1. Raspberry Pi Camera for Measuring Bottle Size
C-4P5
Automatic Beer Bottle Filler and Capper
Special Sensor
Aaron Landy
IMDL Fall 2013
October 31, 2013

2. Design and Operation

3. Overview

4. Bottle Detector Objective: Raspberry Pi Camera Processing using OpenCv
Identify bottles in feed line
Estimate volume of bottle for accurate filling
Determine bottle height for positioning capper actuators
Raspberry Pi Camera
Dedicated serial LVDS interface to SoC, no USB interface
Open source drivers from Raspberry Pi Foundation
Processing using OpenCv

5. Bottle Detector Approaches
Simple Filtering and Area
Blob Detection
Inverse Binary thresholding to isolate bottle against background, filter noise
Count pixels for bottle area
Measure longest range of pixels for bottle height
OpenCV SimpleBlobDetector:
Successive binary thresholding
Find contours in binary images to extract connected components
Group keypoint centers across binary images
Estimate blob centers, radii from grouped components

6. Threshold Calibration
Source 24 32 40 48 64 96
12oz
22oz

7. Pixel area Conversion
Area in pixels must be converted to real 2D area measure
Requires calibration calibration based on bottle sizes
Must factor in relative positions of bottle and moving camera
Area
Width
20587 90
22468 96
29708
135

8. Questions ?

9. Motivation Homebrewing is fun, bottling beer is hard
Time consuming process requires individually filling and capping bottles of different shapes and sizes
~50 bottles per 5 gal batch

10. Objectives Fill bottles with precise amounts
Cap bottles securely without breaking
Support inconsistent bottle shapes and sizes
Seek/retrieve bottles automatically
Do not contaminate, oxidize, damage, or waste beer

11. Mechanisms Four primary mechanisms: Bottle searching/retrieving claw
Infrared and bump sensors to locate bottle
Filling tube
Stainless steel tube lowered into bottle
Tube opening must be pressed against bottom of bottle to minimize agitation to prevent oxidation or contamination
Cap retrieving/placing magnet
Caps must be picked up from top of bottle and held during filling
Cap must be replaced precisely on top of bottle
Capping actuator
Forceful linear actuator with capping “bell” crimps/seals cap onto bottle

12. Electronics Raspberry Pi (Model B rev. 2)
Infrared Range Finder and bump to detect bottles
Raspberry Pi Camera module to calculate bottle height and volume
Arduino + Stepper Motors + Motor Driver to drive linear motion axes
Servos to open and close, turn claw