#video #toread by #Coding-Adventure about analyzing #audio with #DSP
on 02026-01-13#50-things to do with an #RTL-SDR #SDR, mostly using SDR++. #DSP #communications #toread
on 02025-10-10a really comprehensive artice about 1-bit #DACs and #sigma-delta modulation. #DSP #communications
on 02025-08-13#morphology #image-processing operators illustrated by "HIPR2". #DSP
on 02025-08-12image mosaicking explanation from circa 02005 to get a high-resolution image from a sequence of video frames; maybe a class project by Benedict Brown and Philip Shilane? Very nice illustrations of erosion and dilation taken from HIPR2. #image-processing #morphology #DSP
on 02025-08-12Oona Räisänen corrected the flutter in Steamboat Willie #DSP
on 02024-01-25how Shazam uses #DSP to identify music
on 02023-12-06linear interpolation for #DSP sample interpolation for fractional-delay filters
on 02023-10-01#toread about #DSP in Python with #SciPy
on 02023-09-22#Nayuki’s #FLAC #audio #codec implementation in 200loc for the encoder and 300loc for the decoder, in Java and Python. #small-is-beautiful #DSP
on 02023-08-09discussion of Dominic Szablewski’s #qoa #audio #DSP #codec. He comments that it encodes 10× faster and decodes 7× faster than Opus. It also encodes 5.7× faster than ffmpeg mp3.
on 02023-08-09my calculations about Dominic Szablewski’s #qoa #audio #DSP #codec #performance: something like 400 32-bit integer instructions per sample
on 02023-08-09#Sean-Barrett’s public-domain single-file #Ogg Vorbis #audio #DSP decoder, reputed to be fast and easy to integrate. 5kloc.
on 02023-08-09Dominic Szablewski’s #audio #DSP #codec #file-format "qoa" for fast, lossy #compression: “[Quite OK Audio] is fast. It decodes audio 3x faster than Ogg-Vorbis, while offering better quality and compression (278 kbits/s for 44khz stereo) than ADPCM. QOA is simple. The reference en-/decoder fits in about 400 lines of C. The file format specification is a single page PDF.” This might be worthwhile for low-CPU-power audio recorders and maybe the Zorzpad, especially for games. Now supported systemwide in SerenityOS. Based on 4-tap linear prediction? With the weights varying over time?
on 02023-08-09extensive discussion of #DSP #Hogenauer #CIC #filters
on 02023-07-15computational #photography #DSP on new iPhone #cameras screwing up photo quality badly in some cases; explanation of things like dynamic range, diffraction, etc., with lots of comparison photos
on 02023-02-01typographically nice introduction to #DSP with DHTML animations called “Seeing circles, sines, and signals: a compact primer on digital signal processing” #explorable-explanations
on 02020-01-16"STK" is the Synthesis Toolkit, for #DSP #audio #music synthesis and processing. It's #free-software, written in C++. #software
on 02020-12-13how to simulate brass instruments for physically based synthesis, from #STK. Looks like 16-32 math operations per sample. #DSP #audio #music
on 02020-12-13really interesting #ebook on #DSP and #SDR using Numpy
on 02020-11-11#DSP and the Nyquist frequency and time-frequency misbehavior tradeoffs
on 02018-11-13on #DSP delay lines and delay-line interpolation; covers implementation issues like memory allocation and lumping of damping, plus implementations in C++ and Matlab, and uses in modeling echos and comb filtering.
on 02018-11-12#ebook on #DSP filters; this chapter analyzes a feedforward+feedback comb filter, and includes implementations of it in Faust, Pure Data, C++, Matlab, and so on.
on 02018-11-12quadrature decoding #DSP in sed
on 02017-11-25#DSP for music-box emulation
on 02017-07-23Rice Wavelet toolbox. #wavelets #DSP
on 02017-07-23#PDF of the 1986 #introduction to the phase #vocoder that launched a million #DSP careers and AutoTune
on 02017-07-01Chapter from Julius O. Smith’s #ebook, “Spectral Audio Signal Processing”, on #DSP. This one is about the channel #vocoder, the original analog version from 1928 with ten bands and a relaxation oscillator.
