title: Interactive visual exploration of overlapping similar structures for three-dimensional microscope images.
abstract: BACKGROUND
  Recent advances in microscopy enable the acquisition of large numbers of tomographic images from living tissues. Three-dimensional microscope images are often displayed with volume rendering by adjusting the transfer functions. However, because the emissions from fluorescent materials and the optical properties based on point spread functions affect the imaging results, the intensity value can differ locally, even in the same structure. Further, images obtained from brain tissues contain a variety of neural structures such as dendrites and axons with complex crossings and overlapping linear structures. In these cases, the transfer functions previously used fail to optimize image generation, making it difficult to explore the connectivity of these tissues.
  
  
  RESULTS
  This paper proposes an interactive visual exploration method by which the transfer functions are modified locally and interactively based on multidimensional features in the images. A direct editing interface is also provided to specify both the target region and structures with characteristic features, where all manual operations can be performed on the rendered image. This method is demonstrated using two-photon microscope images acquired from living mice, and is shown to be an effective method for interactive visual exploration of overlapping similar structures.
  
  
  CONCLUSIONS
  An interactive visualization method was introduced for local improvement of visualization by volume rendering in two-photon microscope images containing regions in which linear nerve structures crisscross in a complex manner. The proposed method is characterized by the localized multidimensional transfer function and interface where the parameters can be determined by the user to suit their particular visualization requirements.
authors.affiliation: Graduate School of Informatics, Kyoto University, Yoshida Honmachi, Sakyo, Kyoto, Japan. megumi@i.kyoto-u.ac.jp.
authors.forename: Megumi
authors.initials: M
authors.lastname: Nakao
authors.affiliation: Graduate School of Informatics, Kyoto University, Yoshida Honmachi, Sakyo, Kyoto, Japan. takemoto@sys.i.kyoto-u.ac.jp.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Takemoto
authors.affiliation: Graduate School of Information Science, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, Japan. sugiura@is.naist.jp.
authors.forename: Tadao
authors.initials: T
authors.lastname: Sugiura
authors.affiliation: Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido, Japan. sawady@ec.hokudai.ac.jp.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Sawada
authors.affiliation: Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido, Japan. rkawascb@es.hokudai.ac.jp.|Research Institute for Electronic Science, Hokkaido University, Sapporo, Japan. rkawascb@es.hokudai.ac.jp.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kawakami
authors.affiliation: Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido, Japan. tn@es.hokudai.ac.jp.|Research Institute for Electronic Science, Hokkaido University, Sapporo, Japan. tn@es.hokudai.ac.jp.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Nemoto
authors.affiliation: Graduate School of Informatics, Kyoto University, Yoshida Honmachi, Sakyo, Kyoto, Japan. tetsu@i.kyoto-u.ac.jp.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Matsuda
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000166:cytology; D003196:Computer Graphics; D003712:Dendrites / Q000378:metabolism; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008099:Liver / Q000166:cytology; D051379:Mice; D018613:Microscopy, Confocal / Q000379:methods*; D009474:Neurons / Q000166:cytology; D012984:Software; D014584:User-Computer Interface