The electronic pantograph: amplifier couples microscope stage to X-Y plotter

Abstract

A system is described that allows the X-Y movement of a microscope stage to be coupled to the movement of the pen of a X-Y plotter. Linear potentiometers are displaced by any X- or Y-axis movement of the microscope's stage and are connected to a DC amplifier which provides a varying DC voltage to the inputs of a X-Y plotter. The pen of the X-Y plotter becomes yoked to the movement of the stage and it is possible to draw or count the image that is being viewed at magnifications which are independent of those used for observation. The coupling DC amplifier provides a DC offset voltage at all gain settings of the pantograph which is sufficient to reposition the pen of the X-Y plotter in the center of the plotter's platen, regardless of the location of the specimen on the microscope slide. The electronic pantograph overcomes the limitations of a camera lucida, and is well suited for analyzing connectional neuroanatomical material with bright- and darkfield, polarized light or florescent illumination at a reasonable price and without the complexity and hardware requirements of a computerized system.