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Infrared (IR) small target enhancement plays a significant role in modern infrared search and track (IRST) systems and is the basic technique of target detection and tracking. In this paper, a coar...

Most typical approaches for measuring color and texture properties are time consuming. An image-based method was used to evaluate the texture and color in freeze-dried potatoes. Microstructure of cooked, cooked freeze-dried and rehydrated potatoes were analyzed by scanning electron microscopy. Texture properties were analyzed by a texture analyzer and image analysis. Color was determined with a spectrocolorimeter and a digital camera. Significant differences (p < 0.05) were obtained for cooked and cooked freeze-dried rehydrated potatoes. A linear trend was applied for instrumental and image features for texture and color values. Results showed that texture features of images, such as contrast, entropy, energy, and homogeneity (calculated from grey level co-occurrence matrix), showed correlations with instrumental texture features, such as hardness, adhesiveness, chewiness, cohesiveness, and resilience. Similar results were also obtained for color features. This study showed that image processing t...

We propose a method for fast grey-to-grey (GTG) switching of a homogeneously aligned liquid crystal (LC) cell. Homogeneously aligned LCs are instantly vertically aligned by applying a vertical electric field for a short time before switching to a target grey level. Once the LCs are vertically aligned, we apply an in-plane voltage higher than the data voltage that corresponds to a target grey level, while maintaining the vertical electric field. Then, at the time the vertical field is removed, we apply a data voltage required for switching to the target grey level. We experimentally demonstrated GTG switching of a homogeneously aligned LC cell, which is 11 times faster than a fringe-field switching cell.

Digital overdriving technique is used to enhance response performance of liquid crystal device for wave front correction, combined with electro-optic effect. Generally, using phase wrapping technique, liquid crystal wave front correction only needs 1 phase retardation. In this new driving scheme, it was increased to 1.2 and only the phase retardation from 0 to 1 was used for real correction. Different from conventional method, transition grey level is needed for each grey level as to accelerate its response. This method could enhance the response time up to 50% and unify all the grey-to-grey responses to one equal value. It can be easily implemented into every conventional Liquid Crystal devices without any additional hardware modification. A liquid crystal on silicon device with synthesised liquid crystal material by our lab was used to demonstrate its feasibility. After optimisation, the response time was reduced from nearly 3.3ms down to 1.55ms.

The consistency in first-year sea ice classification potential of C-band SAR polarimetric parameters was analyzed by comparing the results of two studies conducted for the same ice types under different geophysical settings. The SAR images used in the comparison were acquired at an incidence angle difference of 4°. Probability density functions, grey level parameter images, and classification statistics derived using k-means classifier were used in the comparative analysis. The investigation showed that not all polarimetric parameters exhibit consistency in their classification performance under different geophysical settings. Out of the 20 polarimetric parameters analyzed, 12 demonstrated high levels of classification consistency between the two studies. Among these 12 parameters, only four possessed high classification accuracy and could be applicable for sea ice classification under variable environmental conditions. The parameters that showed the highest classification accuracies in both the studies w...

This article presents original stepwise image processing providing spatial delimitation of urban areas from Google Earth images in West Africa. In such images, converted to grey level images, urban areas are distinguished from their surroundings thanks to a specific textural aspect that may be retrieved by means of relevant morphological filters. Extraction of urban patterns consists of image analysis based on methods of mathematical morphology. The morphological filters used in the stepwise processing are chosen according to the spatial resolution, the visual quality of the original images and the environmental characteristics of the towns under study. Results are then compared with spatial data provided by a public geographical database.

This article is an attempt to suggest a new approach for eliminating the lengthy process of selecting various parameters for extracting texture features and to quantify the relative importance of the parameters affecting textural classification. A multivariate data analysis technique called ‘conjoint analysis’ has been used in the study to analyse the relative importance of these parameters. Results indicate that the choice of texture feature and window size have higher relative importance in the classification process than quantization level or the choice of image band for extracting texture feature. Results of the classification of an Indian urban environment using spatial property (texture) have also been reported. It was observed that the classification incorporating texture features using grey level co-occurrence matrix and wavelet-based approach improves the overall accuracy in a statistically significant manner in comparison to pure spectral classification.

