8/19/2019 RTI Summary http://slidepdf.com/reader/full/rti-summary 1/5 Refectance Transormation Imaging This document is intended to help you locate all of the equipment and software which you will need to make your own RTIs. Before we begin looking at the practicalities I will briey re-introduce the technique and describe how it works. RTI stands for Reectance Transformation Imaging and describes a set of techniques which use ‘multi-light photography to produce interacti!e representations of a sub"ect. #e make an RTI by taking between $%-&% identical photographs. #ithin each photograph we light the sub"ect from a di'erent direction. By combing these photographs (using software called RTI builder) we are able to make interacti!e !isualisations which allow users to mo!e the light and change the surface appearance. This can be useful in a range of archaeological*heritage scenarios including reading gra!estones+ in!estigation of gra,ti and imaging documents. Project Website ou can check for more information on the pro"ect that we ha!e been working on with churches across the /. http0**ourti.org*
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8/19/2019 RTI Summary
http://slidepdf.com/reader/full/rti-summary 1/5
Refectance Transormation Imaging This document is intended to help you locate all of the equipment and software
which you will need to make your own RTIs. Before we begin looking at the
practicalities I will briey re-introduce the technique and describe how it works.
RTI stands for Reectance Transformation Imaging and describes a set of
techniques which use ‘multi-light photography to produce interacti!e
representations of a sub"ect. #e make an RTI by taking between $%-&% identical
photographs. #ithin each photograph we light the sub"ect from a di'erent
direction. By combing these photographs (using software called RTI builder) weare able to make interacti!e !isualisations which allow users to mo!e the light
and change the surface appearance. This can be useful in a range of
archaeological*heritage scenarios including reading gra!estones+ in!estigation of
gra,ti and imaging documents.
Project Website ou can check for more information on the pro"ect that we ha!e been working on
RTI Equipment The basic equipment which you will need to make an RTI0
• 7 camera (with the ability to manually focus and manually ad"ust e:posuresettings)
• 7 remote to ;re the camera (alternati!ely+ you can ;re your camera from a
laptop+ connecting it with a cable and using software pro!ided with your
camera+ or this free !ersion0 http0**digicamcontrol.com* for #indows)• 7 tripod - for the camera
• 7 black*red*sil!er shiny ball < the key is that this is spherical and reecti!e
• 7 powerful light with a nice e!en beam i.e. no rings or imperfections in the
beam.
2rom this basic set you can start to build a more comple: RTI kit. The two areas
where you can impro!e the setup abo!e are0
1) Elevating te !all" ou will need to support the ball somehow unless you
are able to lay it on the oor ne:t to the ob"ect you are recording. #e use a
tripod which has been adapted to hold a ball on a metal rod. 7 studio umbrella
clamp (=&-=>?) is screwed onto a tripod+ this holds a piece of threaded bar which
is then attached to a ball. ou will need to make sure that the ball can be
screwed onto a threaded bar. This can be done by gluing an @A nut to its surface
or by cutting a thread into the ball.
#) Te $igt" #hile you can get away with a torch+ it is useful to get a ashgunas this will make your setup more !ersatile. It will mean that you can use it in
any light conditions as they tend to be !ery bright compared to other portable
lights. ou will also need a way to connect the ash to the camera. ou can use a
physical cable but we recommend using a wireless ash trigger set which allows
you to mo!e the ash as much as you like without pulling on the camera.
RTI %ot&are7ll software needed to process and !iew RTI ;les can be downloaded from
3ultural 5eritage Imaging an organisation dedicated to pro!iding training andaccess to RTI technology. Cn their website you will also ;nd comprehensi!e
guidance and a lot of good e:amples. ou will need two softwares RTIBuilder to
make your RTIs and RTIDiewer to see the ;nished results.