{"id":21001721,"url":"https://github.com/v4lli/fourier","last_synced_at":"2026-04-27T06:34:58.829Z","repository":{"id":145948623,"uuid":"122755145","full_name":"v4lli/fourier","owner":"v4lli","description":"CS Applications of the Discrete Fourier Transformation","archived":false,"fork":false,"pushed_at":"2018-03-10T00:43:01.000Z","size":2087,"stargazers_count":0,"open_issues_count":0,"forks_count":0,"subscribers_count":1,"default_branch":"master","last_synced_at":"2026-01-01T01:16:15.945Z","etag":null,"topics":[],"latest_commit_sha":null,"homepage":null,"language":"Jupyter Notebook","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"mit","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/v4lli.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null}},"created_at":"2018-02-24T16:00:05.000Z","updated_at":"2018-02-27T00:20:56.000Z","dependencies_parsed_at":null,"dependency_job_id":"3063c390-92c6-4335-82c9-d5421abca2e9","html_url":"https://github.com/v4lli/fourier","commit_stats":null,"previous_names":[],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/v4lli/fourier","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/v4lli%2Ffourier","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/v4lli%2Ffourier/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/v4lli%2Ffourier/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/v4lli%2Ffourier/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/v4lli","download_url":"https://codeload.github.com/v4lli/fourier/tar.gz/refs/heads/master","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/v4lli%2Ffourier/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":32326112,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-04-26T23:26:28.701Z","status":"online","status_checked_at":"2026-04-27T02:00:06.769Z","response_time":128,"last_error":null,"robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":true,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":[],"created_at":"2024-11-19T08:16:17.731Z","updated_at":"2026-04-27T06:34:53.820Z","avatar_url":"https://github.com/v4lli.png","language":"Jupyter Notebook","funding_links":[],"categories":[],"sub_categories":[],"readme":"# CS Applications of the Discrete Fourier Transformation\n\nThis repository contains two iPython notebooks (based on SageMath\n7.5.1), showing two applications of the _Discrete Fast Fourier\nTransformation_.\n\n\n## DTMF tone recognition\n\nDTMF tones, the distinct sounds associated with a certain number\non most telephone keyboards can be identified from a continuous audio\nstream using the Fourier Transformation. This is how a telephone computer\nmight work.\n\n[➡️ View Notebook](https://github.com/v4lli/fourier/blob/master/dtmf.ipynb)\n\nDon't forget to listen to the audio sample (dtmf.wav) first.\n\n## Lossy JPEG compression\n\nThe original JPEG standard uses the _Discrete Cosine Transformation_\n(very similar to the DFT). This notebook shows what's at least\nnecessary to lossfully compress an example image. The notebook shows\nhow different compression ratios affect file size and image quality.\n\n[➡️ View Notebook](https://github.com/v4lli/fourier/blob/master/GhettoJPEG.ipynb)\n\n_Note: The example image (commonly known as Lena, called Lisa.png in the notebook) is *not* MIT-licensed. See\nhttps://en.wikipedia.org/wiki/Lenna_\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fv4lli%2Ffourier","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fv4lli%2Ffourier","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fv4lli%2Ffourier/lists"}