruler in view and click on known distances from the frame's center.
  • Calibration data is saved to camruler_cal.csv and loaded on startup.
  • Supports non-linear calibration (different scales at different distances from the lens center).
• Live Parameter Adjustments (for Auto Mode & Display):
  • Threshold: Adjust the binary threshold for object detection (Key: T + Mouse L/R).
  • Gaussian Blur: Modify the Gaussian blur kernel size to smooth the image before thresholding (Key: G + Mouse L/R).
  • Min Object Area Percent: Filter out small noise by setting a minimum object size relative to the frame (Key: P + Mouse L/R).
  • Normalize (Brightness/Contrast): Adjust image brightness and contrast (Key: N + Mouse L/R).
• Keyboard Controls:
  • Q: Quit the application.
  • R: Rotate the camera feed by 180 degrees (useful if your camera is mounted upside down).
  • A: Toggle between Manual Measurement Mode and Auto Measurement Mode.
  • C: Enter/Exit Calibration Mode.
  • T: Enter/Exit Threshold adjustment mode (use mouse left/right to adjust, click or press T again to set).
  • G: Enter/Exit Gaussian Blur adjustment mode.
  • P: Enter/Exit Minimum Object Area Percentage adjustment mode.
  • N: Enter/Exit Normalize (brightness/contrast) adjustment mode.
  • U: Cycle through measurement units (mm, cm, inches).
• On-Screen Display (OSD):
  • Camera information (index, resolution, FPS).
  • Coordinates of the last clicked point and current mouse position (in pixels).
  • Current operating mode and values of adjustable parameters.
  • Help text listing available keyboard commands.

Prerequisites

• Python 3.x
• OpenCV (opencv-python)
• NumPy

Installation

1. Clone the repository or download the script (camruler_app.py).
2. Install the required Python libraries:

   pip install opencv-python numpy

3. Ensure you have a webcam connected to your computer.

How to Run

Navigate to the directory containing camruler_app.py in your terminal or command prompt and run:

python camruler_app.py