Color Monitor Research Articles

Primary productivity and nitrogen fixation by Trichodesmium spp. in the Arabian Sea

Trichodesmium was studied with the purpose of understanding its distribution, organic production and nitrogen fixation in the Arabian Sea. Out of the 143 stations sampled, a total of 93 stations showed the presence of Trichodesmium filaments. Two species of Trichodesmium namely, T. thiebautii and T. erythraeum were found. These were distributed on the basis of the physico-chemical conditions of the Arabian Sea. This was the first time that we managed to detect and record the presence of Trichodesmium thiebautii bloom in the Arabian Sea at depths as deep as 60–70m. Total counts of Trichodesmium varied between 0 and 400737 filamentsL−1. T. thiebautii developed in offshore waters during the fall intermonsoon, when the water temperature was around 28°C and nitrate content was as low as 0.34μM. After the northeast monsoon, Trichodesmium erythraeum developed in the offshore area and then spread to coastal waters. Both species of Trichodesmium together produced a total of 0.263TgCyear−1 and fixed a total of 0.2976TgNyear−1 in the Arabian Sea. The study revealed that Trichodesmium was a major contributor to the organic matter productivity of the Arabian Sea during the period from November to April. The seasonality of the blooms of Trichodesmium is discussed with the help of Ocean Color Monitoring (OCM) data and biogeochemical implication of these findings in the Arabian Sea.

Atmospheric Correction and Vicarious Calibration of Oceansat-1 Ocean Color Monitor (OCM) Data in Coastal Case 2 Waters

The Ocean Color Monitor (OCM) provides radiance measurements in eight visible and near-infrared bands, similar to the Sea-viewing Wide Field-of-View Sensor (SeaWiFS) but with higher spatial resolution. For small- to moderate-sized coastal lakes and estuaries, where the 1 × 1 km spatial resolution of SeaWiFS is inadequate, the OCM provides a good alternative because of its higher spatial resolution (240 × 360 m) and an exact repeat coverage of every two days. This paper describes a detailed step-by-step atmospheric correction procedure for OCM data applicable to coastal Case 2 waters. This development was necessary as accurate results could not be obtained for our Case 2 water study area in coastal Louisiana with OCM data by using existing atmospheric correction software packages. In addition, since OCM-retrieved radiances were abnormally low in the blue wavelength region, a vicarious calibration procedure was developed. The results of our combined vicarious calibration and atmospheric correction procedure for OCM data were compared with the results from the SeaWiFS Data Analysis System (SeaDAS) software package outputs for SeaWiFS and OCM data. For Case 1 waters, our results matched closely with SeaDAS results. For Case 2 waters, our results demonstrated closure with in situ radiometric measurements, while SeaDAS produced negative normalized water leaving radiance (nLw) and remote sensing reflectance (Rrs). In summary, our procedure resulted in valid nLw and Rrs values for Case 2 waters using OCM data, providing a reliable method for retrieving useful nLw and Rrs values which can be used to develop ocean color algorithms for in-water substances (e.g., pigments, suspended sediments, chromophoric dissolved organic matter, etc.) at relatively high spatial resolution in regions where other software packages and sensors such as SeaWiFS and Moderate Resolution Imaging Spectrometer (MODIS) have proven unsuccessful. The method described here can be applied to other sensors such as OCM-2 or other Case 2 water areas.

TU-E-217A-01: Informatics 1: DICOM and the QMP, Assessment of Color Displays.

1. Understand the processes involved with development of the DICOM Standard. 2. Learn how any Medical Physicist can become involved in the process of developing the DICOM Standard 3. Learn the charge and structure of WG28 and their current Work Items. Medical color monitors are now widely used for Diagnostic Radiology interpretations. Business class monitors are otherwise used for medical image presentation in clinical departments. Both the AAPM and IEC are now developing recommendations and standards for color monitor performance assessment in medicine. The basic principles of color vision and metrology will be reviewed and current progress with AAPM and IEC working groups will be summarized. 1. Understand the tristimulus model for human color vision. 2. Understand the ICC color management framework. 3. Understand the ICC color management framework. 4. Learn how to make color measurements. 5. Learn new recommendations for color white point specification.

