On Fri, 2010-10-29 at 13:22 -0500, Chris Radek wrote: ... snip > I'm not sure I know the right terminology to describe it, but they use > a second piece of glass with the same pitch (?) lines in front of the > master one. The second glass is at a slight angle so as you watch the > light shining through it as you move the head, there is something like > a moire pattern (?) that makes large areas of light and dark move > perpendicular to the head's motion. It is these lines that are > detected optically. For this reason I doubt there is interpolation. > I bet the lines are the resolution of the device. I think they were > too fine to see by naked eye. > > I bet very basic signal conditioning (thresholding) will be adequate > to read this at full resolution. > > Chris ... snip
Another possibility might be a vernier sensor. Over the span of four in-line sensors, there is a mask with a pitch of the scale pitch -1. This would present a dark region that would travel across the four sensor area. Each sensor would have a peak every scale line to line span/4 of movement. Another thought is that the designers might have tried to allow for variable bulb brightness, so two sets of two sensors are set up to have their peak and valley at the same location so the difference could be used as the signal threshold. How many bulbs are there? -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ Nokia and AT&T present the 2010 Calling All Innovators-North America contest Create new apps & games for the Nokia N8 for consumers in U.S. and Canada $10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store http://p.sf.net/sfu/nokia-dev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
