Field-portable wide-field microscopy of dense samples using multi-height pixel super-resolution based lensfree imaging

• Published in: Lab on a chip Vol. 12; no. 7; pp. 1242 - 1245
• Main Authors: Greenbaum, Alon, Sikora, Uzair, Ozcan, Aydogan
• Format: Journal Article
• Language: English
• Published: England 07.04.2012
• Subjects: Algorithms; Amplitudes; Female; Holograms; Holography; Humans; Imaging; Lenses; Microscopes; Microscopy; Papanicolaou Test; Pixels; Uterine Cervical Neoplasms - diagnosis; Vaginal Smears
• ISSN: 1473-0197; 1473-0189; 1473-0189
• DOI: 10.1039/c2lc21072j

We report a field-portable lensfree microscope that can image dense and connected specimens with sub-micron resolution over a large field-of-view of 30 mm 2 ( i.e. , 6.4 mm 4.6 mm) using pixel super-resolution and iterative phase recovery techniques. Weighing 122 grams with dimensions of 4 cm 4 cm 15 cm, this microscope records lensfree in-line holograms of specimens onto an opto-electronic sensor-array using partially coherent illumination. To reconstruct the phase and amplitude images of dense samples (with >0.3 billion pixels in each image, i.e. , >0.6 billion pixels total), we employ a multi-height imaging approach, where by using a mechanical interface the sensor-to-sample distance is dynamically changed by random discrete steps of e.g. , 10 to 80 m. By digitally propagating back and forth between these multi-height super-resolved holograms (corresponding to typically 25 planes), phase and amplitude images of dense samples can be recovered without the need for any spatial masks or filtering. We demonstrate the performance of this field-portable multi-height lensfree microscope by imaging Papanicolaou smears (also known as Pap tests). Our results reveal the promising potential of this multi-height lensfree computational microscopy platform for e.g. , pathology needs in resource limited settings. We present a field-portable and cost-effective lensfree pixel super-resolution microscope that offers sub-micron resolution over a field-of-view of 30 mm 2 for imaging of dense and connected specimens on a chip.