Present car audio systems make use of a number of loudspeakers in order to obtain a flat response in each of the seating positions within the car cabin. However, it is difficult to achieve an optimum audio quality because of unstable localization effects, differences in sound quality with seating position and a feeling of sound pressure caused by modes in the low frequency range.
To solve these problems, the authors have constructed an in-car sound system with loudspeakers placed solely on the dashboard. This system controls localization using the HAAS effect and uses active mode control to produce a sound field similar to that found in a normal room with forward localization and without a feeling of sound pressure.
In a vehicle, the driver is often required to adjust the audio level to counter-act engine noise, tire to road noise or wind-whistle. In order to reduce the necessity for such adjustments the authors have developed an automatic noise compensation system. This uses a DSP IC to create a compensation characteristic which can be optimized for different vehicles; in development of this system a Toyota Celsior (Lexus LS400) was used.
The authors examined road conditions in both Japan and the USA and were able to tune the system to achieve an optimum sound level under a variety of conditions.
The authors have designed a sound effect which makes the sound source appear to be at a distant location. This effect was developed on the suggestion of a psychosomatic physician with long experience in music therapy who pointed out that sounds which appear to originate from a distance location could be effective in inducing relaxation.
Using a digital reverberator the reverberation times of the lower and higher frequency ranges were made shorter than the mid-frequency range. At the same time, by setting the density of the reverberation to be less than that of a typical reveberator the desired sound effect was achieved.
The effectiveness of this sound effect was measured experimentally by monitoring the heart rate of a group of listeners. The results show a drop in both heart rate and variations of heart rate (LF/HF) for listeners subjected to the sound effect compared to listeners not subject to the effect. This drop was statistically significant (p<0.05) and suggests that the sound effect can have a calming effect on the listener.
The Dolby Digital Consumer Encoder (DDCE) is a low cost version of a professional encoder capable of encoding 2 channel PCM audio. It is designed to be similar in complexity to a 5.1 channel encoder and creates ATSC standard A/52 compliant "AC-3" bit-streams.
The authors developed firmware to enable real-time audio encoding with DDCE for use with a DVD Video recorder. The DDCE used in the Video recorder makes use of general purpose DSP and memory ICs and marks the first time that a DDCE has been certified by Dolby Laboratories.
The EFX-500 Effector has been developed for use by DJ's in live performances and reflects the opinions and comments of DJs in it's specifications. The unit uses a DSP to produce a variety of effects and it is the aim of this report to detail the construction, functionality and design process of the unit with the focus on the signal processing done by the DSP.
DVD-Audio Specifications specify an audio application format within DVD-ROM Specifications. While retaining compatibility with the DVD-Video format, the DVD-Audio format is a generation of audio disc media format which makes full use of the features and functions specific to DVD. Pioneer, as a core member of DVD Forum group, has been engaged in working out the DVD-Audio Specifications. This book outlines these Specifications.
Michihiro Kaneko, Kiyomi Suzuki
We have developed a new platform for DVD car navigation systems. The platform consists of hardware and system software. The hardware contains high performance devices such as a CPU, a Graphics Display Controller and so on. The system software contains a Realtime Operating System and a BIOS software and so on.
The hardware also contains an ASIC which we have developed and which integrates many I/O functions useful for navigation systems. The DVD car navigation system employing this platform, is smaller and has more functions than the former model.
Within the GPS, a newly developed LSI has been utilized to increase processing speed and achieve real hybrid processing. Also, the position detection system uses a new 3D hybrid sensor which is able to detect heiGht differentials along a route by adding an extra G sensor to the existing gyro sensor to enable road slope detection.
Finally, a "variable multi-path candidacy selection" methodology has been added to the map matching system. This uses the above-mentioned 3D hybrid sensor's output to accurately determine which road a vehicle is running on even when a raised highway and a normal road run parallel and overlapped; a determination which competitor navigation systems are unable to achieve.
