SpareChange

*Bundle identifier = edu.usc.acm.app7897897

Overview

The idea behind SpareChange is to find out the value of your spare change with a single photo. Simply turn out your pockets or empty your piggy-bank onto a table, take a picture, calibrate, and let the app figure out how much money has actually been collecting in your back pocket or under your couch.

Features

Image recognition of common U.S. hard currency.

Automatic shape detection and size classification.

Steps

1. Lay out your coins on a flat surface. For best results, make sure no coins overlap.
2. Take a picture of the coins from directly overhead. Try to keep the phone level with the ground.
3. Resize a circle to approximately match the size of one quarter.
4. Press the Calculate button.
5. Confirm the colorized coin classification (change any incorrect matches).
6. See how much your spare change is worth!

Design

Screens

Data

Data information goes here

Algorithms

Hough Circle Detection algorithm – ported from Java

— Needs inital radius value (solved during user calibration)

Simple iPhone image processing library – for inital image conversion, optimization, and pixel access

Possible thoughts

Accelerometer data during image capture to prevent or correct for tilted pictures

Color information

Ignore irrelevant objects

Possible goals

Multiple currencies/languages

Automatic coin detection (easier calibration)

Random facts about your coins:

• Weights
• Savings per year
• What you can buy
• Donate change amount to a charity