Interpolation and extrapolation

Interpolation and extrapolation

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  INTERPOLATION 9/19/2014 Brainbitz1
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  INTERPOLATION • Usedin • Zooming • Shrinking • Rotating • Geometric corrections 9/19/2014 brainbitz 2
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  Concept • Interpolationworks by using known data to estimate values at unknown points. 9/19/2014 brainbitz 3
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  IMAGE RESIZE EXAMPLE NO INTERPOLATION 9/19/2014 brainbitz 4
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  WITH INTERPOLATION 9/19/2014brainbitz 5
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  TYPES OF INTERPOLATION • Adaptive -It change depending on what they are interpolating (sharp edges vs. smooth texture) • Non adaptive – It treat all pixels equally. – Nearest neighbor algorithm – Bilinear algorithm – Bicubic algorithm 9/19/2014 brainbitz 6
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  Nearest neighbour interpolation • The output pixel is assigned the value of the pixel that the point falls within • No other pixels are considered. • It only considers one pixel — the closest one to the interpolated point. • Requires the least processing time of all the interpolation algorithms • This has the effect of simply making each pixel bigger. 9/19/2014 brainbitz 7
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  BILINEAR INTERPOLATION •The output pixel value is a weighted average of pixels in the nearest 2-by-2 neighborhood • Considers the closest 2x2 neighborhood of known pixel values surrounding the unknown pixel • It then takes a weighted average of these 4 pixels to arrive at its final interpolated value. • This results in much smoother looking images than nearest neighbor. 9/19/2014 brainbitz 8
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  9/19/2014 brainbitz 9
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  BICUBIC INTERPOLATION •The output pixel value is a weighted average of pixels in the nearest 4-by-4 neighborhood • Bicubic produces noticeably sharper images than the previous two methods, and is perhaps the ideal combination of processing time and output quality. 9/19/2014 brainbitz 10
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  9/19/2014 brainbitz 11