2C3-03 手の非接触三次元形状計測の定量的評価に関する研究(モデル化と変形・応力解析)

In this paper, we report our attempt of finding the suitable signal-to-noise ratio for measuring and modeling 3-D human hand shape with a marketed highs-speed range finder and 3-D CAD system. We had approached the problem applying a method in quality engineering to analyze and understand the correlation of the controllable factors in the measurement environment and procedure. The factors that affect the precision of the hand shape were selected based on the knowledge which was gained through our experience of using the range finder or provided as advices from expert researcher in the field. Experiments were conducted varying the parameters of the factors in 2 or 3 levels and measuring the errors in the hand shape surface model. The results were compared and the significance of the selected factors was discussed evaluating the error variance and sensitivity. A sufficient combination of the factors was conditioned and confirmation exam was made to verify the suitability.

System calibration, which usually involves complicated and time-consuming procedures, is crucial for any 3-D shape measurement system. In this work, a novel systematic method is proposed for accurate and quick calibration of a 3-D shape measurement system we developed based on a structured light technique. The key concept is to enable the projector to "capture" images like a camera, thus making the calibration of a projector the same as that of a camera. With this new concept, the calibration of structured light systems becomes essentially the same as the calibration of traditional stereovision systems, which is well established. The calibration method is fast, robust, and accurate. It significantly simplifies the calibration and recalibration procedures of structured light systems. This work describes the principle of the proposed method and presents some experimental results that demonstrate its performance.

System calibration is crucial for any 3-D shape measurement system. An accurate method is proposed to calibrate a 3-D shape measurement system based on a structured light technique. The projector is treated as a camera to unify the calibration procedures of a structured light system and a well-established stereo vision system. The key to realizing this method is to establish a highly accurate correspondence between camera pixels and projector pixels and generate digital micromirror device (DMD) image sets for projector calibration. A phase-shifting method is used to accomplish this task. A precalibrated lookup table and a linear interpolation algorithm are proposed to improve the accuracy of the generated DMD image, and accordingly improve the accuracy of the projector calibration and the 3-D measurement. Some experimental results are presented to demonstrate the performance of the system calibration.

Perception of colour depends on the spectral composition of light that reaches retina and depends as well on various mechanisms of visual system that processes information flow. The few important mechanisms can be distinguished in colour perception: colour adaptation, colour constancy and colour contrast. If the visual field has only one coloured object, then colour perception will be determined by spectral composition of the light and colour adaptation. Whereas mechanisms of colour constancy and colour contrast switches on when in the visual field there are at least two colour objects. Von Kries (1905) have attributed colour constancy phenomenon to theory of receptoral adaptation. But this is theory is applicable to local processes happening in relatively small size of visual field. Craven and Foster (1992) shows that receptor excitation ratios remains constant during change of illumination. But again remains unexplained colour change during adaptation. So, the hypothesis is raised that two processes attribute colour perception: local colour contrast calculation and global adaptation to the background. Therefore the experiments have been carried out to establish the colour contrast and background adaptation impact on colour perception.Four subjects with normal colour vision participated in the experiments. 40 Munsell samples (value 7 and chroma 4) illuminated with one reference illuminant (standard C) and 6 test illuminants (standard A, standard S, cardinal red, cardinal green, cardinal yellow and cardinal blue) were simulated on computer monitor. The dark-adapted subjects have been shown colour samples on neutral background illuminated with one of test illuminants. The task was to match the colour stimuli appearance under reference illuminant. The sequential asymmetric matching procedure was carried out. First subject adapts to neutral background under illuminan C then test stimulus and test background appears for limited time followed by readaptation to neutral background. Then subject is asked to adjust the colour mach under illuminant C. Two different experiment paradigms have been used. In the first one the stimulus had 2° on neutral background covering 20° of visual field. In the second paradigm the stimulus size was the same but the background was covering the all visual field. The adaptation and presentation timings were 1, 5, 30 or 60 seconds.Results under the first experiment paradigm show partial colour constancy for all subjects and for all test illuminants under various adaptation times. Despite quite a long adaptation time of 30 seconds subjects was unable to achieve full colour constancy. Colour constancy improves under second experiment paradigm. 60-second adaptation time is enough to achieve full colour constancy. The less adaptation time (1 or 30 second) gives partial colour constancy.The subject sees two colours (stimulus and background) during the experiment. The colour perception of stimulus and background changes during adaptation time. In the first 5 seconds of adaptation 40–60% of full adaptation level is reached (Fairchild and Reniff, 1995; Werner et al., 2000). Wesner and Shevell (1992, 1994) shown that signals from all visual field have influence on colour perception of object. The first part of our experiment shows that neutral background of 20° gives partial adaptation to background colour. Therefore, increase background illumination to full visual field gives full adaptation to background. So, subject perceives different coloured background under various illuminants as the same neutral (grey) background.We can state that two different systems have been distinguished in the process of colour perception. One system evaluates the colour difference between the stimulus and the background. Second system evaluates the colour of the background. Perceived colour difference during adaptation does not change much, but perceived colour of the background changes a lot and drifts towards neutral colour. The hypothesis of two level colour perception is supported by experimental data.

