  Detection of phase variations across optically transparent samples is often a
difficult task. We propose and demonstrate a compact, lightweight and low cost
quantitative phase contrast imager. Light diffracted from a pinhole is incident
on a thick object and the modulated light is collected by an image sensor and
the intensity pattern is recorded. Two optical configurations namely lens-based
and lensless cases are compared. A modified phase-retrieval algorithm is
implemented to extract the phase information of the sample at different axial
planes from a single camera shot.
