Sataporn Chanhorm

Highly accurate and fast optical penetration-based silkworm gender separation system

Based on our research work in the last five years, this paper highlights our innovative optical sensing system that can identify and separate silkworm gender highly suitable for sericulture industry. The key idea relies on our proposed optical penetration concepts and once combined with simple image processing operations leads to high accuracy in identifying of silkworm gender. Inside the system, there are electronic and mechanical parts that assist in controlling the overall system operation, processing the optical signal, and separating the female from male silkworm pupae. With current system performance, we achieve a very highly accurate more than 95% in identifying gender of silkworm pupae with an average system operational speed of 30 silkworm pupae/minute. Three of our systems are already in operation at Thailand’s Queen Sirikit Sericulture Centers.

Development and Beam-Shape Analysis of an Integrated Fiber-Optic Confocal Probe for High-Precision Central Thickness Measurement of Small-Radius Lenses

This work describes a new design of a fiber-optic confocal probe suitable for measuring the central thicknesses of small-radius optical lenses or similar objects. The proposed confocal probe utilizes an integrated camera that functions as a shape-encoded position-sensing device. The confocal signal for thickness measurement and beam-shape data for off-axis measurement can be simultaneously acquired using the proposed probe. Placing the probe’s focal point off-center relative to a sample’s vertex produces a non-circular image at the camera’s image plane that closely resembles an ellipse for small displacements. We were able to precisely position the confocal probe’s focal point relative to the vertex point of a ball lens with a radius of 2.5 mm, with a lateral resolution of 1.2 µm. The reflected beam shape based on partial blocking by an aperture was analyzed and verified experimentally. The proposed confocal probe offers a low-cost, high-precision technique, an alternative to a high-cost three-dimensional surface profiler, for tight quality control of small optical lenses during the manufacturing process.

Fault-tolerant optical-penetration-based silkworm gender identification

Fault-tolerant optical-penetration-based silkworm gender identification is proposed.The key idea lies in the use of dual wavelength illumination.Female pupa can be identified with 26.38ms and accuracy of 92.5% for white light.Silkworms, whose gender are still unknown, are investigated again under red light.The total accuracy is improved to 98% with a slower response time of 53ms. This paper proposes and experimentally demonstrates a fault-tolerant optical-penetration-based silkworm gender identification. The key idea lies in the exploitation of the inherent dual wavelength of white and red light illumination. In particular, the image of the posterior area of the silkworm pupa created under white light is not only transformed into an optical region-of-interest but also is used for pinpointing the female silkworm pupa, thus speeding up the identification time twice. For the male and unidentified female silkworm pupae, their images are later on analyzed under red light illumination, implying fault-tolerant operation of the system. Other important features include low cost, ease of implementation, and simplicity in terms of process control. Experimental demonstration shows a highly accurate 92.5% in identifying female silkworm pupae with a faster average system speed of 26.38ms under white light illumination. Under red light illumination, the remaining male and unidentified female silkworm pupae are clarified with an improved accuracy of 98.9% and the total average analytical time of 53.50ms.

Fiber-optic confocal probe with an integrated real-time apex finder for high-precision center thickness measurement of ball lenses

This paper describes the development of a fiber-optic confocal probe suitable to measuring the central thickness of highcurvature small-diameter optical ball lenses. The confocal probe utilizes an integrated camera that functions as a realtime apex-sensing device. An additional camera is used to monitor the shape of the reflected light beam. Placing the instrument sensing spot off-center from the apex will produce a non-circular image at the camera plane that closely resembles an ellipse for small displacement. By analyzing the shape of the reflected light spot, we are able to precisely determine the focus point of the confocal probe relative to the apex point to better than 2-μm precision for ball lenses with diameters in the range of 3 – 10 mm. The proposed confocal probe offers a low-cost alternative technique for quality control of ball lenses during the manufacturing process.

