Handheld Image Research Articles

Feasibility of Use of a Handheld Image Capture Device to Assess Dietary Intake in Patients With End Stage Renal Disease on Hemodialysis

Feasibility of Use of a Handheld Image Capture Device to Assess Dietary Intake in Patients With End Stage Renal Disease on Hemodialysis

Compensating specular highlights for non-Lambertian projection surfaces

This paper concerns the compensation of specular highlight for handheld image projectors. By employing a projector-camera configuration, where the camera is aligned with the viewer, the distortion caused by nonideal (e.g., colored, reflective) projection surfaces can be estimated from the captured image and compensated for accordingly to improve the projection quality. This works fine when the viewing direction relative to the system is fixed. However, the compensation becomes inaccurate when this condition changes, because the position of the specular highlight changes as well. We propose a novel method that, without moving the camera, can estimate the specular highlight seen from any position and integrate it with Grossberg’s radiometric compensation framework to demonstrate how view-dependent compensation can be achieved. Extensive results, both objective and subjective, are provided to demonstrate the performance of the proposed algorithm.

A Self-Environment Adaption Model for Cross-Media Reproduction of Digital Image

A self- environment adaption model for cross-media reproduction of digital image is presented in this paper.This model is used to color conversion, makes image adaptive display according to ambient light changes. Experimental results show that this model can be used in all kinds of image processing systems for the displaying of image, particularly suitable for handheld image display apparatus.

Towards Automatic Estimation of the Body Condition Score of Dairy Cattle Using Hand-held Images and Active Shape Models

The Body Condition Score (BCS) is considered a critical value for dairy farms, since its observation can be used to optimize milk production. Usually, the BCS is calculated by human experts after visual inspection in a time-consuming and subjective process. There are already some papers where this process is almost automated using image processing on some kinds of pictures and, in this work, the first steps towards a fully automated method based on pictures taken with common photographic cameras are described. Active Shape Models (ASM) are used to obtain a set of features that describe the back shape of cows and those features feed a classifier that computes the BCS. We show that the BCS can be estimated using only a set of angles from the back view with an error similar to that calculated between scores of two experts. To obtain those angles automatically is the hardest step in this process, but we have already achieved reasonable results on that point too.

Handheld devices for radiologists: as good as monitors?

Handheld computers, such as personal digital assistants (PDAs) and smartphones, have become commonplace in recent years, and the range of social and professional applications available for these technologies has also undergone rapid expansion. The portability and flexibility offered by handheld devices invites many attractive ideas in the field of medicine, including in radiology. For instance, the possibility of radiologists having fast access to patient images from any location, either in or remote from the hospital, is immediately appealing, particularly in the context of urgent or unusual cases. However, the introduction of handheld devices as radiological displays is not a straightforward issue, with many considerations to take into account. Security and confidentiality, costs and data transfer speed all must be borne in mind when considering the introduction of handheld device-based image viewing. Perhaps the greatest and most obvious concern, however, is whether handheld devices could possibly display images at sufficient quality to allow an accurate opinion or report to be given. Can handheld displays equal the conventional monitor in radiological image viewing?

Automatic extraction of lean-tissue contours for beef quality grading

In evaluating beef quality, proper extraction of the boundary of lean-tissue from the section of beef rib is the crucial first step. The quality features of a beef carcass are determined by size, marbling state, and the colour of the lean-tissue on the 13th rib. Because of the inhomogeneous distribution and fuzzy pattern of the fat and lean-tissues on various beef-cuts, it is difficult to automatically extract a proper contour of the lean-tissue. In this research, image-processing algorithms have been developed to automatically extract the boundary of the lean-tissue in a robust way as human expert does. Algorithms include automatic threshold determination using Renyi entropy for beef-cut segmentation and contour modification, along with binary morphological approaches. The algorithms were applied to 36 beef-cut samples and successfully demonstrated contour extraction with average percentage error of 2.63% and average pixel distance error of 2.51 pixels when compared to results from a human expert. Computing time for the contour extraction process was around 5 s. A mobile image acquisition and processing system was also developed for on-site application. The system was composed of a hand-held image acquisition unit and a mobile computing unit mounted with a touch-pad screen. The algorithms developed were applied to the mobile processing unit as a supplementary grading device.