We propose to use a calibration target with a narrow spectral color range for the background (e.g., from blue) and broader spectral color range for the feature points (e.g., blue + red circles), and fringe patterns matching the background color for accurate phase extraction. Since the captured fringe patterns are not affected by the high contrast of the calibration target, phase information can be accurately extracted without edging artifacts. Those feature points can be clearly "seen" by the camera if the ambient light matches the feature color or without the background color. We extract each calibration pose for three-dimensional coordinate determination for each pixel, and then establish pixel-wise relationship between each coordinate and phase. Comparing with our previously published method, this method significantly fundamentally simplifies and improves the algorithm by eliminating the computational framework estimate smooth phase near high-contrast feature edges. Experimental results demonstrated the success of our proposed calibration method.

Failure analysis and engineering mechanics modeling methods of a stitched ceramic sandwich structure

In the digital preservation and display of Cantonese embroidery patterns, computer-human-computer interaction technology is particularly important. By utilizing computer-assisted human-machine interaction technology, this article presents a cutting-edge digital preservation and display of the image algorithm model for Xiangyun yarn patterns. The research method scanned high-resolution data by capturing the complex texture of auspicious cloud colours in Cantonese embroidery patterns. The use of image processing algorithms eliminates a series of noise generated during the process of capturing pattern tones and sharpens details. Following this, the refined image undergoes vectorization and precise modelling via CAD software, yielding an editable and scalable digital representation. Additionally, we've crafted an interactive exhibition system that immerses viewers in the cultural allure of Cantonese Embroidery through HCI. Experimental results demonstrate that our enhanced model outperforms the original AlexNet in embroidery classification, notably improving accuracy, recall, precision, and the F1 score. This underscores the significance of tailoring deep learning models to specific applications.

This study discusses the operators' operating performance and mental workload while performing the reactor shutdown task in an advanced nuclear power plant (NPP) in the cases of different levels of automation, manual and semi-automation. At the same time, the key factors that affected the operators' mental workload and operating performance were identified as using the NASA task-load index (NASA-TLX). The experimental results showed that operators have the worse operating performance, highest mental workload, and more human error in the manual operation. This was mainly affected by the factor of physical requirement. In the semi-auto operation, the subjects have high level of frustration. Furthermore, the operating time of both manual and semi-auto operation have close correlation with mental demand. In summary, the design of automation of the human-system interface (HSI) in the advanced NPPs needs to be carefully considered and improved.

The perception of color noise is important for image processing and for understanding the human vision mechanism. To reveal the perception of color noise quantitatively, we have conducted subjective experiments with modeled color noises. We use vector color noises varied in a CIELAB ab-plane to study the perception properties of color noise in detail. Our results show that the perception of color noise depends on background colors, luminance, spatial frequencies and noise models. The perception of vector color noises shows bipolar shape. The bipolar shapes of high spatial frequency noises rotate a little clockwise than the ones of low spatial frequency. Noises with low spatial frequencies are perceived easier than noises with high spatial frequencies. Using these experimental results, we make a perception model for color noise levels. We also propose a denoising workflow by applying the perception model to a random sampling filter.

One of method to diagnose Tuberculosis (TB) disease is sputum test. The presence and number of Mycobacterium tuberculosis (MTB) in sputum are identified. The presence of MTB can be seen under light microscope. Before investigating through stained light microscope, the sputum samples are stained using Ziehl–Neelsen (ZN) stain technique. Because there is no standard procedure in staining, the appearance of sputum samples may vary either in background colour or contrast level. It increases the difficulty in segmentation stage of automatic MTB identification. Thus, this study investigated the colour models to look for colour channels of colour model that can segment MTB well in different stained conditions. The colour models will be investigated are each channel in RGB, HSV, CIELAB, YCbCr, and C-Y colour model and the clustering algorithm used is k-Means. The sputum image dataset used in this study is obtained from community health clinic in a district in Indonesia. The size of each image was set to 1600x1200 pixels which is having variation in number of MTB, background colour, and contrast level. The experiment result indicates that in all image conditions, blue, hue, Cr, and Ry colour channel can be used to segment MTB in one cluster well.

Life Sciences Discovery and Technology Highlights

3-D shape measurement systems by contactless method are required in the quality inspections of metal molds and electronic parts in industrial fields. A grating projection method with phase-shifting method has advantages of high precision and high speed. Recently, the size of a BGA (ball grid array) becomes smaller. So the pitch of a grating pattern projected onto the specimen should be smaller. In conventional method, fringe pattern is projected using an imaging lens. The focal depth becomes smaller in the case of reduced projection. It is therefore difficult to project a grating pattern with small pitch onto an object with large incident angles. Authors recently proposed a light source stepping method using a linear LED device. It is easy to shrink the projected grating pitch with a lens because this projection method does not use an imaging lens. The pitch of the projected grating depends on the width of the light source. There is a limit to shrink the projected grating pitch according to the size of the LED chip. In this paper, a small pitch fringe projection method with multiple linear fiber arrays for 3D shape measurement is proposed. The width of the fiber array is 30μm. It is one digit smaller than the width of the LED chip. The experimental result of 3-D shape measurement with small pitch projection with large incident angles is shown.