Regionally tuned algorithm to study the seasonal variation of suspended sediment concentration using IRS-P4 Ocean Colour Monitor data

Satellite data product validation and algorithm development activities both require the substantial accumulation of high-quality in situ observations. Data were acquired from Ocean Colour Monitor (OCM) and in situ observations for tuning of Tassan’s algorithm (Tassan, 1994) to retrieve the suspended sediment concentration (SSC) in the coastal waters off southern Karnataka, India. Tassan’s algorithm has been modified regionally by adopting statistical/graphical criteria to characterize the spatial and seasonal distribution of SSC. A concurrent and collocated datasets (n=120) of in situ SSC and OCM based remote sensing reflectance [Rrs(λ) in bands 490, 555 and 670nm] were regressed. The linear fit yielded regionally tuned new coefficients which were replaced in place of Tassan’s global coefficients. The tuned algorithm was shown to retrieve SSC with range of 1.1–37.12mg/l, which means it can be used for coastal waters. Since in situ samples were collected within the continental margin (average depth of ∼20m), we retain the global SSC algorithm (Tassan, 1994) approach for deeper bathymetric values (>50m depth) where we have no in situ measurements. Comparative analysis indicated statistically significant relationship (R2=0.99; n=45; p<0.05 at 95% confidence level) between in situ SSC and regionally tuned algorithm based SSC, with bias of 0.36mg/l and root mean square (RMS) difference of 0.73mg/l. This result clearly demonstrated the improvement of SSC measurement from OCM using regionally tuned Tassan’s algorithm (RMS=0.73mg/l) over the globally coefficient based Tassan’s algorithm (RMS=16.1mg/l).The tuned regional algorithm was used to estimate SSC in 2004, 2005 and 2007 which shows the concentration varied from 1.13 to 28.1mg/l in 2004, 1.84 to 23.12mg/l in 2005 and 2 to 27.85mg/l in 2007. Graphical and statistical methods using analysis of variance (ANOVA) have shown significant seasonal variability and inter-station spatial variability in SSC. Peak concentrations were recorded in the post-monsoon followed by the pre-monsoon period. The wind, wave and current pattern associated with southwest monsoon possibly controls the seasonal distribution, while nearshore turbulence and littoral transport influence the spatial distribution. This paper clearly demonstrated the potential application of regionally tuned algorithm for SSC mapping to study the spatial and seasonal pattern in shallow water off southern Karnataka.

Comparison of the Commercial Color LCD and the Medical Monochrome LCD Using Randomized Object Test Patterns

Workstations and electronic display devices in a picture archiving and communication system (PACS) provide a convenient and efficient platform for medical diagnosis. The performance of display devices has to be verified to ensure that image quality is not degraded. In this study, we designed a set of randomized object test patterns (ROTPs) consisting of randomly located spheres with various image characteristics to evaluate the performance of a 2.5 mega-pixel (MP) commercial color LCD and a 3 MP diagnostic monochrome LCD in several aspects, including the contrast, resolution, point spread effect, and noise. The ROTPs were then merged into 120 abdominal CT images. Five radiologists were invited to review the CT images, and receiver operating characteristic (ROC) analysis was carried out using a five-point rating scale. In the high background patterns of ROTPs, the sensitivity performance was comparable between both monitors in terms of contrast and resolution, whereas, in the low background patterns, the performance of the commercial color LCD was significantly poorer than that of the diagnostic monochrome LCD in all aspects. The average area under the ROC curve (AUC) for reviewing abdominal CT images was 0.717±0.0200 and 0.740±0.0195 for the color monitor and the diagnostic monitor, respectively. The observation time (OT) was 145±27.6 min and 127±19.3 min, respectively. No significant differences appeared in AUC (p = 0.265) and OT (p = 0.07). The overall results indicate that ROTPs can be implemented as a quality control tool to evaluate the intrinsic characteristics of display devices. Although there is still a gap in technology between different types of LCDs, commercial color LCDs could replace diagnostic monochrome LCDs as a platform for reviewing abdominal CT images after monitor calibration.

