Bishara Waheb, Su Ting-Wei, Coskun Ahmet F, Ozcan Aydogan
Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA.
Opt Express. 2010 May 24;18(11):11181-91. doi: 10.1364/OE.18.011181.
We demonstrate lensfree holographic microscopy on a chip to achieve approximately 0.6 microm spatial resolution corresponding to a numerical aperture of approximately 0.5 over a large field-of-view of approximately 24 mm2. By using partially coherent illumination from a large aperture (approximately 50 microm), we acquire lower resolution lensfree in-line holograms of the objects with unit fringe magnification. For each lensfree hologram, the pixel size at the sensor chip limits the spatial resolution of the reconstructed image. To circumvent this limitation, we implement a sub-pixel shifting based super-resolution algorithm to effectively recover much higher resolution digital holograms of the objects, permitting sub-micron spatial resolution to be achieved across the entire sensor chip active area, which is also equivalent to the imaging field-of-view (24 mm2) due to unit magnification. We demonstrate the success of this pixel super-resolution approach by imaging patterned transparent substrates, blood smear samples, as well as Caenoharbditis Elegans.
我们展示了一种片上无透镜全息显微镜，在约24平方毫米的大视场范围内实现了约0.6微米的空间分辨率，对应约0.5的数值孔径。通过使用来自大孔径（约50微米）的部分相干照明，我们以单位条纹放大率获取了物体的低分辨率无透镜同轴全息图。对于每个无透镜全息图，传感器芯片上的像素大小限制了重建图像的空间分辨率。为了克服这一限制，我们实施了一种基于亚像素移位的超分辨率算法，以有效恢复物体的更高分辨率数字全息图，从而在整个传感器芯片有源区域实现亚微米空间分辨率，由于单位放大率，该区域也等同于成像视场（24平方毫米）。我们通过对图案化透明基板、血涂片样本以及秀丽隐杆线虫进行成像，证明了这种像素超分辨率方法的成功。
