The Control of Colour by Using Measurement and Feedback

Colour simulation on CAD computer screens is a potentially important aid to rapid response in product development. Control of screen colour in high-resolution CRT monitors can be achieved on the basis of the principles of additive colour-mixing. The use of trichromatic-unit colour specifications is extended to include RGB drive values and provide a measured feedback signal for correcting colour. Measurement and feedback control are shown to be sucessful and are employed in the Shademaster CAD system for colour-range development.     

Identification of aroma‐active compounds in fresh and stored ‘Mor’ mandarins

In this study, gas chromatography–olfactometry (GC‐O) (sniffing) combined with gas chromatography–mass spectrometry (GC‐MS) analysis was applied to identify volatile aroma‐active compounds in homogenised segments of fresh and stored ‘Mor’ mandarins. The GC‐O nasal impact frequency method was used to identify Twenty‐three aroma‐active compounds, of which seventeen odorants were identified by GC‐MS. The aroma of fresh ‘Mor’ mandarins derived from a mixture of eleven odorants that contribute ‘green’ [(E)‐3‐hexenol and hexanal], ‘fresh’ [(E)‐carveol], ‘fruity’ (ethyl 2‐methylbutanoate), ‘citrus’ (limonene), ‘floral’ (linalool), ‘musty’ (β‐myrecene and γ‐terpinene), ‘potato’ (α‐terpinene), ‘mushroom’ (unknown 2) and ‘cabbage’ (α‐cubebene) odours. During postharvest, storage losses were observed in ‘green’ [(E)‐3‐hexenol] and ‘fresh’ [(E)‐carveol] odours, accompanied by increases in ‘fruity’ (ethyl propanoate) and several unpleasant aromas, such as ‘alcohol’ (ethanol), ‘musty’ [α‐pinene, (E)‐2‐nonenal and 1‐terpinen‐4‐ol] and ‘fatty’ (octyl acetate and δ‐cadinene) odours, all of which possibly account for the observed decrease in sensory acceptability after harvest.     

A frequency domain algorithm for multiframe detection andestimation of dim targets

An algorithm for detecting moving targets by imaging sensors and estimating their trajectories is proposed. The algorithm is based on directional filtering in the frequency domain, using a bank of filters for all possible target directions. The directional filtering effectively integrates the target signal, resulting in an improved signal-to-noise ratio. Working in the frequency domain facilitates a considerable reduction in computational requirements compared to time-domain algorithms. The algorithm is described in detail, and its false alarm and detection probabilities are analyzed     

Shock chloramination: potential treatment for Chironomidae (Diptera) larvae nuisance abatement in water supply systems

In the early 1990s, infestations of midge larvae (Chironomidae, Chironomus sp.) were discovered in the potable water system of Tel Aviv, Israel. Control measures, such as draining and cleaning tanks, spraying water into the tank's air space, and electrocution traps of midge adults, were either inadequate or ineffective. In this system, monochloramine concentrations of up to 0.75 mg/liter are used routinely as a secondary disinfectant. This chemical was tested in the laboratory as a toxicant of midge larvae. The mortality of 4th instar midge larvae after short exposure to high chloramine concentrations (LC50 values of 32 mg/liter for 75 min) suggested the efficacy of instituting a Shock Chloramination treatment program. Tanks were partially drained until they contained only 20 cm of water and were then temporarily disconnected. Chloramine was added to this water to produce a concentration of approximately 70 mg/liter for 1-2 h. Subsequently, all dead chironomids were flushed out, and the tank was refilled to attain the operational volume of water. A 2nd identical treatment of water in the tank was suggested 7 d later to kill midges from reproductive adults and egg-masses that survived the 1st treatment. This treatment program was tested in commercial covered tanks and gave complete control of these pests for 6-10 wk. These results suggest that this treatment program may effectively prevent midge outbreaks in Israel's drinking water supply system during the height of the summer.     

Antibiotic resistance pattern of enterotoxigenic Escherichia coli isolated from infants and young adults in Israel

BACKGROUND: The usual methods of closure of major chest and abdominal wall defects have significant disadvantages. Skin grafts provide no structural support and result in incisional hernias. Synthetic mesh requires skin cover and is prone to infection and wound breakdown. The tensor fasciae latae (TFL) myocutaneous flap offers skin cover and a semi-rigid fascial layer. We document our unit's experience in pedicled and free TFL flaps. METHODS: The TFL flap closure of trunk defects was undertaken in 10 patients between August 1989 and April 1997. All cases were not amenable to primary closure and repair with synthetic mesh or skin grafts. RESULTS: The defect was satisfactorily repaired in all cases without subsequent herniation. The closure techniques using a pedicled TFL flap and a TFL flap for a free-tissue transfer are described. CONCLUSIONS: We conclude that the TFL flap is the method of choice for repairs of major truncal defects.     

Localized texture processing in vision: analysis and synthesis inthe Gaborian space

Recent studies of cortical simple cell function suggest that the primitives of image representation in vision have a wavelet form similar to Gabor elementary functions (EF's). It is shown that textures and fully-textured images can be practically decomposed into, and synthesized from, a finite set of EF's. Textured-images can be synthesized from a set of EF's using image coefficient library. Alternatively, texturing of contoured (cartoon-like) images is analogous to adding chromaticity information to contoured images. A method for texture discrimination and image segmentation using local features based on the Gabor approach is introduced. Features related to the EF's parameters provide efficient means for texture discrimination and classification. This method is invariant under rotation and translation. The performance of the classification appears to be robust with respect to noisy conditions. The results show an insensitivity of the discrimination to relatively high noise levels, comparable to the performances of the human observer.     

Curve segmentation under partial occlusion

2-D shape boundary segmentation is required as a fundamental and important stage in the recognition of partially occluded objects. We introduce here a new segmentation method capable of extracting a controlled number of segments along a smooth boundary curve. This new approach is invariant to similarity transformation, and partial occlusion has only marginal influence on the segmentation of the visible part. The basic concept is to transform the curve into another one which intersects itself. Points of intersection of the new curve are re-transformed to the original curve and serve as endpoints of segments. Properties of the transform are discussed, and conditions for existence of intersection points are given. Simulation results of gray level images are presented, and advantages of our method over conventional approaches relying on singular points of the curvature are discussed     

Can one evaluate the Gabor expansion using Gabor's iterativealgorithm?

D. Gabor's original (1946) approach for calculation of expansion coefficients was examined and it was found that convergence of the suggested algorithm is conditional on the window function chosen. The method of analysis enables a process of synthesis, whereby eligible windows can be defined, ensuring convergence of the algorithm for every represented signal. For windows having a finite support of width D , the coefficients calculated according to the algorithm are obtained after a single iteration. It is proved that in the special case of a Gaussian window the algorithm converges only for specific signals. On the basis of the conclusions drawn, conditions are formulated which ensure convergence of the Gabor algorithm, permitting examination of alternative windows