Low-resolution Color Research Articles

Visual Monitoring of Food Spoilage Based on Hydrolysis-Induced Silver Metallization of Au Nanorods.

Colorimetric detection of biogenic amines, well-known indicators of food spoilage, plays an important role for monitoring of food safety. However, common colorimetric sensors for biogenic amines suffer from low color resolution or complicated design and intricate output for the end-users. Herein, we explored a simple but effective strategy for visual monitoring of biogenic amines with multiple color change based on hydrolysis-induced silver metallization reaction to tune the localized surface plasmon resonance (LSPR) adsorption of Au nanorods (NRs). The color change and blue shift of longitudinal LSPR peak of Au NRs were closely related to the concentration of biogenic amines. This strategy provided a simple, sensitive, robust, nondestructive, cost-effective, and user-friendly platform for in situ evaluating the freshness of foodstuffs.

Precise localization of eye centers in low resolution color images

The localization of eye centers and tracking of gaze constitutes an integral component of many human–computer interaction applications. A number of constraints including intrusiveness, mobility, robustness and high-price of eye tracking systems have hindered the way of the integration of eye trackers in everyday applications. Several ‘passive’ systems based on a single camera have been lately proposed in the literature, exhibiting though subordinate precision compared to the commercial, hardware-based eye tracking devices. In this paper we introduce an automatic, non-intrusive method for precise eye center localization in low resolution images, acquired from single low-cost cameras. To this end, the proposed system uses color information to derive a novel eye map that emphasizes the iris area and a radial symmetry transform which operates both on the original eye images and the eye map. The performance of the proposed method is extensively evaluated on four publicly available databases containing low resolution images and videos. Experimental results demonstrate great accuracy in challenging cases and resilience to pose and illumination variations, achieving significant improvement over existing methods.

An approach to the radiometric aerotriangulation of photogrammetric images

Harnessing the radiometric information provided by photogrammetric flights could be useful in increasing the thematic applications of aerial images. The aim of this paper is to improve relative and absolute homogenization in aerial images by applying atmospheric correction and treatment of bidirectional effects. We propose combining remote sensing methodologies based on radiative transfer models and photogrammetry models, taking into account the three-dimensional geometry of the images (external orientation and Digital Elevation Model). The photogrammetric flight was done with a Z/I Digital Mapping Camera (DMC) with a Ground Sample Distance (GSD) of 45 cm. Spectral field data were acquired by defining radiometric control points in order to apply atmospheric correction models, obtaining calibration parameters from the camera and surface reflectance images. Kernel-driven models were applied to correct the anisotropy caused by the bidirectional reflectance distribution function (BRDF) of surfaces viewed under large observation angles with constant illumination, using the overlapping area between images and the establishment of radiometric tie points. Two case studies were used: 8-bit images with applied Lookup Tables (LUTs) resulting from the conventional photogrammetric workflow for BRDF studies and original 12-bit images (Low Resolution Color, LRC) for the correction of atmospheric and bidirectional effects. The proposed methodology shows promising results in the different phases of the process. The geometric kernel that shows the best performance is the Lidense kernel. The homogenization factor in 8-bit images ranged from 6% to 25% relative to the range of digital numbers (0–255), and from 18% to 35% relative to levels of reflectance (0–100) in the 12-bit images, representing a relative improvement of approximately 1–30%, depending on the band analyzed.

Scale-dependent and example-based grayscale stippling

We present an example-based approach to synthesizing stipple illustrations for static 2D images that produces scale-dependent results appropriate for an intended spatial output size and resolution. We show how treating stippling as a grayscale process allows us to both produce on-screen output and to achieve stipple merging at medium tonal ranges. At the same time we can also produce images with high spatial and low color resolution for print reproduction. In addition, we discuss how to incorporate high-level illustration considerations into the stippling process based on discussions with and observations of a stipple artist. Also, certain features such as edges can be extracted and used to control the placement of dots to improve the result. The implementation of the technique is based on a fast method for distributing dots using halftoning and can be used to create stipple images interactively. We describe both a GPU implementation of the basic algorithm that creates stipple images in real-time for large images and an extended CPU method that allows a finer control of the output at interactive rates.

