UCLA Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA.
Lab Chip. 2011 Jul 7;11(13):2222-30. doi: 10.1039/c1lc20127a. Epub 2011 May 16.
We present a field-portable lensfree tomographic microscope, which can achieve sectional imaging of a large volume (∼20 mm(3)) on a chip with an axial resolution of <7 μm. In this compact tomographic imaging platform (weighing only ∼110 grams), 24 light-emitting diodes (LEDs) that are each butt-coupled to a fibre-optic waveguide are controlled through a cost-effective micro-processor to sequentially illuminate the sample from different angles to record lensfree holograms of the sample that is placed on the top of a digital sensor array. In order to generate pixel super-resolved (SR) lensfree holograms and hence digitally improve the achievable lateral resolution, multiple sub-pixel shifted holograms are recorded at each illumination angle by electromagnetically actuating the fibre-optic waveguides using compact coils and magnets. These SR projection holograms obtained over an angular range of ±50° are rapidly reconstructed to yield projection images of the sample, which can then be back-projected to compute tomograms of the objects on the sensor-chip. The performance of this compact and light-weight lensfree tomographic microscope is validated by imaging micro-beads of different dimensions as well as a Hymenolepis nana egg, which is an infectious parasitic flatworm. Achieving a decent three-dimensional spatial resolution, this field-portable on-chip optical tomographic microscope might provide a useful toolset for telemedicine and high-throughput imaging applications in resource-poor settings.
我们展示了一种便携的无透镜断层显微镜，它可以在芯片上对大约 20mm3 的大体积进行截面成像，轴向分辨率小于 7μm。在这个紧凑的断层成像平台（重量仅约 110 克）中，24 个发光二极管（LED）每个都与光纤波导对接，通过一个具有成本效益的微处理器进行控制，从而从不同角度顺序照明样品，记录放置在数字传感器阵列顶部的样品的无透镜全息图。为了生成像素超分辨率（SR）无透镜全息图，并因此在数字上提高可实现的横向分辨率，通过使用紧凑的线圈和磁铁对光纤波导进行电磁驱动，在每个照明角度记录多个亚像素移位的全息图。在 ±50°的角度范围内获得的这些 SR 投影全息图被快速重建，以生成样品的投影图像，然后可以对这些图像进行反向投影，以计算传感器芯片上物体的断层扫描图像。通过对不同尺寸的微珠以及一种感染性寄生扁形虫 Hymenolepis nana 卵进行成像，验证了这种紧凑轻便的无透镜断层显微镜的性能。该显微镜实现了相当好的三维空间分辨率，可能为远程医疗和资源匮乏环境下的高通量成像应用提供了有用的工具集。
