Investigating the lateral resolution in a plenoptic capturing system using the SPC model

Abstract

Complex multidimensional capturing setups such as plenoptic cameras (PC) introduce a trade-off between various system properties. Consequently, established capturing properties, like image resolution, need to be described thoroughly for these systems. Therefore models and metrics that assist exploring and formulating this trade-off are highly beneficial for studying as well as designing of complex capturing systems. This work demonstrates the capability of our previously proposed sampling pattern cube (SPC) model to extract the lateral resolution for plenoptic capturing systems. The SPC carries both ray information as well as focal properties of the capturing system it models. The proposed operator extracts the lateral resolution from the SPC model throughout an arbitrary number of depth planes giving a depth-resolution profile. This operator utilizes focal properties of the capturing system as well as the geometrical distribution of the light containers which are the elements in the SPC model. We have validated the lateral resolution operator for different capturing setups by comparing the results with those from Monte Carlo numerical simulations based on the wave optics model. The lateral resolution predicted by the SPC model agrees with the results from the more complex wave optics model better than both the ray based model and our previously proposed lateral resolution operator. This agreement strengthens the conclusion that the SPC fills the gap between ray-based models and the real system performance, by including the focal information of the system as a model parameter. The SPC is proven a simple yet efficient model for extracting the lateral resolution as a high-level property of complex plenoptic capturing systems.

Depth and angular resolution in plenoptic cameras

“…Results are obtained by applying the SPC-based depth resolution extractor to the integral imaging setup specified in [13]. Figure 4 gives an insight into this observation.…”

“…The Sampling Pattern Cube (SPC) model was introduced in [12] and has been successfully utilized for extraction of the spatial resolution in integral imaging setups [13] and state of the art plenoptic cameras [14,15]. In contrast to the previous models, the SPC model considers the light samples in the form of light cones, which are bundles of light rays, with a tip position and an angular span (see Figure 1).…”

“…The camera properties such as the spatial resolution in various depth planes is extracted by looking into the distribution and the overlaps of the light cones in the SPC model of the camera. In the process of extracting the spatial resolution of plenoptic cameras, the SPC model has offered lower complexity compared to the wave-optic-based models and higher accuracy relative to the principal-ray-model which assigns a single principal ray to each pixel [13]. The SPC model is bound to the realm of the geometrical optics which gives a wider scope compared to e.g.…”

“…Contribution of new light cones, which gives the position of the resolvable depth planes, does not occur uniformly in depth and the transformation through the main lens only amplifies this nonuniformity. Figure 6 illustrates the distance between consecutive resolvable depth planes in an integral imaging setup specified in [13], using the SPC-based depth resolution extractor. Figure 6 shows that by going farther from the camera, the period and amplitude of the cycles increase (but not necessarily the distance between two consecutive resolvable depth planes).…”

Spatial resolution in a multi-focus plenoptic camera

“…The lightfield model has proven useful for applications spanning computer graphics, digital photography, and 3D reconstruction [6], but to our best knowledge, has not been utilized for extraction of the high-level camera properties. Attempts are made for model-based extraction of the high-level camera properties such as spatial resolution, using the principal ray model, the previously proposed SPC model and the complete wave-optics-based simulations [7,8]. In each case, 978-1-4799-5751-4/14/$31.00 ©2014 IEEE Fig.…”