The vocabulary and grammar of color patterns

We determine the basic categories and the hierarchy of rules used by humans in judging similarity and matching of color patterns. The categories are: (1) overall color; (2) directionality and orientation; (3) regularity and placement; (4) color purity; (5) complexity and heaviness. These categories form the pattern vocabulary which is governed by the grammar rules. Both the vocabulary and the grammar were obtained as a result of a subjective experiment. Experimental data were interpreted using multidimensional scaling techniques yielding the vocabulary and the hierarchical clustering analysis, yielding the grammar rules. Finally, we give a short overview of the existing techniques that can be used to extract and measure the elements of the vocabulary.     

Color quantization and processing by Fibonacci lattices

Color quantization is sampling of three-dimensional (3-D) color spaces (such as RGB or Lab) which results in a discrete subset of colors known as a color codebook or palette. It is extensively used for display, transfer, and storage of natural images in Internet-based applications, computer graphics, and animation. We propose a sampling scheme which provides a uniform quantization of the Lab space. The idea is based on several results from number theory and phyllotaxy. The sampling algorithm is very much systematic and allows easy design of universal (image-independent) color codebooks for a given set of parameters. The codebook structure allows fast quantization and ordered dither of color images. The display quality of images quantized by the proposed color codebooks is comparable with that of image-dependent quantizers. Most importantly, the quantized images are more amenable to the type of processing used for grayscale ones. Methods for processing grayscale images cannot be simply extended to color images because they rely on the fact that each gray-level is described by a single number and the fact that a relation of full order can be easily established on the set of those numbers. Color spaces (such as RGB or Lab) are, on the other hand, 3-D. The proposed color quantization, i.e., color space sampling and numbering of sampled points, makes methods for processing grayscale images extendible to color images. We illustrate possible processing of color images by first introducing the basic average and difference operations and then implementing edge detection and compression of color quantized images.     

Wavelet image extension for analysis and classification ofinfarcted myocardial tissue

Some computer applications for tissue characterization in medicine and biology, such as analysis of the myocardium or cancer recognition, operate with tissue samples taken from very small areas of interest. In order to perform texture characterization in such an application, only a few texture operators can be employed: the operators should be insensitive to noise and image distortion and yet be reliable in order to estimate texture quality from the small number of image points available. In order to describe the quality of infarcted myocardial tissue, the authors propose a new wavelet-based approach for analysis and classification of texture samples with small dimensions. The main idea of this method is to decompose the given image with a filter bank derived from an orthonormal wavelet basis and to form an image approximation with higher resolution. Texture energy measures calculated at each output of the filter bank as well as energies of synthesized images are used as texture features in a classification procedure. The authors propose an unsupervised classification technique based on a modified statistical t-test. The method is tested with clinical data, and the classification results obtained are very promising. The performance of the new method is compared with the performance of several other transform-based methods. The new algorithm has advantages in classification of small and noisy input samples, and it represents a step toward structural analysis of weak textures     

Attitudes of oncologists, family doctors, medical students and lawyers to euthanasia

OBJECTIVE: To evaluate clearance of the vaccine strain, immunologic responses, and potential shedding of Brucella abortus strain RB51 organisms after vaccination of bison calves. ANIMALS: Fourteen 7-month-old female bison calves. PROCEDURE: 10 bison calves were vaccinated SC with 1.22 x 10(10) colony-forming units of B abortus strain RB51. Four bison calves were vaccinated SC with 0.15M NaCl solution. Rectal, vaginal, nasal, and ocular swab specimens were obtained to evaluate potential shedding by vaccinated bison. The superficial cervical lymph node was biopsied to evaluate clearance of the vaccine strain. Lymphocyte proliferative responses to strain RB51 bacteria were evaluated in lymph node cells obtained from biopsy specimens and also in peripheral blood mononuclear cells. RESULTS: Strain RB51 was recovered from superficial cervical lymph nodes of vaccinates examined 6, 12, and 18 weeks after vaccination (4/4, 3/4, and 1/4, respectively) but not in vaccinates examined at 24 weeks (0/3) after vaccination or nonvaccinates examined at all sample collection times (n = 1 bison/sample period). Serologic, immunologic, and bacterial culture techniques failed to reveal shedding of strain RB51 by vaccinates or infection of nonvaccinated bison. Lymphocyte proliferative responses were evident in lymph node cells and blood mononuclear cells from strain RB51-vaccinated bison beginning 12 weeks after vaccination. CONCLUSION: Strain RB51 was cleared from bison by 18 to 24 weeks after vaccination. Bison vaccinated with strain RB51 did not shed the vaccine strain to nonvaccinated bison housed in close proximity. Strain RB51 did not induce antibody responses in bison that would interfere with brucellosis surveillance tests, but did stimulate cell-mediated immunity.