Pitch Spelling Algorithms

Pitch Spelling Algorithms
Pitch spelling algorithm is the process of assigning appropriate pitch names that are consistent with the key context to numeric representations of pitch, such as, MIDI or pitch class numbers.

-Cambouropoulos
They introduce two new notions of approximate matching with application in computer assisted music analysis and also present algorithms for each notion of approximation: for approximate string matching and for computing approximate squares.

-Chew and Chen
The algorithm is spiral array model.

Introduction to Fourier Optics

Aperture effect
When the incident wave goes through an aperture, the observed field is the combination. If a distant object is viewed through a small circular aperture that is placed close to the eye, there is an apparent "shadowing" of the center of the viewed image, while the inner perimeter of the aperture is bright.

What is Fourier Optics?(quoted from http://www.fourieroptics.org.uk/ )
Fourier optics describes the propagation of light using Fourier analysis. It can be used to describe Fresnel and Fraunhofer diffraction. The Fraunhofer diffraction pattern is the Fourier transform of the diffracting object.
Fresnel diffraction describes the diffracted light field a large distance away from the object compared to the wavelength of light, but not so large the curvature of the wavefront can be neglected. Fraunhofer diffraction describes the diffracted light field a large distance away from the object such that the curvature of the wavefront can be neglected.
Possible uses are:
• Describing image formation
• Modelling the aberrations of an optical system
• Studying the performance of a lens
• Modelling diffraction patterns and light propagation
• Optical signal processing
• Optical computing

A New Video Coding Standard in China

What's AVS?
“Audio and Video Coding Standard” A second generation source coding standard developed by AVS workgroup of China.

Algorithms
1. Inter prediction( Progressive and Interlaced): P frame and B frame
2. Interpolation: AVS supports to quarter-pel MV precision
3. Intra prediction(Luma and Chroma)
4. Transform coding: Coding scheme-> Transform -> Quantization
5. Entropy coding: Exp-Golomb coding for all syntax elements
6. In-loop deblocking: Determine boundary strength by coded model and apply filter of different strength.

To know more details, you can check the following website.
http://www.avs.org.cn/en/

Multimedia Watermarking

(quoted from Kwangwoon University digital media lab)
Speaker: Bede Liu(Princeton University)
Digital watermark
What?
-Secondary information embedded in media data
-Watermarking and data hiding
How?
-Natural images
-Document: binary images, sketches, maps, Check 21,…
Attacks
-To render watermarking ineffective
-Legal issues

How to insert watermark
How to extract watermark

Spread spectrum embedding
Ideas
-Place watermark in perceptually significant spectrum
-Use random vector as wmk to avoid artifacts

Robustness
-scaling JPEG, dithering, cropping

Comment
-Need original unmarked image
-May need to perform registration
-Other attacks

How to embed watermark
-Additive embedding ex spread spectrum
-Forcing a relationship ex odd-even

Data hiding for error concealment
-recovery of blocks lost in transmission
-simple interpolation gives poor image quality

Edge estimation and interpolation
-Edge estimation from surrounding blocks

Error concealment using date hiding
-Need s good neighboring blocks
-Two steps of error concealment estimation edge

Shuffling for binary images
-Uneven distribution of flappable pixels among blocks
-Random shuffling “equalized” distribution

A dilemma
-To prove that a watermark W has been embedded in an image.
-Given inages->block DCT(32x32)->subset X
-Prove existence of W