Revealing Visual Details via High Dynamic Range Gigapixels Spherical Panorama Photography: The Tempurung Cave Natural Heritage Site Muhammad Jafni Jusof
Hj. Ruslan Abd. Rahim
Centre for Creative Content and Digital Innovation University of Malaya Kuala Lumpur, MALAYSIA
[email protected]
Faculty of Art and Design Universiti Teknologi MARA Shah Alam, MALAYSIA
[email protected]
Abstract—This paper is focused on creating an efficient workflow process for high dynamic range spherical panoramas for preserving heritage sites taking the Tempurung Cave as a working model. Although there are several methods for producing HDR spherical panorama, higher-resolution images impose new problems in handling and creating such large size detailed output. Furthermore, high-resolution detail photographic documentation is essential for preservation purposes, as it will serve as a reference for interested parties. With today's technology, achieving higher resolution images is not entirely impossible however, an efficient workflow process is needed to ensure quality output especially when involve combination of multiple techniques. The hundred million years old cave is one of the largest limestone caves in Peninsular Malaysia. The tunnel cave runs down through two hills, covering a distance of two kilometers deep made up of five large domes previewing a magnificent display of stalagmites and stalactites. While the naturally form heritage was kept safe before, the increasing number of tourists and visitors today saw constructions built within the caverns such as the walkway and electric lighting for viewer’s better sightings. The heritage is very well known and protected; the digitization of the cave is an effort to keep a digital copy of such natural heritage not only for visitors to experience but also for interested parties to study the formations and habitat within through detailed documentation of the site. High Dynamic Range (HDR) photography is adapted into a user-navigable spherical virtual environment as a method to reveal details hidden within dark areas while the interactive panorama is a way to let the viewer be immersed into the environment seeing as if on site. Exploration in this technique will show the possibilities of HDR to display beyond what can actually be seen with human eyes. The immersive visual experience is enhanced with detailed luminance between the lightest and darkest areas. Todays capture devices, which can capture in high number of pixels while enhancing details and quality of images does impose some issues in the workflow of HDR spherical panorama. The very large file size of each image that needs more computing resources lead to a search for a more efficient workflow process. This paper outlines an efficient workable process method of creating a HDR gigapixels spherical panorama using the Tempurung Cave in Ipoh, Malaysia as a case study. Keywords— High Dynamic Range Photography; Gigapixels Spherical Panorama; Tempurung Cave; Preservation
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I. INTRODUCTION A. High Dynamic Range Photography High dynamic range (HDR) photography technique has been around for a very long time. In the early days if was not referred by a different term, its purpose remains to compensate the inadequacies of the camera metering system to provide accurate exposure readings. A camera metering system cannot measure light in full exposure value (EV) compare to human eyes even with rapid technological advancement in image sensors (Tylor, 2012, p. 8[1]; McCollough, 2008, p. 47[2]; Gulbins & Gulbins, 2010, p. 135[3]; Brown, 2006[4]). This results in compromise EV only for subject in focus producing low dynamic range image, not what human eyes can actually see. McCollough (2008, p. 14)[2] states compare to human eyes, which has dynamic range of 1, 000, 000:1 equivalent to 20EVs, digital image sensors can barely compare with an average of 300:1 or approximately 14EVs. According to Hirsch (2008, p. 125)[5], dynamic range refers to the variation of luminance from the brightest to the darkest area of a scene. HDR technique was first introduced by Le Gray through his seascape prints while the famous photographer Ansel Adam had made it even more memorable with his zone system technique (Davis, 2012, p. 17)[6]; Langford & Bilissi, 2008, p. 165)[7]. In conventional photography technique, a high contrast image has deep shadows or burn highlights that conceals the details within. However, HDR photography technique is a process of merging images with different EVs and creating balance contrast across a composition. Digital photography has made HDR image making a lot more simpler and faster using computer software that could produce not only close to the real image, but exceeding of what the human eye can really see (Fitzgerald, 2008)[8]. Although Gwilt (2004 through Roussou, 2008, p. 230)[9] states that photographers should refer to the original when in the process of creating images, the possibility beyond normal human vision is an interesting area to explore, which could open up a new discovery of visual dimension (Adam n.d. through McCollough, 2008, p. 40)[2]. The possible usage of HDR could be endless; previously popular amongst three-
