Development of a vision-based pH reading system

• Published in: Journal of the Korean Physical Society Vol. 67; no. 8; pp. 1448 - 1453
• Main Authors: Hur, Min Goo, Kong, Young Bae, Lee, Eun Je, Park, Jeong Hoon, Yang, Seung Dae, Moon, Ha Jung, Lee, Dong Hoon
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Physical Society 01.10.2015; 한국물리학회
• Subjects: Mathematical and Computational Physics; Particle and Nuclear Physics; Physics; Physics and Astronomy; Theoretical; 물리학; pH; Radiopharmaceutical; Vision; Quality control
• ISSN: 0374-4884; 1976-8524
• DOI: 10.3938/jkps.67.1448

pH paper is generally used for pH interpretation in the QC (quality control) process of radiopharmaceuticals. pH paper is easy to handle and useful for small samples such as radio-isotopes and radioisotope (RI)-labeled compounds for positron emission tomography (PET). However, pHpaper-based detecting methods may have some errors due limitations of eye sight and inaccurate readings. In this paper, we report a new device for pH reading and related software. The proposed pH reading system is developed with a vision algorithm based on the RGB library. The pH reading system is divided into two parts. First is the reading device that consists of a light source, a CCD camera and a data acquisition (DAQ) board. To improve the accuracy of the sensitivity, we utilize the three primary colors of the LED (light emission diode) in the reading device. The use of three colors is better than the use of a single color for a white LED because of wavelength. The other is a graph user interface (GUI) program for a vision interface and report generation. The GUI program inserts the color codes of the pH paper into the database; then, the CCD camera captures the pH paper and compares its color with the RGB database image in the reading mode. The software captures and reports information on the samples, such as pH results, capture images, and library images, and saves them as excel files.