# Documentation

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# Filters, Transforms, and Enhancements

FIR filtering, frequency and Hough transforms, Gaussian pyramiding, deinterlacing, contrast enhancement, noise removal

## Functions

 `integralFilter` Filter using integral image `integralImage` Integral image `isfilterseparable` Determine whether filter coefficients are separable `imfilter` N-D filtering of multidimensional images `imwarp` Apply geometric transformation to image `integralKernel` Define filter for use with integral images

## System Objects

 `vision.Convolver` Compute 2-D discrete convolution of two input matrices `vision.FFT` Two-dimensional discrete Fourier transform `vision.IFFT` Two–dimensional inverse discrete Fourier transform `vision.DCT` Compute 2-D discrete cosine transform `vision.IDCT` Compute 2-D inverse discrete cosine transform `vision.Deinterlacer` Remove motion artifacts by deinterlacing input video signal `vision.Pyramid` Perform Gaussian pyramid decomposition

## Blocks

 2-D Convolution Compute 2-D discrete convolution of two input matrices 2-D FFT Compute two-dimensional fast Fourier transform of input 2-D IFFT 2-D Inverse fast Fourier transform of input 2-D DCT Compute 2-D discrete cosine transform (DCT) 2-D IDCT Compute 2-D inverse discrete cosine transform (IDCT) 2-D FIR Filter Perform 2-D FIR filtering on input matrix Contrast Adjustment Adjust image contrast by linearly scaling pixel values Deinterlacing Remove motion artifacts by deinterlacing input video signal Edge Detection Find edges of objects in images using Sobel, Prewitt, Roberts, or Canny method Histogram Equalization Enhance contrast of images using histogram equalization Median Filter Perform 2-D median filtering Hough Transform Find lines in images Hough Lines Find Cartesian coordinates of lines described by rho and theta pairs Gaussian Pyramid Perform Gaussian pyramid decomposition

## Topics

### MATLAB Workflow

Blur an Image Using an Average Filter

Apply a 7-by-7 average filter to blur an image.

Find Vertical and Horizontal Edges in Image

Construct Haar-like wavelet filters to find vertical and horizontal edges in an image.

Adjust the Contrast of Intensity Images

This example shows you how to modify the contrast in two intensity images using the Contrast Adjustment and Histogram Equalization blocks.

Adjust the Contrast of Color Images

This example shows you how to modify the contrast in color images using the Histogram Equalization block.

Remove Salt and Pepper Noise from Images

Median filtering is a common image enhancement technique for removing salt and pepper noise.

Sharpen an Image

To sharpen a color image, you need to make the luma intensity transitions more acute, while preserving the color information of the image.

Detect Lines in Images

Find lines within images

Detect Edges in Images

Find the edges of rice grains in an intensity image