• Wyszukiwanie zaawansowane
  • Kategorie
  • Kategorie BISAC
  • Książki na zamówienie
  • Promocje
  • Granty
  • Książka na prezent
  • Opinie
  • Pomoc
  • Załóż konto
  • Zaloguj się

 » książki  » Computers - Image Processing

zaloguj się | załóż konto
Logo Krainaksiazek.pl

koszyk

konto

szukaj
topmenu
Księgarnia internetowa
Szukaj
Książki na zamówienie
Promocje
Granty
Książka na prezent
Moje konto
Pomoc
 
 
Wyszukiwanie zaawansowane
Pusty koszyk
Bezpłatna dostawa dla zamówień powyżej 20 złBezpłatna dostawa dla zamówień powyżej 20 zł

Kategorie główne

• Nauka
 [2946600]
• Literatura piękna
 [1856966]

  więcej...
• Turystyka
 [72221]
• Informatyka
 [151456]
• Komiksy
 [35826]
• Encyklopedie
 [23190]
• Dziecięca
 [619653]
• Hobby
 [140543]
• AudioBooki
 [1577]
• Literatura faktu
 [228355]
• Muzyka CD
 [410]
• Słowniki
 [2874]
• Inne
 [445822]
• Kalendarze
 [1744]
• Podręczniki
 [167141]
• Poradniki
 [482898]
• Religia
 [510455]
• Czasopisma
 [526]
• Sport
 [61590]
• Sztuka
 [243598]
• CD, DVD, Video
 [3423]
• Technologie
 [219201]
• Zdrowie
 [101638]
• Książkowe Klimaty
 [124]
• Zabawki
 [2473]
• Puzzle, gry
 [3898]
• Literatura w języku ukraińskim
 [254]
• Art. papiernicze i szkolne
 [8170]
Kategorie szczegółowe BISAC

Kategoria BISAC: Computers >> Image Processing

ilość książek w kategorii: 1996

Wyświetl książki:
Dostępne języki:
Cena:
od:
do:
ilość na stronie:


 Machine Learning for Vision-Based Motion Analysis: Theory and Techniques Wang, Liang 9780857290564 Not Avail
Machine Learning for Vision-Based Motion Analysis: Theory and Techniques

ISBN: 9780857290564 / Angielski / Twarda / 388 str.

ISBN: 9780857290564/Angielski/Twarda/388 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Liang Wang; Guoying Zhao; Li Cheng

Techniques of vision-based motion analysis aim to detect, track, identify, and generally understand the behavior of objects in image sequences. With the growth of video data in a wide range of applications from visual surveillance to human-machine interfaces, the ability to automatically analyze and understand object motions from video footage is of increasing importance. Among the latest developments in this field is the application of statistical machine learning algorithms for object tracking, activity modeling, and recognition.

Developed from expert contributions to the first and...

Techniques of vision-based motion analysis aim to detect, track, identify, and generally understand the behavior of objects in image sequences. Wit...

cena: 605,23 zł

 Applied Signal and Image Processing: Multidisciplinary Advancements Qahwaji, Rami 9781609604776 Information Science Publishing
Applied Signal and Image Processing: Multidisciplinary Advancements

ISBN: 9781609604776 / Angielski / Twarda / 414 str.

ISBN: 9781609604776/Angielski/Twarda/414 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Rami Qahwaji; Roger Green; Evor Hines
Applied Signal and Image Processing: Multidisciplinary Advancements highlights the growing multidisciplinary nature of signal and image processing by focusing on emerging applications and recent advances in well-established fields. This book covers state-or-the-art applications in both signal and image processing, which include optical communication and sensing, wireless communication management, face recognition and facial imaging, solar imaging and feature detection, fractal analysis, and video processing.
Applied Signal and Image Processing: Multidisciplinary Advancements highlights the growing multidisciplinary nature of signal and image processing by ...
cena: 917,20 zł

 Guide to Three Dimensional Structure and Motion Factorization Guanghui Wang Q. M. Jonathan Wu 9780857290458 Not Avail
Guide to Three Dimensional Structure and Motion Factorization

ISBN: 9780857290458 / Angielski / Twarda / 230 str.