The Effect of High Intensity UV Irradiation on Color Behavior of Poly(Vinyl Chloride)

A detailed study of color change in poly(vinyl chloride) (PVC) sheets due to high intensity ultraviolet (UV) irradiation was undertaken, focusing on the first 50 h of change. Color changes were monitored with a Datacolor check spectrophotometer and compared with a set of controls. Measurements were taken after 1, 3, 5, 10, 15, and 20 h of irradiation, then at 10 h intervals for the next 40 h. Further measurements were conducted at 100, 240, and 480 h. Data were analyzed using the reflectance spectra (350–800 nm) as well as the CIE (International Commission on Illumination) L* a* b* color values (L*, a*, and b* are lightness value, redness-greenness value, and yellowness-blueness value, respectively) and the total color change (ΔE). The majority of color changes were found to occur within the first 50 h. After 50 h, the color change slowed and began to reverse toward 480 h. Surface microstructure properties, such as morphology, surface tension and oxidized products, were characterized to allow a comparison of sensitivity between the color monitoring methods and a comprehensive understanding of the color change. The results show that color evolution was attributable to the competition between the formations of polyene sequences (dehydrochlorination reaction) and their subsequent oxidation (photobleaching), which was slightly different from the behavior under a xenon arc lamp. According to the color behavior and the microstructure analysis a general scheme accounting for the mechanism of ageing behavior of PVC under high intensity UV irradiation is proposed.

Observation of Algal Bloom in the Northwest Arabian Sea Using Multisensor Remote Sensing Satellite Data

Algal bloom observed using Indian Remote Sensing Satellite IRS-P4 Ocean Color Monitor (OCM) derived chlorophyll images during December 23, 2003–January 8, 2004, off the Oman coast. High chlorophyll concentration (∼20 mg m−3) patches were observed. MODIS-Aqua data of January 1, 2004, were analyzed to generate normalized water leaving radiance (nLw) images for seven visible channels: 412, 443, 488, 531, 551, 667 and 678 nm. The channels 667 and 678 nm showed interesting algal bloom features. The bloom features were detected in OCM image of January 2, 2004, using Subramanian's Trichodesmium detection Protocol. MODIS-Aqua retrieved Sea Surface Temperature (SST) around the bloom patches was observed to be >240°C. The OCM chlorophyll mean observed to be very high (>10.0 mg m−3) in two bloom pockets. Quickscat scatterometer derived wind speed was found to be optimum in the range of 3–5 m/sec.

Binning algorithm for high-resolution IRS-P4 OCM chlorophyll image

Daily chlorophyll-a concentration from the Ocean Colour Monitor (OCM) sensor onboard the Indian Remote Sensing satellite (IRS-P4) is used to make weekly and monthly chlorophyll-a concentration maps. The pathwise swath data at 12 noon for every alternate day over the north Indian Ocean (NIO) during February 2004 and February 2005 were used to compare the existing algorithms for binning the data. Atmospherically corrected and geocorrected OCM data were used in the comparative study of three averaging algorithms – arithmetic mean (AVG), geometric mean (GEO) and maximum likelihood estimator (MLE). The analysis shows that the AVG algorithm is best suited when compared with the two other algorithms. However, for case 1 water, MLE gives nearly the same value as AVG. Based on this result, AVG was selected for operational weekly and monthly averaging of OCM data over the NIO. These high-resolution-derived chlorophyll-a weekly and monthly products will be useful to resolve inter-annual-to-decadal changes in chlorophyll-a concentration over the NIO.

Application of Satellite Remote Sensing for Investigation of Suspended Sediment Dispersion Pattern in the Near Shore Region: A Case Study from the Central West Coast of India

NAYAK, S.R.; HEGDE, V.S.; SHALINI, R.; RAJAWAT, A.S.; ALI, M.; VENKATESHWARLU, B., and RAMANA, I.V., 2012. Application of satellite remote sensing for investigation of suspended sediment dispersion pattern in the near shore region: A case study from the Central West Coast of India.Indian Remote Sensing -P4 (IRS P4) Ocean Color Monitor (OCM) data is used to understand seasonal variations in suspended sediment (SS) dispersal pattern in the near-shore waters of the Central West Coast of India. Four distinct patterns of sediment dispersion are observed. (1) During monsoon, plume-like sediment dispersion seaward is observed especially in the mouths of rivers. (2) As the monsoon progresses, there is northerly transport of sediments with anticlockwise pattern within the plumes. (3) During NE monsoon, sediment concentration is less and its transport is southward. (4) During premonsoon, SS concentration is high in the near-shore water and transport is landward. Sequential OCM data analyses indicated the influence of tidal currents, especially during premonsoon in the vicinity of the river mouths on sediments dispersion. During rising tide, sediments move into the estuary, and during falling tide they flow seaward resulting in erosion and formation of shoals. Sediment-dispersal patterns largely follow wind and wave patterns, a characteristic feature of the mesotidal coast. Presence of a number of mudflats within the estuary along with the siltation in the channels suggests that a net landward transport of sediments occur in the region.