In these authors’ previous paper, it was shown that grey‐level stability is one of the main drawbacks of the time‐sequential stereoscopic 3D display. In the present study, it was demonstrated that a videoluminance meter can be used to rapidly and easily check the quality of such display. A dedicated pattern was applied to simultaneously check the effect of the grey level on the other eye and the effect of the temporal synchronization. The results were compared with those provided by a temporal model of the display, which was obtained by measuring its temporal behavior. The visual impact of the grey‐level instabilities was precisely quantified, and they were found to be a major source of imperfections for the aforementioned display.

To evaluate the colour stability of orthodontic elastomeric module material exposed to dietary media.An in vitro laboratory study.Coloured and clear orthodontic elastomeric modules from four companies were exposed to coffee, cola, tea and spices for 72 h. The difference in colour components was measured with a Minolta chromameter before and after exposure.Significant changes in colour, including grey level and chromaticity, both as a function of colour and company of elastomeric ligature module were found following exposure to beverages and spices. Colour change was most affected by Deltab* (yellowness) and most significant in clear modules. Modules made using injection mouldings were more resistant to colour change than those by extrusion. Spice mix had the most effect and cola beverage the least. Clinically, these changes compromised both colour stability and esthetics of the elastomeric module.Clinicians should make patients aware of the effect of consuming beverages and spices on the colour stability of their selected ligature modules. Clinicians should favour modules made with injection moulding. Darker colour modules may be preferred to clear modules to avoid excessive colour degradation through dietary media such as beverages and food spices. Patients consuming large amounts of spices or coffee should avoid clear modules made by extrusion processing because of their tendency to discolour.

Most visual secret sharing (VSS) schemes need to encrypt a pixel of the secret image into m subpixels on the share; obviously, the shares are enlarged and so are the stacked images. A handful of studies try to solve the problem of pixel expansion, but little information is available on improving the visual effect of the stacked image. In addition, most of them do not mention how to deal with grey-level images. Since the secret is decoded by the human eye, the visual effect of the stacked image is an important issue in the study of the VSS scheme. This paper proposes two visual cryptographic methods to solve the problem of pixel expansion and to improve the visual effect of the stacked image at the same time. Unlike in previous studies, multiple pixels are simultaneously encoded each time. With the help of halftoning, the methods can be applied to encoding grey-level images. The experimental results show that these methods have a better visual effect on the stacked image compared with other researc...

Heterogeneity, the degree of dissimilarity, is one of the most important and widely applicable concepts in ecology. It is highly related to ecosystem conditions and wildlife habitat. In this study, the feasibility of applying RADARSAT-1 HH polarization synthetic aperture radar (SAR) imagery to heterogeneity studies is tested at the Grasslands National Park (GNP) and surrounding pastures, Saskatchewan, Canada. A RADARSAT-1 HH standard mode image acquired on 7 August 2003 was complemented by fieldwork in June and July 2003. Height heterogeneity index, Shannon's index, and standard deviation of biophysical parameters were calculated based on field data. Parameters from texture analysis and standard deviation of the backscatter were correlated with biophysical parameters to measure grasslands biophysical heterogeneity. The results showed that different parameters had various abilities to detect field heterogeneity. Grey level co-occurrence matrix mean, correlation, dissimilarity, and contrast showed the abili...

Experiments were conducted to see the effects of a set of factors on the Resilient backpropagation (Rprop) artificial neural network classification of an Indian urban environment using IRS‐IC satellite data. Factors investigated were sample size, number of neurons in hidden layers and number of epochs. The effect of including texture information in the form of neighbourhood information and grey level co‐occurance matrix (GLCM) features in the classification process has been explored. Statistically similar overall classification accuracy is achieved for Rprop and Gaussian maximum likelihood classification (GMLC). Investigations have revealed that a large sample size gave higher test accuracy; variation in number of neurons in hidden layer did not affect the overall classification accuracy significantly; lesser number of epochs resulted in higher overall test accuracy. Incorporation of texture information by both approaches improved classification accuracy in a statistically significant manner.

