Webcams

What are Webcams?

Webcams give your robot vision! They capture images that can be processed to detect objects, recognize colors, identify AprilTags, and enable autonomous navigation.

Common uses in FTC:

• 📍 Robot localization with AprilTags
• 🎯 Object detection and tracking
• 🔴 Color-based game element identification
• 📊 Position and distance estimation

Recommended Cameras

Logitech C920/C922

Specifications:

• Resolution: Up to 1920x1080
• Frame rate: 30 FPS at 1080p
• Field of view: 78° diagonal
• Autofocus: Yes
• Price: ~$70-100

Pros:

• Excellent image quality
• Wide availability
• Good low-light performance
• Reliable autofocus

Cons:

• More expensive
• Larger/heavier

Best for: Teams prioritizing detection accuracy and have room/budget

Logitech C270

Specifications:

• Resolution: Up to 1280x720
• Frame rate: 30 FPS at 720p
• Field of view: 60° diagonal
• Autofocus: No
• Price: ~$25-35

Pros:

• Budget-friendly
• Compact and lightweight
• Sufficient for most tasks
• Easy to mount

Cons:

• Lower resolution
• Fixed focus
• Smaller field of view

Best for: Budget-conscious teams, basic detection tasks

ELP USB Cameras

Specifications:

• Resolution: Various (up to 1080p)
• Frame rate: 30-60 FPS
• Field of view: Various lens options
• Customizable: Wide angle, fisheye, etc.

Pros:

• Interchangeable lenses
• Compact module design
• Good value
• Various mounting options

Cons:

• May require tuning
• Variable quality between models
• Less common in FTC

Best for: Custom applications, specific field-of-view needs

Camera Mounting

Mounting Best Practices

1. Stability is Critical

   • Use rigid mounts (no flex!)
   • Secure all screws/fasteners
   • Vibration causes blur

2. Height Considerations

   • Mount at consistent height
   • Consider viewing angle to targets
   • Don't obstruct driver's view

3. Angle and Orientation

   • Face forward for navigation
   • Angle down for ground objects
   • Consider tilting for AprilTags on walls

4. Protection

   • Shield from impacts
   • Protect lens from scratches
   • Consider bumper/guard

Mounting Examples

3D Printed Mounts:

• Custom fit for your camera model
• Lightweight
• Adjustable angle
• Easy to iterate

REV Extrusion Mounts:

• Quick attachment to REV Robotics extrusion
• Adjustable positioning
• Reusable between robots

Cable Management:

• Route USB cable securely
• Strain relief at camera
• Avoid pinch points
• Leave slack for movement

Camera Configuration

Adding Camera to Robot Configuration

1. Connect Camera

   • Plug USB camera into Robot Controller or Control Hub
   • Wait for detection

2. Open Robot Controller App

   • Tap Configure Robot
   • Select your active configuration

3. Add Webcam Device

   • Tap Webcams category
   • Tap Add
   • Select your camera from dropdown
   • Give it a name (e.g., "Webcam 1")

4. Save Configuration

   • Tap Done
   • Tap Save on configuration screen

5. Verify in Code

   WebcamName webcam = hardwareMap.get(WebcamName.class, "Webcam 1");
   // Name must match configuration exactly!

Multiple Cameras

You can use multiple cameras simultaneously:

WebcamName frontCamera = hardwareMap.get(WebcamName.class, "Front Camera");
WebcamName rearCamera = hardwareMap.get(WebcamName.class, "Rear Camera");

// Create separate VisionPortals
VisionPortal frontPortal = new VisionPortal.Builder()
    .setCamera(frontCamera)
    .addProcessor(frontProcessor)
    .build();

VisionPortal rearPortal = new VisionPortal.Builder()
    .setCamera(rearCamera)
    .addProcessor(rearProcessor)
    .build();

Resolution Settings

Choosing Resolution

Recommended: Start with 640x360 or 640x480 for best balance.

visionPortal = new VisionPortal.Builder()
    .setCamera(webcamName)
    .setCameraResolution(new Size(640, 360))  // Set resolution
    .build();

USB Connection

USB Bandwidth

USB 2.0 bandwidth is shared across all devices:

• Control Hub has limited bandwidth
• Multiple cameras share bandwidth
• High resolution uses more bandwidth

Symptoms of bandwidth issues:

• Slow frame rate
• Connection drops
• Poor image quality

Solutions:

• Lower resolution
• Use powered USB hub
• Reduce frame rate

Powered USB Hubs

For multiple cameras or power-hungry devices:

Recommended: REV Robotics Powered USB Hub

• Provides additional power
• Expands USB ports
• Reduces Control Hub load

Setup:

1. Connect hub to Control Hub
2. Power hub from robot's 12V supply
3. Connect cameras to hub

Troubleshooting

Camera Not Detected

Check:

• USB cable connected firmly
• Camera powered (LED on)
• Driver Station app updated
• Try different USB port
• Test with different camera

Poor Image Quality

Solutions:

• Clean lens with microfiber cloth
• Adjust camera position
• Improve lighting
• Disable auto-exposure
• Change resolution

Lag / Slow Frame Rate

Solutions:

• Reduce resolution
• Disable live preview
• Optimize processing pipeline
• Use powered USB hub
• Check CPU usage

Focus Issues

For autofocus cameras (C920/C922):

• Allow time for autofocus to settle
• May need to manually set focus distance
• Consider fixed-focus camera for consistency

For fixed-focus cameras (C270):

• Adjust camera distance to target
• Optimal focus distance varies by camera
• Test at competition distances

Lighting Considerations

Vision processing is highly sensitive to lighting:

Best Practices:

• Add LED strips to robot for consistent lighting
• White LEDs work well for most tasks
• Position lights to illuminate target area
• Test under competition field lighting
• Tune color thresholds for lighting conditions

Avoid:

• Backlighting (target between camera and light)
• Reflections on glossy surfaces
• Shadows on target objects
• Extreme brightness differences

Legal Rules

Always check current FTC game manual for camera rules:

Typically allowed:

• USB webcams
• Standard commercial cameras
• LED lights for illumination

Typically restricted:

• Laser rangefinders
• Active IR projectors (except built-in)
• Radio transmitters
• Excessive brightness (blinding other robots)

Cost Summary

Budget breakdown for vision system:

Next Steps

Ready to program your webcam? Check out:

• Vision Overview - Start here for complete vision guide
• EasyOpenCV Basics - Custom pipeline approach
• VisionPortal - Modern structured approach
• AprilTag Detection - Precise robot localization
• Color Blob Locator - Quick color detection