Digital Image¶
02-01 Digital Image¶
What is a Digital Image?
How to make an image a computable entity?
Digital Image Formats¶
Raster image formats store a series of colored dots “pixels.”
Number of bits for each pixel represents the depth of color.
1 bit-per-pixel: 2 colors (black or white, binary).
4 bits-per-pixel: 16 colors
8 bits-per-pixel: 256 different colors
Images can also be 16, 24, 32 bits-per-pixel:
24 bits per pixel usually means 8 bits per color
At the two highest levels, the pixels themselves can carry up to 16, 777, 216 colors
Common Raster Image formats
GIF, JPG, PPM, TIF, BMP etc.
Will discuss camera RAW format.
Exercises¶
mathworks.com
opencv.org, python.org
processing.org
02-02 Point Processes¶
Image Processing and Filtering¶
Point Process Computations on an Image
How to combine intensities from 2 images.
Point-process computations
Add / Subtract Images
alpha-blending and it’s applications
Image histograms
02-03 Blending Modes¶
02-04 Smoothing¶
Image Processing and Filtering: Smoothing¶
Smooth an image over a neighborhood of pixels
Median Filtering as a special non-linear filtering and smoothing approach.
Median Filtering¶
Median Filtering: Non Linear Operation often used in image processing.
Reduces noise, but
Preserves edges (Sharp Lines!)
Main Idea: Use median of all pixels in kernel area, instead of mean.