ISBN: 9780857290458/Angielski/Twarda/230 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Guanghui Wang; Q. M. Jonathan Wu

The problem of structure and motion recovery from image sequences is an important theme in computer vision. Considerable progress has been made in this field during the past two decades, resulting in successful applications in robot navigation, augmented reality, industrial inspection, medical image analysis, and digital entertainment, among other areas. However, many of these methods work only for rigid objects and static scenes. The study of non-rigid structure from motion is not only of academic significance, but also has important practical applications in real-world, nonrigid or...

The problem of structure and motion recovery from image sequences is an important theme in computer vision. Considerable progress has been made in ...

cena: 403,47 zł

 Human Recognition at a Distance in Video Bir Bhanu Ju Han 9780857291233 Not Avail
Human Recognition at a Distance in Video

ISBN: 9780857291233 / Angielski / Twarda / 253 str.

ISBN: 9780857291233/Angielski/Twarda/253 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Bir Bhanu; Ju Han

Most biometric systems employed for human recognition require physical contact with, or close proximity to, a cooperative subject. Far more challenging is the ability to reliably recognize individuals at a distance, when viewed from an arbitrary angle under real-world environmental conditions. Gait and face data are the two biometrics that can be most easily captured from a distance using a video camera.

This comprehensive and logically organized text/reference addresses the fundamental problems associated with gait and face-based human recognition, from color and infrared video...

Most biometric systems employed for human recognition require physical contact with, or close proximity to, a cooperative subject. Far more challen...

cena: 403,47 zł

 Distributed Video Sensor Networks Bir Bhanu Chinya V. Ravishankar Amit K. Roy-Chowdhury 9780857291264 Not Avail
Distributed Video Sensor Networks

ISBN: 9780857291264 / Angielski / Twarda / 485 str.

ISBN: 9780857291264/Angielski/Twarda/485 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Bir Bhanu; Chinya V. Ravishankar; Amit K. Roy-Chowdhury

Large-scale video networks are of increasing importance in a wide range of applications. However, the development of automated techniques for aggregating and interpreting information from multiple video streams in real-life scenarios is a challenging area of research.

Collecting the work of leading researchers from a broad range of disciplines, this timely text/reference offers an in-depth survey of the state of the art in distributed camera networks. The book addresses a broad spectrum of critical issues in this highly interdisciplinary field: current challenges and future...

Large-scale video networks are of increasing importance in a wide range of applications. However, the development of automated techniques for aggre...

cena: 605,23 zł

 Prostate Cancer Imaging: Computer-Aided Diagnosis, Prognosis, and Intervention Madabhushi, Anant 9783642159886 Not Avail
Prostate Cancer Imaging: Computer-Aided Diagnosis, Prognosis, and Intervention

ISBN: 9783642159886 / Angielski / Miękka / 146 str.

ISBN: 9783642159886/Angielski/Miękka/146 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Anant Madabhushi; Jason Dowling; Pingkun Yan
Constitutes the refereed proceedings of the International Workshop on Prostate Cancer Imaging, held in conjunction with MICCAI 2010, in Beijing, China, in September 2010. This book includes papers that cover the clinical areas radiology, radiation oncology, digital pathology, and image guided intervention.
Constitutes the refereed proceedings of the International Workshop on Prostate Cancer Imaging, held in conjunction with MICCAI 2010, in Beijing, China...
cena: 201,72 zł

 Signal Recovery Techniques for Image and Video Compression and Transmission Aggelos Katsaggelos Nick Galatsanos 9781441950635 Not Avail
Signal Recovery Techniques for Image and Video Compression and Transmission

ISBN: 9781441950635 / Angielski / Miękka / 302 str.

