Next Generation CT (Computed Tomography) Student: Jaewon Kim - - PowerPoint PPT Presentation

Next Generation CT (Computed Tomography)

Student: Jaewon Kim Advisor: Ramesh Raskar Reader: V. Michael Bove Yasuhiro Mukaigawa Fredo Durand

Dream & Goal

Dream Thesis Goal

Understanding inside of a human body with portable system Wearable, always-on system for health and HCI (no x-ray CT) no x-ray CT Non scanning system and visible light Thesis Prototype: 3D finger vein reconstruction/human Id system

How will CT evolve?

1st : Linear & rotational CT 2nd : Multiple scanning CT 3rd : Fan-beam CT 4th: spiral CT or helical CT

5th ? Non-scanning No Synchronization Compact Safe

Traditional CT

Benefit

 Expensive  Exposure to X-rays  Poor dynamic volume reconstruction Standard CT system  See through human body with X-ray

Limitation: Scanning mechanism makes CT large and cumbersome

Thesis Goal

 A. Avoid mechanical scanning (Also applicable to actual X-ray CT system)  B. Visible light CT and overcome scattering Single shot CT of translucent (non-scattering) objects Imaging through scattering

• bjects

Goal A: Non scanning CT

Prior work

Shield Field Imaging (Lanman, Raskar, Agrawal and Gabriel[2008] )  Opaque object reconstruction from a single photo  Limitation : Lacks support for translucent object

A single shot photo Decoupling to multi-view images 3D Reconstruction Shield Field system

3D Reconstruction of partially transparent objects with a single shot photo  Limitation : low resolution due to decoded multi-view images

single shot photo 3D Reconstruction Decoded multi-view images Single shot CT setup

Goal A: Non scanning CT

My contribution

Reconstruction of partially transparent objects using visible light

3D reconstruction results in high resolution Multi-view images(resolution is 100x200)

Goal A: Non scanning CT

My contribution

Separation of Direct and Scattered component of reflection (Nayar, Krishnan, Grossberg and Raskar [2006] )  Reflection-based method using projected patterns  Limitation : not single shot, no 3d reconstruction, no transmission mode

Photo of mannequin and shower curtain Direct Image Scattered component

Goal B: Visible light CT

Prior work

= +

Transmission-Mode Direct-Global Separation of Scattering Objects (will be submitted to CVPR 2010)  a single LED and lenslet(pinhole) array method  Acquiring a clear image for objects inside of scattering media

Goal B: Visible light CT

My contribution

Photo of mannequin and shower curtain Direct Image Scattered component

= +

Imaging Setup

Finger vein imaging using near-infrared LED by Hitachi and Sony (ML disclosure filed as 3D Finger Vein Authentication )

vein authentication+lightfield camera

Near-infrared image of finger vein

Example Application

Single shot 3D vein reconstruction

Limitations & Future directions

 Replacing traditional CT system by single shot compact system  Health and HCI applications with portable and safe CT machines  Self imaging of CT images by patients  Difficult to see through dense area of a human body with visible light  Decreased resolution of processed light field images  Need for multiple light sources for non scanning CT system Future Limitations

Evaluation

Goal B: 3D finger vein CT system with a resolution of 100x100x100 Evaluation: Id using vein pattern from 20 people database by 3D matching Goal A: dynamic volume reconstruction of translucent objects with a resolution of 100x200x200 Evaluation: Comparing 3D reconstruction results in proposed and normal tomographic techniques Comparing SNR between lightfield and normal images

Dream & Goal

Dream Thesis Goal

Understanding inside of a human body with portable system Wearable, always-on system for health and HCI (no x-ray CT) no x-ray CT Non scanning system and visible light Thesis Prototype: 3D finger vein reconstruction/human Id system