Smooth functions | Singularity theory | Multivariable calculus

Ridge detection

In image processing, ridge detection is the attempt, via software, to locate ridges in an image, defined as curves whose points are local maxima of the function, akin to geographical ridges. For a function of N variables, its ridges are a set of curves whose points are local maxima in N − 1 dimensions. In this respect, the notion of ridge points extends the concept of a local maximum. Correspondingly, the notion of valleys for a function can be defined by replacing the condition of a local maximum with the condition of a local minimum. The union of ridge sets and valley sets, together with a related set of points called the connector set, form a connected set of curves that partition, intersect, or meet at the critical points of the function. This union of sets together is called the function's relative critical set. Ridge sets, valley sets, and relative critical sets represent important geometric information intrinsic to a function. In a way, they provide a compact representation of important features of the function, but the extent to which they can be used to determine global features of the function is an open question. The primary motivation for the creation of ridge detection and valley detection procedures has come from image analysis and computer vision and is to capture the interior of elongated objects in the image domain. Ridge-related representations in terms of watersheds have been used for image segmentation. There have also been attempts to capture the shapes of objects by graph-based representations that reflect ridges, valleys and critical points in the image domain. Such representations may, however, be highly noise sensitive if computed at a single scale only. Because scale-space theoretic computations involve convolution with the Gaussian (smoothing) kernel, it has been hoped that use of multi-scale ridges, valleys and critical points in the context of scale space theory should allow for more a robust representation of objects (or shapes) in the image. In this respect, ridges and valleys can be seen as a complement to natural interest points or local extremal points. With appropriately defined concepts, ridges and valleys in the (or in some other representation derived from the intensity landscape) may form a scale invariant skeleton for organizing spatial constraints on local appearance, with a number of qualitative similarities to the way the Blum's medial axis transform provides a for binary images. In typical applications, ridge and valley descriptors are often used for detecting roads in aerial images and for detecting blood vessels in retinal images or three-dimensional magnetic resonance images. (Wikipedia).

Video thumbnail

Ridgecrest Aftershocks Observed by Fiber Optic Cable

Caltech's Zhongwen Zhan deployed a system to record seismic activity using existing fiber optic cable in the ground and recorded a M4.3 aftershock near Ridgecrest, California. More info: https://www.caltech.edu/about/news/seismologists-monitor-ridgecrest-aftershocks-using-novel-fiber-opti

From playlist Our Research

Video thumbnail

Linear Desface

Here we show a quick way to set up a face in desmos using domain and range restrictions along with sliders. @shaunteaches

From playlist desmos

Video thumbnail

How To Do Face Detection And Tagging In Video With Deep Learning | Session 03 | #AI

Don’t forget to subscribe! In this project series, you will learn how to do face detection and tagging in video with deep learning. In this project, you are going to learn how to use deep neural networks for face detection, tracking, and redaction. Face recognition is a broad problem o

From playlist Face Detection And Tagging In Video With Deep Learning

Video thumbnail

How To Do Face Detection And Tagging In Video With Deep Learning | Session 04 | #AI

Don’t forget to subscribe! In this project series, you will learn how to do face detection and tagging in video with deep learning. In this project, you are going to learn how to use deep neural networks for face detection, tracking, and redaction. Face recognition is a broad problem o

From playlist Face Detection And Tagging In Video With Deep Learning

Video thumbnail

How To Do Face Detection And Tagging In Video With Deep Learning | Session 02 | #AI

Don’t forget to subscribe! In this project series, you will learn how to do face detection and tagging in video with deep learning. In this project, you are going to learn how to use deep neural networks for face detection, tracking, and redaction. Face recognition is a broad problem o

From playlist Face Detection And Tagging In Video With Deep Learning

Video thumbnail

How To Do Face Detection And Tagging In Video With Deep Learning | Session 01 | #AI

Don’t forget to subscribe! In this project series, you will learn how to do face detection and tagging in video with deep learning. In this project, you are going to learn how to use deep neural networks for face detection, tracking, and redaction. Face recognition is a broad problem o

From playlist Face Detection And Tagging In Video With Deep Learning

Video thumbnail

How To Do Face Detection And Tagging In Video With Deep Learning | Introduction | #AI

Don’t forget to subscribe! In this project series, you will learn how to do face detection and tagging in video with deep learning. In this project, you are going to learn how to use deep neural networks for face detection, tracking, and redaction. Face recognition is a broad problem o

From playlist Face Detection And Tagging In Video With Deep Learning

Video thumbnail

Posing as a Journalist to Sneak onto the Gold Claim! | Gold, Lies, and Videotape

Stream Gold, Lies, and Videotape on discovery+ ► https://www.discoveryplus.com/show/gold-lies-videotape-us #goldliesandvideotape #discovery #gold Subscribe to Discovery: http://bit.ly/SubscribeDiscovery Follow Us on TikTok: https://www.tiktok.com/@Discovery We're on Instagram! https:

