Coherence aware GPU‐based ray casting for virtual colonoscopy

goes here. This is completion of the research and update of the previous work that was published in 2013[1]. The paper describes our recent experimental study of the impact of mobile screen size on the user comprehension of health information and application structures. An experiment was conducted to measure the impact of screen size on user comprehension and retention. Participants were given the same simple scenario, which consisted of searching from different menus, navigating and reading some contents. They were timed and tracked for correctness. Also, a follow-up survey was given to each participant that consisted of a rating scale to assess usability features, comprehension and retention abilities of the participants based on different mobile screen sizes. Results showed that there was a significant difference between mobile phone screen size and the time taken to read the contents, which was at its highest on small screens (p-value=0.02). Also, reading characters was hardest on a small screen (p-value=0.003). In addition, there was a significant difference between the three screen sizes regarding the organization of the application's information, showing that the smaller the screen size, the more organized the information. On the other hand, there was no significant impact of screen size on user comprehension, retention scores, number of errors or effective task completion but it was generally better if a large screen size was used. This study concludes that the screen size is not the main concern in comprehension of the contents or application structure. However, reading speed improves with the larger screen size and positively influences the task completion and understanding of the application elements.

With increasing privacy concerns and security demands present within mobile devices, behavioral biometric solutions, such as touch based user recognition, have been researched as of recent. However, several vital contextual behavior factors (i.e., screen size, physical and application context) and how those effect user identification performance, remains unaddressed in previous studies. In this paper we first introduce a context-aware mobile user recognition method. Then a comparative experiment to evaluate the impacts of these factors in relation to user identification performance is presented. Experimental results have demonstrated that a user's touch screen usage behavior may be affected given different contextual behavior information. Furthermore, several interesting occurrences have been found in the results: 1) screen size of a smartphone device changes the way a user touches and holds the device. A larger screen size will provide more potential methods of interacting with the device and in effect, a higher user recognition accuracy as well; and 2) application context and physical activity context can aid in achieving higher accuracy for user recognition.

Real-time, dynamic level-of-detail management for three-axis NC milling simulation

Compressed sensing for reduced hardware footprint in medical ultrasound

Rising numbers of computed tomography (CT) examinations worldwide have led to a focus on dose reduction in the latest developments in CT technology. Iterative reconstruction (IR) models bear the potential to effectively reduce dose while maintaining adequate image quality. To assess the impact of adaptive statistical iterative reconstruction (ASIR) technique on dose reduction and image quality in a dedicated whole body CT (WBCT) protocol for trauma patients. A total of 122 subjects with multiple trauma was prospectively included in our study. Subjects who had to undergo a WBCT following a severe trauma were randomly assigned to two different groups: Group A was examined with an ASIR protocol for the body series (n = 64), group B (n = 58) was examined using a standard filtered back projection (FBP) protocol. Image quality was assessed both quantitatively by calculating signal-to-noise ratio (SNR) and contrast-to-noise ratios (CNRs) and qualitatively by two observers who evaluated image quality using a 5-point scale system. Applied dose was analyzed as CTDIvol (mGy), total DLP (mGyxcm), and effective dose (mSv). Applied dose for the body series in group A was about 23% lower than in group B (P < 0.05). SNR and CNRs for different tissues were not significantly different. Subjective image quality ratings were excellent and showed no significant difference, with a high inter-reader agreement. ASIR contributes to a relevant dose reduction without any loss of image quality in a dedicated WBCT protocol for patients with multiple trauma.

Four groups of about 86 pigs from a common source were fed a grower diet from 25 kg to 45 kg liveweight, and then from 45 to 107 kg liveweight they were offered one of four diets ad libitum: A) normal commercial feed, ground through a 3 mm screen (the control diet), B) the same diet ground through a 6 mm screen, C) the control diet to which lucerne meal was added before the diet was ground to increase its crude fibre content, and D) the control diet to which was added 400 ppm S-methylmethionine-sulphonium chloride (MMSC). All the diets were pelleted. Approximately 21 per cent of the animals fed the control diet had severe oesophagogastric erosions and/or ulcers after slaughter. The addition of 400 ppm MMSC decreased (P = 0.066) the proportion of severe oesophagogastric erosions and/or ulcers by about 50 per cent compared with the control diet. The diet with the higher crude fibre content (but finely ground) did not have a significant effect on the proportion of severe oesophagogastric erosions and/or ulcers. There was a tendency for the pigs fed the diet ground through a 6 mm screen instead of a 3 mm screen, to have fewer severe oesophagogastric erosions and/or ulcers. However, there were only small differences between the particle size distribution obtained from the wet sieve analysis of the two diets. As a result, the observed tendency for a decrease in the proportion of severe oesophagogastric erosions and/or ulcers in pigs fed the diet milled through the larger screen size was of questionable significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Volume rendering is a technique that visualize 2D image of object from 3D volume data on image screen. Ray casting algorithm, one of popular volume rendering techniques, generate image with detail and high quality compared with other volume rendering algorithms but since this is a highly time consuming process given large number of voxels, many acceleration techniques have been developed. Here we introduce new acceleration technique, efficient space leaping method. Our new space leaping method traverse volume data and projects 3D location of voxel onto image screen to find pixels that have non-zero value in final volume image and locations of non-empty voxels that are closest to ray. During this process, adaptive run-length encoding and line drawing algorithm are used to traverse volume data and find pixels with non-zero value efficiently. Then we cast rays not through entire screen pixel but only through projected screen pixels and start rendering process from non-empty voxel location directly. This new method shows significant time savings applied to surface extraction without loss of image quality.

