Precinct Ballot Counter

Precinct Ballot Counter

Background

The Precinct Ballot Counter (PBC) device is used in a polling place, to scan a paper ballot for errors (e.g., over-votes, possible under-votes), and if error-free to retain the data from the ballot, for tabulation (since typically a scanned ballot goes immediately into a secured ballot box.)

The PBC device is comprised of

1. application-specific software (contained on a boot disk created by the Device Manager) and
2. hardware that includes a commercial off-the-shelf (“COTS”) optical scanning device.

The PBC uses a COTS scanner to provide the functions of a conventional Precinct Count Optical Scan (PCOS) device. Each “duty cycle” of the PBC software begins when the scanner provides a ballot image to be processed. The PBC software performs digital image processing to find marks in target areas (specified in the election-specific configuration data) and maps the marks to election-specific interpretations of contests, candidate, choices, etc. Apparent over-votes and under-votes are identified and handled in a typical manner for PCOS systems.

At the end of session (typically a full election day of service in a precinct or voting center or early voting center), the PBC produces vote tallies for each contest, and audit logs that include each ballot image and the interpretation of the image, together with records of over/under-votes, under-vote overrides, etc.

All of this information is written out on write-once removable media that, together with the paper ballots, comprise the election evidence from the precinct that is subject to chain of custody requirements. No election information is retained on the hardware; just as the hardware starts out empty before the system is started from the boot disk, the hardware remains empty after the PBC software has finished executing.

Ballot Scanning

A sub-problem is how to interpret the image of a ballot as scanned by some kind of scanning device. In other words, we create an image, in the form, for example of a TIF file, of a ballot. Now we need to figure out which candidates got votes, whether the ballot is properly voted, and so on. For this we turn to image processing.

Progress Report

This paper reports on results of our the prototyping and experimental work on the scanning and image analysis of ballots. For these experiments we used a very common ballot design, but we are confident that the same results would be ob- tained with other kinds of ballots. Here is the full progress report on that work: Progress Report on Scanning and Scoring Ballots