Color Video Camera Research Articles

An integrated learning approach to environment modelling in mobile robot navigation

We extend the approach to learning a topological description of the environment with recurrent neural networks. Usually, a predetermined reactive behavior and a predefined criterion for decision points are used. In our extended approach, both the reactive behavior and the criterion for the decision points are adaptive and therefore more flexible. The reactive behavior is learnt using reinforcement learning supplemented by a new, psychologically grounded mechanism that enables the robot to autonomously explore the environment in a useful way for the purposes of modelling. Decision points or situations where a deviation from the reactive behavior is allowed are learnt on-line using a novel criterion based on the information theory. Results of experiments conducted with a simulated mobile robot equipped with proximity sensors and a color video camera show applicability of the proposed approach.

An Imaging Colorimeter for Noncontact Skin Color Measurement

There has been a considerable effort made in several medical fields in the objective color analysis and characterization of biological tissues. Conventional colorimeters have proved inadequate for this purpose, since they do not provide spatial color information and because the measuring procedure randomly affects the color of the tissue. In this paper an imaging colorimeter is presented where the non imaging optical photodetector of the instrument is replaced with a charge-coupled device (CCD) sensor of a color video camera, enabling the independent capture of color information for any spatial point within its field of view. Combining imaging and colorimetry, the acquired image is calibrated and corrected under several ambient light conditions, providing non contact reproducible color measurements free of the errors and limitations present in conventional colorimeters. The technique has been used in hospital clinics for a wide variety of patients. These features highlight the potential of the imaging colorimeters as clinical and research tools for the standardization of clinical diagnosis and the objective evaluation of treatment efficacy.

New Experimental Results of a Single Ridge Passing Through an EHL Conjunction

The micro-elastohydrodynamic lubrication of a single transverse ridge is revisited using an experimental technique, which combines an optical interferometry technique and a high-speed color video camera. The purpose of this study is to augment prior experimental analyses, by providing a complete and detailed history of the ridge associated with changes in film thickness as it passes through a high-pressure conjunction. An enhanced experimental procedure has been developed to enable an automatic analysis of the interferograms. In particular, the methodology allows abrupt changes in film thickness and rapid variations of interference orders to be taken into account. The observations presented in this paper exhibit interesting and fascinating features that have not been previously reported. In particular, it is observed that under rolling/sliding conditions the ridge undergoes further deformations as it proceeds to the exit to the contact. In addition, there appears to be an important contribution of pressure flow to the transport of lubricant and, contrary to current understanding, entrapped lubricant is seen to accompany the ridge as it passes through the contact, therefore appearing not to move at the entraining velocity.

Sprite observations from the space shuttle during the Mediterranean Israeli dust experiment (MEIDEX)

The Mediterranean Israeli dust experiment (MEIDEX) flew on-board the space shuttle in winter 2003, in a 39°-inclination orbit for 16 days, passing over the major thunderstorm regions on Earth. The primary science instrument of the MEIDEX payload is a Xybion IMC-201 image-intensified radiometric camera with six narrow band filters, boresighted with a wide-FOV color video camera. During the nightside of the orbit there will be dedicated observations toward the Earth's limb above areas of active thunderstorms, in an effort to image transient luminous events (TLEs) from space. Optical observations from space will be conducted with the 665 nm filter that matches the observed wide peak centered at 670 nm that typifies red sprites, and also with the 380 and 470 nm filters for recording blue jets. Observations will consist of a continuous recording of the Earth's limb, from the direction of the dusk terminator towards the nightside. Areas of high convective activity will be forecasted and uplinked to the crew before the observation. The astronaut will direct the camera toward areas with lightning activity, observed visually through the windows and on monitors in the crew cabin. Simultaneously with the optical observations from space, dedicated ground measurements will be conducted on a global scale. Two field sites in the Negev Desert in Israel will be used to collect electromagnetic data in the ELF and VLF frequency range. Additional ground stations in Germany, Hungary, USA, Antarctica, Chile, South Africa, Australia, Taiwan and Japan will also record Schumann resonance and VLF signals. The coordinated measurements from various locations on Earth and from space will enable us to triangulate the location and determine the polarity and charge moment of the parent lightning of the optically observed TLEs. The success of the campaign will further clarify the geographical distribution of Sprites, Elves and Jets.