on 02017-07-01#PDF lecture notes from the MIT OCW course from 2006 on discrete-time #DSP explaining the #Goertzel algorithm and the chirp transform.
on 02017-07-01using #DSP #comb-filters to remove 50Hz mains hum and all its harmonics, with and without removing DC, optimizing the filter coefficients using #downhill-simplex #optimization
on 02017-05-19#explorable-explanations of #DSP in Python using Jupyter
on 02017-04-30#FFT #algorithms for #DSP expressed or explained in BASIC. #smallisbeautiful
on 02017-03-22“ISP” is "image signal processing", and VSIPL used to be the standard library for it; it seems to have died around 2008. #DSP #history
on 02017-01-16an #ebook with #source-code on #Kalman-filters. With exercises, in IPython/Jupyter. #DSP
on 02016-11-21a new #DSP library for music processing under Affero GPL: “an extensive collection of reusable algorithms which implement audio input/output functionality, standard digital signal processing blocks, statistical characterization of data, and a large set of spectral, temporal, tonal and high-level music descriptors”
on 02016-10-10William Jones’s #PLL #DSP IPython notebook for his floppy disk controller.
on 02016-10-03a simple #introduction to the Fourier transform, part of an #ebook on #DSP. The formatting is exemplary. #math
on 02016-09-23Simulating water ripples efficiently with integer #DSP time-space filtering: d[i] = ((s[i-1]+s[i+1]+s[i-320]+s[i+320]) >> 1) - d[i]; d[i] -= d[i] >> 5;. #graphics
“Principles of Digital Waveguide Models of Musical Instruments”, a book chapter on #DSP
on 02016-07-04The Kelly-Lochbaum tapped-delay-line model of the vocal tract for singing, from 1962, synthesized formants by acoustic tube modeling; but then was replaced by more purely spectral models like LPC. #DSP
on 02016-07-04feedforward comb #filters in parallel are equivalent to tapped delay lines. #DSP
on 02016-07-04ladder filters in #DSP for, in particular, digital waveguide synthesis for music
on 02016-07-04phased array passive sonar for #audio imaging, like what HASAS does for anti-submarine warfare; using MEMS microphones, it becomes affordable to feed a lot of microphones to a #FPGA #hardware at once for #DSP #beamforming. Like holy shit 65536 microphones. By Artem Litvinovich.
on 02016-06-29#TI appnote ("application brief") SPRA252: “How Can Comb Filters be Used to Synthesize Musical Instruments on a TMS320 #DSP?” from 1997. Covers the basic form of #Karplus-Strong string synthesis, with C and assembly source code. Contains basic errors, but it’s pretty amazing to see a synthesizer in four instructions. 11 pages. #pdf
on 02016-06-23quantitative information on formants for speech synthesis. Q factors for the first few formants seem to range around 5 to 30. #dsp
on 02016-06-06This is the overall collection of Rice University #DSP software.
on 02016-05-09Rice University has released a bunch of #DSP software as Matlab toolboxes; this one is for doing stuff with #wavelets. It’s under a 3-clause BSD license.
on 02016-05-09"Think DSP" is a #pdf #ebook about #dsp using Python
on 02016-02-02#pdf #paper on Gabor analysis for #DSP image processing. Shows what looks like a reasonable if blurry reconstruction of a zebra image on p.77 (91 of 123) from 0.75% of the Gabor coefficients. GPL implementations in Matlab in the appendix.
on 02016-01-06“FlatCam: Thin, Bare-Sensor Cameras using Coded Aperture and Computation” FlatCam is a thin form-factor lensless camera that consists of a coded mask placed on top of a bare, conventional sensor array. Unlike a traditional, lens-based camera where an image of the scene is directly recorded on the sensor pixels, each pixel in FlatCam records a linear combination of light from multiple scene elements. A computational algorithm is then used to demultiplex the recorded measurements and reconstruct an image of the scene. FlatCam is an instance of a coded aperture imaging system; however, unlike the vast majority of related work, we place the coded mask extremely close to the image sensor that can enable a thin system. We employ a separable mask to ensure that both calibration and image reconstruction are scalable in terms of memory requirements and computational complexity. We demonstrate the potential of the FlatCam design using two prototypes: one at visible wavelengths and one at infrared wavelengths. #DSP #hardware #sensors #cameras #compressed-sensing
on 02015-12-08an overview site about #DSP.
