Large-scale structures from infrared surveys

To use the AKARI All-Sky Survey Point Source Catalogue as a validation sample for future missions such as Planck and to study large-scale structure, we first investigate the AKARI point source detection limit at 90 μm and the nature of bright spurious sources. Due to the degradation of the sensitivity of the AKARI All-Sky Survey and formidable difficulties in filtering out excessive noise, we return to the IRAS Faint Source Catalog to construct a redshift catalogue of over 60,000 galaxies selected at 60 μm, the Imperial IRAS-FSC Redshift Catalogue (IIFSCz). Around 50% of the sources in the IIFSCz have spectroscopic redshifts and a further 20% have photometric redshifts. The luminosity and selection functions are obtained for the IIFSCz flux-limited at 0.36 Jy at 60 μm. The dependence of galaxy clustering on spectral type and luminosity is studied using correlation statistics. A possible detection of the baryon acoustic oscillations in the power spectrum of the flux-limited sample of the IIFSCz is discussed. Finally, we present future research directions which include the FIR-radio correlation, ultraluminous and hyperluminous infrared galaxies, galaxy bias in the SWIRE Photometric Redshift Catalogue and convergence of the cosmological dipole

An Adaptive Spatial-Temporal Local Feature Difference Method for Infrared Small-moving Target Detection

Detecting small moving targets accurately in infrared (IR) image sequences is a significant challenge. To address this problem, we propose a novel method called spatial-temporal local feature difference (STLFD) with adaptive background suppression (ABS). Our approach utilizes filters in the spatial and temporal domains and performs pixel-level ABS on the output to enhance the contrast between the target and the background. The proposed method comprises three steps. First, we obtain three temporal frame images based on the current frame image and extract two feature maps using the designed spatial domain and temporal domain filters. Next, we fuse the information of the spatial domain and temporal domain to produce the spatial-temporal feature maps and suppress noise using our pixel-level ABS module. Finally, we obtain the segmented binary map by applying a threshold. Our experimental results demonstrate that the proposed method outperforms existing state-of-the-art methods for infrared small-moving target detection

Photoacoustic brain imaging: from microscopic to macroscopic scales

Human brain mapping has become one of the most exciting contemporary research areas, with major breakthroughs expected in the coming decades. Modern brain imaging techniques have allowed neuroscientists to gather a wealth of anatomic and functional information about the brain. Among these techniques, by virtue of its rich optical absorption contrast, high spatial and temporal resolutions, and deep penetration, photoacoustic tomography (PAT) has attracted more and more attention, and is playing an increasingly important role in brain studies. In particular, PAT complements other brain imaging modalities by providing high-resolution functional and metabolic imaging. More importantly, PAT’s unique scalability enables scrutinizing the brain at both microscopic and macroscopic scales, using the same imaging contrast. In this review, we present the state-of-the-art PAT techniques for brain imaging, summarize representative neuroscience applications, outline the technical challenges in translating PAT to human brain imaging, and envision potential technological deliverables