School of Electronic Engineering, Institute of Engineering, Suranaree University of Technology, 111 University Ave., Muang, Nakhon Ratchasima 30000, Thailand.
Photonics Technology Laboratory, National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahon Yothin Rd., Pathumthai 12120, Thailand.
Sensors (Basel). 2018 Nov 19;18(11):4026. doi: 10.3390/s18114026.
Recent developments in smartphone-based strip readers have further improved the performances of lateral flow test kits. Most smartphone cameras encode an unaltered and nonlinear power-law transfer function that maps the light intensity to a pixel value; this poses some limitations for camera-based strip readers. For faint-color test lines which are almost as white such as with nitrocellulose pads, the slope of the transfer function is low. Therefore, it is difficult to differentiate between the faint test lines and the white background. We show that by manually setting the camera exposure time-instead of using the automatic settings-to the high-slope region of the transfer function, the reader's sensitivity can be improved. We found that the sensitivity and the limit of detection of the subsp. () test kit were enhanced up to 3-fold and 5-fold, respectively, when using the readers at the optimal camera settings, compared to the automatic mode settings. This simple technique can be readily applied to any existing camera-based colorimetric strip reader to significantly improve its performance.
基于智能手机的条带读取器的最新发展进一步提高了侧向流动测试试剂盒的性能。大多数智能手机相机编码一个未经改变的非线性幂律传递函数，将光强度映射到像素值；这对基于相机的条带读取器提出了一些限制。对于几乎与白色一样的浅色测试线，例如硝化纤维素垫，传递函数的斜率较低。因此，很难区分微弱的测试线和白色背景。我们表明，通过手动将相机曝光时间设置为传递函数的高斜率区域（而不是使用自动设置），可以提高读取器的灵敏度。我们发现，与自动模式设置相比，使用优化的相机设置时，（）测试试剂盒的灵敏度和检测限分别提高了 3 倍和 5 倍。这种简单的技术可以很容易地应用于任何现有的基于相机的比色条带读取器，以显著提高其性能。