Small object monitoring for sensitive indoor compounds

This paper describes the development of an automatic human monitoring system for indoor environments. The aim was to develop a system that allows general movement of one or more people to be determined using a very low-resolution colour sensor. The sensor has sufficiently low resolution that objects are not resolved – to protect privacy. It is demonstrated that movement can be monitored to a high degree of accuracy using spectral un-mixing techniques adapted from satellite remote sensing applications. These algorithms allow the fractional contributions from different colours within each pixel to be estimated and this can then be used to assist in the detection and tracking of small objects. Of particular interest is the robustness of the monitoring algorithms in a series of real-life challenging scenarios such as quickly changing illumination conditions and occlusion of objects

Intensive care requirements in paediatric burns revisited

This study sought to assess the validity of independent, blinded reporting of Laser Doppler Imaging (LDI) prediction of burn wound outcome in children. Two experienced paediatric burn consultants were invited to report on LDI scans performed routinely within 3 days of burn. They were provided with the LDI flux image, a low-resolution colour digital photograph of the burnt area and a basic history. Report predictions were correlated with outcome. Reports were compiled on 50 scans performed on 31 patients at a mean of 54 h post burn. Of the 100 reports generated, mean correlation with outcome was 97%. If the LDI predicted a deep burn, it was always correct. Non-correlations were due to a number of factors including inadequate scanning of the affected area, excessive movement and residual wound debris. Accurate prediction of burn wound outcome could be made via the standard information generated by LDI and appeared more reliable than clinical prediction. The correlation improved with increasing experience with LDI.

Laser Doppler Imaging of paediatric burns: Burn wound outcome can be predicted independent of clinical examination

This study sought to assess the validity of independent, blinded reporting of Laser Doppler Imaging (LDI) prediction of burn wound outcome in children. Two experienced paediatric burn consultants were invited to report on LDI scans performed routinely within 3 days of burn. They were provided with the LDI flux image, a low-resolution colour digital photograph of the burnt area and a basic history. Report predictions were correlated with outcome. Reports were compiled on 50 scans performed on 31 patients at a mean of 54 h post burn. Of the 100 reports generated, mean correlation with outcome was 97%. If the LDI predicted a deep burn, it was always correct. Non-correlations were due to a number of factors including inadequate scanning of the affected area, excessive movement and residual wound debris. Accurate prediction of burn wound outcome could be made via the standard information generated by LDI and appeared more reliable than clinical prediction. The correlation improved with increasing experience with LDI.

Grayscale aerial and space image colorization using texture classification

This paper introduces a new approach to colorization of grayscale aerial or space imagery. Proposed method is based on a simple premise: similar textures should have similar color distributions. This premise is formalized by using Bayesian texture classification of grayscale destination imagery with a set of textural prototypes or swatches from source color imagery. Only 2D distributions of chrominance channels are transferred and original luminance value is retained. A special segmentation technique is proposed in order to increase the performance of the algorithm. Examples on real images show high quality of colorization neither without using low-resolution color imagery nor without any user intervention. Appropriate prototype selection enables modeling of season changes of vegetation. It is shown that the proposed approach can be successfully applied to color infrared (CIR) imagery transform into visible RGB colors and for color image remapping.

A real time adaptive visual surveillance system for tracking low-resolution colour targets in dynamically changing scenes

This paper presents a variety of probabilistic models for tracking small-area targets which are common objects of interest in outdoor visual surveillance scenes. We address the problem of using appearance and motion models in classifying and tracking objects when detailed information of the object's appearance is not available. The approach relies upon motion, shape cues and colour information to help in associating objects temporally within a video stream. Unlike previous applications of colour and complex shape in object tracking, where relatively large-size targets are tracked, our method is designed to track small colour targets commonly found in outdoor visual surveillance. Our approach uses a robust background model based around online Expectation Maximisation to segment moving objects with very low false detection rates. The system also incorporates a shadow detection algorithm which helps alleviate standard environmental problems associated with such approaches. A colour transformation derived from anthropological studies to model colour distributions of low-resolution targets is used along with a probabilistic method of combining colour and motion information. A data association algorithm is applied to maintain tracking of multiple objects under circumstances. Simple shape information is employed to detect subtle interactions such as occlusion and camouflage. A novel guided search algorithm is then introduced to facilitate tracking of multiple objects during these events. This provides a robust visual tracking system which is capable of performing accurately and consistently within a real world visual surveillance arena. This paper shows the system successfully tracking multiple people moving independently and the ability of the approach to maintain trajectories in the presence of occlusions and background clutter.

