Compressed Sensing in Python
In this post I’ll be investigating compressed sensing (also known as compressive sensing, compressive sampling, and sparse sampling) in Python. Since the idea of compressed sensing can be applied in wide array of subjects, I’ll be focusing mainly on how to apply it in one and two dimensions to things like sounds and images. Specifically, I will show how to take a highly incomplete data set of sign
Understanding and Decoding a JPEG Image using Python - Yasoob Khalid
Understanding and Decoding a JPEG Image using Python July 14, 2020 Hi everyone! 👋 Today we are going to understand the JPEG compression algorithm. One thing a lot of people don’t know is that JPEG is not a format but rather an algorithm. The JPEG images you see are mostly in the JFIF format (JPEG File Interchange Format) that internally uses the JPEG compression algorithm. By the end of this arti
画像っぽい素数をつくる - Qiita
700000000000000007 000000222222000000 000022222222220000 000222000002222000 000000000022220000 000000000222200000 000000002222000000 000000222200000000 000022220000000000 000222222222222000 000222222222222000 700000000000000003 という素数を紹介していました。 同様に、マリオが現れる素数というのも紹介されています。 https://akiyah.hatenablog.com/entry/2017/12/05/144440 一方で、2が現れる素数が奇跡だという人に物申す https://qiita.com/elzup/items/1d882f3af040506aec8b
ゼロから作るRAW現像 - その１ - Moiz's journal
追記 このブログ記事「ゼロから作るRAW現像」を大きく再構成してより読みやすくした書籍「PythonとColabでできる-ゼロから作るRAW現像」を【技術書典6】にて頒布しました。 現在はBOOTHにて入手可能です。書籍+PDF版は2200円プラス送料、PDF版は1200円です。 moiz.booth.pm 追記 はじめに RAWファイルおよびRAWデータについて カメラ画像処理 準備 RAW画像読み込み 画像データ変換 ブラックレベル補正 簡易デモザイク ホワイトバランス補正 カラーマトリクス補正 ガンマ補正 まとめ 最後に 次の記事 改定履歴 はじめに 会社の同僚にrawpyというPython用のライブラリの存在を教えてもらいました。 これを使うと各種デジカメのRAWファイルから、BayerのRAWデータを抽出できます。以前はDCRAWのソースコードを改造してrawデータのダンプなどし
画像のカラーハーフトーン処理について - Qiita
Pythonの画像ライブラリ「pillow」を使って、画像のカラーハーフトーン処理を実装しました。 写真をアメコミ調に変換したいときに、スクリーントーンのような陰影を再現したいときなどに使います。 ハーフトーンは、アメコミのような画風にしたり、ポップなデザインによく使われる効果です。 カラーハーフトーンはCMYKに色分解し、角度をずらしたハーフトーンを重ねる処理です。 カラーの印刷物のような効果になります。 当初は簡単に実装できるだろうとタカをくくっていたのですが、意外と面倒な処理でした。日本語の技術資料はほとんどなかったため、共有＆精度向上のためにメモしておきます。 ハーフトーン処理の概要 ハーフトーンは、画像をある角度で配置された単色ドットでグラデーションを擬似的に表現するものです。 角度45°で、pitchはドットの間隔、rはドットの最大半径とすると、下図のようになります。 ここで問
Compressing and enhancing hand-written notes
Why do it by hand if you can code it in just quadruple the time? I wrote a program to clean up scans of handwritten notes while simultaneously reducing file size. Example input and output: Left: input scan @ 300 DPI, 7.2MB PNG / 790KB JPG. Right: output @ same resolution, 121KB PNG.1 Disclaimer: the process described here is more or less what the Office Lens app does already, and there’s probably
The Welch-Berlekamp Algorithm for Correcting Errors in Data
This article was ported from my old Wordpress blog here, If you see any issues with the rendering or layout, please send me an email. In this post we’ll implement Reed-Solomon error-correcting codes and use them to play with codes. In our last post we defined Reed-Solomon codes rigorously, but in this post we’ll focus on intuition and code. As usual the code and data used in this post is available
色恒常性仮説に基づいた画像色補正ライブラリcolorcrrect - Qiita
はじめに Gunosyの粟飯原(@shunsukeaihara)です。社内でのポジションはピエール瀧です。Gunosy Advent Calender2014では三度目の登場です。今回は自作のPython製の画像処理ライブラリ、colorcorrectの紹介をします。 colorcorrect colorcorrectは、色恒常性仮説に基づき、ホワイトバランスのズレや、画像の褪色・変色を自動で補正するライブラリです。古い画像の色の復元のような事もできますが、画像認識などの前処理としてこのライブラリで色の補正を入れることで画像認識の精度を向上させることが可能になります。CVPR2013の論文などで実際に利用されています。1 numpyで実装されていますが、速度が必要な部分はC++で書いたものをnumpy.ctypesでラップして呼び出しています。作成したのがかなり昔の物なので、Pythonの
Building image search an engine using Python and OpenCV - PyImageSearch