Visual search in natural scenes explained by local color properties

Success in visually searching for a small object or target in a natural scene depends on many factors, including the spatial structure of the scene and the pattern of observers' eye movements. The aim of this study was to determine to what extent local color properties of natural scenes can account for target-detection performance. A computer-controlled high-resolution color monitor was used to present images of natural scenes containing a small, randomly located, shaded gray sphere, which served as the target. Observers' gaze position was simultaneously monitored with an infrared video eye-tracker. About 60% of the adjusted variance in observers' detection performance was accounted for by local color properties, namely, lightness and the red-green and blue-yellow components of chroma. A similar level of variance was accounted for by observers' fixations. These results suggest that local color can be as influential as gaze position in determining observers' search performance in natural scenes.

Monitoring buried jejunum free flaps with a sentinel: A retrospective study of 20 cases

The free jejunum transfer has become a widely used reconstruction option after total laryngopharyngectomy. The aim of this study was to evaluate the effectiveness of using an exteriorized jejunal segment for flap monitoring. Case series. Twenty patients with tumors involving the pharynx, larynx, or cervical esophagus were subjected to total laryngopharyngectomy and neck dissection. The resulting esophageal defect was reconstructed with a free jejunal flap based on a major branch of the superior mesenteric artery and vein. After completion of anastomoses with the recipient vessels, the flap was divided into two segments of common vascular supply. The smaller segment was exteriorized in the cervical region for direct monitoring of serosal color, temperature, peristalsis, and bleeding during the postoperative period. This sentinel was resected once the viability of the flap was judged appropriate. Of the 20 patients who had free jejunum transfers for pharyngoesophageal reconstruction, 14 had an uneventful postoperative course, and six needed re-exploration due to signs of arterial insufficiency in the sentinel segment. On re-exploration, four flaps were found to have arterial thrombosis and two had no abnormality at the anastomotic site. One of the flaps that developed thrombosis was subsequently lost. Monitoring of buried free jejunal flap with a sentinel is an effective method of assessing flap viability after total laryngopharyngectomy and guides re-exploration in cases of anastomotic complications.

Derivation of Calibration Coefficients for OCM-2 Sensor for Coastal Waters

The radiometric calibration coefficients that are required to enhance the preflight calibration coefficients to improve the performance of the Ocean Colour Monitor (OCM-2) onboard the Indian Remote Sensing Satellite (IRS) are determined using in-situ measurements in coastal waters around southern India. These coefficients were applied to OCM-2 data acquired over coastal waters off Point Calimere (Palk Strait) and Gulf of Mannar of the Bay of Bengal, and are compared with similar coefficients included in the SeaDAS software and those provided by the Space Application Centre (SAC). Two atmospheric correction algorithms were used in conjunction with these coefficients to obtain the water-leaving radiances (Lw) from OCM-2 data, namely the CAAS algorithm and SeaDAS algorithm. An evaluation of the results of these coefficients and atmospheric correction algorithms showed large deviations in Lw values derived with the SAC (positive deviation) coefficients and SeaDAS (negative deviation) coefficients when applied to OCM-2 data along with the SeaDAS atmospheric correction algorithm. The deviations were less remarkable with new coefficients when the same (SeaDAS) atmospheric correction algorithm was used. However, application all three coefficients to OCM-2 using the CAAS algorithm showed a similar trend but with less deviations with respect to in-situ Lw data. The results obtained with the new coefficients showed good agreement with the in-situ water-leaving radiances (except channels 412-443nm). These results suggest that the new calibration coefficients can be used along with the CAAS atmospheric correction algorithm to improve the performance of OCM-2 sensor for quantitative assessments of the various water constituents in coastal waters (including bloom) around India.

On-line color monitoring of solid foods during supercritical CO 2 pasteurization

An on-line color monitoring system for solid foods to be used during supercritical carbon dioxide (SC-CO 2) pasteurization was designed and tested. The experimental apparatus described here allowed for the measurement of reflectance spectra and color parameters ( L ∗, a ∗, b ∗) during (on-line) as well as before and after treatments (off-line). The results demonstrated that SC-CO 2 pasteurization applied at 12.0 MPa, 40 °C slightly affected the color of freshly cut pieces of coconut and carrot during the process performed at different treatment times (10, 20, and 30 min). Reflectance spectra of coconut, acquired on-line, showed that CO 2 influenced the color immediately upon treatment: lightness ( L ∗) changed from 86.10 ± 2.80 at 1 min to 79.57 ± 0.74 at 30 min. The decompression was demonstrated to be the critical parameter affecting the color of carrot. The off-line measurements showed that 30 min of treatment induced 38% and 22% decrease of redness ( a ∗) and yellowness ( b ∗), respectively. The proposed apparatus allowed for a non-invasive, immediate and direct monitoring of food color before, during and after SC-CO 2 pasteurization.