Determination of crop rows by image analysis without segmentation

A method based on computer vision for detection and localisation of crop rows, especially of small-grain crops, is described. The method is intended for use in a system for automatic guidance of agricultural implements in selective treatment of rows and/or inter-row spaces, e.g. with an inter-row cultivator. The computer vision system consists of a colour video camera and a computer. The camera is focussed on the field surface from an inclined angle to obtain images that cover up to about five rows simultaneously. New images are continuously transferred to the computer, which processes them and calculates the necessary lateral movements of the implement. The processing method does not include a segmentation step, which is found in most other methods for plant detection. The segmentation step has been replaced by computation of centres of gravity for row segments in the image. This approach has proven to reduce the computational burden of the image processing software. The estimation of the orientation and the lateral position of the centre lines of the rows is accomplished by weighted linear regression. The accuracy of the estimation was determined by comparing the calculated row centre line with the position of a reference string, which was placed parallel to the row along the centre line of an adjacent inter-row space.

Multichannel method for absolute shape measurement using projected fringes

The multichannel approach is combined with the reduced temporal phase unwrapping scheme for rapid shape measurement. The shape is measured using projected fringes and optical triangulation. Fringes are projected using a colour video projector and recorded by a CCD-camera. Using a colour video projector and a colour video camera makes it possible to use the red, green and blue channels individually. This is the multichannel method. In each channel, the blue, green and red carries fringe maps with different fringe pitch. A short sequence of phase-stepped images is projected and acquired sequentially in time. This reduces measurement time by a factor of three when compared to using one channel. From the acquired images, it is possible to calculate absolute phase using the reduced temporal phase unwrapping analysis scheme. For each channel, it is also possible to calculate fringe contrast and fringe amplitude. Therefore, it is possible to retrieve the colour of an object without acquiring an extra image. The method is demonstrated by measuring the shape of two generally coloured and complex shaped objects.

Three-dimensional reconstruction of Haversian systems in ovine compact bone.

Haversian systems or secondary osteons are an integral component of compact bone. However, as their exact shape is debatable, this study describes a technique to view their morphology in three dimensions. Bone remodeling in adult ovine long bones was labelled at intervals using a series of chelating fluorochromes. A series of longitudinal sections were cut at 25 microm intervals through blocks of the distal radius embedded in methylmethacrylate using a sledge macrotome. The chelating agents were used as markers of bone formation in the study of bone growth and osteon morphology. The two-dimensional image of each section was examined using an epifluorescence microscope. Images were transferred to a PC via a CCD low light colour video camera. Surface reference points were noted on each of the sections and, using computer software, a three-dimensional image of a refilling labelled osteon was reconstructed and its dimensions measured. Haversian systems may have a gentle spiral course along the longitudinal axis of the bone. They intertwine with adjacent osteons and give multiple branches along their course producing a complex pattern of organization. The mean labelled length and diameter of the osteons was 1.4 + 1 mm and 145 + 0.42 microm [Mean + S.D], respectively.

Hand-held digital video-camera for eye examination and follow-up

We developed a hand-held digital colour video-camera for eye examination in primary care. The device weighed 550 g. It featured a charge-coupled device (CCD) and corrective optics. Both colour video and digital still images could be taken. The video-camera was connected to a PC with software for database storage, image processing and telecommunication. We studied 88 normal subjects (38 male, 50 female), aged 7-62 years. It was not necessary to use mydriatic eye drops for pupillary dilation. Satisfactory digital images of the whole face and the anterior eye were obtained. The optic disc and the central part of the ocular fundus could also be recorded. Image quality of the face and the anterior eye were excellent; image quality of the optic disc and macula were good enough for tele-ophthalmology. Further studies are needed to evaluate the usefulness of the equipment in different clinical conditions.

Optical imaging and automated melanoma detection: questions and answers.

Early detection and prompt excision of cutaneous melanoma is of paramount importance to improve patient survival, and the clinician should be aware of the clinical features that suggest the presence of a malignant lesion. The clinical diagnosis is mainly based on observation of the colour and shape of a given skin lesion. Unfortunately, evaluation of a pigmented lesion is to a large extent subjective and is closely related to the experience of the clinician. To overcome this problem, optical imaging techniques using different instrumentation (i.e. colour video camera, epiluminescence microscopy, reflectance spectrophotometry) and computer image analysis have been proposed in an attempt to provide quantitative measurements in an objective and reproducible fashion. The different procedures employed to perform the diagnosis automatically all have a common denominator: mimicking the eye and the brain of the clinician by image processing and computerized analysis programs, respectively. Sensitivity and specificity data reported in the literature suggest that the computer-based diagnosis of melanoma does not greatly differ from the diagnostic capability of an expert clinician, and is independent of the optical acquisition method employed to analyse the lesions. Most of the computer-processed morphometric variables useful in automated diagnosis are not recognizable nor can be objectively evaluated by the human eye, except that of lesion dimension. However, several questions should be answered before assessing the actual usefulness, including the potential and limitations, of computer-based diagnostic procedures. The purpose of this study was to briefly review the different kinds of instrumentation being used to diagnose melanoma, and to raise questions and whenever possible provide answers in an attempt to establish whether there will be a future for these computerized systems.

