Visual Detection and Two-Dimensional Rotation Control in Zebrafish Larva Heart Microinjection

Zebrafish larva heart microinjection has emerged as an important technology that enables delivery of a wide variety of vehicles into hearts of small individuals. However, traditional manual microinjection is laborious and time consuming, and most existing automated injection systems can be costly or complicated to assemble. In this paper, a semiautomated and simple-structure vision servosystem of Zebrafish larva heart microinjection is presented. A robust vision recognition algorithm is developed to locate heart of anesthetized larvae with different postures. A rolling model that utilizes slice figures of larva body is constructed to estimate larva heart height. The two-dimensional rotation control that positions and orients larva by a motorized translational stage and a glass capillary is also proposed to meet the requirement of successful holding. Experimental results show that the developed visual detection method can achieve a success rate of 100% when larva heart is towards left or right and 90% in other postures. The rotation control approach also achieves a high success rate of 97% with rotation resolution of 0.5${}^{\circ}$. As a high-efficiency and high-cost-performance microinjection system, our system has a potential application in other organs injection of Zebrafish larvae.