Visualization of 3D variable in time object based on data gathered by active measurement system

Research and development of an accurate 3D shape measurement system based on fringe projection: Model analysis and performance evaluation

Abstract. The Vltava River and its surroundings had many different faces and functions in the past centuries. The Vltava is the longest river running through the heart of Bohemia, probably the most famous and popular river in the Czech Republic, one of the national symbols, important trade and transport route in the past, river with beautiful landscape favourite by poets, travellers, and tourists, place where the biggest dam reservoir system in the Czech Republic was built, popular recreational area in the present and many more. Therefore, many different documents are dealing with the Vltava River and its riverine landscape. The main objective of the project supported by the Ministry of Culture of the Czech Republic is to create comprehensive information system about the Vltava River aggregating and incorporating various historical and modern documents and data. This system will allow maintaining and documenting a wealth of information about the history of the Vltava River, including immovable and movable cultural heritage using new technologies. The project is focused on the upper three quarters of the Vltava River from its springs to confluence with the Berounka River close to Prague in the period from mid 18th century up to the present day. Riverine landscape along the Vltava underwent an intensive transformation in many aspects. Firstly, the cultural landscape with mostly minor settlement combined with appreciated but even feared wild natural narrow valleys has changed intensively along with a construction of the dam cascade especially in the middle part of the river in the second half of the 20th century. Small but widespread settlements, transport function of the river and wild nature were replaced by dams producing electric energy and retaining extensive water reservoirs providing water supply and protection from frequent inundations and last but not least being very popular for recreation. Unfortunately, many houses, water mills, chapels, churches, picturesque natural places, etc. have been flooded. The former face of the Vltava riverine landscape is preserved only in various archival documents and their online presentation is the main project goal. There are large volumes of miscellaneous historical and modern data sources dealing with the Vltava river which are being used in the project. Extensive research of various public and institutional archives is currently still being carried out. Some resources such as old photographs and postcards are found also in private collections. First of all, there are various works from old cadastral maps, old river maps with cross sections, longitudinal profiles of the river, old site plans and interesting building plans, State Derived Map and aerial photographs from 1950s, site and constructional plans of dams to the up to date cadastral map, orthophotos and DTM. The Imperial Imprints of the Stable Cadastre (scale 1 : 2 880) from the years 1826–1843 rank among the most valuable and very useful. Due to their geometric precision and visual attractiveness, these maps are suitable for vectorization, and form an excellent base layer for the web mapping application and 3D visualization. Another very important map is the State Derived Map (scale 1 : 5 000; its first issue) from the early 1950s containing planimetry as well as altimetry. It shows situation of area just before the dam reservoirs cascade construction was started hence it allows reconstruction of former Vltava valley. Maps and plans are complemented by old photographs, postcards, iconography and also text sources. All data sources described above have to be carefully processed before their incorporation into the information system and subsequent 2D- or 3D- applications could be designed. Speaking in particular about maps and plans, they have to be digitised, georeferenced and selected map content is vectorised. The majority of data sources are obtained in the analogue paper form, thereby a high resolution scanning has to be done to acquire digital copies of requested maps and plans. Then the scanned data is georeferenced employing suitable global or local transformations depending on the type of map. Carefully selected map content is vectorised and the database of significant features (buildings or objects of cultural, social, production and water management importance) with important attributes is being filled up. Every feature has its location, at least approximately if precise position is unknown. Also the old photographs and postcards are geolocated to be incorporated into the information system. 2D web mapping application (Figure 1) has been created based on processed data and it is being updated. It presents and compares various layers (georeferenced maps and plans, vectorised data model, objects of interest, etc.). The application allows overlaying of various raster and vector layers from different times using the swipe tool. Objects of interest and photographs are represented by points, where each point leads to a popup with more information. Online 3D visualisation is effective and popular way of geographical data presentation thus besides the 2D also 3D application may bring a new perspective to former Vltava landscape. The Vltava River valley, often narrow and deep, is perfect for the 3D presentation, especially if it is completed by other objects or phenomena (e.g. extinct settlements, important buildings, historical or potential floods). Precise 3D modelling of important structures in CAD software is a common but time-consuming process. Therefore, it is not possible to model the whole extinct settlements in 3D and thus procedural modelling is applied instead. It allows to visualise a simplified reconstructive model of flooded villages in the entire area of interest even in various periods of time. The mission of the project is, in particular, to document information on the changes of the Vltava riverine landscape within the last three centuries in the context of various events, as well as to make it subsequently available to the general public. Thus, it might act as a transfer of historical science into education through modern cartographic methods. The project itself is actually in its first phase and the activities proceed continuously.