An in vitro model for the study of human implantation.

Implantation remains the rate-limiting step for the success of in vitro fertilization. Appropriate models to study the molecular aspects of human implantation are necessary in order to improve fertility. First trimester trophoblast cells are differentiated into blastocyst-like spheroids (BLS) by culturing them in low attachment plates. Immortalized human endometrial stromal cells and epithelial cells (ECC-1) were stably transfected with GFP or tdTomato. Co-culture experiments were monitored using Volocity imaging analysis system. This method demonstrates attachment and invasion of BLS, formed by trophoblast cells, into stromal cells, but not to uterine epithelial cells. We have developed an in vitro model of uterine implantation. The manipulation of this system allows for dual color monitoring of the cells over time. Additionally, specific compounds can be added to the culture media to test how this may affect implantation and invasion. This model is a helpful tool in understanding the complexity of human implantation.

Atmospheric correction of ENVISAT/MERIS data over case II waters: the use of black pixel assumption in oxygen and water vapour absorption bands

The Medium Resolution Imaging Spectrometer (MERIS) sensor, with its good physical design, can provide excellent data for water colour monitoring. However, owing to the shortage of shortwave-infrared (SWIR) bands, the traditional near-infrared (NIR)–SWIR algorithm for atmospheric correction in inland turbid case II waters cannot be extended to the MERIS data directly, which limits its applications. In this study, we developed a modified NIR black pixel method for atmospheric correction of MERIS data in inland turbid case II waters. In the new method, two special NIR bands provided by MERIS data, an oxygen absorption band (O2 A-band, 761 nm) and a water vapour absorption band (vapour A-band, 900 nm), were introduced to keep the assumption of zero water-leaving reflectance valid according to the fact that both atmospheric transmittance and water-leaving reflectance are very small at these two bands. After addressing the aerosol wavelength dependence for the cases of single- and multiple-scattering conditions, we further validated the new method in two case lakes (Lake Dianchi in China and Lake Kasumigaura in Japan) by comparing the results with in situ measurements and other atmospheric correction algorithms, including Self-Contained Atmospheric Parameters Estimation for MERIS data (SCAPE-M) and the Basic ERS (European Remote Sensing Satellite) & ENVISAT (Environmental Satellite) (A)ATSR ((Advanced) Along-Track Scanning Radiometer) and MERIS (BEAM) processor. We found that the proposed method had acceptable accuracy in the bands within 560–754 nm (MERIS bands 5–10) (average absolute deviation (AAD) = 0.0081, average deviation (AD) = 0.0074), which are commonly used in the estimation models of chlorophyll-a (chl-a) concentrations. In addition, the performance of the new method was superior to that of the BEAM processor and only slightly worse than that of SCAPE-M in these bands. Considering its acceptable accuracy and simplicity both in principle and at implementation compared with the SCAPE-M method, the new method provides an option for atmospheric correction of MERIS data in inland turbid case II waters with applications aiming for chl-a estimation.

In-Line Monitoring of Particulate, Color, and Water Content in Lubricating Oils to Facilitate Predictive Maintenance, Reduce Wear, and Provide Real Time Alarming

Abstract Imaging techniques for characterizing particle shapes and sizes in lubricating oils can be a valuable tool toward improving the life span and reliability of mechanical equipment. ASTM currently specifies several tests to monitor the condition of lube oil; however, most of these are off-line, lab based tests. Vision based systems are well designed to perform the examination of the lube oil, either in line or off line, as they are the only instrument systems that can determine particle shape, which is a critical parameter in determining the source of wear in a mechanical system. The visual capability allows the user to input his or her knowledge of the process to work in making meaningful analyses. Imaging filters can be applied to the analysis to sort through noise and focus on the important particle information that must be monitored. This paper describes a vision based system used for particle sizing that provides a true two-dimensional size and shape analysis. The paper also discusses the fundamentals of a vision system that allow for accurate and repeatable analysis of a wide range of processes.

