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  Image Segmentation-Based Face Tracking on Thermal Images for Automatic Estimation of Psychophysiological States Using Facial Skin Temperature Distribution

  Open Access

  Abstract:  In human-machine system, human and machine need to recognize each other’s state with continuously, quantitatively and real-time property. Facial skin temperature could be measured with these properties by infrared thermography. The non-contact property is a great advantage in bioinstrumentation. Previous studies have been reported the availability of facial skin temperature for evaluation of psychophysiological states of a human such as stress, drowsiness and emotion. On the other hand, the development of the face detection and tracking techniques on thermal images are necessary for the automatic evaluation of psychophysiological states of a human based on facial skin temperature, measured by infrared thermography. The objective of this study is to establish the technique for face detection and tracking on thermal images. In this study, the algorithm consisting of three phases: (A) human detection based on inter-frame difference, (B) face detection based on image segmentation, and (C) face tracking based on temporal analysis, is proposed. As a result, the face region on thermal images could be detected and tracked with high precision. However, a part with low temperature such as the back of nasal and cheek was classified as a region other than a face.

   

  Keywords: Thermal image; face tracking; image segmentation

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  Effect of Shoes on Lower Extremity Pain and Low Back during Prolonged

  Open Access

  Abstract: Media with 16^o slope is an effective solution to reduce low back pain risk caused by prolonged standing. In this study, we examine the effect of shoes on lower back pain caused by prolonged standing for 2 hours on sloping medium. However, prolonged standing has another major risk: lower extremity pain. Many studies have shown that this risk can be affected by shoes type or characteristic. Hence, lower extremity pain risk is the main concern in this research. Two types of shoes observed in this study are Safety Shoes and Slip-On Shoes, as these are the most widely used in the manufacturing industry. Using the Surface Electromyography (S-EMG) method, the difference in Medial Gastrocnemius muscle response was measured against both types of shoes. The study showed that both types of shoes have different muscle activation values and the Safety Shoes showed greater activation. This result proves that, type of shoes may affect the amount of lower extremity pain caused while standing for 2 hours on sloping medium and Safety Shoes poses a greater lower extremity risk. Both Visual Analog Scale (VAS) and Foot Pain Questionnaire methods supported the finding. While the results of VAS method found standing for 2 hours on sloping medium has a greater lower extremity pain than low back pain risk. Foot Pain Questionnaire method indicated that the activity of standing for 2 hours over sloping medium causes a high pain on thumb toe and the back of foot. Based on this study, it can be concluded that it is necessary to design a special shoe for prolonged standing occupation on a sloping medium that can reduce the lower extremity pain risk, besides low back pain risk

  Keywords: Biomechanics, ergonomics, lower extremity pain, low back pain, prolonged standing, shoes, surface-electromyography.

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  Calibration of Surgical Knife-Tip Position with Marker-Based Optical Tracking Camera and Precise Evaluation of Its Measurement Accuracy

  Open Access

  Abstract:  We have been developing a liver surgery support system in collaboration with Kansai Medical University Hospital. Our surgical support system issues a warning when the surgical knife approaches a vital nerve or large blood vessel that should not be cut. It is also able to navigate the knife-tip to appropriately resect a tumor. Our system estimates the position and orientation of the surgical knife and the target organ using two distance cameras during surgery. The distance between the knife-tip and the blood vessels inside the organ is measured in real-time. In this paper, we present the details of our liver surgery support system and report the accuracy of the knife-tip positioning. The experimental results show that the position estimation error of the knife-tip is 0.3 mm and the standard deviation is 0.3 mm. The error of the distance between the estimated knife-tip positions on the neighboring grid points was 0.1 mm. This result satisfies the doctor’s surgical requirement.

  Keywords: Surgical knife positioning; Calibration; Liver; Accuracy;

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  An Implementation of Medical Image Mosaicing System Based on Oriented FAST and Rotated BRIEF Approach

  Open Access

  Abstract:  Image stitching is a technique that combines two or more images that are taken from different view of the same scene to obtain a panoramic image. Image stitching is used in medical applications for stitching of X-ray images. As the traditional system of X-ray machine cannot capture the whole body structure in a single image. So, images stitching solves this problem by combining two or more x-ray images into a large view one. This paper proposes an algorithm which automatically stitches the x-ray images with overlapped region. The stitching method is based on ORB features (Oriented FAST and Rotated BRIEF features). The proposed system is designed with five stages, preprocessing, features extraction, features matching, Homography estimation and images stitching. In feature detection stage, Oriented FAST approach is used. In feature description stage, Rotated BRIEF approach is applied. The two primary parameters for measuring the stitching performance are the quality of the resultant image and the processing time. Therefore, the main objective of this paper is to produce a high quality image stitching system with low processing time. First, we compare many different features detectors. We test SIFT method, SURF method, Harris corner detector and ORB approach to measure the correct detection rate of the feature points and computation time. Second, we measure the quality of result images that produced by stitching system of different feature detection methods. From experimental results, we conclude that ORB approach is the fastest, more accurate, and higher performance.

  Keywords: Biomedical images; Feature based approach ; Image stitching; ORB features ; Panorama

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