Active One-Shot Scan for Wide Depth Range Using a Light Field Projector Based on Coded Aperture

Abstract

The central projection model commonly used to model cameras as well as projectors, results in similar advantages and disadvantages in both types of system. Considering the case of active stereo systems using a projector and camera setup, a central projection model creates several problems; among them, narrow depth range and necessity of wide baseline are crucial. In the paper, we solve the problems by introducing a light field projector, which can project a depth-dependent pattern. The light field projector is realized by attaching a coded aperture with a high frequency mask in front of the lens of the video projector, which also projects a high frequency pattern. Because the light field projector cannot be approximated by a thin lens model and a precise calibration method is not established yet, an image-based approach is proposed to apply a stereo technique to the system. Although image-based techniques usually require a large database and often imply heavy computational costs, we propose a hierarchical approach and a feature-based search for solution. In the experiments, it is confirmed that our method can accurately recover the dense shape of curved and textured objects for a wide range of depths from a single captured image.

Learning-based active 3D measurement technique using light field created by video projectors

“…These results show that the basis represents the features of the training image set for different types of light field. [12]. Our method performed better than the previous technique except Kinect…”

“…However, as mentioned earlier, because of its complicated nature, only limited research has been done to analyze of a synthetic light field created by projectors. Kawasaki et al proposed a technique to capture the entire light field by a special sampling machine [12], but the dataset size proved to be very large and calculation time high. In contrast, we propose two approaches to create a blur-free light field and to recover 3D information using compact data representation and low computational time.…”

“…2 and 3. Figure 2 shows a configuration using a single or multiple video projectors incorporating a coded aperture [12]. In this system, both the aperture mask and projected pattern involve mutually parallel lines.…”

“…Figure 2a shows an example of a case requiring actual image capturing. When a coded aperture is installed in a projector, interference between the light source and the lens makes virtual capture of sample images difficult [12]. Therefore, actual image capturing is necessary.…”

Depth Estimation Using Structured Light Flow — Analysis of Projected Pattern Flow on an Object’s Surface

“…If decoding the positional information fails for some reason, such as noise, specularity, blur, etc., shape reconstruction will subsequently fail. To avoid this limitation, some techniques are based on geometric constraints rather than decoding [15,13,8,20] or active usage of defocus effect by coded aperture [7]. One problem with such techniques is that, because they are heavily dependent on geometric constraints or special devices, strong motion blur cannot be handled.…”