In vivo depth estimation of features in the chick eye by digital signal processing of ultrasonic pulse echoes

An existing biological instrumentation system which measures the depth of tissue boundaries in the chick eye has been modified to use National Instruments LabVIEW as a graphical interface for the operator. This system is used in a study to assess the effectiveness of pharmaceuticals designed to slow the progression of myopia, in which a high-speed data acquisition card digitizes the output of an ultrasound sensor to provide in vivo depth measurements of the eyeball structure. LabVIEW not only provides a real-time visualization of the ultrasonic scan, but it also allows for the interactive assessment of axial length as well as the creation of archival databases. A LabVIEW implementation of a matched filter with an echo-shaped impulse response applied to a simulated noisy ultrasound signal produces distinct peaks corresponding to the structural interfaces, suggesting a possible approach to automated peak detection.