Detection of Crassostrea virginica hinge lines with machine vision: software development

Shucking (removing the meat from the shell) an oyster requires that the muscle detachments to the two shell valves and the hinge be severed. Described here is the computer vision software needed to locate the oyster hinge line so it can be automatically severed, one step in the development of an automated oyster shucker. Oysters are first prepared by washing and trimming off a small shell piece on the oyster hinge end to provide access to the outer hinge surface. A computer vision system employing a color video camera then grabs an image of the hinge end of the oyster shell. This image is processed by the computer using software. The software is a combination of commercially available and custom written routines that locate the oyster hinge. The software uses four feature variables, circularity, rectangularity, aspect-ratio, and Euclidian distance, to distinguish the hinge object from other dark colored objects on the hinge end of the oyster. Several techniques, including shrink–expand, thresholding, and others, were used to secure an image that could be reliably and efficiently processed to locate the oyster hinge line.

모션캡쳐 애니메이션을 위한 거리 측정방법

본 논문에서는 모션캡쳐를 위해 컬러 스테레오 카메라를 이용한 거리 측정 알고리즘을 제안하였다. 현실공간의 연기자 각 관절 부위에 컬러마커를 부탁시키고 이를 컬러 스테레오 카메라를 이용해 촬영한 후, 본 논문에서 제안한 컬러 매칭방법과 컬러 영역중심의 분석방법에 의해 카메라로부터 마커가지의 거리를 계산한다. 스테레오 영상에서 마커의 컬러영역을 추출하기 위해 국부지역내의 각 픽셀의 RGB(red, green, blue) 컬러 정보를 CIE(Commission Internationale de1'Eclairage) 컬러 공간으로 변환시켜 컬러의 파장을 계산하고, 국부지역의 우월 파장이 마커의 컬러파장과 일치하는지를 검색한다. 가상공간에서의 캐릭터의 움직임은 시간에 따른 마커의 위치 변화정보를 처리하는 프로그램에 의하여 제어된다. In this paper, a distance measuring algorithm for motion capture using color stereo camera is proposed. The color markers attached on articulations of an actor are captured by stereo color video cameras, and color region which has the same color of the marker's color in the captured images is separated from the other colors by finding dominant wavelength of colors. Color data in RGB (red, green, blue) color space is converted into CIE (Commission Internationale del'Eclairage) color space for the purpose of calculating wavelength. The dominant wavelength is selected from histogram of the neighbor wavelengths. The motion of the character in the cyber space is controlled by a program using the distance information of the moving markers.

Visualization of light dispersion and structural phase transitions with light figures

Employment of light figures for visualization of light dispersion effects and structural phase transitions in anisotropic materials is described. A polarizing microscope attached with a full color video camera, a temperature variable cryostat and a powerful source of monochromatic light has been demonstrated as a convenient technique for readily attainable and fast visualization. Wavelength dispersion of the largest partial birefringence and ferroelectric structural phase transition through an intermediate incommensurate phase are visualized in acute bisectrix light figures of biaxial TlInS 2, TlGaSe 2 and TlGaS 2 ternary compounds with a layered structure.

Turbulence modification by the clusters of settling particles in turbulent water flow in a horizontal duct

Simultaneous visualization is carried out for depositing fine copper particles and fluorescent tracer particles in turbulent water flow in a horizontal duct with a new technique by using the color video camera. Particle image velocimetry (PIV) and particle tracking velocimetry (PTV) techniques are applied to the images of the scattered light from the depositing particles and those of the fluorescence of the tracer particles, respectively. It is found that the increase in the streamwise and downward mean velocities and the decrease in the streamwise turbulence intensity are mainly caused by some copper-particle clusters, which modify near-wall turbulence structure, and some other clusters, which fall with higher velocity than the still-fluid settling velocity and are elongated in the vertical direction. The Stokes number based on the initial state for the group of particles introduced into the flow is found to be one of the criteria for particle clustering in the flow.

Ultra-high-definition Color Video Camera with four 8M-pixel CCDs

Ultra-high-definition Color Video Camera with four 8M-pixel CCDs

A Television System for Determining Dynamic Thermal Fields in Self-Propagating High-Temperature Synthesis Processes

A television measuring-computing system based on a standard commercial color video camera (analog or digital) and a computer, which enables the thermal space-time characteristics of a combustion wave to be measured in self-propagating high-temperature synthesis processes, is described. The procedure for measuring temperature is outlined.

