Range imaging by multi-focus camera with coded aperture

http://www-sens.sys.es.osaka-u.ac.jp/users/shinsaku/research/MFC/index.html

We proposed two ideas to make a practical depth from defocus (DFD) method. In particular, we focused on the issues of robustness of calculation and and compactness of ecquipment. At first, we introduced the multi-focus camera, which is a novel compact image sensor for depth from defocus (DFD) range measurement. Although it is as small as an usual CCD camera, it can capture three images focused on different distances simultaneously. Then we introduced a coded aperture to make the method more robust. That optics make it possible to design and control the characteristics of the blurring, so the robustness and simplicity of the depth estimation algorithm are significantly improved. To prove that principle, we tried to use two types of optics and corresponding analysis algorithms. The former method utilizes 1D Fourier analysis to acquire a depth map and a all-in-focus image from three defocused images taken with a pair of pinholes. The latter one is based on the spatial domain computation using 2D convolution for fast and precise depth measurement using a coded aperture with several pinholes. Since the camera has NTSC color video signal as a output , and also our proposed methods with coded aperture are robust enough for noisy recorded images, it is possible to measure a moving object by recording the sequences of three images. Fast image processor also enables to compute the depth map in real-time. Simplicity and parallelism of our method help to implement our algorism on massive parallel SIMD processor array. Experimental results showed that the multi-focus camera works well as a practical DFD range sensor and that the coded apertures much improve its range estimation capability for real world scenes.

Shinsaku Hiura, Gaku Takemura and Takashi Matsuyama: Depth Measurement by Multi-Focus Camera, proc. of Model-Based 3D Image Analysis, 35-44 (Jan. 1998 at Mumbai)

Shinsaku Hiura and Takashi Matsuyama: Depth Measurement by the Multi-Focus Camera, Proc. of CVPR'98, 953-959 (Jun. 1998 at Santa Barbara)

Category:

Science & Technology

Tags:

• depth from defocus
• range image
• range finder
• realtime