- Visual Media Processing Using MATLAB Beginner's Guide
- Table of Contents
- Visual Media Processing Using MATLAB Beginner's Guide
- Credits
- About the Author
- About the Reviewers
- www.PacktPub.com
- Preface
- 1. Basic Image Manipulations
- Getting acquainted with the MATLAB environment
- The ribbon
- The editor
- Importing and displaying an image
- Time for action – importing and displaying an image
- Time for action – using imtool to extract useful information
- Applying geometric transformations
- Time for action – rotating an image and displaying the result
- Time for action – mirroring an image and displaying the result
- Time for action – cropping and resizing an image, then saving it as BMP
- Summary
- 2. Working with Pixels In Grayscale Images
- Accessing image pixels and changing their values
- Time for action – whiten an area and blacken another
- Thresholding an image
- Calculating and displaying histograms with imhist
- Histogram equalization for contrast enhancement
- Contrasting enhancement using imadjust
- Contrasting enhancement using imcontrast
- Adaptive histogram equalization using adapthisteq
- Custom functions for complex tasks
- Time for action – using imtool to pinpoint differences
- Restoring old photographs
- Time for action – restoring your ancestors' photographs
- Summary
- 3. Morphological Operations and Object Analysis
- The importance of binary images
- Time for action – understanding the value of thresholding
- Enlarging and shrinking a region of interest
- Time for action – using dilation and erosion to refine ROIs
- Altering structuring elements from strel to suit our needs
- Time for action – ROI refinement using strel
- Manually defining a non-rectangular ROI
- Time for action – making a custom object eraser function
- Analyzing objects in an image
- Summary
- 4. Working with Color Images
- An introduction to color image processing
- Basic color image manipulations
- Setting a rectangular area to a specified color
- Time for action – repainting two areas in a color image
- Thresholding color images
- Time for action – isolating the red pixels in an image
- Achieving color masking
- Time for action – color isolation
- The importance of different color spaces
- Time for action – color space transformation
- CIE-L*a*b* for more efficient color masking
- Time for action – color isolation using CIE-L*a*b*
- Fixing illumination issues in RGB color images
- Fixing illumination issues in CIE-L*a*b*
- A practical example – red eye reduction
- Time for action – writing a function for red eye reduction
- Taking advantage of eye circularity
- Time for action – automating our function for red eye reduction
- Summary
- 5. 2-Dimensional Image Filtering
- An introduction to image filtering
- Processing neighborhoods of pixels
- The basics of convolution
- The ugly mathematical truth
- Time for action – applying averaging filters in images
- Alternatives to convolution
- Using imfilter
- Creating filters with fspecial
- Different ways to blur an image
- Time for action – how much blurring is enough
- Time to make art using blurring
- Time for action – creating the bokeh effect in an image
- Removing noise using blurring
- Time for action – trying to remove different types of noise
- The importance of the median filter
- Time for action – removing salt & pepper with medfilt2
- Bringing back the details
- Time for action – enhancing the edges in our images
- Brighten up the lights
- Time for action – brighten up the lights in our soldier picture
- Summary
- 6. Mixing Images for Science or Art
- The importance of mixing or combining images
- Using multispectral imaging
- Loading and manipulating the multispectral images
- Time for action – visible spectrum from a multiband image of Rio
- Time for action – working with invisible spectrums
- Creating composite images
- Time for action – cloning the seagull
- One step beyond – blending selected image regions
- Time for action – directing a threatening scene
- Creating High Dynamic Range images
- Time for action – composing your own HDR images
- Stitching images for the creation of panoramas
- Time for action – basic approach to panorama stitching
- Summary
- 7. Adding Motion – From Static Images to Digital Videos
- An introduction to digital videos
- The meaning of frames
- Loading videos in MATLAB
- Playing back videos in MATLAB
- Time for action – reading and playing back a video
- Making videos from static images
- Time for action – constructing and saving a video
- Inspecting a video using montage
- Time for action – don't wait for the ball
