Imaging via diffuser modulation by translating a sample
An imaging system includes a sample mount for holding a sample to be imaged, a light source configured to emit a light beam to be incident on the sample, a translation mechanism coupled to the sample mount and configured to scan the sample to a plurality of sample positions in a plane substantially perpendicular to an optical axis of the imaging system, a mask positioned downstream from the sample along the optical axis, and an image sensor positioned downstream from the mask along the optical axis. The image sensor is configured to acquire a plurality of images as the sample is translated to the plurality of sample positions. Each respective image corresponds to a respective sample position. The imaging system further includes a processor configured to process the plurality of images to recover a complex profile of the sample based on positional shifts extracted from the plurality of images.
1. An imaging system comprising:
a sample mount for holding a sample to be imaged;
a light source configured to emit a light beam to be incident on the sample;
a translation mechanism coupled to the sample mount and configured to scan the sample to a plurality of sample positions in a plane substantially perpendicular to an optical axis of the imaging system;
a mask positioned downstream from the sample along the optical axis;
an image sensor positioned downstream from the mask along the optical axis, the image sensor configured to acquire a plurality of images as the sample is translated to the plurality of sample positions, each respective image corresponding to a respective sample position; and
a processor configured to process the plurality of images to recover a complex profile of the sample based on positional shifts extracted from the plurality of images.
2. The imaging system of claim 1 , wherein the positional shifts are extracted from the plurality of images using cross-correlation or mutual information among the plurality of images.
3. The imaging system of claim 1 , wherein the sample is scanned in one dimension or two dimensions.
4. The imaging system of claim 1 , wherein the complex profile of the sample comprises an intensity image and a phase image of the sample.
5. The imaging system of claim 1 , wherein the light beam is coherent or partially coherent.
6. The imaging system of claim 1 , wherein the mask is positioned adjacent a top surface of the image sensor.
7. The imaging system of claim 1 , wherein the mask comprises a diffuse pattern formed thereon.
8. The imaging system of claim 7 , wherein a portion of the mask is free of the diffuse pattern.
9. The imaging system of claim 7 , wherein the processor is further configured to process the plurality of images to recover an image of the diffuse pattern.
10. The imaging system of claim 1 , wherein the mask comprises a phase mask.
11. The imaging system of claim 10 , wherein the phase mask comprises a slab of a transparent material with varying thicknesses across a lateral plane perpendicular to the optical axis of the imaging system.
12. The imaging system of claim 11 , wherein the phase mask comprises a wedge-shaped prism.
13. The imaging system of claim 11 , wherein the phase mask is characterized by a multi-step cross section.