The basic colour terms of Ndebele∗

Abstract We report a field study of the colour terms of the Bantu language Ndebele. The main purposes of the study were to describe the Ndebele colour term inventory, and to determine which colour terms were basic in order to test Berlin & Kay's theory of colour universals. A sample of school children and a sample of adults from Matabeleland performed a list task ('tell me as many colour terms as you know') in order to identify Ndebele colour terms and to establish the relative salience of the terms. The adults also took part in a low resolution colour mapping task which provided a preliminary estimate of the range of referents of each term. Our results show that Ndebele has four definite basic terms: terms for white, black, red and green with blue (grue). In addition, the children had a basic term for yellow, and as this term was taught formally in school, it may eventually become basic for the majority of the population. Both sets of basic terms are consistent with Berlin & Kay's theory.

Simulation of a Power Wheelchair

A computer-based wheelchair simulation will be demonstrated. Such a wheelchair simulator could be used in rehabilitation both to prescribe controls for patients and to develop new types of wheelchairs. The selection of a wheelchair controller and control dynamics for a specific patient currently involves the actual use of a variety of power wheelchairs. A valid simulator could reduce costs by eliminating the need to test and evaluate a set of power wheelchairs for each patient, increase safety of the patient by eliminating the risk associated with learning to operate a new power wheelchair, and ease collection of performance data by providing automated data collection. Further, the simulation could be used to test control dynamics as related to the user's perspective view when developing new power wheelchair products. The simulation runs on a personal computer with low resolution color display. The realism of the display is augmented by the use of a Fresnel lens to increase the three-dimensional effect. The display is updated frequently to ensure accurate control feedback. The performance measures used to test the simulation include both time and accuracy to move through a computer simulated course and an identical physical course. The initial results from user testing are being used as the basis for an iterative redesign process before formal testing is initiated.

A low-resolution colour graphics system for viewing molecules

A low-resolution colour graphics system for viewing molecules

Displays on Display

In the July 1981 issue of IEEE CG&A (p. 49), James E. George and Anders Vinberg provided an example of a typical two-dimensional engineering data set along with eight black-and-white graphics methods for displaying this type of data. The methods they presented included carpet plots (solutions 7 and 8) as effective ways of presenting the data; this discussion continued in the May 1982 issue with E. P. Miles's low-resolution color solutions (pg. 102).

A New Technique for Improving the Sharpness of Television Pictures

In conjunction with the CBS color-television system a method has been developed for improving the apparent picture definition, called "crispening." It uses nonlinear circuitry to decrease the apparent rise time of an isolated step input which is applied to a bandwidth limited system. This gives the color-television pictures (with the exception of repetitive patterns representing frequencies beyond system cutoff) the appearance of having been transmitted through a system of greater bandwidth. The basic idea is to add to a waveform with a slow transition a second waveform, representing the difference between the desired waveform and the original waveform. A simple circuit is described which utilizes nonlinear means for reforming the roughly triangular differential of the step signal into a narrower "spike," roughly triangular in shape, which is superimposed on the original waveform to obtain a response corresponding to about half the original rise time. Various crispening circuits have been designed for specific applications and will be discussed in more detail. These crispening circuits can be applied to standard monochrome pictures. The resultant increase in sharpness, however, would be less apparent because of the law of diminishing returns. The doubling of the bandwidth, that is, halving of the rise time (which is the effect of crispening) will be less apparent in the already high-resolution monochrome pictures than in the lower resolution color pictures. Various subject matter and test patterns as photographed from the screen of color receivers are shown for 4.