Autofocusing and edge detection schemes in cell volume measurements with quantitative phase microscopy

• Published in: Optics express Vol. 17; no. 8; pp. 6476 - 6486
• Main Authors: Lee, Seungrag, Lee, Ji Yong, Yang, Wenzhong, Kim, Dug Young
• Format: Journal Article
• Language: English
• Published: United States 13.04.2009
• Subjects: Algorithms; Artificial Intelligence; Cell Size; Cells, Cultured; Erythrocytes - cytology; Erythrocytes - physiology; Humans; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Imaging, Three-Dimensional - methods; Microscopy, Phase-Contrast - methods; Pattern Recognition, Automated - methods; Reproducibility of Results; Sensitivity and Specificity
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.17.006476

We have proposed and demonstrated a very sensitive volume measurement scheme for a live cell with a quantitative phase microscopy (QPM) utilizing auto-focusing and numerical edge detection schemes. An auto-focusing technique with two different focus measures is applied to find the focus dependent errors in our live cell volume measurement system. The volume of a polystyrene bead sample with 3 mum diameter has been measured for the validity test of our proposed method. We have shown that a small displacement of an object from its focusing position can cause a large volume error. A numerical edge detection technique is also used to accurately resolve the boundary between a cell and its suspension medium. We have applied this method to effectively suppress errors by the surrounding medium of a single red blood cell (RBC).