Search Results (3)

The present study proposes a fiducial marker for location systems that uses computer vision. The marker employs a set of tape-shaped markers that facilitate their positioning in the environment, allowing continuous reading to cover the entire perimeter of the environment and making it possible to minimize interruptions in the location service. Because the marker is present throughout the perimeter of the environment, it presents hierarchical coding patterns that allow it to be robust against multiple detection scales. We implemented an application to help the user generate the markers with a floor plan image. We conducted two types of tests, one in a 3D simulation environment and one in a real-life environment with a smartphone. The tests made it possible to measure the performance of the tape-shaped marker with readings at multiple distances compared to ArUco, QRCode, and STag with detections at distances of 10 to 0.5 m. The localization tests in the 3D environment analyzed the time of marker detection during the journey from one room to another in positioning conditions (A) with the markers positioned at the baseboard of the wall, (B) with the markers positioned at camera height, and (C) with the marker positioned on the floor. The localization tests in real conditions allowed us to measure the time of detections in favorable conditions of detections, demonstrating that the tape-shaped-marker-detection algorithm is not yet robust against blurring but is robust against lighting variations, difficult angle displays, and partial occlusions. In both test environments, the marker allowed for detection at multiple scales, confirming its functionality. Full article

Using a single RGB camera to obtain accurate body dimensions, rather than measuring these manually or via more complex multicamera systems or more expensive 3D scanners, has a high application potential for the apparel industry. We present a system that estimates upper human body measurements using a hybrid set of techniques from both classic computer vision and recent machine learning. The main steps involve (1) using a camera to obtain two views (frontal and side); (2) isolating in the image pair a set of main body parts; (3) improving the image quality; (4) extracting body contours and features from the images of body parts; (5) indicating markers on these images; (6) performing a calibration step; and (7) producing refined final 3D measurements. We favour a unique geometric shape, that of an ellipse, to approximate human body main horizontal cross-sections. We focus on the more challenging parts of the body, i.e., the upper body from the head to the hips, which, we show, can be well represented by varying an ellipse’s eccentricity for each individual. Then, evaluating each fitted ellipse’s perimeter allows us to obtain better results than the current state-of-the-art methods for use in the fashion and online retail industry. In our study, we selected a set of two equations, out of many other possible choices, to best estimate upper human body section circumferences. We experimented with the system on a diverse sample of 78 female participants. The results for the upper human body measurements in comparison to the traditional manual method of tape measurements, when used as a reference, show ±1 cm average differences, which are sufficient for many applications, including online retail. Full article

In the conventional real-time polymerase chain reaction (RT-PCR) technique, DNA amplification is confirmed by quantitatively analyzing the increase in the fluorescence brightness using a fluorescent label. However, when using a fluorescence label-based technology, an optical structure enabling the accurate and expensive fluorescence detection is required, and the pretreatment of the sample is required to attach a visible fluorescence marker. In order to overcome this problem, many technologies have been studied for label-free detection using electrical sensors. Impedance has the characteristic of being highly correlated with the concentration of the sample solution and the fragment length of the DNA. If a change in the amount of DNA can be detected by a change in impedance during the PCR process, a detection device with a small and simple structure can be implemented without including an optical detection unit. In this paper, we propose a PCR chip and detection system based on impedance spectroscopy. Two types of chips were made using two types of flexible printed circuit boards (PCBs) with different electrode shapes, double-sided tape, and a plastic film. The system for driving the PCR process includes a microcontroller and is configured to control temperature and process measured values. The DNA sample solutions, diluted to various concentrations, were injected into the two types of chips, and the impedance values for each concentration were measured. The measured values were analyzed for each concentration and electrode type. As a result, it was found that although there is a difference in the size of the measured value depending on the type of chip, it is possible to distinguish between them by concentration. Full article