Monday, January 14, 2008

T-shirts a passion


A T-shirt is a shirt, usually buttonless, collarless, and pocketless, with a round neck and mostly but not necessarily short sleeves.T-shirts have also become a medium for self-expression and advertising, with any imaginable combination of words, art and even photographs on display.T-shirts with prominent designer-name logos have been popular, especially with teenagers and young adults. These garments allowed consumers to flaunt their taste in designer brands in an inexpensive way.T-shirt exchange is an activity where people trade their tshirts they are wearing. Some designs specifically write on the shirt "trade with me"
In the early 1950s several companies based in Miami, Florida, started to decorate tee shirts with different resort names and various characters. The first company was Tropix Togs, under founder Sam Kantor, in Miami. They were the original licensee for Walt Disney characters that included Mickey Mouse and Davey Crockett. Later other companies expanded into the tee shirt printing business that included Sherry Manufacturing Company also based in Miami. Sherry started in 1948 by its owner and founder Quinton Sandler as a screen print scarf business and evolved into one of the largest screen printed resort and licensed apparel companies in the United States.
The most common form of commercial t-shirt decoration is screen-printing. In screen-printing, a design is separated into individual colors. Plastisol or water based inks are applied to the shirt through mesh screens which limits the areas where ink is deposited. In most commercial T-shirt printing, the specific colors in the design are used. To achieve a wider color spectrum with a limited number of colors, process printing (using only cyan, magenta, yellow and black ink) or simulated process (using only white, black, red, green, blue, and gold ink) is effective. Process printing is best suited for light colored shirts. Simulated process is best suited for dark colored shirts.
courtesy:wikipedia

Sunday, January 13, 2008

ANNS in Brain Signal Process

1. Feature extraction, classification, and pattern recognition: ANNs here serve mainly as non-linear classifiers. The inputs are preprocessed so as to form a feature space. ANNs are used to categorize the collected data into distinct classes. In other cases, inputs are not subjected to preprocessing but are given directly to an ANN to extract features of interest from the data.

2. Adaptive filtering and control: ANNs here operate within closed loop systems to process changing inputs, adapting their weights “on the fly” to filter out unwanted parts of the input (adaptive filtering), or mapping their outputs to parameters used in online control (adaptive control).

3. Linear or nonlinear mapping: Here ANNs are used to transform inputs to outputs of a desired form. For example, an ANN might remap its rectangular input data coordinates to circular or more general coordinate systems.

4. Modeling: ANNs can be thought of as function generators that generate an output data series based on a learned function or data model. ANNs with two layers of trainable weights have been proven capable of approximating any nonlinear function.

5. Signal separation and deconvolution: These ANNs separate their input signals into the weighted sum or convolution of a number of underlying sources using assumptions about the nature of the sources or of their interrelationships (e.g., their independence).

6. Texture analysis and image segmentation: Image texture analysis is becoming increasingly important in image segmentation, recognition and understanding. ANNs are being used to learn spatial or spatial-frequency texture features and, accordingly, to categorize images or to separate an image into sub images (image segmentation).

7. Edge detection: In an image, an edge or boundary between two objects can be mapped to a dark band between two lighter areas (objects). By using the properties of intensity discontinuity, ANNs can be trained to “recognize” these dark bands as edges, or can learn to "draw" such edges based on contrast and other information.