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In image processing, the balanced histogram thresholding method (BHT), [1] is a very simple method used for automatic image thresholding. Like Otsu's Method [ 2 ] and the Iterative Selection Thresholding Method , [ 3 ] this is a histogram based thresholding method.
In this way, each thresholded pixel has one of the three values. Neighboring pixels are combined after thresholding into a ternary pattern. Computing a histogram of these ternary values will result in a large range, so the ternary pattern is split into two binary patterns. Histograms are concatenated to generate a descriptor double the size of LBP.
Multi-block LBP: the image is divided into many blocks, a LBP histogram is calculated for every block and concatenated as the final histogram. Volume Local Binary Pattern(VLBP): [ 11 ] VLBP looks at dynamic texture as a set of volumes in the (X,Y,T) space where X and Y denote the spatial coordinates and T denotes the frame index.
hists is a 2D-histogram of grayscale value and neighborhood average grayscale value pair. total is the number of pairs in the given image.it is determined by the number of the bins of 2D-histogram at each direction. threshold is the threshold obtained.
Histogram shape-based methods, where, for example, the peaks, valleys and curvatures of the smoothed histogram are analyzed. [3] Note that these methods, more than others, make certain assumptions about the image intensity probability distribution (i.e., the shape of the histogram),
For example, if applied to 8-bit image displayed with 8-bit gray-scale palette it will further reduce color depth (number of unique shades of gray) of the image. Histogram equalization will work the best when applied to images with much higher color depth than palette size, like continuous data or 16-bit gray-scale images.
Sturges's rule [1] is a method to choose the number of bins for a histogram.Given observations, Sturges's rule suggests using ^ = + bins in the histogram. This rule is widely employed in data analysis software including Python [2] and R, where it is the default bin selection method.
Most threshold selection algorithms assume that the intensity histogram is multi-modal; typically bimodal. However, some types of images are essentially unimodal since a much larger proportion of just one class of pixels (e.g. the background) is present in the image, and dominates the histogram. In such circumstances many of the standard ...