Both Owen and I were in Rochester in the mid 70’s. Owen was a Xerox and I was at the U of Rochester. We were working with the same people but somehow never met.
In the early 80’s I did some consulting with National Computing Systems. They made the machines that read and scored standardized tests, the ones in which you answered by darkening little circles with a pen or pencil. The machines were very much like copiers and had many of the same problems with papers. The way they worked was that as the paper was passed through the system it went through a pairs of leds and photo detectors that would sense if a circle was filled. You remember that on these kinds of test all the circles had to be lined up vertically so as to match the positions of the sensors on the scoring machine.
The nature of paper, as described in the New Yorker article posed some interesting problems. First, paper is noisy. When you shine light though , you can see this, so the scoring can get messed up with cheap paper. But the big problems were due the thermal properties of paper and lawyers. Paper expands and contracts with temperature. Under high temperature, the paper can expand so much that the circles may not be line up with the sensors and the test will be scored incorrectly. At that time, California gave all its standard tests using these machines. The state was faced with a number of lawsuits from parents contending that their kids’ test were misscored, which occasionally was true due due to thermal expansion of the test paper. The state would up deciding to warehouse all tests so they would be available for inspection. It was costing them quite a bit so NCS was designing a better machine, which was what I was consulting about. The solution had much in common with copiers and used a one-dimensional scanner the width of page that could read across the paper as it flowed by. With that, the computer could detect filled/unfilled circles even if the page expanded or contracted.
Ed
_______________________
Ed Angel
Founding Director, Art, Research, Technology and Science Laboratory (ARTS Lab)
Professor Emeritus of Computer Science, University of New Mexico
1017 Sierra Pinon
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