From playlist Adventure & Exploration

Video thumbnail

Spot Launch

Spot is an agile mobile robot that you can customize for a wide range of applications. The base platform provides rough-terrain mobility, 360-degree obstacle avoidance, and various levels of navigation, remote control, and autonomy. You can customize Spot by adding specialized sensors, sof

From playlist Robotics

Video thumbnail

Speech Analysis and a Tour of the Math Behind it #SoME2

What you are looking at right now is a spectragram of my voice as I am speaking into a microphone. When I first saw this I was quite perplexed by all the strange shapes and features embedded within the image. It made me wonder just how speech analysis is done? I was so intrigued by this t

From playlist Summer of Math Exposition 2 videos

Video thumbnail

3 Ridiculously Extreme Black Holes

Black holes are some of the most extreme astronomical objects out there, but there are some that really standout. Let's look at black holes that grow larger, consume more, and spin faster than the rest. Get 10% off today —WITH FREE WORLDWIDE SHIPPING—by going to http://ridge.com/SCISHOW

From playlist SciShow Space

Video thumbnail

Californium (new) - Periodic Table of Videos

An extensive video about Californium, which reportedly costs up to $27m per gram. We go to where it's made in Oak Ridge, Tennessee. More links and info in full description ↓↓↓ This video features Professor Martyn Poliakoff at the University of Nottingham. And Julie Ezold and Rose Boll at

From playlist All Chemical Elements in Order - Periodic Videos

Video thumbnail

Stanford researchers suggest water may be common within Europa’s ice shell

Ice-penetrating radar data from Greenland suggests that shallow water pockets may be common within Europa’s ice shell, increasing the potential for detecting signs of habitability near the surface of Jupiter's moon. Read more 🗞: https://news.stanford.edu/2022/04/19/scientists-explain-forma

From playlist Stanford Highlights

Video thumbnail

Looking For Mike (Mysterious Death Documentary) | Real Stories

Looking For Mike (Mysterious Death Documentary) | Real Stories Looking For Mike follows filmmaker Dylan Reibling as he investigates the mysterious death of his friend, computer salesman Michael De Bourcier. Mike's sudden death in 2002 has remained an unsolved cold case with the Toronto Po

From playlist Conspiracy Documentaries

Video thumbnail

Tunnel Warfare During World War 1 I THE GREAT WAR Special

Check out the WW1 Centennial Podcast: http://bit.ly/WW1CCPodcast Tunnel and mining warfare was an important part of World War 1, especially on the Western Front and to a lesser, but still deadly, degree on the Italian Front. The dangers for the tunnelers were immense. And the destruction

From playlist SPECIAL EPISODES - The Great War

Video thumbnail

GRCon20 - Enabling Performance Portability of GNU Radio on Heterogeneous Systems

Presented by Seth Hitefield, Jeffrey Vetter and Seyong Lee at GNU Radio Conference 2020 https://gnuradio.org/grcon20 Future heterogeneous computing systems, such as those planned by the DSSoC program, will be extraordinarily complex in terms of processors, memory hierarchies, and intercon

From playlist GRCon 2020

Video thumbnail

Coming soon to MASSOLIT – Geography: Drivers of Plate Tectonics

MASSOLIT Featured Course of the Month This video is one part of a series of lectures that make up one MASSOLIT course. The full course is freely available for one month and will be removed from YouTube at the end of January 2023. More info is available at massolit.io/?source=yt -- In t

From playlist Geography

Video thumbnail

Neil deGrasse Tyson: 3 mind-blowing space facts | Big Think

Neil deGrasse Tyson: 3 mind-blowing space facts Watch the newest video from Big Think: https://bigth.ink/NewVideo Join Big Think+ for exclusive videos: https://bigthink.com/plus/ ---------------------------------------------------------------------------------- Astrophysicist Neil de

From playlist Top 10 Big Think Videos of 2020

Video thumbnail

A Simple Way to Help Study Earthquakes

If you have a computer and an Internet connection, you can volunteer to be part of a new network that is going to be the world's largest high-density array of seismic sensors devoted to the study of earthquakes. Stanford University: http://www.stanford.edu/ Stanford News: http://n

From playlist Stanford News 2011

Video thumbnail

Cameras Capture Secret Lives of Jasper Ridge Animals

Motion-activated cameras at Jasper Ridge Biological Preserve provide scientists a window into the secret lives of the animals there. Some, like the hummingbirds, flit about during the day. Others come out at night. Among the cast are mountain lions, bobcats, deer, coyotes, foxes and skunks

From playlist Stanford News 2012

Related pages

Maxima and minima | Binary image | Topological skeleton | Hessian matrix | Medial axis