on 02015-11-25"Pure" is Albert Gräf’s 2009 successor to his well-known #term-rewriting #programming-language “Q”, originally designed for #DSP for computer music.
on 02015-11-22an #active-essay on #DSP (requiring WebGL and specifically Chrome) #explorable-explanations
on 02015-11-17"TensorFlow" is a high-throughput #dataflow array computing library and IDE with built-in reverse-mode #automatic-differentiation for optimization, with Python and C++ APIs and #IPython integration. At this moment in history, the growth of computer power has made a bunch of important #DSP and statistical tasks just feasible, so we are seeing things like self-driving cars, superhuman image recognition, and so on. But it’s been very difficult to take advantage of the available computational power, because it’s in the form of GPUs and clusters. So this is designed to make it easy to do exactly these things, and to scale them with your available computing power, along with libraries of the latest tricks in neural networks, machine learning (which is pretty close to "statistics").
on 02015-11-09“signal processing for communications” #DSP #ebook in one big HTML page! This is the book that gives the 25th-century-BC tracking of seasonal Nile levels as its example of the earliest known digital signal processing.
on 02015-09-11a #pdf #ebook “Linear Predictive Coding and the Internet Protocol”, by Robert M. Gray, explaining the history of #LPC #speech-codecs in #DSP and the history of the development of IP, especially UDP. Covers all the #math of LPC. #protocols
on 02015-09-04an #ebook on “#music and computers” with some math stuff but mostly simple #DSP stuff, along with how it's used in practice in synthesizers.
on 02015-09-04explanation of #DSP zero-phase #filters in the “Introduction to Digital Filters with Audio Applications” #ebook.
on 02015-09-01An #ebook on #DSP filtering operations for #computer-vision.
on 02015-09-01A #DSP book chapter on the frequency response of linear time-invariant systems, including, in particular, different #FIR filters.
on 02015-08-26“Prefix Sums and Their Applications”, Blelloch 93. This is the definitive #paper on #prefix-sum #algorithms as of uh 22 years ago. It mentions specifically a #regular-expression #search-engine and #lexing as two of the applications of prefix sum! I think the “parallel solution of recurrence problems” mentioned here can be applied to #DSP IIR filtering. This is just “Chapter 1” (of what, I have no idea), but it promises more meat in chapters 2, 3, and 4, mostly to do with linked lists and trees.
on 02015-08-15a bit about high-frequency #trading as a #DSP problem. Also explains adverse selection. I like the quote, “When a market maker trades with an informed investor, he is taking the wrong side of that trade.” I’m skeptical of his explanation about thresholds; wouldn’t you avoid that with hysteresis?
on 02015-08-13#examples of doing #image-processing #registration with #Python and #RANSAC on starfield images, which allow the use of a particularly simple feature detector ☺ #dsp
on 02015-08-13A #DSP framework for light reflection for #3D reconstruction (“inverse #rendering”) and #BRDF (bidirectional reflectance distribution function) estimation using #spherical-harmonics. Aka #photometric-stereo. #toread
on 02015-08-10Another boxes-and-wires image-processing system kind of like Khoros. #DSP
on 02015-08-05A boxes-and-wires image processing system which can be used as a GIMP plugin, kind of like Khoros. #DSP
on 02015-08-05Super awesome #ebook about #DSP for #music. This chapter is about why you’d use #wavelet transforms or McAulay-Quatieri analysis.
on 02015-08-05#AVR #modem using short and long pulses for 12 kilobit per second #audio data transfer, avoiding heavy-duty #DSP.
on 02015-08-05