Objective Print Quality Analysis and The Portable Personal IAS® Image Analysis System

While color and density have been synonymous with print quality for a long time,the importance of other print quality attributes such as sharpness and details,and printing artifacts such as bleed, edge acuity, banding, and gloss non-uniformity can hardly be overemphasized. The growing recognition of the importance of such“non-color and density”attributes has been partly driven by the introduction of many digital printing processes that exacerbate such print quality (PQ) problems. To advance digital printing technology and to solve PQ problems,a necessary first step is to objectively quantify the critical print quality attributes beyond density and color, hence creating a demand for new tools other than the familiar densitometer or spectrophotometer. Responding to this need,image analyzers have been developed in parallel with the development of the digital printing industry over the last two decades. The early image analyzers were typically large tabletop units that were often installed in a central laboratory and required the support of a specialist. Bringing the technology of PQ analysis to a much broader community of users, a handheld image analyzer called the Personal IAS was introduced by QEA in 2001. This batterypowered,portable instrument makes it possible for the first time to make objective print quality measurements anywhere,including in the field and on the production line. This paper describes the design of the instrument and demonstrates its capabilities by means of a series of practical applications in digital printing.

Lava effusion rates from hand-held thermal infrared imagery: an example from the June 2003 effusive activity at Stromboli

A safe, easy and rapid method to calculate lava effusion rates using hand-held thermal image data was developed during June 2003 at Stromboli Volcano (Italy). We used a Forward Looking Infrared Radiometer (FLIR) to obtain images of the active lava flow field on a daily basis between May 31 and June 16, 2003. During this time the flow field geometry and size (where flows typically a few hundred meters long were emplaced on a steep slope) meant that near-vertical images of the whole flow field could be captured in a single image obtained from a helicopter hovering, at an altitude of 750 m and ∼1 km off shore. We used these images to adapt a thermally based effusion rate method, previously applied to low and high spatial resolution satellite data, to allow automated extraction of effusion rates from the hand-held thermal infrared imagery. A comparison between a thermally-derived (0.23–0.87 m3 s−1) and dimensionally-derived effusion rate (0.56 m3 s−1) showed that the thermally-derived range was centered on the expected value. Over the measurement period, the mean effusion rate was 0.38±0.25 m3 s−1, which is similar to that obtained during the 1985–86 effusive eruption and the time-averaged supply rate calculated for normal (non-effusive) Strombolian activity. A short effusive pulse, reaching a peak of ∼1.2 m3 s−1, was recorded on June 3, 2003. One explanation of such a peak would be an increase in driving pressure due to an increase in the height of the magma contained in the central column. We estimate that this pulse would require the magma column to attain a height of ∼190 m above the effusive vent, which is approximately the elevation difference between the vent and the floor of the NE crater. Our approach gives an easy-to-apply method that has the potential to provide effusion rate time series with a high temporal resolution.

Evaluating the quality of light fields computed from hand-held camera images

Given an image sequence recorded by a hand-held camera we examine the computation of a light field without any further input data. Using structure-from-motion algorithms and optimization techniques camera motion and a 3-D reconstruction of the scene are established. The light field is completed by computing local depth information for each input image. During experimental evaluation a special focus is set on the effects of falsely estimated intrinsic parameters as well as different depth representations on the quality of the resulting light fields.

Radiology on handheld devices: image display, manipulation, and PACS integration issues.

Handheld personal digital assistants (PDAs) have undergone continuous and substantial improvements in hardware and graphics capabilities, making them a compelling platform for novel developments in teleradiology. The latest PDAs have processor speeds of up to 400 MHz and storage capacities of up to 80 Gbytes with memory expansion methods. A Digital Imaging and Communications in Medicine (DICOM)-compliant, vendor-independent handheld image access system was developed in which a PDA server acts as the gateway between a picture archiving and communication system (PACS) and PDAs. The system is compatible with most currently available PDA models. It is capable of both wired and wireless transfer of images and includes custom PDA software and World Wide Web interfaces that implement a variety of basic image manipulation functions. Implementation of this system, which is currently undergoing debugging and beta testing, required optimization of the user interface to efficiently display images on smaller PDA screens. The PDA server manages user work lists and implements compression and security features to accelerate transfer speeds, protect patient information, and regulate access. Although some limitations remain, PDA-based teleradiology has the potential to increase the efficiency of the radiologic work flow, increasing productivity and improving communication with referring physicians and patients.