ISBN: 9781441950635/Angielski/Miękka/302 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Aggelos Katsaggelos; Nick Galatsanos
Signal Recovery Techniques for Image and Video Compression and Transmission establishes a bridge between the fields of signal recovery and image and video compression. Traditionally these fields have developed separately because the problems they examined were regarded as very different, and the techniques used appear unrelated. Recently, though, there is growing consent among the research community that the two fields are quite closely related. Indeed, in both fields the objective is to reconstruct the best possible signal from limited information.
The field of signal...
Signal Recovery Techniques for Image and Video Compression and Transmission establishes a bridge between the fields of signal recove...
cena: 605,23 zł

 Radar Signal Processing and Its Applications Jian Li                                  Robert Hummel Petre Stoica 9781441953452 Not Avail
Radar Signal Processing and Its Applications

ISBN: 9781441953452 / Angielski / Miękka / 279 str.

ISBN: 9781441953452/Angielski/Miękka/279 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Jian Li; Robert Hummel; Petre Stoica

Radar Signal Processing and Its Applications brings together in one place important contributions and up-to-date research results in this fast-moving area. In twelve selected chapters, it describes the latest advances in architectures, design methods, and applications of radar signal processing.

The contributors to this work were selected from the leading researchers and practitioners in the field.

This work, originally published as Volume 14, Numbers 1-3 of the journal, Multidimensional Systems and Signal Processing, will be valuable to anyone...

Radar Signal Processing and Its Applications brings together in one place important contributions and up-to-date research results ...

cena: 403,47 zł

 Video Coding with Superimposed Motion-Compensated Signals: Applications to H.264 and Beyond Flierl, Markus 9781441954329 Not Avail
Video Coding with Superimposed Motion-Compensated Signals: Applications to H.264 and Beyond

ISBN: 9781441954329 / Angielski / Miękka / 161 str.

ISBN: 9781441954329/Angielski/Miękka/161 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Markus Flierl; Bernd Girod
Appendices 133 A Mathematical Results 133 A.1 Singularities of the Displacement Error Covariance Matrix 133 A.2 A Class of Matrices and their Eigenvalues 134 A.3 Inverse of the Power Spectral Density Matrix 134 A.4 Power Spectral Density of a Frame 136 Glossary 137 References 141 Index 159 Preface This book aims to capture recent advances in motion compensation for - ficient video compression. It investigates linearly combined motion comp- sated signals and generalizes the well known superposition for bidirectional prediction in B-pictures. The number of superimposed signals and the sel- tion...
Appendices 133 A Mathematical Results 133 A.1 Singularities of the Displacement Error Covariance Matrix 133 A.2 A Class of Matrices and their Eigenval...
cena: 403,47 zł

 Maximum Entropy and Bayesian Methods: Seattle, 1991 Smith, C. R. 9789048142200 Not Avail
Maximum Entropy and Bayesian Methods: Seattle, 1991

ISBN: 9789048142200 / Angielski / Miękka / 474 str.

ISBN: 9789048142200/Angielski/Miękka/474 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
C. R. Smith; G. Erickson; Paul O. Neudorfer
Bayesian probability theory and maximum entropy methods are at the core of a new view of scientific inference. These new' ideas, along with the revolution in computational methods afforded by modern computers, allow astronomers, electrical engineers, image processors of any type, NMR chemists and physicists, and anyone at all who has to deal with incomplete and noisy data, to take advantage of methods that, in the past, have been applied only in some areas of theoretical physics.
This volume records the Proceedings of Eleventh Annual Maximum Entropy' Workshop, held at Seattle University...
Bayesian probability theory and maximum entropy methods are at the core of a new view of scientific inference. These new' ideas, along with the revolu...
cena: 806,99 zł

 Mathematical Morphology: 40 Years on: Proceedings of the 7th International Symposium on Mathematical Morphology, April 18-20, 2005 Ronse, Christian 9789048168668 Not Avail
Mathematical Morphology: 40 Years on: Proceedings of the 7th International Symposium on Mathematical Morphology, April 18-20, 2005

ISBN: 9789048168668 / Angielski / Miękka / 490 str.