Mobile-platform for automatic fever screening system based on infrared forehead temperature

In this paper, automatic fever screening system is proposed and experimentally implemented using an IR camera and a mobile phone. Our system locates position of patients automatically using face detection algorithm on RGB image and obtains temperature from IR image at detected location. Advantages are fast, portable, non-contacting and simultaneously temperature measurement. Furthermore, face detection algorithm allows the system to track patients face position. Hence, robust and non-contacting temperature measurement can be properly done even patients are not stand still. Our system has been field-tested to measure temperature and screen ill patients at a children medical clinic. In this experiment, the system is calibrated to measure temperature of patients at 1 meter away and gives an alarm sound when the measured temperature is above the desired setting threshold. According to experimental results, the correlation coefficient between temperature obtained from our system and commercial infrared forehead skin thermometer [2] is more than 0.80. In addition, our system achieves a 100% sensitivity and 70% specificity. Although our approach loses specificity, all fever patients are identified correctly. Thus, they are significantly correlated. Therefore, this system can reliably estimate body temperature of patients and can be used for effectively pre-screening fever patients.

Erratum: Sutapun, B. et al. Development and Beam-Shape Analysis of an Integrated Fiber-Optic Confocal Probe for High-Precision Central Thickness Measurement of Small-Radius Lenses. Sensors, 2015, 15, 8512-8526

The source of the funding of this work disclosed on the published paper [1] was incorrect. The authors would like to correct the acknowledgements of this article as follows: Acknowledgments: This work was funded by Suranaree University of Technology’s research and development fund. The authors would like to apologize for any inconvenience this may have caused to the readers.

Design and implementation of a portable TEC-based heat-to-electricity converting module

Converting infrared radiation in the form of heat into electricity is one of the interesting energy conversion approaches. This can be simply accomplished through thermoelectric effect with the well-known device called thermoelectric cooler (TEC). In this paper, we briefly overview TEC-based concepts, demonstrations, and products for converting heat into electricity. We then propose our own portable TEC-based heat-to-electricity converting module. Experimental proof of concept is also highlighted showing a promising output voltage of 5VDC and 0.224A suitable for low voltage applications. Future work relates to design optimization, engineering improvement, and testing in real world scenario.

Tablet-based two-dimensional measurement for estimating the embryo area of brown rice

The embryo or germ of a rice seed is growing to the shoot and the root parts of a seedling. In the early stage, the germinated embryo directly receives food from the endosperm. How healthy of the seedling can be physically predicted by measuring the areas of the embryo and endosperm. In this work, we show for the first time how the embryo and endosperm areas of a brown rice can be spatially measured. Our key design is based on the utilization of a tablet equipped with our lens module for capturing the rice seed image under white light illumination. Our Windows-based program is developed to analyze and separate the image of the whole brown rice into the embryo and endosperm parts within 2 seconds per seed. Our tablet-based system is just 30×30×6 cm3 with 1 kilogram in weight, capable to easily carry to perform in the field.

Portable optical dimensions analyzer for rice grains

Dimensions of grains are important factors in evaluating the physical quality of the grains. In this work, we show for the first time that the thickness, the width, and the length of rice grains can be simultaneously measured. Rather than imaging rice grains only above from a two-dimensional plane, our key idea is to insert a tilt reflective surface on the measuring plane such that the side view of the rice grains can be observed at the same time. Demonstration from our prototype shows a very promising result in determining the thickness, the width, and the length of the rice grain with maximum values of 2.20 mm, 3.65 mm, and 10.27 mm, respectively. It offers a very high average resolution of 22 μm and a measured response time of 205 ms. Additional key features include low cost, low components count, and ease of implementation.

Lessons learned from primary school students with photonics learning-by-playing approach

We encourage primary school students in the grades 4-6 to challenge themselves on exploring light in everyday life. At the beginning, we bring in the critical-thinking approach where we use open-ended questions in applications of photonics around them. Later on, we engage them to our photonics lessons via our “Long Len” photonics kit. With our educational kit, we observe that most students in 21 schools from different parts of Thailand are amazed about photonics. They try to play with our kit in their ways, enjoy learning with their friends, and give us back many interesting questions. Based on their evaluations on our approach, 90-98% of them understand more about topics they already know. They also gain new knowledge and can see how it is applied to everyday life. The remaining percentage relates to students who are shy to interact with us.