Fixed-time adjustable dose site-specific fertilizer nitrogen management in transplanted irrigated rice ( Oryza sativa L.) in South Asia

In the quest of enhancing nitrogen (N) use efficiency in irrigated transplanted rice beyond that observed with blanket recommendation, leaf colour chart (LCC) is being used to apply N whenever colour of the first fully opened leaf from the top is less green than a critical colour shade. So as to avoid frequent (every 7–10 days) monitoring of leaf colour, criteria were developed to apply fertilizer N at critical growth stages of rice but by adjusting the dose of N as per colour of the leaf measured with LCC. A series of experiments were carried out at Ludhiana and Gurdaspur locations from 2007 to 2010 with treatments refined progressively to work out appropriate combination of fixed and adjustable rates of fertilizer N at critical stages of transplanted rice. A dose of 30 kg N ha −1 at transplanting as prescriptive N management proved to be adequate for achieving high yields of rice. Corrective N management consisting of adjustable N doses was worked out as application of 45, 30 or 0 kg N ha −1 depending upon leaf colour to be <LCC shade 4, between LCC shade 4 and 5 or ≥LCC shade 5 both at maximum tillering and panicle initiation stages, and 30 kg N ha −1 only if leaf colour is less green than LCC shade 4 at initiation of flowering. A combination of these prescriptive and corrective N management strategies resulted in optimum rice grain yield and high N use efficiency with less fertilizer N application than the blanket recommendation. For some rice cultivars, particularly in years with favorable climate, fixed date adjustable dose N management produced yield levels higher than those achieved by applying blanket recommendation for fertilizer N and resulted in agronomic efficiency higher than 25 kg grain/kg N.

Reducing mortality in individuals at high risk for advanced melanoma through education and screening

Incidence and mortality rates of melanoma throughout most of the developed world have increased in the past 25 years. We propose that reduction of deaths from melanoma can be best enhanced by strong collaborations between experts in dermatology, primary care, oncology, cancer education and health systems research, epidemiologists, and behavioral scientists, among others. Public and professional educational campaigns should be guided by an understanding of 3 underlying but overlapping roots: epidemiology and preventable mortality (an understanding of who is most likely to be given the diagnosis of thick or late-stage melanoma), biology (an investigation of tumor types that are relatively common but potentially most lethal), and sociology (an analysis of the changes needed in social structures to improve access to those most in need of early detection programs). We review these major concepts, concentrating on the key risk factors for advanced melanoma.

Application Research Color Management in the Transfer Printing Based on the Linear Regression Algorithm

There are many factors that effect the quality of the heat transfer printing products. The CRT in prepress is the most important factor. In this paper, the color ladder segmentation is spaced at 5. The color of the CRT is tested with X-RITE color monitor optiomizer. According to the data and the curve, the function model of color characteristic features is set up. We made the common test plates which is to verify the error of the function model. As a result, The range of color error in the heat transferring printing is reduced. The color management profile is put forward, the quality of transferring printing is improved. A reference is provided for the color management in the heat transfer printing.

Visually Guided Male Urinary Catheterization: A Feasibility Study

Ten percent to 15% of urinary catheterizations involve complications. New techniques to reduce risks and pain are indicated. This study examines the feasibility and safety of male urinary catheterization by nursing personnel using a visually guided device in a clinical setting. The device, a 0.6-mm fiber-optic bundle inside a 14F triple-lumen flexible urinary catheter with a lubricious coating, irrigation port, and angled tip, connects to a camera, allowing real-time viewing of progress on a color monitor. Two emergency nurses were trained to use the device. Male patients 18 years or older presenting to the emergency department with an indication for urinary catheterization using a standard Foley or Coudé catheter were eligible to participate in the study. Exclusion criteria were a current suprapubic tube or gross hematuria prior to the procedure. Twenty-five patients were enrolled. Data collected included success of placement, total procedure time, pre-procedure pain and maximum pain during the procedure, gross hematuria, abnormalities or injuries identified if catheterization failed, occurrence of and reason for equipment failures, and number of passes required for placement. All catheters were successfully placed. The median number of passes required was 1. For all but one patient, procedure time was ≤ 17 minutes. A median increase in pain scores of 1 point from baseline to the maximum was reported. Gross hematuria was observed in 2 patients. The success rate for placement of a Foley catheter with the visually guided device was 100%, indicating its safety, accuracy, and feasibility in a clinical setting. Minimal pain was associated with the procedure.