ISBN: 9789048168668/Angielski/Miękka/490 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Christian Ronse; Laurent Najman; Etienne Decenciere

Mathematical Morphology is a speciality in Image Processing and Analysis, which considers images as geometrical objects, to be analyzed through their interactions with other geometrical objects. It relies on several branches of mathematics, such as discrete geometry, topology, lattice theory, partial differential equations, integral geometry and geometrical probability. It has produced fast and efficient algorithms for computer analysis of images, and has found applications in bio-medical imaging, materials science, geoscience, remote sensing, quality control, document processing and data...

Mathematical Morphology is a speciality in Image Processing and Analysis, which considers images as geometrical objects, to be analyzed through the...

cena: 403,47 zł

 Visualisierung: Grundlagen Und Allgemeine Methoden Schumann, Heidrun 9783540649441 Springer, Berlin
Visualisierung: Grundlagen Und Allgemeine Methoden

ISBN: 9783540649441 / Niemiecki / Twarda / 370 str.

ISBN: 9783540649441/Niemiecki/Twarda/370 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Heidrun Schumann; Wolfgang Muller
Das Buch stellt die Grundlagen der Visualisierung und den Visualisierungsprozess ausfuhrlich dar. Bei der Entwicklung der grundlegenden Visualisierungstechniken betrachten die Autoren detailliert die visuellen Variablen Position und Grosse, Farbe und Textur, Form und Tiefe sowie Bewegung.
Konzepte zur Visualisierung spezieller Datenklassen, insbesondere die Visualisierung von Multiparameterdatensatzen werden vorgestellt. Bei der Visualisierung von Volumendaten, die z.B. bei medizinischen und technischen Anwendungen anfallen, stehen anwendungsbezogene Aspekte im Vordergrun
Das Buch stellt die Grundlagen der Visualisierung und den Visualisierungsprozess ausfuhrlich dar. Bei der Entwicklung der grundlegenden Visualisierung...
cena: 377,09 zł

 Calibration and Orientation of Cameras in Computer Vision Armin Gruen Thomas S. Huang 9783642084638 Springer
Calibration and Orientation of Cameras in Computer Vision

ISBN: 9783642084638 / Angielski / Miękka / 236 str.

ISBN: 9783642084638/Angielski/Miękka/236 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Armin Gruen; Thomas S. Huang
This book was conceived during the Workshop "Calibration and Orientation of Cameras in Computer Vision" at the XVIIth Congress of the ISPRS (In ternational Society of Photogrammetry and Remote Sensing), in July 1992 in Washington, D. C. The goal of this workshop was to bring photogrammetry and computer vision experts together in order to exchange ideas, concepts and approaches in camera calibration and orientation. These topics have been addressed in photogrammetry research for a long time, starting in the sec ond half of the 19th century. Over the years standard procedures have been...
This book was conceived during the Workshop "Calibration and Orientation of Cameras in Computer Vision" at the XVIIth Congress of the ISPRS (In ternat...
cena: 403,47 zł

 Intelligent Video Event Analysis and Understanding Jianguo Zhang Ling Shao Lei Zhang 9783642175534 Not Avail
Intelligent Video Event Analysis and Understanding

ISBN: 9783642175534 / Angielski / Twarda / 251 str.

ISBN: 9783642175534/Angielski/Twarda/251 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Jianguo Zhang; Ling Shao; Lei Zhang
With the vast development of Internet capacity and speed, as well as wide adop- tion of media technologies in people's daily life, a large amount of videos have been surging, and need to be efficiently processed or organized based on interest. The human visual perception system could, without difficulty, interpret and r- ognize thousands of events in videos, despite high level of video object clutters, different types of scene context, variability of motion scales, appearance changes, occlusions and object interactions. For a computer vision system, it has been be very challenging to achieve...
With the vast development of Internet capacity and speed, as well as wide adop- tion of media technologies in people's daily life, a large amount of v...
cena: 403,47 zł

 Signal Processing and Multimedia: International Conferences, Sip and Mulgrab 2010, Held as Part of the Future Generation Information Technology Confer Pal, Sankar Kumar 9783642176401 Not Avail
Signal Processing and Multimedia: International Conferences, Sip and Mulgrab 2010, Held as Part of the Future Generation Information Technology Confer

ISBN: 9783642176401 / Angielski / Miękka / 328 str.

