And the minor but difficult to engineer, is the optical path parallel to the spindle axis
Also look for the term telecentric lens, http://www.opto-engineering.com/resources/telecentric-lenses-tutorial Dave Caroline On 07/11/2013, Sebastian Bachmann <[email protected]> wrote: > The problem ist that the terms high magnification and depth of field does > not fit well together. > > if you take a look at the equations for optical systems you see that there > are lot of equations for DOF: > http://en.wikipedia.org/wiki/Depth_of_field#DOF_formulas > > the problem is now if you need a decent DOF, lets say 2mm and you are > 200mm away from your workpiece and you want a resoltion of x mm/pixel you > can do the math and will see that this will not work out quite well.. > you can tweak it by using a small sensor diagonal (which will cause to > have a low circle of confusion) and high aperture (which will cause a > better hyperfocal distance on large focal length (see that f goes with the > square in that particular formular!)) - but that will of course decrease > your resolution and increase your need for good light setup. > > -sebastian > > > On Thu, 7 Nov 2013 11:15:41 +0000 (GMT), [email protected] (Russell > Brown) wrote: >> I've been playing around with camview and a little 10mm endoscope type >> USB camera to see if I could rig such a thing up as an edge finder >> permanently mounted my mill's head. >> >> That's OK but you have to get very very close to the workpiece for even >> a half decent resolution which doesn't work when there's a collett >> holder and tool in the spindle (part of the reason for doing this is to >> avoid chucking the edge finder so I don't want a spindle type camera). >> >> I also tried a USB 'microscope' but the depth of field is very small >> again you have to get pretty close and twiddle with the focus to get a >> useful resolution. >> >> Has anyone found a USB camera with both a high magnification and a >> decent depth of field? (I've a feeling that these are mutually >> exclusive) or even one that can focus at a high resolution from a >> workable (~200mm?) distance? >> >> TIA > > ------------------------------------------------------------------------------ > November Webinars for C, C++, Fortran Developers > Accelerate application performance with scalable programming models. > Explore > techniques for threading, error checking, porting, and tuning. Get the most > > from the latest Intel processors and coprocessors. See abstracts and > register > http://pubads.g.doubleclick.net/gampad/clk?id=60136231&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ November Webinars for C, C++, Fortran Developers Accelerate application performance with scalable programming models. Explore techniques for threading, error checking, porting, and tuning. Get the most from the latest Intel processors and coprocessors. See abstracts and register http://pubads.g.doubleclick.net/gampad/clk?id=60136231&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
