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

Design and Operation

Overview

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

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

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

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

Questions ?

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

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

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

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