- A tool just for your playback needs – implay
- Creating time-lapse videos
- Time for action – time-lapsing a regular video
- Saving your time-lapse videos in a gif file
- Summary
- 8. Acquiring and Processing Videos
- Using MATLAB for digital video recording
- Time for action – capturing a video using a firewire connection
- The importance of video compression
- Working with uncompressed videos
- Time for action – making an edge detection video
- Acquiring frames for time-lapse videos
- Time for action – using MATLAB as an intervalometer
- Real-time processing of time-lapse videos
- Time for action – creating time-lapses with isolated colors
- Real-time processing of normal videos
- Time for action – adjusting the contrast of the video
- Time for action – adding preview in our code
- Summary
- 9. Spatiotemporal Video Processing
- Basic video processing with MATLAB
- Time for action – loading, cropping, resizing, and saving a video
- Time for action – reducing the blocking effect
- Deinterlacing videos in MATLAB
- Deinterlacing with the Computer Vision System Toolbox
- Time for action – deinterlacing a video using the vision toolbox
- Deinterlacing with the custom functions
- Time for action – deinterlacing with line repetition
- Time for action – deinterlacing with the scan line interpolation
- Inter-frame filtering for the deinterlacing tasks
- Time for action – deinterlacing with field merging
- Temporal deinterlacing by field averaging
- Time for action – deinterlacing with field averaging
- Mixing intra-frame and inter-frame deinterlacing
- Time for action – vertical and temporal interpolation method
- Adding a new dimension to the filters
- Time for action – implementing a spatiotemporal averaging filter
- Time for action – spatiotemporal averaging filter with the convn function
- Summary
- 10. From Beginner to Expert – Handling Motion and 3-D
- Detecting and estimating motion in videos
- Time for action – detecting a moving object in a still scene
- Time for action – detecting motion in a complex scene
- Estimating the motion
- Time for action – tracking people with Horn-Schunck optical flow
- Time for action – warping frames using optical flow
- Compensating camera motion using feature tracking
- Time for action – tracking feature points for motion compensation of a shaky video
- Working with stereoscopic images
- Time for action – creating a 3-D video from left and right videos
- Time for action – creating a 3-D video from a regular one
- Summary
- A. Pop Quiz Answers
- Chapter 1, Basic Image Manupulation
- Chapter 2, Working with Pixels in Grayscale Images
- Chapter 3, Morphological Operations and Object Analysis
- Chapter 4, Working with Color Images
- Chapter 5, 2-Dimensional Image Filtering
- Chapter 6, Mixing Images for Science or Art
- Chapter 7, Adding Motion – From Static Images to Digital Videos
- Chapter 8, Acquiring and Processing Videos
- Chapter 9, Spatiotemporal Video Processing
- Chapter 10, From Beginner to Expert – Handling Motion and 3-D
- Index
This chapter gave you a rather detailed tool of two-dimensional filtering in MATLAB. The basic mathematic ideas behind image filtering were explained and practical examples were given. You got to see various techniques for using two-dimensional filtering in everyday problems such as removing noise from images, or enhancing areas that are blurred. You also learned some artistic effects caused by image filtering and practiced on ways to use them in your images. More specifically, this chapter covered:
- An introduction to neighborhood-based operations on an image
- An explanation of what convolution is and why it is important
- The alternative way to perform filtering, by using correlation
- The usage of
imfilterfor performing image filtering - How you make kernels with
fspecial, for image filtering usage - How to blur images and why it is important
- How to create artistic effects using blurring
- How to remove noise using blurring
- How to enhance edges in an image, why it is important, and how it is connected to edge detection
- How to brighten up light sources in a night image using edge enhancement
In the next chapter, we will get to discuss exciting and practical examples about artistic and scientific implementations of image processing. We will work on examples of multispectral images, panoramas, and HDR images. We will also discuss other artistic effects by mixing some of the techniques you've learnt so far. All our examples will be accompanied by hands-on tasks, as always.
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