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CREG Journal 90 (0-24)
This issue has a cover date of June 2015 and was published on 16 June 2015.

Front Cover (1)
Bob Mehew adjusting the rope on the Bradford Pothole Club's instrumented rope test rig. Photo: Bob Mehew

Contents (2)
List of contents and masthead information.

Bringing Computational Photography to Cenotes and Flooded Caves (3-5)
Computational photography has been providing new ways to document physical sites in terrestrial applications for many years but typically involves complex equipment that is limited to fairly benign environments. By designing and deploying new hardware and software optimized for use in underwater cave environments, Corey Jaskolski and Guillermo de Anda show how we can use computational photography to non-invasively build detailed archaeological and geological records of these sites.

Using AMSS on BBC Radio 4 to Send Data to Subsurface Locations (6)
AMSS (AM Signalling System) was originally developed by the BBC to transmit data, using a subcarrier, on a long-wave broadcast transmission. Similar in concept to the more well-known RDS (Radio Data System) that operates on VHF stations, AMSS was standardised in 2006 by ETSI as an extension to the Digital Radio Mondiale system. Because long-wave broadcasts can be received underground, AMSS may, as David Gibson explains, provide a convenient method of broadcasting emergency data to miners trapped underground.

An Arduino-Compatible Bat Call Data Recorder (7-8)
Building on his previous work for detecting and logging bat activity, Tony Messina presents an Arduino-compatible design which doesn't rely on the availability of commercial data loggers or circuit boards.

Stereoscopic Vision with Reduced Definition in One Eye (9)
Practical experiments with stereo pairs show that an adequate stereoscopic image can be formed by the human brain even when one of the images is considerably defocussed or pixelated. In a digital data transmission, the reduced-definition image can have a bandwidth (pixels x palette size) as low as 1/48th that of the full-definition image. David Gibson suggests that this could have useful implications in the transmission of stereoscopic images over reduced bandwidth channels.

Field Meeting Preview (10)
The next CREG Field Meeting is to be held near Ingleton on the weekend of 22-23 August 2015. Rob Gill looks at what is likely to be on offer and at re-establishing these meetings as regular events.

Improving the Quality of Light in White LEDs (11-13)
In a follow-up to his discussion on how the quality of a light source is quantified, Mike Bedford uncovers some of the methods that are being used to bring us white LEDs that are warmer and provide improved colour rendering.

Developing a Dynamic Rope Tester - Work Still in Progress (14-17)
In a continuation of his work on measuring the failure mode of ropes, Bob Mehew describes the development of a device to measure rope extension at sub-millisecond intervals over three metre distances at sub-centimetre precision.

We Hear (18)
News and events - Mike Bedford brings us the latest to impact the world of cave radio and electronics. Electric Caving Suit One Step Closer, Handheld Stabilised Camera Coming Soon, Heider CFX Torch, Mainstream Laser Scanning, Introducing ScribbleMAPS.

Letters and Announcements (19)
SPELEO-GRAF LB and FERRA systems, A Question of Range, Diary Dates.

Web Watch (19)
Some more links from Peter Ludwig, as he probes the Internet for unusual and interesting items.

Introducing ICEMS - the Integrated Caves Environmental Monitoring System (20-24)
Jana Marikovicova, Jozef Omelka and Adam Krovina of MicroStep-MIS outline their data-logging system for monitoring a cave's microclimatic and environmental conditions for scientific research. These integrated systems build on the use of individual sensors as reported previously in CREGJ.

The Adventures of GREG (24)
Illustrations by Adrian Higgins with words by Mike Bedford.