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
02-04 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.