Using these newly developed technologies the AVIC-D9000 series of products is able to calculate a vehicle's position 4 times every second and offers an accuracy of less than 5 m; a requisite for very high zoom modes such as the 10m scale display or the drivers view display.
Kazunori Ishizu , Yoshiaki Iwai, Takahiro Shimura, Yoichi Hara, Takamasa Yamaguchi
A car television system has been developed with the aim of improving picture quality and functionality.
In order to improve picture quality, technology for a weak-field environment and an "intelligence dimmer" function which automatically adjusts the picture luminosity to compensate for external light conditions were developed. Advanced functionality was achieved by enabling two different visual sources to be viewed at the same time using a "PinP" or "PsideP" display along with a multi-source display function.
Yoshiaki Iwai, Tadashi Sasaki, Naoki Sato, Takahiro Shimura
Kouichi Ono, Ikuo Fujita, Takahiro Iwata, Hiroshi Saito, Takashi Hanyuda
Speaker-independent voice recognition middleware has been developed and installed into the new DVD Car navigation systems (AVIC-D9000 series) launched in May,1999.
Concerns that the use of middleware would reduce the voice recognition response speed compared with previous models were addressed by overall improvements in the algorithms used. The methods used to improve response time and results obtained are also shown.
Finally,this paper introduces new features available using the voice recognition human I/F such as phone number input using connected-digit speech recognition,the utilization of large-vocabulary recognition and a convenient voice input mode named "direct start".
We have developed a faster drawing process, and optimized its algorithm on the Car Navigation. As a consequence, we have introduced a much easier to understand and better operativity Car Navigation product.
Keisuke Mochizuki, Sosuke Ishida
A new scrolling method was developed utilizing the Q2SD graphic chip to achieve a smoother map scroll without compromising map detail.
Two new modes of map display were also developed in order to distinguish the Pioneer navigation system from those of its competitors. The "Driver's View" display shows the view from a driver's perspective while the "Visual City Map" shows buildings three-dimensionally based on actual height data. These two new display modes enabled the realization of a product which is visually appealing.
We developed a new route guidance algorithm, and describe an overview of the route guidance process and how to create guidance points, that is applied to a vehicle navigation system. Particularly, the method of the creating guidance points is shown with some concrete examples. With the method shown in this paper, a simpler route guidance is obtained compared to the previous algorithm.
Takeshi Satou, Nobuo Ishida, Shinichi Naohara, Hitoshi Yamazaki, Kenji Wakatsuki, Kenji Uchiyama
The authors have developed the "MS1", a second generation DVD-ROM drive for Car use. This is a DVD and CD Compatible module which features double speed playback and high speed search capabilities. Using an adaptive liquid Crystal tilt servo, the drive is able to adapt to a wide variation of disc tolerances. The drive is 40 % smaller (volume) than the previous generation.
Toshiaki Nakano, Ichiro Hatano
A natural integration of the real-time information gathering ability of the Internet with the functions of a car navigation system has been achieved which goes beyond the simple combination of a car-navigation user interface and a PC's WWW browser.
1st generation Internet car-navigation systems had only a simple WWW browser in which users viewed WWW pages by entering the URL manually via a remote controller. This was very tedious and took a large amount of time to access the required information. The 2nd generation system developed is much easier to use as the user need not enter characters manually via the remote control.
With the "Weather Live" function, weather forecast information is superimposed directly onto the car-navigation's digital map. The car-navigation system accesses the weather forecast data via the Internet and colors the map based on the information received ( ex. rain is "blue", fine is "yellow", cloudy is gray. ) "Direct Internet Access" links an institution's name with it's URL. A user can access the home-page of an institution by selecting it from the car-navigation's menu "directly".
The authors have developed software to monitor the position of a helicopter in flight. This Software can display the helicopter's position on a digitized map based on information received from the Aircraft Map Display System "Airmap". Used in conjunction with the "HeliTV" system, the software is able to display video taken by the helicopter alongside a digital map with the position of the helicopter superimposed, indicating the location of the videoed area.