ISBN: 9783642176401/Angielski/Miękka/328 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Sankar Kumar Pal; William I. Grosky; Niki Pissinou
Welcome to the proceedings of the 2010 International Conferences on Signal Proce- ing, Image Processing and Pattern Recognition (SIP 2010), and Multimedia, C- puter Graphics and Broadcasting (MulGraB 2010) - two of the partnering events of the Second International Mega-Conference on Future Generation Information Te- nology (FGIT 2010). SIP and MulGraB bring together researchers from academia and industry as well as practitioners to share ideas, problems and solutions relating to the multifaceted - pects of image, signal, and multimedia processing, including their links to compu- tional...
Welcome to the proceedings of the 2010 International Conferences on Signal Proce- ing, Image Processing and Pattern Recognition (SIP 2010), and Multim...
cena: 201,72 zł

 Advanced Concepts for Intelligent Vision Systems: 12th International Conference, ACIVS 2010, Sydney, Australia, December 13-16, 2010, Proceedings, Part I Jacques Blanc-Talon, Don Bone, Wilfried Philips, Dan Popescu, Paul Scheunders 9783642176876 Springer-Verlag Berlin and Heidelberg GmbH &
Advanced Concepts for Intelligent Vision Systems: 12th International Conference, ACIVS 2010, Sydney, Australia, December 13-16, 2010, Proceedings, Part I

ISBN: 9783642176876 / Angielski / Miękka / 491 str.

ISBN: 9783642176876/Angielski/Miękka/491 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Jacques Blanc-Talon;Don Bone;Wilfried Philips
This volume collects the papers accepted for presentation at the 12th Int- national Conference on "Advanced Concepts for Intelligent Vision Systems" (ACIVS 2010). Following the ?rst meeting in Baden-Baden (Germany) in 1999, whichwaspartofalargemulticonference, theACIVSconferencethendeveloped into an independent scienti?c event and has ever since maintained the tradition of being a single track conference. ACIVS 2010 attracted computer scientists from 29 di?erent countries, mostly from Europe, Australia, and the USA, but also from Asia. Although ACIVS is a conference on all areas of image and...
This volume collects the papers accepted for presentation at the 12th Int- national Conference on "Advanced Concepts for Intelligent Vision Systems" (...
cena: 201,72 zł

 Advanced Concepts for Intelligent Vision Systems: 12th International Conference, ACIVS 2010, Sydney, Australia, December 13-16, 2010, Proceedings, Part II Jacques Blanc-Talon, Don Bone, Wilfried Philips, Dan Popescu, Paul Scheunders 9783642176906 Springer-Verlag Berlin and Heidelberg GmbH &
Advanced Concepts for Intelligent Vision Systems: 12th International Conference, ACIVS 2010, Sydney, Australia, December 13-16, 2010, Proceedings, Part II

ISBN: 9783642176906 / Angielski / Miękka / 379 str.

ISBN: 9783642176906/Angielski/Miękka/379 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Jacques Blanc-Talon;Don Bone;Wilfried Philips
This book constitutes the refereed proceedings of the 12th International Conference on Advanced Concepts for Intelligent Vision Systems, ACIVS 2010, held in Changchun, China, in August 2010. The 78 revised full papers presented were carefully reviewed and selected from 144 submissions. The papers are organized in topical sections on image processing and analysis; segmentation and edge detection; 3D and depth; algorithms and optimizations; video processing; surveillance and camera networks; machine vision; remote sensing; and recognition, classification and tracking.
This book constitutes the refereed proceedings of the 12th International Conference on Advanced Concepts for Intelligent Vision Systems, ACIVS 2010, h...
cena: 201,72 zł

 Automatic Digital Document Processing and Management: Problems, Algorithms and Techniques Ferilli, Stefano 9780857291974 Not Avail
Automatic Digital Document Processing and Management: Problems, Algorithms and Techniques

ISBN: 9780857291974 / Angielski / Twarda / 297 str.