dimensional (3D) computer generated imagery (CGI) artist for realistic image rendering, Ward (2001)[10] states preservation works can also make use of HDR. B. Spherical Panorama In short, panorama which a combination of two words; 'pan' means all and 'horama' means sight (Benosman& Kang, 2001, p. 5)[11], is defined as a large field of view (FOV) (Woeste, 2009)[12] that should covers wider than 135-degree of viewing angle (Frish, 2007, p. 6)[13]. It started in 1767 when Robert Parker, an English painter patented the idea (Jacobs, 2004, p. 1)[14] which was in the form of a very large painting mounted on a circular wall (Watson & Rappaport, 2013, 34)[15] where viewers will stand in the middle of the room immersed inside the environment. The immersive experience of panorama drove Frederich Von Martens to experiment using photography technique (Benosman & Kang, 2001, p. 7)[11]. Since then, many panoramic related apparatus had been invented starting with panoramic cameras such as the 'Kodak Model No. 4'. In the late 20th century, digital technology had much influence many other fields to rapidly evolve. In 1994, Apple Computer invented QuickTime VR (QTVR), a virtual reality extension to its proprietary QuickTime media player, which is a photo based virtual reality compared to CGI 3D models. As stated by Barnes (2000)[16], it is a way of viewing photographic panorama image on computer screen. Instead standing in a large dome, viewer has the ability to navigate the virtual environment using digital input devices. More advance display methods could be used to enhance viewer's immersive viewing experience. The photo based interactive panorama represents the realness of visual and real world navigation into a virtual environment and thus, the immersive experience and interaction is the same as how human sees and navigate in the real world (Murphy, 1999)[17]. This is true especially in a spherical panoramic projection just like standing inside a ball where a viewer can pan and tilt all around without any boundary. Unlike any other type of projections, a spherical panorama has no visible edges between blended images or limitation to panning and tilting angles Spherical panorama also permits viewing of the top and bottom ground. Although had long been invented and has been through many revolutions and innovations such as way of presentations, image acquisition method and processing or even equipment, most panoramas is still focused on landscaping and tourism. For instance, studies by Khoon (2010)[18] had proven that panorama gives positive response towards the tourism industry with many respondents having an immersive experience of a panoramic virtual environment. However, the application of a spherical panoramic virtual environment could be expanded to other fields such as documentation and preservation. The capture of surroundings in multiple nodes that can be linked together creates a complete real site representation. Other media such as videos, audio, images and textual information can be overlaid on top of a panorama to create a multimedia rich content. It would be more engaging for viewers to experience this type of staging rather than static forms of
presentation. Furthermore, the exploration through interactive feature is a good means of encouraging viewers to learn and communicate (Hein, 1998 through Economou & Tost, 2008, p. 243)[19]. By stimulating various human sensory, the learning process can be enhanced and the knowledge through experiences is more memorable. C. Preserving Natural Heritage In a convention dated back in November 1972, UNESCO in their Convention Concerning The Protection Of The World Cultural And Natural Heritage had defined natural heritage as "natural areas of outstanding universal value from the point of view of science, conservation or beauty." (UNESCO, 1972)[20]. In an interview with Encik Shahrudin Mohamed Som, a Heritage Officer at the Conservation Unit, National Heritage Council, Malaysia, the recordings for preservation purposes have to meet a certain criteria as listed below: i. ii. iii. iv.
