Several miniaturized viscometers, or microviscometers, have been developed exploiting numerous rapid prototyping techniques. Among them, paper microstrips, famously known as microfluidic paper-based analytical devices ( μ\mu PADs), have become popular due to their cost-efficacy, simple fabrication, fast response, and easily disposable. Many fabrication methods are existing to develop paper microstrips. Herein, an alternative fabrication method is proposed where fused deposition modeling (FDM)-based 3-D printer (3DP) has been employed using polycaprolactone (PCL) filament. F, image processing has been utilized to measure viscosity in such microfluidic domain. Viscosity was calculated by measuring the time taken by the fluid to cover a fixed length between two spots in the microchannel based on the programed and color-coded regions-of-interest. The image processing program was developed considering the change in the gray scale in the virtual region of interests (ROIs) in the microchannel during the fluid flow in the paper microstrips. A 3-D printed handheld platform, containing raspberry pi with on-board camera and display, was developed to execute the image processing and automate the entire work flow. In the proposed device, the accuracy was measured to be >92%.

中文翻译：

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具有 3D 打印纸微带的自动化迷你平台，用于基于图像处理的生物样品粘度测量


已经利用多种快速原型技术开发了几种小型粘度计或微粘度计。其中，纸微带，被称为微流控纸基分析装置（μ\mu PAD），由于其成本效益、制造简单、响应速度快且易于一次性而变得流行。现有许多制造方法来开发纸微带。在此，提出了一种替代制造方法，其中使用聚己内酯（PCL）灯丝采用基于熔融沉积建模（FDM）的3D打印机（3DP）。 F，图像处理已被用来测量这种微流体域中的粘度。根据编程和颜色编码的感兴趣区域，通过测量流体覆盖微通道中两个点之间的固定长度所需的时间来计算粘度。图像处理程序的开发考虑了纸微带中流体流动期间微通道中虚拟感兴趣区域（ROI）的灰度变化。开发了一个 3D 打印手持平台，其中包含带有板载摄像头和显示屏的树莓派，用于执行图像处理并自动化整个工作流程。在所提出的设备中，测得准确度为 >92%。