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Filters, Transforms, and Enhancements

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

Functions

integralFilterFilter using integral image
integralImageIntegral image
isfilterseparableDetermine whether filter coefficients are separable
imfilterN-D filtering of multidimensional images
imwarpApply geometric transformation to image
integralKernel Define filter for use with integral images

System Objects

vision.ConvolverCompute 2-D discrete convolution of two input matrices
vision.FFTTwo-dimensional discrete Fourier transform
vision.IFFTTwo–dimensional inverse discrete Fourier transform
vision.DCTCompute 2-D discrete cosine transform
vision.IDCTCompute 2-D inverse discrete cosine transform
vision.DeinterlacerRemove motion artifacts by deinterlacing input video signal
vision.PyramidPerform Gaussian pyramid decomposition

Blocks

2-D ConvolutionCompute 2-D discrete convolution of two input matrices
2-D FFTCompute two-dimensional fast Fourier transform of input
2-D IFFT2-D Inverse fast Fourier transform of input
2-D DCTCompute 2-D discrete cosine transform (DCT)
2-D IDCTCompute 2-D inverse discrete cosine transform (IDCT)
2-D FIR FilterPerform 2-D FIR filtering on input matrix
Contrast AdjustmentAdjust image contrast by linearly scaling pixel values
DeinterlacingRemove motion artifacts by deinterlacing input video signal
Edge DetectionFind edges of objects in images using Sobel, Prewitt, Roberts, or Canny method
Histogram EqualizationEnhance contrast of images using histogram equalization
Median FilterPerform 2-D median filtering
Hough TransformFind lines in images
Hough LinesFind Cartesian coordinates of lines described by rho and theta pairs
Gaussian PyramidPerform 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.

Simulink Workflow

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