Illustrating significance Quality and accuracy Accessibility Clarity
The first principle explains that each type of recording should demonstrate the significance value of certain heritage such as elements for scientific research or beauty of natural heritage as referred to UNESCO definition. The quality of the recording should also be in exceptional quality that it can be use as a source of reference and documentation. Thus it has to be accurate and detail in its representation of actual reality. This digital record must be accessible and shared amongst interested parties through any means of media without degradation taking consideration that it should not be misused. Such record has to represent a clear representation of the real that can be measured, for instance in terms of size, form, color, texture, etc. This paper is in interest to suggest the use of high-resolution gigapixels HDR spherical panorama as a means of preserving natural heritage in parallel with other conventional and established methods already being used. The outcome of this study meets all the criteria’s mentioned. The significance of gigapixels HDR spherical panorama towards replicating heritage in high-resolution digital form is very much needed. The detail replica can be a source of reference or a true record of its existence. The visual properties of such artwork displayed in very high quality that details are revealed within the shadows inside the cave beyond normal human eyes capability. Since the virtual representation of the cave is a photography-based recording, the representation is an accurate copy of the real as it is not remodel through estimated 3D modeling. The digital replica of the cave can be easily disseminated through Internet without the limitation of accessibility to the actual site. This can act a digital surrogate to the real site for viewers around the globe without actually be there. HDR imaging adds more value to the visual experience not only enhancing the image, but also display clear cave representation and details of the material formations. Serving as virtual representation and source of
reference, this digital replica in the form of high-resolution imagery could extend the life of heritage sites, which is always under constant threat from Mother Nature as well as human factors. D. The Tempurung Cave The million years old Tempurung cave is located near Gopeng, a small town some 25 kilometers from Ipoh, the capital city of Perak. There is a deep tunnel cave concealed within the Gunung Tempurung and Gunung Gajah consisting a five huge domes (Golden Flowstone Cavern, Gergasi Cavern, Tin Mine Cavern, Alam Cavern & Battlefield Cavern) with stunning stalagmites, stalactites, rim stone pools, curtains, straws, calcite crystals and pillars (Ipoh Tourism Board, n.d.)[21]. The fascinating galleries of limestone and marble inside the multi size caverns were made up of different materials, temperature and water levels. An underground river running through the cave is the source of life for the life forms within the cave such as fish, snakes, birds etc. According to Malaysia Traveller (n.d.)[22], these caves have their own story to be told; each differs from one to another. Some stated that communist terrorists used it during World War II and the Emergency while others stated that the Japanese used it as a prison during their occupation in Malaya. Whatever the stories are, the natural heritage values that had been and still continues to form today is fragile. Furthermore, there is not much visual detail information regarding the cave can be found let alone the history and use of the cave in its early days. Most information is from online-based references. In 1995, the cave was open to public as a tourist attraction spot. Concrete staircases, pathways and viewing platforms were constructed for visitors convenient. Spotlights were also installed along the tunnel cave for added safety and to illuminate the cave attractive features. Since then, more and more tourist had visited the place and the management today has organized many interesting activities outside the cave aside from the main tour. It is fear that with excessive tourism activities and further disruption of that fragile natural heritage could accelerate the deterioration process of the cave. Natural disasters and environmental factors are the main contributors to damaging heritage. Thus, although many actions had been taken to conserve and preserve the cave, a digital copy of it can be made as a way to further extend the life of any heritage, which is essential for research and studies as well as reference for future generations to come. E. Related Works There are some a few research regarding adapting HDR into panorama package through virtual heritage environment for instance Jinsong, Yanbing and Jigong (2009)[23] from Foshan University of China. Their research paper discussed on the use of HDR spherical panorama and the importance of preserving China ancient cultural heritage. Their effort uses one of the newest technologies for recording HDR spherical panorama. The same thing was done by Woeste (2009)[12], See (2012)[24] and Carr and Correll (2009)[25]; combining HDR and panorama into one package, although they use more
conventional method compare to the team from China. Woeste, See, Carr and Correll all use normal digital single lens reflex (DSLR) with mosaic panoramic capture to get all the images. Even though the method can be the same, increasing the pixel count could impose new challenges towards the workflow process of HDR spherical panorama. II. THE PROCESS A. Established Methods In present practice, most photographers are using wide angle or fisheye lenses to create spherical panorama either with or without HDR. This reduces the number of images needed and also the overall resolution of the panoramic image. Lohrman (2007)[26] and Gawthrop (2007)[27] use fisheye lens to do the capturing and in theory it only takes three to four images for a complete sphere. Although Clark (2009)[28] states that human eye covers a wide FOV, very similar to wide angel lenses, they do not distort the image (Weitz, n.d)[29]. Therefore a normal lens is more likely suitable for capturing process, closely replicating a human being’s field of vision - FOV. Regardless of lens focal length use, the workflow process of combining HDR into spherical panorama remains the same. McCollough (2008, p. 137)[2] had outline three methods in creating HDR spherical panorama as listed in Table I below: TABLE I. Method Stitch > Merge > Tone Map/Exposure Fusion (Stitch first)
1.
