PhotoMetrix and colorimetric image analysis using smartphones

Abstract

The steady advances in technology employed in smartphones, coupled with the high availability and the ease access to these devices, increased the interest in applying it to analytical purposes. The main goal is to develop simple, fast, and low-cost analytical methods, generating immediate results. Different analytical strategies using smartphones have been proposed to identify or determine different analytes in a wide range of matrices. Some of them use the smartphone to capture the images, to process them, and to provide the analytical results. Others use this device just for image acquisition. In this context, this review aimed to relate previous works that used smartphones to acquire images for analytical purposes, with a special focus on PhotoMetrix application, which is a tool for chemical analysis. This application allows the decomposition of digital images acquired by smartphone cameras and to process them within the same device, allowing in situ chemical analysis.

Current Challenges and Future Trends of Enzymatic Paper-Based Point-of-Care Testing for Diabetes Mellitus Type 2

“…The accelerated advancement in smartphone optical technology and their wide availability make them very attractive candidates for application in imaging and processing coupled to POC test platforms, especially those based on colorimetric methods. To exploit the capabilities of these devices, applications designed to detect signals and allow their processing on the same device, even allowing a preliminary analysis of the results, have been reported [ 1 , 38 ]. An example of this is “Glucosensing”, explicitly designed for glucose detection [ 39 ].…”

Classification of ballpoint pen inks based on selective extraction and subsequent digital color and cluster analyses

“…23 The cost-efficiency of both the equipment needed to perform the analysis and the analysis itself can nowadays be achieved through the use of inexpensive reading devices: scanners, 24 digital cameras 25 and even smartphones. [26][27][28][29] The digital color analysis finds application both in the analysis of solutions for the content of colored compounds per se and in tandem with optical sensor devices. Despite the active development of the DCA method and its wide application for chemical, 30 medical, 25,31,32 food, 33,34 and forensic 35,36 analysis, there are only pilot studies on the use of DCA for the analysis of the coloring components of pen inks.…”

Smartphone-based digital image colorimetry for the determination of vancomycin in drugs

“…Various apps for different types of smartphone-based detection in chemical analysis were developed [25]. One of the mobile tools for colorimetric analysis is the application PhotoMetrix with further extensions PhotoMetrix PRO ® and PhotoMetrix UVC ® [32,38]. These applications allow the decomposition of digital images recorded by the smartphone camera and their processing in the same device, enabling detection without the need to use additional computer equipment.…”

“…The analytical signal was measured for a single channel. Methods based on the use of multivariate analysis, including Principal Component Analysis (PCA) and Partial Least Squares (PLS) were also developed [32,38].…”