Different with Matlab?

[graetz23]

Different with Matlab?

[DionK90]

Sorry, I forgot to mention that printing the image is done by treating the normalized wavelet coefficient as pixel values.

[cscheiblich]

Hi DionK90,

sorry for being late in answer but I am very busy those days.

Thanks for your input, great job!
I did the same around 7 years ago with images in C++ code instead java and MATLAB.

I have two answers for you:

First, If you have a precsion betweenn a 2.E-0 and a 2.9799526887373042E-12, the E-12 can be seen as "numerical zero", independently of the sign.

Second, by wavelets theory you have the possiblity to implement the transform algorithms in several ways, due to having an orthogonal (orthonormal) basis, the wavelets. My implementation adds up each level (step) to the coefficients (low pass, engery & high pass, details) before, and splits it up again in the reverse transform. This allows for not having larger matrices while transforming and, therfore, opens the way to a very efficient image compression.

My fwt works for the Haar like:

signal: low0_1, low0_2, low0_3, low0_4, low0_5, low0_6, low0_7, low0_8
haar_fwt1: low1_1, low1_2, low1_3, low1_4, high1_1, high1_2, high1_3, high1_4
haar_fwt2: low2_1, low2_2, high2_1, high2_1, high1_1, high1_2, high1_3, high1_4
haar_fwt3: low3_1, high3_1, high2_1, high2_1, high1_1, high1_2, high1_3, high1_4
(8=2^3 => 3 steps useful)

As a note, independent of how the transform algorithm is implemented, displaying information using any orthogonal wavelet basis is the big gain.

best
Christian

[RenanFucci]

Hey Guys!
Could you give me a code example of how to do a fastWaveletTransform, forward or reverse, in an image java from reading to the writing.
I would appreciate a lot, thanks!!!