2. Merge > Stitch > Tone Map/ Exposure Fusion (Stitch second) Merge > Tone Map/Exposure Fusion > Stitch (Stitch last)
3. 1. 2. 3. 1. 2. 3.
Description To stitch each exposure set into panorama, meaning there are three panoramas with three different exposure values. Merge the panoramas into one 32-‐ bit HDR file. Tone map the 32-‐bit HDR file. Merge every set of section into 32-‐ bit HDR files. Stitch the 32-‐bit HDR files into a panorama. Tone map the HDR file. Merge every set of section into 32-‐ bit HDR files. Tone map each HDR files. Stitch the HDR files into one panorama.
Three different methods of creating HDR panorama as listed by McCollough.
Adaptation of HDR into spherical panorama will bring an entirely new understanding to visual look and experience. It gives amazing results to any subject especially in scenes with challenging lighting condition. The visual attraction of HDR spherical panorama especially presented in an interactive form where the viewers are immersing within the environment can be very persuasive. Roussou (2008, p. 228)[9] explains that in an immersive representation that is so realistic that viewers are unable to distinguish between reality and virtually constructed environment. The reality of HDR spherical panoramic presentation is as close to how human see and navigate the world. High-resolution panoramic image on the other hand can be considered as an added value to the presentation. While HDR can enhance and reveals the hidden details within dark
areas, gigapixels panorama enables viewers to zoom in to a certain area on the panorama maintaining details. These two features are actually beyond natural human eyes capability if not completely better. However, in creating gigapixels panorama, a longer telephoto lens is needed and theoretically, using a longer lens with narrower FOV captures only a small portion of a scene onto the same sensor resolution. Table II shows the comparison between 60mm lens and 105mm lens capturing the same subject at the same distance using the same capture device. The 105mm telephoto lens brings the image closer and thus reveals more details. TABLE II. 60mm
105mm
was used this time reducing the capture time needed. RAW is a non-destructive file format that requires further processing before it can be used. It is like a digital negative and holds all the sensor's information (Rodriguez, 2007, p. 25[29]; Davis 2012, p. 32[6]; Busch, 2005, p. 88[31]). A single RAW file is enough to capture the entire dynamic range of a scene (Leiva, n.d. through McCollough, 2008, p. 64)[2] especially with the current technology. The RAW file is saved in 14-bit depth format, the maximum bit depth available within any DSLR camera compare to only 8-bit for either JPEG or TIFF file format. Rodriguez (2007, p. 9)[29], Gulbins and Gulbins (2010, p. 138)[3] and Joffre, Puech, Comby and Joffre (n.d.) all agrees that even a 12-bit RAW file has more dynamic range compare to 8-bit JPEG or TIFF. The extra bit depth made is possible for single RAW HDR recording. Figure I shows the rotational degrees for the capture. Focusing was a bit of a problem due to limited illumination and at some angle manual focusing was required. FIGURE I.
Comparison between using shorter and longer lens focal length showing extra details. Both lens were mounted on Nikon D800 DSLR approximately half a meters from subject at ISO:100, Shutter:1.6" and Aperture:f/22
Using longer focal length therefore will require more images for a complete spherical. Adding HDR into the equation increases the complexity of capturing and post-processing. In today's 35mm digital camera standard, Nikon D800 has the highest resolution image sensor with 36MP and producing approximately 10MB per JPEG file or 70MB of RAW file. The capture process will opt for the highest quality to get as much details as possible using Nikon D800 camera body paired with a Sigma 105mm f/2.8 Macro lens and set to the highest quality possible depending on site condition. B. Capture Process The first step in the process of creating gigapixels HDR spherical panorama is using the longest focal length. A customize L-bracket was made to be coupled with the Manfrotto 300N base rotator and the Nodal Ninja QRC-6 M2 upper rotator to occupy Sigma 105mm f/2.8 lens. ISO was set at 400; aperture at f/11 and shutter varies depending on camera angle. ISO400 was chosen due to the longest shutter speed achievable was already 25 seconds per exposure. A total of 614 images are needed for a complete spherical taking approximately four and half hours to capture. Although lower ISO renders less noise, the D800 can still produce decent photos even at ISO 3200 and need to avoid using bulb mode, thus for an average of 15 seconds of the slowest shutter speed, ISO400 was the lowest it could get. The same setup was done in 2009 with different setting. During that time the capture device used was a 10.2MP Nikon D200 paired with Nikkor AFS DX 35mm f/1.8G lens. With that lens, the APS-C sensor size gives a crop factor of 1.5x equivalent to 45mm in full frame 35mm format. ISO was at 800, f/8.0 aperture and using multiexposure JPEG sequence. Three different exposures ware taken in two stops interval at each camera angle taking 1194 images and took more than four hours to complete. A single RAW file
Horizontal and vertical degrees for capturing a complete spherical panorama.