In Japan, soft-copy diagnoses shift rapidly, and the method for facilities applying it is necessary for soft-copy diagnosis. Digital mammography has high resolution and a large matrix size. On a monitor, the image is either displayed partially at 1:1 pixel mapping or narrowed to fit the screen, resulting in loss of image quality. Therefore, we developed a digital phantom for soft-copy diagnosis in digital mammography. This phantom is like the Contrast Detail Phantom and comprises 12 different shapes and eight different brightness levels. It becomes one group of nine, and each signal is located at the prime number coordinate from a central signal coordinate. Visual evaluation refers to the visibility of the nine signal coordinates when the image is adjusted to fit the monitor's display. Although digital phantoms have been implemented at 120 facilities, at two other facilities, viewer problems were detected.

For the first year or so after Android 1.0 was released, all production Android devices had the same screen resolution (HVGA, 320×480 pixels) and size (around 3.5 inches, or 9 centimeters). Starting in late 2009, though, devices started arriving with widely disparate screen sizes and resolutions, from tiny QVGA (240×320) screens to much larger WVGA (480×800) screens. In late 2010, tablets and Google TV devices appeared, offering yet more screen sizes, and with the release of Honeycomb and Ice Cream Sandwich, tablet and larger screen sizes exploded.

MDCT angiography assessment of renal artery in-stent restenosis: Can we reduce the radiation exposure burden? A feasibility study

To meet various transmission and storage constraints, it is desirable that a compression algorithm allows a range of compression ratios. In this paper we analyze the JPEG compression algorithm, the international standard for compressing continuous tone images, and show how higher compression ratios can be achieved with minimal loss in image quality. We compare three methods to achieve variable compression with JPEG. Through a comprehensive analysis using 8 standard monochrome images from the USC database, we propose a method that offers substantial visual quality advantages for high compression ratios. The comparisons have been made by using an objective distortion measure which corresponds well to subjective assessments of visual quality. The paper provides detailed motivation for the algorithms, and suggests the choice of parameters to obtain variable compression with minimal loss in visual quality. >

Noise corruption degrades the R-D performance of H.264/AVC encoders because of a loss of image quality and an increase in bit-rate. Previous noise reduction techniques attempt to avoid the loss of image quality, but they do not take the effect of noise on compression efficiency into serious consideration. In this paper, the noise effect on an H.264/AVC encoder is analyzed and a blockbased adaptive denoising algorithm is proposed. The proposed algorithm applies the denoising operation adaptively to blocks which do not include image details that need to be preserved. Furthermore, the proposed noise filter is not applied when the quantization parameter is larger than a pre-defined threshold because noise is filtered by a quantization operation in the encoder. As a result, both residual and information bits are decreased by the proposed noise filtering operation. Edge blurring caused by the filtering operation is also reduced as a result of the adaptive application of the filtering operation. Compared to cases where filtering is not used, the proposed method shows a maximum PSNR enhancement of 1.98 dB and a maximum bitrate reduction of 41%.

Telemedicine (more specific TeleCardiology), including teleteaching and teleguidance, is a rapidly growing area in cardiology. The availability of hand-held network ready ultrasound equipment is one of the accelerators for furthers developments. A pilot project for both teleteaching and -guiding was started in our institution. For teleteaching the requirements were not too strict, e.g. no real-time interaction with the remote site necessary and some loss in image quality was allowed. For teleguidance however, near real-time transmission of images with no loss in diagnostic quality was demanded For both teleprojects solutions were found and/or developed with complete satisfactory to the clinical demands.

Prolonged excitation of fluorescent probes leads eventually to loss of their capacity to emit light. A decrease in the number of detected photons reduces subsequently the resolving power of a fluorescence microscope. Adverse effects of fluorescence intensity loss on the quality of microscopic images of biological specimens have been recognized, but not determined quantitatively. We propose three human-independent methods of quality determination. These techniques require no reference images and are based on calculation of the actual resolution distance, information entropy, and signal-to-noise ratio (SNR). We apply the three measures to study the effect of photobleaching in cell nuclei stained with propidium iodide (PI) and chromomycin A3 (CA3) and imaged with fluorescence confocal microscopy. We conclude that the relative loss of image quality is smaller than the corresponding decrease in fluorescence intensity. Furthermore, the extent of quality loss is related to the optical properties of the imaging system and the noise characteristics of the detector. We discuss the importance of these findings for optimal registration and compression of biological images.

New pixel-decimation patterns for block matching in motion estimation