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Purpose – User authentication is generally used to protect personal information such as phone numbers, photos and account information stored in a mobile device by limiting the user to a specific person, e.g. the owner of the device. Authentication methods with password, PIN, face recognition and fingerprint identification have been widely used; however, these methods have problems of difficulty in one-handed operation, vulnerability to shoulder hacking and illegal access using fingerprint with either super glue or facial portrait. From viewpoints of usability and safety, strong and uncomplicated method is required. Design/methodology/approach – In this paper, a user authentication method is proposed based on grip gestures using pressure sensors mounted on the lateral and back sides of a mobile phone. Grip gesture is an operation of grasping a mobile phone, which is assumed to be done instead of conventional unlock procedure. Grip gesture can be performed with one hand. Moreover, it is hard to imitate grip gestures, as finger movements and grip force during a grip gesture are hardly seen by the others. Findings – The feature values of grip force are experimentally investigated and the proposed method from viewpoint of error rate is evaluated. From the result, this method achieved 0.02 of equal error rate, which is equivalent to face recognition. Originality/value – Many researches using pressure sensors to recognize grip pattern have been proposed thus far; however, the conventional works just recognize grip patterns and do not identify users, or need long pressure data to finish confident authentication. This proposed method authenticates users with a short grip gesture. [ABSTRACT FROM AUTHOR]

A metric of the 3D image quality of autostereoscopic displays based on optical measurements is proposed. This metric uses each view's luminance contrast, which is defined as the ratio of maximum luminance at each viewing position to total luminance at that position. Conventional metrics of the autostereoscopic display based on crosstalk, which uses 'wanted' and 'unwanted' lights. However, in case of the multiple-views-type autostereoscopic displays, it is difficult to distinguish exactly which lights are wanted lights and which are unwanted lights. This paper assumes that the wanted light has a maximum luminance at the good stereoscopic viewing position, and the unwanted light also has a maximum luminance at the worst pseudo-stereoscopic viewing position. By using the maximum luminance that is indexed by view number of the autostereoscopic display, the proposed method enables characterizing stereoscopic viewing conditions without using wanted/unwanted light. A 3D image quality metric called 'stereo luminance contrast,' the average of both eyes' contrast, is proposed. The effectiveness of the proposed metric is confirmed by the results of optical measurement analyses of different types of autostereoscopic displays, such as the two-view, scan-backlight, multi-view, and integral. [ABSTRACT FROM AUTHOR]

A hierarchical matching is the most efficient way to recognize a 3-D object. In most conventional methods of 3-D object recognition, a hierarchical structure is formed after the detailed 3D structure of an object has been extracted by dividing it coarsely. This approach is very inefficient, since it is difficult to obtain a detailed 3D structure initially in addition to a large amount of computation time. This paper proposes a method which extracts a multiscale 3D structure directly from coarse to fine. In this method, a space containing an object is divided into coarse voxels, and a ‘3D voting’ is applied. This voting adds a certain value to a voxel through which a back-projected line connects the center of the camera lens and a feature point on an image. A voxel having a high value is regarded as a region containing a 3D feature point, and this is extracted. Extraction of a hierarchical structure is carried out by repeating the dividing process from coarse voxels to fine voxels so that the operation becomes efficient. This paper also analyzes the effects of the deviation of a feature point in an image and the deviation of the camera center on the 3D voting. The paper shows also that an application of a &nubla;2G filter to the voxel space (after 3D voting) is effective in suppressing the errors due to the deviations. The method has been confirmed successfully by processing six complex test images. [ABSTRACT FROM AUTHOR]

With the recent development of input, presentation. and processing technologies for three-dimensional (3-D) images as the background, the demand for the effective storage and management of 3-D images is expected to increase. This paper aims at the effective storage and retrieval of the 3-D images and proposes a 3-D shape indexing by the superquadrics. The features of superquadrics are that the expression is simple and various shapes can be represented using a smaller number of parameters. To examine the applicability of the function, the technique based on superquadrics is compared with conventional 3-D modeling from the viewpoint of the power for representing the feature and shape as the technical requirement for the indexing. The purpose of the conventional modeling technique is to represent the shape from the visual sensation. However, this resulted in a problem whereby it is difficult to determine the shape from the modeled data structure. By contrast, with superquadrics, the functional parameters are easily related to the shape; thus realizing a sufficient applicability as the indexing. An image retrieval system is constructed using the superquadrics parameters as the indexes, and the usefulness of the proposed indexing technique is demonstrated. [ABSTRACT FROM AUTHOR]

The cancer cell exhibits a cyclic change in its morphology, and the discussion of the cyclic change in cell morphology is very important in cytology, considering the relation between the cell growth and the distribution of the protein granules. At present, this kind of analysis is made by human observation through a microscope. This paper describes a method which recognizes the cyclic morphological changes of the cancer cell by image processing. First, various feature parameters of the nucleus and the cytoplasm are calculated by computerized image processing. In the extraction of the cell image from the original image, the binarization rather than ternarization is applied separately to the nucleus and the cytoplasm. Based on the calculated feature parameters, three decision criteria are set based on the discriminant analysis to recognize the cell morphology. As a result of experiment, the recognition rate of 93.9 percent was achieved for the training data, indicating that the cell morphology can be recognized by a computer. [ABSTRACT FROM AUTHOR]

The mechanism of the lymph flow is not fully understood, Since the lymphatic system has no pump apparatus such as a heart in the blood vessel system, it is important to study the relationship between the lymph flow and the contractile movement of its wall. This paper analyzes the rhythmical contraction of the lymphatics of the rat mesentery in viva. Only the image of the lymph vessel wall was extracted from the microscopic image of the mesentery recorded on video tape. An algorithm was developed which was suited to the continuous measurement of the vessel diameter. In the process of the automatic ex- traction of the lymph vessel wall, not only its derivative and the direction, but also the running state of the lymph vessel were utilized as information. A circular scanning was employed for the first time as a method which realized an accurate diameter measurement of the vessel that always changed its shape with time. By the proposed image processing system, the periodic movement of the lymph vessel could be analyzed quantitatively. [ABSTRACT FROM AUTHOR]

Objective: To investigate interdigestive gastroduodenal motility with an infused catheter and measure plasma motilin levels in eight normal individuals and 18 patients with dysmotility-like dyspepsia. Methods and Results: All normal individuals had normal gastroduodenal interdigestive migrating complexes. Patients with dysmotility-like dyspepsia were classified into three subgroups on the basis of gastric antral motility: 1) seven patients with normal interdigestive migrating complexes, 2) five patients without interdigestive migrating complexes and with gastric phase II predominant over phase I, and 3) six patients without interdigestive migrating complexes and with phase I predominance. The maximum and mean plasma motilin levels were significantly different in normal individuals from those in subgroup 3 (Kruskal-Wallis test, p < 0.05). Conclusions: Dysmotility-like dyspepsia appears to be a heterogeneous condition. Abnormal motilin secretion may cause dysmotility in subgroup 3, but dyspepsia in subgroup 1 and the absence of interdigestive migrating complexes in subgroup 2 could not be explained only on this basis. [ABSTRACT FROM AUTHOR]

We report a rare case of benign esophagobronchial fistula associated with achalasia. The fistula healed spontaneously after esophagocardioplasty with a gastric patch, suggesting the utility of this procedure. [ABSTRACT FROM AUTHOR]