Turning a conventional camera into a 3D camera with an add-on

Abstract

We propose to add an optical component in front of a conventional camera to improve depth estimation performance of depth from defocus (DFD), an approach based on the relation between defocus blur and depth. The add-on overcomes ambiguity and the dead zone, which are the fundamental limitations of DFD with a conventional camera, by adding an optical aberration to the whole system that makes the blur unambiguous and measurable for each depth. We look into two optical components: the first one adds astigmatism and the other one chromatic aberration. In both cases, we present the principle of the add-on and experimental validations on real prototypes.

Probabilistic Modeling and Inference for Sequential Space-Varying Blur Identification

“…b) Defocus blur: Defocus space-varying blurs have been considered for example in [50] in the context of depth estimation in digital camera images. Defocus blur kernel can be parametrized by ρ = (θ, s) with θ ∈ R and s ∈ (0, +∞) 2 .…”

Performance model of depth from defocus with an unconventional camera

“…In the sequel we use "valid" convolutions where the support of the scene is enlarged with respect to the one of the image according to the PSF support [Section 4.3.2 17]. In [4], (b): colored aperture shape of [6], (c): add-on with chromatic aberration of [8] and (d): the 3D camera with chromatic aberration of [7] which is further studied in Section 6. sections 4.1 and 5.1, a more precise description of quantities Y , X and H z will be given, specific to the considered application.…”

“…Figure 16 shows example of the restored image corresponding to the image of Figure 15, using a high frequency transfer. As in [7,8], the weights of the transfer is defined with respect to the estimated distance from the depth maps. The zoom on the image allows to see the improvement of image quality due to the restoration process.…”

“…Many recent works focus on single image DFD with coded aperture that reinforces the depth information contained within the defocus blur [4,5]. References [6][7][8] exploit RGB images from a color camera equipped with an unconventional lens leading to a spectral variation of the relationship between blur and depth. This is obtained by changing the aperture shape with the color [6] or by using a lens with chromatic aberration [7,8].…”

“…References [6][7][8] exploit RGB images from a color camera equipped with an unconventional lens leading to a spectral variation of the relationship between blur and depth. This is obtained by changing the aperture shape with the color [6] or by using a lens with chromatic aberration [7,8]. Some of these unconventional lens used for DFD are illustrated in Fig.…”