similar to: smoothing techniques

I am always fascinating by good programming techniques. R contains a lot of very good examples I have been learning from. Since I am using some functions from package "wmtsa", I though I could borrow the elegant example, in the documentation of function "wavBestBasis" to compute the entropy from the Wavelet Transform coefficients. In the following I have pasted the excerpt,

R Friends, I have data from which I would like to learn a more general (smoothened) trend by applying data smoothing methods. Data points follow a positive stepwise function. | x x | xxxxxxxx xxxxxxxx | x x |xxxx xxx xxxx | xxxxxxxxxxxxxxxxx | |

Hello, For those interested, I have improved the entropy coding scheme for wavelet coeffs compression.This scheme is now more complete, it is also faster, the compression gain is around 50-100octets, I would have expected more..., but it is getting harder to save bits for this part.Update at http://nhwcodec.blogspot.com/ . Now the discussions on video compression will be certainly focused on the

Hello, I forgot in my last reply that my DWT implementation can be speed up, for example I'm doing for now: for (;_X1<_E_;_X1++,_RES+=2) //dilatation { _RES[0]=_X1[0]<<3; _RES[1]=(_X1[1]+_X1[0])<<2; } then for (;_X2<_E_;_X2++,_RES+=2) //details { _RES[0]-=(_X2[1]+_X2[0])<<1; _RES[1]+=6*_X2[1]-_X2[2]-_X2[0];

Hello, Definitely not any (constructive) comments on the NHW Image codec? According to my tests, it can compare good with reference codecs like x264 intra and WebP. Yes, the codec is still experimental and is optimized for visual (subjective) evaluation, not PSNR.Its main feature is again that it would have a little more neatness/sharpness and a little less precision (residual coding is applied

Hello, I have improved a little the NHW codec.I have improved the dequantization in the wavelet HH band, and little improved the -l2 (and lower) quality setting.I have also added a -l3 lower quality setting (-15Ko, exp), I have increased the quantization for this other setting, and I start to remove higher wavelet coefficients, but this is not optimal... The artifacts start to be noticeable for

Hello, I am still progressing with very high compression and I have corrected a processing, so now very high compression (-l10 to -l13 quality settings) has really better precision and so better quality. I have also released a first draft of a new -l14 very high compression quality setting. More at: http://nhwcodec.blogspot.com/ Just a remark, the entropy coding schemes start to be less

Hello, I know there is no community around NHW, but I would have liked to know what you would like to see improved in the NHW codec.I know its results are not perfect for now compared to high-end AV1/VVC codecs for example, but could be ok giving its extremely fast speed.-However on high quality images, I notably like its good results because of its neatness.- Regarding things to improve, there

Hello, I have just tested new next lower quality settings (-l3 and -l4), I can diminish residual coding but if I increase wavelet coeffs threshold there is more aliasing.And even in the current mid quality settings there is some aliasing, this is the big drawback of the NHW codec. SPIHT algorithm is good for that as for example Rududu codec doesn't have aliasing at all at mid compression and

Raphael, I do not believe it is possible to build a viable community around most hardware projects except super-universal based on very cheap/high-volume products like Pi or Arduino. We see the commercial benefits of Free Software/Open Hardware as it adds value to the hardware as users are ready to pay extra for the Freedom. Andrey ---- On Thu, 02 Dec 2021 12:59:34 -0700 Raphael Canut

Hello, For those interested, I have added a -l8 "very high compression" setting to the NHW Project. I have added an experimental processing to remove details and preserve neatness.I have also now a fast estimation of entropy of wavelet coefficients and I use it accordingly to the image complexity but it is a very first version... With these new processings, the entropy coding schemes

Hello, I am slowly working on the NHW codec, I think now that I will remove the (multistage) residual coding, because it consumes too much bits while leaving still some artifacts.Instead, it seems better to simply have a finer quantization (and use a quantization step of 4 instead of 8).For the higher compression settings, I will need a good "psycho-visual" quantization to know which

Hello, I don't have advanced on the NHW codec, but now, as a lot of people, I am following the AOMedia AV1 codec.Just a (late) update of my previous post, there won't be problem in AOM AV1 with the CABAC scheme, as the codec will use Daala's multi-symbol entropy coder and/or ANS.That's great! I have even read on the wiki page, that AV1 will use Daala's PVQ as quantization

Hi Andrey, Thank you for your answer.Actually, NHW is very low-power so I think it could be geared toward any hardware.But actually I don't have hardware skills, so NHW is not a real hardware project for now maybe? I agree with you that it is extremely difficult (for me) to build a community around NHW, I'm certainly very bad/underskilled at it.Any help is welcome! Cheers, Raphael Le

Hello, The -l8 "very high compression" setting I posted was not really good.Now I have corrected and improved it, and now the -l8 quality setting is really better, more precision and more neatness. I think now it is a good setting, and I have started to compare it with x265 and it can be now competitive. More at: http://nhwcodec.blogspot.com/ Do not hesitate to test it and give me

Hello, Just a quick message to correct what I have said in my previous post.It finally seems not that easy to code small wavelet coefficients to have a good precision, and SPIHT is certainly a very good algorithm for that, -and I know there are SPIHT experts that can make very good SPIHT-based codecs-.I have chosen a new and different approach, the multistage residual coding, so I will try to

aa <- (structure(list(X.0.85 = c(-1.02, -1.17, -1.29, -1.39, -1.46, -1.5, -1.52, -1.5, -1.46, -1.39, -1.3, -1.19, -1.07, -0.93, -0.79, -0.65, -0.5, -0.36, -0.22, -0.08, 0.05, 0.18, 0.3, 0.41, 0.52, 0.62, 0.72, 0.81, 0.89, 0.98, 1.05, 1.13, 1.19, 1.25, 1.29, 1.31, 1.31, 1.29, 1.24, 1.16, 1.06, 0.93, 0.77, 0.58, 0.38, 0.16, -0.07, -0.31, -0.89, -1.05, -1.19, -1.31, -1.41, -1.47, -1.51, -1.51,

Raphael, Some 15 years ago I implemented limited functionality Theora in our cameras FPGA (it took me 6 month of hard labor), and then gave up - it is a very crowded space and it is difficult to compete with more advanced codecs. And for our other work we anyway need almost raw image data, so we are using JPEG-based JP4 format (https://community.elphel.com/jp4) that we originally developed for

Dear list, in short: I would like to calculate the mean frequency of a signal (e.g. time series) using the wavelet transform. with details: I did not find a R function to calculate a mean frequency using one of the cran packages. My searches using R Site Search returned: **(1)waveclock {waveclock} R Documentation Reconstruction of the modal frequencies in a time series using continuous

Hi Raphael, On Fri, Aug 25, 2017 at 2:30 PM, Raphael Canut <nhwcodec at gmail.com> wrote: > I'll see what Monty will do on his side (and when he has time), but he also > told me that the NHW codec has merits but there must be an effort to > demonstrate them. Well, if you want to pursue a collaborative project, you need to attract others to work on it. Perhaps 'demo'