C. Image Processing And Management Since the capture was done using only a single RAW file per angle, underexposed and overexposed image sequence has to be created by exposure extraction from the RAW file using RAW conversion software. However, RAW file is a proprietary file format exclusive only to the camera manufacturer. Although there are third parties RAW converters that can read this type of file, the reader has to be updated from time to time to enable reading from newer camera model. From an experiment done, it is found that Adobe Lightroom has the ability to extract 11EVs of exposures from the RAW file compare to other software. This means that it can creates more variation of underexpose and overexpose images form a single RAW. Table III below shows the comparison between some the most used RAW conversion software’s. Table III. Application Adobe Lightroom v5.4 Nikon Capture NX v2.3.0 DxO Labs Optics Pro v9.5 PhaseOne Capture One v6.3.5 Apple Aperture v3.5.1 Corel AfterShot Pro v2.0
Number of exposure extractions 11EVs (+-5EVs) 5EVs (+-2EVs) 9EVs (+-4EVs) 6EVs (+-2.5EVs) 5EVs (+-2EVs) 7EVs (+-3EVs)
Comparison of exposure extraction between some of popular RAW image editing applications.
According to reports from DxO Labs, a Nikon D800 sensor is capable of recording 14.33EVs while D200 can only records 11.47EVs. This means that the Nikon D800 has more than three stops of EVs reserved. Exposure extraction was done through Adobe Lightroom v5.4, extracting images in two stops interval for each RAW file as shown in Figure II.. For every RAW file, there are three images in a set of underexpose, normal exposure and overexpose images. These files are exported to uncompressed TIFF file in 16-bit ProRGB settings. This is to maintain the highest quality of exported files. Each TIFF file is a massive 200MB in size within a working folder that consist gigabytes of images. The set of three images will later be merged into one 32-bit image before exposure fusion process. Exposure fusion is the same as tone mapping with few differences; it does not requires huge computing resources and produce better result especially very minimal halos effect. Compare to tone mapping, exposure fusion uses complex algorithm selecting only good pixels from a number of images to create one perfect expose image. FIGURE II.
pieces into one panorama. Stitching is done lastly. All three ways was experimented. E. Creating HDR Images A sequence of underexposed, normal exposure and overexposed images are organized in a set of three for better management. All the images are named accordingly with ascending numbers followed by the filename and extension. This is to ensure that there are no missing or overlapping exposures in the sequence. In this study, the software used for creating HDR images is Photomatix v4.0, which is user friendly and straightforward. The creation process runs in batch mode with Exposure Fusion/Average setting to get a more neutral look instead of a dreamy or oversaturated output. It averages the highlights and shadows to reveal details and at the same time reduce unwanted aberrations. The number of images needs to be fused into one HDR image is the set of three exposures. Alignment is unnecessary because the capture was done using a tripod and utilizing a single RAW file per camera angle, thus there shouldn't be any misalignment, saving some extra time. Figure III shows the step in setting up Photomatix. This process is for merging a number of images and applicable only to the third method (Merge > Tone Map/Exposure Fusion > Stitch). Method one and two requires merging and mapping finished panorama instead of pieces of images. FIGURE III.
Exposure extraction from a single RAW file.