Examples of Image Search Engines Image Search Engine Basics Tutorials by Adrian Rosebrock on December 1, 2014 Let’s face it. Trying to search for images based on text and tags sucks. Whether you are tagging and categorizing your personal images, searching for stock photos for your company website, or simply trying to find the right image for your next epic blog post, trying to use text and keyword
Detecting Barcodes in Images with Python and OpenCV - PyImageSearch
Image Processing Tutorials by Adrian Rosebrock on November 24, 2014 UPDATE: The introduction to this post may seen a little “out there”. For some context, I had just finished watching the South Park Black Friday episodes prior to writing this post so I definitely had some inspiration regarding zombie shoppers, Black Friday chaos, and Game of Thrones. Black Friday is coming. Hordes of angry shopper
Making Hybrid Images
This article was ported from my old Wordpress blog here, If you see any issues with the rendering or layout, please send me an email. The Mona LisaLeonardo da Vinci’s Mona Lisa is one of the most famous paintings of all time. And there has always been a discussion around her enigmatic smile. He used a trademark Renaissance technique called sfumato, which involves many thin layers of glaze mixed wi
Normalized Cuts on Region Adjacency Graphs
In my last post I demonstrated how removing edges with high weights can leave us with a set of disconnected graphs, each of which represents a region in the image. The main drawback however was that the user had to supply a threshold. This value varied significantly depending on the context of the image. For a fully automated approach, we need an algorithm that can remove edges automatically. The
Super fast color transfer between images - PyImageSearch
Course information: 86+ total classes • 115+ hours hours of on-demand code walkthrough videos • Last updated: May 2025 ★★★★★ 4.84 (128 Ratings) • 16,000+ Students Enrolled I strongly believe that if you had the right teacher you could master computer vision and deep learning. Do you think learning computer vision and deep learning has to be time-consuming, overwhelming, and complicated? Or has to
Medium
You can find (just about) anything on Medium — apparently even a page that doesn’t exist. Maybe these stories will take you somewhere new?
Color Detection | Lyst Engineering Blog
Some of these colors can be deciphered by a human but all are very difficult for a computer. Even simple colors such as snakeskin or periwinkle can be hard to process automatically. In the past, we used a range of techniques to map retailer colors to lyst colors, from simple keyword matching to complex ML models. We found that these methods produced unsatisfactory results due to complexity of colo
ŷhat | Image Processing with scikit-image
This is a post about image analysis using my new favorite Python import: scikit-image. Intro Take a couple words, alter them a bit and you've got a CAPTCHA. You've also got an image which is practically unidentifiable by even the most state of the art algorithms. Image analysis is hard, and even a simple task like distinguishing cats from dogs requires a large amount of graduate level mathematics.
jack.minardi.org : What's in a Shadow?
If you'd rather read python than english you can go straight to the code on github: https://github.com/jminardi/volume-from-shadow Motivation I was having fun casting shadows with my laser pointer the other day. I began to wonder about the 3D information that was embedded in the 2D shadow. Given enough shadows of an object, could you recreate it? What information is lost, what is preserved? I need
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Sinnlose Geschichten aus Lucas' Mikrokosmos — The Girl with the Brick Earring
GitHub - fbessho/PyPoi: "Py"thon program for "Poi"sson Image Editing
Making GIFs from Video Files with Python - __del__( self )
