Biomedical Engineering Reference
In-Depth Information
8
Grayscale Graphical Softness
Tactile Display
8.1 Introduction
One essential and challenging element of haptic and robotic surgery is tactile display which
enables the user to experience the sense of touch by using a remote teletaction system
from which information is collected and processed. Recently, different technologies have
been developed to address this need and Chapters 1 and 7 present some of the state-of-
the-art work in this area. This chapter elaborates on graphical softness tactile displays that
can be used to convert the sense of touch into images readily recognizable by a surgeon.
Using our proposed system, the surgeon can visually determine the softness of a grasped
tissue and detect the presence (or absence) of unusual lumps, such as a tumor, by grasping
a suspect tissue using a smart endoscopic grasper or robotic end effector equipped with
appropriate tactile sensors. One major advantage of a graphical tactile display is that the
surgeon receives information visually, thereby freeing his/her hands for other tasks. In
the case of a physical tactile display, the display has to be in contact with the surgeon's
hands which limits movement. In the case of the graphical tactile display, since there is
always a monitor that the surgeon uses to view the site of operation, the tactile data can be
presented to the surgeon using the same monitor. Two methods can be considered, one that
allocates a corner of the monitor to show tactile information, the second superimposes
the real image of the site of an operation coming from an endoscope and constructed
tactile images.
This chapter is organized in two parts. The first part presents the graphical display for
representing the softness of objects held by an minimally invasive surgery (MIS) grasper.
The second part is devoted to detection and localizing lumps embedded inside tissue.
8.2 Graphical Softness Display
The system used for this study consists of an endoscopic grasper integrated with an
array of tactile sensors, a data acquisition interface (DAQ), and appropriate signal algo-
rithms that process information from the sensor to the display. The complete system is