Analysis of Skin Color Development in Live Goldfish Using a Color Machine Vision System

Abstract A color machine vision system (CMVS) was used to measure and quantify color development in the skin of live goldfish Carassius auratus raised in pond or well water and fed rations of different commercial feeds. Goldfish were of the ornamental Red Oranda variety, 3 months of age, 0.15 ± 0.01 g (mean ± SD) in body weight and 1.38 ± 0.22 cm in total length. Data on color development were acquired through a charge-coupled display color video camera and an image capture card attached to a personal laptop computer. We used a color analysis program developed at the University of Florida, Department of Food Science and Human Nutrition, to interpret the skin color patterns. Pixels from the computerized image were compared and matched to one of 64 color blocks (standards) representing the entire color spectrum. Pixel groupings were represented and recorded as a frequency (percentage) of occurrence for each color standard. The CMVS provided an objective method for measuring the skin color of goldfish and al...

Determination of stem and calyx location on apples using automatic visual inspection

Automatic surface blemish detection systems for apples can be confused by the stem, calyx, and concavities. If the stem and calyx are incorrectly classified as blemishes, a false grade will be assigned to a fruit. A new method to determine the location of these concavities is described. The apples were illuminated by blue linear light sources and a standard colour video camera was employed to detect the reflection patterns. Blue lights were employed because they were outside the spectrum of interest for blemish detection. This enables the technique to be used simultaneously with blemish detection. The reflection patterns were in the form of light stripes, with a shape dependent on the shape and orientation of each apple. Analysis of these patterns made it possible to identify the location of stem and calyx regions. Details of a laboratory implementation of the acquisition system and an outline of the algorithms, are presented together with some preliminary results.

Nkx2-5 activity is essential for cardiomyogenesis.

The homeobox transcription factor tinman is essential for heart vessel formation in Drosophila. In contrast, mice lacking the murine homologue Nkx2-5 are defective in cardiac looping but not in cardiac myocyte development. The lack of an essential role for Nkx2-5 in cardiomyogenesis in mammalian systems is most likely the result of genetic redundancy with family members. In this study, we used a dominant negative mutant of Nkx2-5, created by fusing the repressor domain of engrailed 2 to the Nkx2-5 homeodomain, termed Nkx/EnR. Expression of Nkx/EnR inhibited Me(2)SO-induced cardiomyogenesis in P19 cells but not skeletal myogenesis. Nkx/EnR inhibited expression of cardiomyoblast markers, such as GATA-4 and MEF2C, but not of mesoderm markers, such as Brachyury T and Wnt5b, or of skeletal lineage markers, such as MyoD and Mox1. To identify the minimal region of Nkx2-5 that can trigger cardiomyogenesis, we analyzed the activity of various Nkx2-5 deletion mutants. The C-terminal domain was not necessary for the ability of Nkx2-5 to induce cardiomyogenesis and loss of this domain did not enhance myogenesis. Therefore, Nkx2-5 function is essential for commitment of mesoderm into the cardiac muscle lineage, and the N-terminal region, together with the homeodomain, is sufficient for cardiomyogenesis in P19 cells.

Measurement of fluid contents by light transmission in transient three‐phase oil‐water‐air systems in sand

Most three‐phase flow models lack rigorous validation because very few methods exist that can measure transient fluid contents of the order of seconds of whole flow fields. The objective of this study was to develop a method by which fluid content can be measured rapidly in three‐phase systems. The method uses the hue and intensity of light transmitted through a slab chamber to measure fluid contents. The water is colored blue with CuSO4. The light transmitted by high‐frequency light bulbs is recorded with a color video camera in red, green, and blue and then converted to hue, saturation, and intensity. Calibration of hue and intensity with water, oil, and air is made using cells filled with different combinations of the three fluids. The results show that hue and water content are uniquely related over a large range of fluid contents. Total liquid content is a function of both hue and light intensity. The air content is obtained by subtracting the liquid content from the porosity. The method was tested with static and transient experiments. Measurements made with the light transmission method (LTM) and synchrotron X rays of the static experiment agreed well. In the transient experiments, fingers were formed by dripping water on the surface in a two‐dimensional slab chamber with partially oil‐saturated sand. The LTM is able to capture the spatial resolution of the fluid contents and can provide new insights in rapidly changing, three‐phase flow systems.

Grindability soft-sensors based on lithological composition and on-line measurements

The grinding efficiency evaluation can be performed through the comparison of the operational work index with the ore work index Wi. In this work, the development of an ore grindability soft-sensor (ESTMOL) is presented. The ore work index is estimated on the basis of its lithological composition. Also addressed is the experimental development of a lithological composition sensor (ACOLITO) for ores on a conveyor belt. The lithological composition is determined from image analysis on samples obtained by a color video camera. Finally, a global operational work index for a complete grinding section is defined here, and its on-line estimation (PREDIMOL) is addressed, including the required soft-sensors to overcome the measurement problems. The experimental work is done with samples obtained from the CODELCO - Andina grinding plant. All the sensors have given up to now good results.