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Essay On Feature Extraction

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Feature plays a very important role in the area of image processing. Different feature extraction techniques are applied on different types of images to get features that will be useful in classifying and recognition of images. Features describes the important information of images that helps to classify images correctly and remarkably reduce the dimension of the images. In pattern recognition and image processing, feature extraction is a special form of dimensionality reduction. The main goal of feature extraction is to obtain the most relevant information from the original data and represent that information in a lower dimensional space. Effective feature extraction from various intensity or color in images have been an important topic…show more content…
The histogram gives the feature vector for entire window. Example of LBP feature extraction is given in the Figure 2.1

Figure 2.1: Finding decimal value for central pixel using LBP

LBP has some limitations that reduces its application fields. LBP is not rotation invariant and the size of the features increases exponentially with the number of neighbors which leads to an increase of computational complexity in terms of time and space.
2.2.1 Noise Adaptive Binary Pattern (NABP)
Noise adaptive binary pattern [12] is a modification of local binary pattern. Though LPB is powerful in extraction local features, it has a lack of discriminative power and sensitive to noise. LBP may produce same pattern for big difference and same difference of the central pixel with neighboring pixel. LBP is also affected by noise. So, a modification is proposed on LBP to face fluctuation of intensity and noise in image. They proposed a threshold (square root of central pixel + central pixel). If neighboring pixel value is greater than the pixel then the pattern value is 1 otherwise 0. Figure 2.2 illustrates calculation of NABP.

Figure 2.2: Finding decimal value for central pixel using NABP

2.2.3 Completed Local Binary Pattern (CLBP)
CLBP [1] is also very similar to LBP. Main
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