Hadamard single-pixel imaging versus Fourier single-pixel imaging

Single-pixel imaging is an innovative imaging scheme and has received increasing attentions in recent years. It is applicable to imaging at non-visible wavelengths and imaging under low light conditions. However, single-pixel imaging has once encountered problems of low reconstruction quality and long data-acquisition time. This situation has been changed thanks to the developments of Hadamard single-pixel imaging (HSI) and Fourier single-pixel imaging (FSI). Both techniques are able to achieve high-quality and efficient imaging, remarkably improving the applicability of single-pixel imaging scheme. In this paper, we compare the performances of HSI and FSI with theoretical analysis and experiments. The results show that FSI is more efficient than HSI while HSI is more noise-robust than FSI. Our work may provide a guideline for researchers to choose suitable single-pixel imaging technique for their applications

Full-field Fourier ptychography (FFP): spatially varying pupil modeling and its application for rapid field-dependent aberration metrology

Digital aberration measurement and removal play a prominent role in computational imaging platforms aimed at achieving simple and compact optical arrangements. A recent important class of such platforms is Fourier ptychography, which is geared towards efficiently creating gigapixel images with high resolution and large field of view (FOV). In current FP implementations, pupil aberration is often recovered at each small segment of the entire FOV. This reconstruction strategy fails to consider the field-dependent nature of the optical pupil. Given the power series expansion of the wavefront aberration, the spatially varying pupil can be fully characterized by tens of coefficients over the entire FOV. With this observation, we report a Full-field Fourier Ptychography (FFP) scheme for rapid and robust aberration metrology. The meaning of 'full-field' in FFP is referred to the recovering of the 'full-field' coefficients that govern the field-dependent pupil over the entire FOV. The optimization degrees of freedom are at least two orders of magnitude lower than the previous implementations. We show that the image acquisition process of FFP can be completed in ~1s and the spatially varying aberration of the entire FOV can be recovered in ~35s using a CPU. The reported approach may facilitate the further development of Fourier ptychography. Since no moving part or calibration target is needed in this approach, it may find important applications in aberration metrology. The derivation of the full-field coefficients and its extension for Zernike modes also provide a general tool for analyzing spatially varying aberrations in computational imaging systems

Correlation between Aphids, Aphidiinae and Hyperparasitoids in Different Habitats

Aphids are one of the major pests of economical crops in China. Field surveys showed that Macrosiphum avence, Rhopalosiphum padi, Schizaphis graminum, Myzus persicae, Aphis glycines and Lipaphis erysimi are the main aphid species found in agricultural fields. Besides lady beetles and spiders, aphidiine braconids also play an important role in controlling aphids, including Ephedrus plagiator, E. nacheri, Aphidius euenae, Diaeretiella rapae, A. ervi, and A. picipes. However, Aphidiinae are also attacked by many hyperparasitoids, which include Aphidencyrtus aphidivorus, Pachyneuron aphidis, Asaphes vulgaris, Lygocerus koebelai and Figites sp.Originating text in Chinese.Citation: Zhang, Guoan, Guan, Yue, Wang, Qinghai. (2000). Correlation between Aphids, Aphidiinae and Hyperparasitoids in Different Habitats. 8th National Biological Control Conference, Symposium on Insect Control by Microbiology, 29-29