Forceps tracking is an important element of high-level surgical assistance such as visual servoing and surgical motion analysis. In many computer vision algorithms, artificial markers are used to enable robust tracking; however, markerless tracking methods are more appropriate in surgical applications due to their sterilizability. This paper describes a robust, efficient tracking algorithm capable of estimating the full state parameters of a robotic surgical instrument on the basis of projective contour modeling using a 3-D CAD model of the forceps. Thus, the proposed method does not require any artificial markers. The likelihood of the contour model was measured using edge distance transformation to evaluate the similarity of the projected CAD model to the microscopic image, followed by particle filtering to estimate the full state of the forceps. Experimental results in simulated surgical environments indicate that the proposed method is robust and time-efficient, and fulfills real-time processing requirements.

The master and slave surgical assistant systems have been studied actively. However, regarding the master system, the manipulator should be designed for each surgical field because the target workspace and precision are different. Furthermore, operability is important for safety reasons. Therefore, the authors analyzed the motion of surgeon first and then developed a master manipulator suitable for the operation of micro neuro surgery. Some experiments were conducted to evaluate the control method and show the effectiveness of the proposed manipulator control method.

A low-band spectrum envelope reconstruction method was tested to see if it could improve the sound quality of speech modified by the PSOLA (pitch synchronous overlap add) method. In the conventional TD (time domain)-PSOLA method, the spectrum envelope extracted using a Hanning window with a two-pitch-period length had no reliable information in the band of frequencies lower than original F/sub 0/. This problem causes the sound degradation of the F/sub 0/ modified speech. In the proposed method, the low-band spectrum envelope was properly modified according to the F/sub 0/ modification rate. The amplitude of the F/sub 0/ harmonic components in the low-band was reproduced based on the spectral tilt of the spectrum envelope. Subjective listening test results suggest this proposed method yields better sound quality than the conventional TD-PSOLA method when the downward modification rate exceeds 0.4 octave.

In order to synthesize natural-sounding Japanese phonetic words, a novel VCV-concatenation synthesis with an advanced word database is proposed. The word database consists of VCVbalanced phonetic words which are uttered forcibly in type-0 and type-1 pitch accents. The advantage of using the advanced word database is that a variety of VCV-segments with the same phonetic chains and the different pitch patterns could be collected efficiently at the same time. The following pitch modification techniques are used to achieve the sound quality: (1) The optimal VCV-segment set which minimizes the pitch modification rate is selected. (2) Pitch waveforms are extracted by referring to excitation points. (3) Wavelengths of pitch waveforms are adjusted depending on the pitch modification rates. (4) Natural prosody in the VCV-segments in the database is effectively used. Superiority of the proposed database is ensured by means of the pitch pattern matching measurement and the subjective quality evaluation.