# 7.2 A hierarchy of detail in the haar system

 Page 1 / 1

Given a mother scaling function $\phi (t)\in {ℒ}_{2}$ —the choice of which will be discussed later—let us construct scaling functions at"coarseness-level- $\mathrm{k"}$ and "shift- $n$ " as follows: ${\phi }_{k,n}(t)=2^{-\left(\frac{k}{2}\right)}\phi (2^{-k}t-n)\text{.}$ Let us then use ${V}_{k}$ to denote the subspace defined by linear combinations of scaling functions at the ${k}^{\mathrm{th}}$ level: ${V}_{k}=\mathrm{span}(\{{\phi }_{k,n}(t)\colon n\in \mathbb{Z}\})\text{.}$ In the Haar system, for example, ${V}_{0}$ and ${V}_{1}$ consist of signals with the characteristics of ${x}_{0}(t)$ and ${x}_{1}(t)$ illustrated in .

We will be careful to choose a scaling function $\phi (t)$ which ensures that the following nesting property is satisfied: $\dots \subset {V}_{2}\subset {V}_{1}\subset {V}_{0}\subset {V}_{-1}\subset {V}_{-2}\subset \dots$ $\text{coarse}\text{}\text{detailed}$ In other words, any signal in ${V}_{k}$ can be constructed as a linear combination of more detailed signals in ${V}_{k-1}$ . (The Haar system gives proof that at least one such $\phi (t)$ exists.)

The nesting property can be depicted using the set-theoretic diagram, , where ${V}_{-1}$ is represented by the contents of the largest egg (which includes the smaller two eggs), ${V}_{0}$ is represented by the contents of the medium-sized egg (which includes the smallest egg), and ${V}_{1}$ is represented by the contents of the smallest egg.

Going further, we will assume that $\phi (t)$ is designed to yield the following three important properties:

• $\{{\phi }_{k,n}(t)\colon n\in \mathbb{Z}\}$ constitutes an orthonormal basis for ${V}_{k}$ ,
• ${V}_{\infty }=\{0\}$ (contains no signals).
While at first glance it might seem that ${V}_{\infty }$ should contain non-zero constant signals ( e.g. , $x(t)=a$ for $a\in \mathbb{R}$ ), the only constant signal in ${ℒ}_{2}$ , the space of square-integrable signals, is the zero signal.
• ${V}_{-\infty }={ℒ}_{2}$ (contains all signals).
Because $\{{\phi }_{k,n}(t)\colon n\in \mathbb{Z}\}$ is an orthonormal basis, the best (in ${ℒ}_{2}$ norm) approximation of $x(t)\in {ℒ}_{2}$ at coarseness-level- $k$ is given by the orthogonal projection,
${x}_{k}(t)=\sum_{n=()}$ c k , n φ k , n t
${c}_{k,n}={\phi }_{k,n}(t)\dot x(t)$

We will soon derive conditions on the scaling function $\phi (t)$ which ensure that the properties above are satisfied.

#### Questions & Answers

are nano particles real
Missy Reply
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
Lohitha
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

### Read also:

#### Get Jobilize Job Search Mobile App in your pocket Now!

Source:  OpenStax, Digital signal processing (ohio state ee700). OpenStax CNX. Jan 22, 2004 Download for free at http://cnx.org/content/col10144/1.8
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Digital signal processing (ohio state ee700)' conversation and receive update notifications?

 By OpenStax By Alec Moffit By By Brenna Fike By Rhodes By Sheila Lopez By Brooke Delaney By Stephanie Redfern By Stephen Voron By Rebecca Butterfield