Volumetric reconstruction of label-free living cells from non-destructive optical microscopic images reveals cellular metabolism in native environments. However, current optical tomography techniques require hundreds of 2D images to reconstruct a 3D volume, hindering them from intravital imaging of biological samples undergoing rapid dynamics. This poses the challenge of reconstructing the entire volume of semi-transparent biological samples from sparse views due to the restricted viewing angles of microscopes and the limited number of measurements. In this work, we develop Neural Volumetric Prior (NVP) for high-fidelity volumetric reconstruction of semi-transparent biological samples from sparse-view microscopic images. NVP integrates explicit and implicit neural representations and incorporates the physical prior of diffractive optics. We validate NVP on both simulated data and experimentally captured microscopic images. Compared to previous methods, NVP significantly reduces the required number of images by nearly 50-fold and processing time by 3-fold while maintaining state-of-the-art performance. NVP is the first technique to enable volumetric reconstruction of label-free biological samples from sparse-view microscopic images, paving the way for real-time 3D imaging of dynamically changing biological samples.

The focus on rapid software delivery inevitably results in the accumulation of technical debt, which, in turn, affects quality and slows future development. Our primary aim is to discover how companies keep their codebases maintainable and how code improvements might be automated. Method: we investigate Meta practices by collaborating with engineers on code quality (via action research) and by analyzing rich source code change history using mixed-methods to reveal a range of practices used for continual improvement of the codebase. Results: Code improvements at Meta range from completely organic grass-roots done at the initiative of individual engineers, to regularly blocked time and engagement via gamification of Better Engineering (BE) work, to major explicit initiatives aimed at reengineering the complex parts of the codebase or deleting accumulations of dead code. Over 14% of changes are explicitly devoted to code improvement and the developers are given "badges" to acknowledge the type of work and the amount of effort. Based on the interactions with development teams we suggest metrics to help prioritization of code improvement efforts. Finally, our models of the impact of reengineering activities revealed substantial improvements in quality and speed and reductions in code complexity. Overall, code improvement activities are relatively effort intensive yet simple enough to be prime targets for automation.

In this paper, we introduce a novel system to assist 6D object pose estimation network training, which is only deployed in the training progress to optimize the network parameters, and does not work in the testing stage, called Online training and offline testing system (OTOT). OTOT consists of two modules: a feature fusion module and a supervision module. The feature fusion module fuses several feature maps from the pose estimation network in a specified order to obtain a fused feature. Then, the supervision module uses the encoder–decoder structure network to implicitly extract useful features from the fused feature and optimizes the pose estimation network online through the back-propagation mechanism. OTOT can be migrated to any network with encoder–decoder structure. The network trained with OTOT achieves 56.11% accuracy in terms of the VSD metric on the TLESS dataset using RGB inputs, compared to the 46.70% accuracy of the original network trained without OTOT. Experiments show that OTOT greatly improves the accuracy of the pose estimation network, and since OTOT is not deployed in the testing stage, it does not increase any parameters during testing and affect the original speed of the network.

The light field camera has significantly advanced conventional imaging methods and microscopy over the past decades, providing high-dimensional information in 2D images and enabling a variety of applications. However, inherent shortcomings persist, mainly due to the complex optical setup and the trade-off between resolution. In this work, we propose a Neural Defocus Light Field (NDLF) rendering method, which constructs the light field without a micro-lens array but achieves the same resolution as the original image. The basic unit of NDLF is the 3D point spread function (3D-PSF), which extends the 2D-PSF by incorporating the focus depth axis. NDLF can directly solve the distribution of PSFs in 3D space, enabling direct manipulation of the PSF in 3D and enhancing our understanding of the defocus process. NDLF achieves the focused images rendering by redefining the focus images as slices of the NDLF, which are superpositions of cross-sections of the 3D-PSFs. NDLF modulates the 3D-PSFs using three multilayer perceptron modules, corresponding to three Gaussian-based models from coarse to fine. NDLF is trained on 20 highresolution (1024 × 1024) images at different focus depths, enabling it to render focused images at any given focus depth. The structural similarity index between the predicted and measured focused images is 0.9794. Moreover, we developed a hardware system to collect the high resolution focused images with corresponding focus depth, and depth maps. NDLF achieves high-resolution light field imaging with a single-lens camera and also resolves the distribution of 3D-PSFs in 3D space, paving the way for novel lightfield synthesis techniques and deeper insights into defocus blur.