Synthetic Aperture Radar (SAR) provides a remote sensing tool to estimate soil moisture. Mapping surface soil moisture from the grey level of SAR images is a demonstrated procedure, but several fac...

Manifestation of texture in high spatial resolution optical satellite data has an inherent potential to provide land cover information. A study has been conducted to explore this utility with IRS-1D panchromatic (PAN) data through its grey values and the derived textural information. A typical test site with a wide range of textures was subjected to textural analysis by the Grey Level Co-occurrence Matrix (GLCM) approach. Entropy at an Inter Pixel Distance (IPD) of 1 and Correlation at an IPD of 9 were found to be the optimised textural features. The data has been independently classified using PAN grey levels, textural information, and PAN combined texture, which showed significantly improved classification accuracy with the addition of textural information. Similar results were obtained over two other independent sites, validating the consistent performance of the optimised textural features.

We report the influence of the rubbing treatment of the alignment layers on the electro-optic characteristics of AFLCD's. We applied a different rubbing treatment on different regions within a pixel. This variation of rubbing strengths causes domains with different surface interaction, which results in a different threshold voltage for each domain. In-pixel variation of the rubbing treatment and of the surface interaction influences the double hysteresis of the transmission-voltage characteristic, which is made less steep. The difference between the voltages at which the transmission starts to increase and the voltage at which the transmission reaches its maximum increases and so the selection of analogue grey levels is made easier. The results also show that the finite slope of the double hysteresis which is observed in normal AFLCD's, without extra rubbing treatment is probably caused by variations of the surface interaction.

This paper investigates the suitability of using airborne SAR images from the GlobeSAR mission for monitoring of growth stages of paddy crops. A large paddy plantation area in Kedah state, Malaysia, was selected for the study. Simple ground‐truth measurements were conducted at the same time as the flight mission. In general, the paddy growth pattern can be divided into three major stages, and the preliminary study of the acquired single channel grey level SAR images indicates that the GlobeSAR images have a great potential for monitoring of the different growth stages of paddy crops. Future work will further explore microwave remote sensing techniques for paddy crop monitoring using images from RADARSAT and JERS‐1.

Due to their memory, non-linear response and threshold, as well as their grey level capacity, ferroelectric liquid crystal spatial light modulators are useful devices for optical implementations of neural networks. We propose a phenomenological explanation of the roles, the different driving parameters like the voltage, the current and the length of the addressing pulse play in achieving and controlling these grey levels. Finally we discuss a possible optical implementation of a self organizing memory based on the model of the Kohonen map, using optically addressed SLMs.

Application of various iterative algorithms to adaptive predictive coding (APC) of image data is described. The variable steepsize steepest descent (VSSD) algorithm, obtained by coupling the adaptive predictor to the adaptive quantizer (Mark, 1976), represents the best candidate in terms of system performance and system complexity. The Kalman algorithm exhibits fast convergence and good distortion measure, but is too complex for implementation. For grey level image coding, an adaptive Laplacian quantizer in conjunction with adaptive predictive coding exhibits superior performance to an adaptive Gaussian quantizer. APC coding of image data offers at least a 7dB improvement in SNR over optimum PCM at any quantization level.

Interpretive problems often arise during the analysis of aerial photographs of archaeological sites when unwanted background variation obscures the signatures of cultural features. A three‐step app...

An analysis of the colour coded reflectivity level (grey level) textures of real aperture radar (RAR) imagery, which were obtained over a monomolecular sea slick, a medium fuel oil spill and a chocolate mousse oil spill, suggests that thick and thin parts within a mineral oil spill can be quickly detected. This offers an additional independent all-weather and day-and-night approach allowing a fast decision on where to start recovering activities by oil combatting vessels.