{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

L7+Notes

L7+Notes - (a(b(c(d Digital Subtraction Angiography(a...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Barrett - CS450 Winter 2011 Lecture 7 Image Arithmetic Objectives : To understand the use of frame-level operations (addition, subtraction, AND, OR, etc.), frame averaging, etc. in image processing. As an excellent supplemental resource on Image Arithmetic see: http://homepages.inf.ed.ac.uk/rbf/HIPR2/arthops.htm 1. Image Addition Adding a constant: H ( x , y ) = I ( x , y ) + C Adding two images: H ( x , y ) = I ( x , y ) + J ( x , y ) Blending two images: H ( x , y ) = α I ( x , y ) + (1- ) J ( x , y ) Applications Brightening an image, Image Compositing, (Additive) Dissolves DEMO : Register two images and blend with the opacity function in Photoshop 2. Image Subtraction Subtracting two images: H ( x , y ) = I ( x , y ) - J ( x , y ) Applications Motion Detection, Frame Differencing for Object Detection, Digital Subtraction Angiography DEMO : Show before and after with Digital Subtraction Angiography
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: (a) (b) (c) (d) Digital Subtraction Angiography. (a) Original “mask” – no contrast (b) with contrast – not vessels (c) Subtraction of (a) and (b) followed by subpixel registration. Note motion artifacts from patient movement. (d) Subtraction with subpixel warping of foreground mask to compensate for motion. 3. Motion Applications Surveilance, Image Compression Barrett - CS450 Winter 2011 4. Frame Averaging Noise Suppression: Suppose n frames, gaussian noise. Why should frame-averaging work? (Gaussian noise: zero mean => noise should cancel. Calculate the SNR.) 5. Logical Operators Applications Masking, Antialising, Blue Screening. (What is an alpha channel? Alpha Blending?)...
View Full Document

{[ snackBarMessage ]}

Page1 / 2

L7+Notes - (a(b(c(d Digital Subtraction Angiography(a...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon bookmark
Ask a homework question - tutors are online