Multi-focus image fusion (MFIF) aims to utilize multiple images with different focal lengths to fuse into a single full-focus image. This process enhances the realism and clarity of the resulting image. In this paper, a MFIF method called MSI-DTrans was proposed. On the one hand, in order to fully utilize all the effective information that the source image carries, the proposed method adopts a multilayer semantic interaction strategy to enhance the interaction of high-frequency and low-frequency information. This approach gradually mines more abstract semantic information, guiding the generation of feature maps from coarse to fine. On the other hand, a parallel multi-scale joint self-attention computation model is designed. The model adopts dynamic sense field and dynamic token embedding to overcome the performance degradation problem when dealing with multi-scale objects. This enables self-attention to integrate long-range dependencies between objects of different scales and reduces computational overhead. Numerous experimental results show that the proposed method effectively avoids image distortion, achieves better visualization results, and demonstrates good competitiveness with many state-of-the-art methods in terms of qualitative and quantitative analysis, as well as efficiency comparison. The source code is available at https://github.com/ouyangbaicai/MSI-DTrans.
In the field of holographic displays, achieving a large viewing angle (LVA) has long been an essential and formidable challenge due to the limited diffraction angle of planar spatial light modulators (SLMs). Spherical holography, which allows observation from all perspectives, represents a practical approach to achieve the LVA. However, the physical limitations of commercial SLMs constrain direct implementation, making the realization of spherical holographic displays almost impractical and thus hindering technological advancement. This paper introduces an optical solution for spherical holographic display system, enabling the accurate reproduction of ultra-wide viewing angles and large objects. Our system utilizes a novel technique involving a convex parabolic mirror to convert an incident plane wave into a spherical wave. This innovative strategy permits the use of a planar SLM to create a 360°spherical holographic display. Additionally, we address the sampling issue for generating spherical holograms by constraining the point spread function (PSF), reducing the number of samples, and adapting it for visible light. Numerical simulations and optical experiments validate our success in achieving an ultra-wide viewing angle with a 360°horizontal angle and an 80°zenith angle range. Our system outperforms the state-of-the-art holographic-optical-elements approach both in computation speed and object size. We believe that our work significantly advances spherical holographic displays and offers a practical solution with vast potential applications in medicine, geology, and astronomy.