D. Creating Gigapixels HDR Spherical Panorama of The Tempurung Cave The real challenge lies here during the process of combining HDR into spherical panorama. As being listed before in Table I, there are three techniques of achieving the intended output. The first technique requires a set of three panoramas, which means all underexpose images are stitch into a panorama. In this technique, there will be three different panoramas; one underexpose panorama, one normally expose panorama and one overexpose panorama. These three panoramas are then merge together into one 32-bit panorama and fuse together. Stitching is firstly done. The second technique merges all the underexposed, normal exposure and overexposed images first to create a sequence of 32-bit image files. All the files are then stitch together to create one 32-bit panorama. The final step is either tone mapping or fusing the panorama using pseudo-HDR method. Stitching is at second stage. In the third technique, the first step is merging all the set of images into a sequence of 32-bit HDR files. These files are then tone map or fuse together. The final stage is stitching the
The sequence of processes involve in creating HDR images using Photomatix.
F. Image Stitching Panorama stitching into a spherical projection is done using PTGui. It is the simplest software to learn and understand. However, the exporting process eats up huge amount of computer resources. The sequence of HDR images is then loaded into PTGui to create a spherical panorama. The loading time depends on the number of images and the file size. PTGui will automatically read the EXIF data and do the alignment based on lens parameters. Controls points are placed strategically between linked images determine the anchor points of side-‐by-‐side images. It is placed based on similar features between the images. Sharp images and bigger overlapping areas provide for more accurate matching control points. However, creating HDR spherical panorama of the Tempurung Cave is not the same as creating evenly lit
scene. Due to small FOV of each image, it is hard to determine similar features between images and which images are side-‐by-‐side. During the capture in 2009, 45mm lens has wider FOV than 105mm lens, thus is much easier to recognize same features between images and its placement. For this particular case, a Papywizard file is needed to help arranging the images correspondents to its coordinate in the sphere. Although approximate alignment can be manually done just like jigsaw puzzle through Panorama Editor, the process is very time consuming considering the number of images involved. It also requires visual and cognitive dexterity to be able to see the similar features between images. A Papywizard is an xml file that lists all the panorama parameters such as image number and its coordinate. With the help of a n automated motorize panoramic head, it is possible to create a Papywizard file to be used during the stitching process even though the capture was done manually. For this study, a motorized panoramic head manufactured by Seitz was used to create the Papywizard file. Figure IV shows the process of crating Papywizard file using Seitz Roundshot VRDrive. A sample of Papywizard file is shown in Figure V while Figure VI shows PTGui in the process of aligning the images. With PTGui, images need to be loaded first before importing Papywizard file through the File > Import menu. FIGURE IV.
FIGURE VI.
Gigapixels spherical panorama image stitching using PTGui.
G. Exporting Gigapixels Spherical Panorama Exporting the gigapixels panorama file through PTGui is the most time consuming job. PTGui will eventually consume the computer resources available making multitasking impossible. However, this depends on the size of the panorama. The HDR spherical panorama of the Tempurung Cave is about 8.7 gigapixels in resolution. Due to a very large image dimension, this is when some of the methods are not usable. PTGui can export into few formats such as QuickTimeVR movie, JPEG, TIFF and PSD/PSB file. A normal panorama would fit into JPEG or TIFF but, TIFF file only permits resolution of less than one gigapixels and file size of less than 4GB. It is found that the only way to export such high-‐resolution panorama is through PSB file. PSB file is a Adobe Photoshop file format for large documents permitting up to four Exabyte in size and covering 300, 000 x 300, 000 in pixel dimension. Unfortunately, not many application supports PSB file format. H. Workable Method For HDR Gigapixels Spherical Panorama
Creating Papywizard file using Seitz Roundshot VRDrive.
FIGURE V.
A sample of Papywizard xml file.
In the production of high-‐resolution gigapixels HDR panorama, there are two photography technique used; one is HDR photography and the other is panoramic photography. Both techniques are combined together to enhance viewers viewing experience. Scholars listed three methods. Due to the advancement of digital technology and image sensors, higher and higher resolution of image sensor was made available. This in a way contributes to higher image quality and huge file size. The creation of HDR gigapixels spherical panorama utilizes a technique called photo mosaic in which a set of smaller images is stitched together to create a higher resolution image. Exceeding one gigapixels mark now impose a problem of supporting file format. Because of only Adobe Photoshop PSB file that can support tremendous file size and very high resolution, not much application can support this file type. Method one (Stitch > Merge > Tone Map/Exposure Fusion) and method two (Merge > Stitch > Tone Map/Exposure Fusion) are not usable.
