  The parabolic structure of the secondary or conjugate spectra of pulsars is
often the result of isolated one-dimensional (or at least highly anistropic)
lenses in the ISM. The curvature of these features contains information about
the velocities of the Earth, ISM, and pulsar along the primary axis of the
lens. As a result, measuring variations in the curvature over the course of a
year, or the orbital period for pulsars in binaries, can constrain properties
of the screen and pulsar. In particular the pulsar distance and orbital
inclination for binary systems can be found for multiple screens or systems
with prior information on $\sin(i)$. By mapping the conjugate spectra into a
space where the main arc and inverted arclets are straight lines, we extract
the full coherent information content from the inverted arclet curvatures and
phases using eigenvectors to uniquely and optimally retrieve phase information.
This allows for a higher precision measurement than the standard Hough
transform for systems where these features are available. Our technique also
directly yields the best fit 1D impulse response function for the interstellar
lens given in terms of the Doppler shift, time delay, and magnification of
images on the sky as seen from a single observatory. This can be extended for
use in holographic imaging of the lens by combining multiple telescopes. We
present examples of this new method for both simulated data and actual
observations of PSR B0834+06.