ISBN: 9780857291974/Angielski/Twarda/297 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Stefano Ferilli
This text reviews the issues involved in handling and processing digital documents. Examining the full range of a document's lifetime, the book covers acquisition, representation, security, pre-processing, layout analysis, understanding, analysis of single components, information extraction, filing, indexing and retrieval. Features: provides a list of acronyms and a glossary of technical terms; contains appendices covering key concepts in machine learning, and providing a case study on building an intelligent system for digital document and library management; discusses issues of security,...
This text reviews the issues involved in handling and processing digital documents. Examining the full range of a document's lifetime, the book covers...
cena: 403,47 zł

 Medical Computer Vision: Recognition Techniques and Applications in Medical Imaging Bjoern Menze, Georg Langs, Zhuowen Tu, Antonio Criminisi 9783642184208 Springer-Verlag Berlin and Heidelberg GmbH &
Medical Computer Vision: Recognition Techniques and Applications in Medical Imaging

ISBN: 9783642184208 / Angielski / Miękka / 226 str.

ISBN: 9783642184208/Angielski/Miękka/226 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Bjoern Menze;Georg Langs;Zhuowen Tu
This book constitutes the thoroughly refereed post-workshop proceedings of the International Workshop on Medical Computer Vision, MCV 2010, held in Beijing, China, in September 2010 as a satellite event of the 13th International Conference on Medical Image Computing and Computer Assisted Intervention, MICCAI 2010. The 10 revised full papers and 11 revised poster papers presented were carefully reviewed and selected from 38 initial submissions. The papers explore the use of modern image recognition technology in tasks such as semantic anatomy parsing, automatic segmentation and quantification,...
This book constitutes the thoroughly refereed post-workshop proceedings of the International Workshop on Medical Computer Vision, MCV 2010, held in Be...
cena: 201,72 zł

 Embedded Computer Vision Branislav Kisacanin Shuvra S. Bhattacharyya Sek Chai 9781849967761 Springer
Embedded Computer Vision

ISBN: 9781849967761 / Angielski / Miękka / 284 str.

ISBN: 9781849967761/Angielski/Miękka/284 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Branislav Kisacanin; Shuvra S. Bhattacharyya; Sek Chai
As a graduate student at Ohio State in the mid-1970s, I inherited a unique c- puter vision laboratory from the doctoral research of previous students. They had designed and built an early frame-grabber to deliver digitized color video from a (very large) electronic video camera on a tripod to a mini-computer (sic) with a (huge ) disk drive about the size of four washing machines. They had also - signed a binary image array processor and programming language, complete with a user s guide, to facilitate designing software for this one-of-a-kindprocessor. The overall system enabled programmable...
As a graduate student at Ohio State in the mid-1970s, I inherited a unique c- puter vision laboratory from the doctoral research of previous students....
cena: 403,47 zł

Pierwsza Podprzednia  7  8  9  Następna Ostatnia

Facebook - konto krainaksiazek.pl



Opinie o Krainaksiazek.pl na Opineo.pl

Partner Mybenefit

Krainaksiazek.pl w programie rzetelna firma Krainaksiaze.pl - płatności przez paypal

Czytaj nas na:

Facebook - krainaksiazek.pl
  • książki na zamówienie
  • granty
  • książka na prezent
  • kontakt
  • pomoc
  • opinie
  • regulamin
  • polityka prywatności

Zobacz:

  • Księgarnia czeska

  • Wydawnictwo Książkowe Klimaty

1997-2025 DolnySlask.com Agencja Internetowa

© 1997-2022 krainaksiazek.pl
     
KONTAKT | REGULAMIN | POLITYKA PRYWATNOŚCI | USTAWIENIA PRYWATNOŚCI
Zobacz: Księgarnia Czeska | Wydawnictwo Książkowe Klimaty | Mapa strony | Lista autorów
KrainaKsiazek.PL - Księgarnia Internetowa
Polityka prywatnosci - link
Krainaksiazek.pl - płatnośc Przelewy24
Przechowalnia Przechowalnia