The first method creates three very large panoramas with different exposure. Although many photographers prefer this method as it gives more control towards tone mapping or exposure fusion, Photomatix and much other HDR creation software are unable to even load the file. Thus merging and tone mapping/exposure fusion of the three different exposure panorama is not possible. The second method on the other hand creates a single 32-‐bit spherical panorama that contains all the dynamic range. However, the same problem as method one occurs. HDR creation software’s do not support PSB file format, which leaves the only working method is the third. This is because the smaller images are already a sequence of tone mapped/fused images. The spherical panorama exported from this method is already a tone mapped/fused HDR image and thus, the final output file can be in any type of file format. Figure VII shows the working workflow process of creating HDR gigapixels spherical panorama of the Tempurung Cave while Figure VIII to Figure X explains the workflow and issues from using Methods One to Three.
FIGURE IX.
Using method two to create HDR spherical panorama.
FIGURE X.
FIGURE VII.
Using method three to create HDR spherical panorama.
I. Viewing Gigapixels HDR Spherical Panorama
The workflow process of creating gigapixels HDR spherical panorama.
FIGURE VIII.
Viewing such large file is not possible though normal image viewers let alone through website. However there is a method of image tiling, which cut a single big image into smaller pieces. This technique was developed by Microsoft Research was DeepZoom Technology. It uses the same concept of mosaic. Through virtual tour authoring software such as Panotour Pro, a large panorama can be made into a package of smaller images for web distribution. Figure XI shows the creation using Panotour Pro software while Figure XII shows the end product viewed through a website. FIGURE XI.
Using method one to create HDR spherical panorama.
Creating tile images of panorama using Panotour Pro.
FIGURE XII.
[10] Ward, G. (2001) High Dynamic Range Imaging. Available at: (http://www.pauldebevec.com/Research/HDR/Ward-HDRImaging20010521.pdf) [11] Benosman, R., & Kang, S. B. (2001). Panoramic Vision: Sensord, Theory and Applications. Springer. [12] Woeste (2009) Mastering Digital Panoramic Photography. Rocky Nook (USA) [13] Frish, A. (2007). Panoramic Photography: From Composition And Exposure To Final Exhibition. Focal Press. [14] Jacobs, C. (2004). Interactive Panorama: Techniques for Digital Panoramic Photography. Springer.
The gigapixels HDR spherical panorama of the Tempurung Cave viewed through web browser.
II. CONCLUSION The documentation in the process and creation of an efficient workflow for the utilization of gigapixels in high dynamic range spherical panoramas is much needed. Although there are several working methods for producing HDR spherical panorama, higher-resolution images have new challenges materializing in handling and creating such large sized detailed output. This paper aspires to introduce a novel approach to this process. Furthermore, high-resolution detailed photographic documentation is essential for preservation purposes, as it will serve as a reference for future generations to come. With the present digital technology, achieving higher resolution images isn’t an insurmountable task, however, an efficient workflow process is needed to ensure a high quality output especially involving a combination of multiple photographic techniques. REFERENCES [1] Tylor, D. (2012). Understanding HDR Photography: The Expanded Guide. Ammonite. [2] McCollough, F. (2008). Complete Guide to High Dynamic Range Digital Photography. Lark Books. [3] Gulbins, J., & Gulbins, R. (2010). Photographic Multishot Technique. Rockynook. [4] Brown, G.J. (2006). RPS Journal. [5] Hirsch, R. (2008). Light And Lens: Photography In The Digital Age. Focal Press. [6] Davis, H. (2012). Creating HDR Photo: The Complete Guide to High Dynamic Range Photography. Amphoto Book. [7] Langford, M., & Bilissi, E. (2008). Langford's Advanced Photography (7th Edition ed.). Focal Press. [8] Fitzgerald, B. (January, 2008). A Brief on HDRI. The Digital Media Club (http://www.dmcscad.com) [9] Roussou (2008). In Y. E. Kalay, T. Kvan, & J. Affleck, New Heritage: New Media and Cultural Heritage. London and New York: Routledge.
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