Lee Seung Ah, Yang Changhuei
Department of Electrical Engineering, California Institute of Technology, 1200 E. California Blvd. Pasadena, CA 91125, USA.
Lab Chip. 2014 Aug 21;14(16):3056-63. doi: 10.1039/c4lc00523f.
Portable chip-scale microscopy devices can potentially address various imaging needs in mobile healthcare and environmental monitoring. Here, we demonstrate the adaptation of a smartphone's camera to function as a compact lensless microscope. Unlike other chip-scale microscopy schemes, this method uses ambient illumination as its light source and does not require the incorporation of a dedicated light source. The method is based on the shadow imaging technique where the sample is placed on the surface of the image sensor, which captures direct shadow images under illumination. To improve the image resolution beyond the pixel size, we perform pixel super-resolution reconstruction with multiple images at different angles of illumination, which are captured while the user is manually tilting the device around any ambient light source, such as the sun or a lamp. The lensless imaging scheme allows for sub-micron resolution imaging over an ultra-wide field-of-view (FOV). Image acquisition and reconstruction are performed on the device using a custom-built Android application, constructing a stand-alone imaging device for field applications. We discuss the construction of the device using a commercial smartphone and demonstrate the imaging capabilities of our system.
便携式芯片级显微镜设备有潜力满足移动医疗保健和环境监测中的各种成像需求。在此，我们展示了如何将智能手机的摄像头改装成紧凑型无透镜显微镜。与其他芯片级显微镜方案不同，该方法使用环境光作为光源，无需集成专用光源。该方法基于阴影成像技术，即将样品放置在图像传感器表面，图像传感器在光照下捕获直接的阴影图像。为了将图像分辨率提高到超过像素尺寸，我们在用户围绕任何环境光源（如太阳或灯）手动倾斜设备时，以不同照明角度拍摄多张图像进行像素超分辨率重建。这种无透镜成像方案能够在超宽视野（FOV）上实现亚微米分辨率成像。图像采集和重建在设备上使用定制的安卓应用程序进行，构建了一个用于现场应用的独立成像设备。我们讨论了使用商用智能手机构建该设备的方法，并展示了我们系统的成像能力。