Coregistered intraoperative ultrasonography in resection of malignant glioma

The authors present their experience with coregistration of preoperative imaging data to intraoperative ultrasonography in the resection of high-grade gliomas, focusing on methodology and clinical observation. Images were obtained preoperatively and coregistered to intraoperative hand-held ultrasound images by merging the respective imaging coordinate systems. After patient registration and imaging calibration, the authors computed the location on the magnetic resonance (MR) space of each pixel on an ultrasound image acquired in the operating room. The data were retrospectively reviewed in 11 patients with high-grade gliomas who underwent ultrasonography-assisted resection at our institution between June 2000 and December 2002. Satisfactory coregistration of intraoperative ultrasound and preoperative MR images was accomplished in all cases. Ultrasound and MR image data were closely congruent. Preoperative setup and intraoperative use of the system were unencumbering. Based on these preliminary results, intraoperative ultrasonography is an attractive neuronavigational alternative, by which a less expensive and constraining imaging technique is used to acquire updated information. Optimal intraoperative guidance can be provided by the integration of this with other imaging studies.

Space Station allows remote sensing of Earth to within six meters

Budgetary challenges and research limitations of the International Space Station, which is currently being constructed, are routinely discussed in the media [e.g., Lawler, 2001]. In spite of these challenges, an Earth remote sensing experiment being conducted from the International Space Station, called Crew Earth Observations [Robinson and Evans, 2001], is already yielding significant data returns by using the successful photographic methods employed in earlier Earth imaging programs from the Space Shuttle and Mir Space Station [Lulla and Dessinov, 2000]. Early results show great improvement in our ability to compensate for the relative motion of the Earth and achieve high remote sensing spatial resolution in handheld images. Images captured for Crew Earth Observations have spatial resolutions of less than 6 m, approaching the highest spatial resolution of color images now available from commercial remote sensing satellites.

An Automated Method of Quantifying Retinal Vascular Responses during Exposure to Novel Environmental Conditions

The width of retinal arteries and veins was measured by digital image analysis using an automated vessel-tracking software program. Mean coefficients of variations in vessel width of less than 3% were easily achieved from digitized 35-mm retinal photographs taken with a table-top or hand-held fundus camera. Retinal images were analyzed from seven subjects exposed to sea level or altitudes equivalent to 10,000 (3048 m), 17,500 (5334 m), and 25,000 (7620 m) ft and nine subjects exposed to sea level and 14,110 ft (4300 m). At each altitude, retinal veins dilated more than did arteries (5 ± 1% versus 0 ± 1% at 10,000 ft and 28 ± 9% versus 9 ± 2% at 25,000 ft; veins versus arteries, respectively). However, widths of retinal arteries and veins were reduced in nine subjects tested after 15 minutes, 24 hours, and 48 hours of 10° head-down tilt; and values varied inversely with intraocular pressures (IOP). Hand-held retinal fundus photography and digital image analysis were found to provide a sensitive and objective method for detecting and quantifying retinal vascular responses in humans exposed to novel environments.

Radiation Dose Implications of a Hand-held Image Intensifier Used for Clinical X Raying of Extremities

Radiation Dose Implications of a Hand-held Image Intensifier Used for Clinical X Raying of Extremities

Atmospheric Emissions Photometric Imaging Experiment

The atmospheric emissions photometric imaging experiment was flown on Spacelab 1 to study faint natural and artificial atmospheric emission phenomena. The instrument imaged optical emission in the region 2000 to 7500 angstroms with a television system consisting of two optical channels, one wide-angle and one telephoto. A third optical channel imaged onto the photochathode of a microchannel plate photomultiplier tube that has 100 discrete anodes. A hand-held image intensifier camera with an objective grating permitted spectral analysis of the earth's airglow and the shuttle glow. Preliminary data show magnesium ion emission features in the lower ionosphere as well as the spececraft glow spectrum.

A Relatively High-Resolution Reading Aid for the Blind

Many direct-translation reading aids for the blind have been built in the past, employing an auditory output consisting of a combination of tones indicating the black regions in a vertical slice through a letter space, or a tactile output consisting of a raised or vibrating image of the letter shapes. Maximum reading rates obtained by the majority of subjects with these reading aids have been less than 10 correct words per minute, and the cause of this limitation has not been well understood. By analyzing the spatial spectral content of letter patterns, we show here that most of these reading aids have violated the well-known sampling theorem. It is suggested that this may be a significant factor in the observed reading-rate limitation. The design of a reading aid is described based on the conclusions from this analysis of the sampling process, and on recent results from tactile research. With this reading aid a hand-held probe images a vertical section of a letter space onto a 24 × 6 array of photosensors, and the probe is manually moved horizontally across the line of print. The signal from each photosensor controls a tactile stimulator in a corresponding array of 144 stimulators, which are placed on a single finger. In preliminary reading tests with this device, four subjects have all read at rates greater than 10 correct words per minute, and two of the subjects have read at rates greater than 20 correct words per minute.