In order to obtain panoramic images in a low contrast underwater environment, an underwater panoramic image mosaic algorithm based on image enhancement and improved image registration (IIR) was proposed. Firstly, mixed filtering and sigma filtering are used to enhance the contrast of the original image and de-noise the image. Secondly, scale-invariant feature transform (SIFT) is used to detect image feature points. Then, the proposed IIR algorithm is applied to image registration to improve the matching accuracy and reduce the matching time. Finally, the weighted smoothing method is used for image fusion to avoid image seams. The results show that IIR algorithm can effectively improve the registration accuracy, shorten the registration time, and improve the image fusion effect. In the field of cruise research, instruments equipped with imaging systems, such as television capture and deep-drag camera systems, can produce a large number of image or video recordings. This algorithm provides support for fast and accurate underwater image mosaic and has important practical significance.

The Permian Tarim large igneous province (TLIP) is located in the Tarim basin, NW China. Although the flood basalt of the TLIP has been intensively studied, other igneous components within TLIP have not yet been sufficiently investigated. The Wajilitag igneous complex is outcropped with a rather limited exposure by regional tectonic uplift. However, various igneous rocks, both mafic–ultramafic and syenitic, can be observed as either intrusions or extrusions in this area. It is an ideal location for studying the magmatic evolution of different components within the TLIP. We systematically examine the geological, geochronological, and geochemical characteristics of the Wajilitag complex, to further constrain the petrogenesis of each component and their interrelationships, as well as the implications to the petrogenetic model of TLIP. The igneous rocks in Wajilitag complex can be classified into two series based on their geochemical features: Series A and Series B. Series A are more alkalic, more trace element enriched and more isotopically depleted than Series B. Series A includes nephelinite, aegirine–nepheline syenite (ANS), and syenite porphyry (SP), whereas the Series B consists of clinopyroxenite, gabbro, diorite, hornblende-bearing syenite (HS), and quartz syenite (QSN). Dolerites can either belong to Series A or Series B depend on its geochemistry. Kimberlitic rocks are independent of the Wajilitag complex geologically, geochemically, and geochronogically. The temporal sequences of Wajilitag complex would be clinopyroxenite→gabbro→ diorite/syenite→nephelinite. The dolerite can be emplaced later than the syenite but can extend to an earlier period. In contrast to the Tarim basalts, the Wajilitag complex belongs to the second stage of magmatism in the TLIP. The mantle source for the Tarim basalts, the Series B and Series A gradually changed from SCLM-dominated to plume-dominated component. Graphical Abstract