A scheme for spot scanning using 11C beams has been developed in order to form and verify a three-dimensionally conformal irradiation field for cancer radiotherapy. By selecting the momentum spread of a 11C beam, we could considerably decrease the distal falloff of the irradiation field, thus conserving the beam quality. To estimate and optimize the dose distribution in the irradiation field, it is essential to evaluate the precise dose distribution of spot beams. The coupling of the lateral dose and depth-dose distributions originating from a wide momentum spread should be taken into account to calculate the dose distribution of 11C beams. The reconstructed dose distribution of the irradiation field was in good agreement with the experimental results, i.e., within ±0.2%. An irradiation field of 35×35×43 mm3 was optimized and spot scanning using 11C beams was carried out. The flatness was within ±2.3% with an error of 1% in the detector resolution.

A laser-driven repetition-rated 1.9 MeV proton beam line composed of permanent quadrupole magnets (PMQs), a radio frequency (rf) phase rotation cavity, and a tunable monochromator is developed to evaluate and to test the simulation of laser-accelerated proton beam transport through an integrated system for the first time. In addition, the proton spectral modulation and focusing behavior of the rf phase rotation cavity device is monitored with input from a PMQ triplet. In the 1.9 MeV region we observe very weak proton defocusing by the phase rotation cavity. The final transmitted bunch duration and transverse profile are well predicted by the PARMILA particle transport code. The transmitted proton beam duration of 6 ns corresponds to an energy spread near 5% for which the transport efficiency is simulated to be 10%. The predictive capability of PARMILA suggests that it can be useful in the design of future higher energy transport beam lines as part of an integrated laser-driven ion accelerator system.

3-D I m a g e R e c o g n i t i o n S y s t e m f o r D r i v e A s s i s t Keiji S a n e y o s h i , Keiji Hanawa, Katsuyuki Kise, Y o s h i y u k i S o g a w aS u b a r u R e s e a r c h C e n t e r Co., ltd. 3-9-6 Ohsawa, Mitaka, Tokyo, 181, J A P A N P h o n e ( ABSTRACT (1) Detectable d i s t a n c e T h e d e t e c t a b l e d i s t a n c e is e v a l u a t e d A n e w t h r e e -d i m e n s i o n a l i m a g e f r o m t h e v e l o c i t y o f t h e v e h i c l e a n d a recognition system has been d e v e l o p e d t o t o t a l t i m e w h i c h i n c l u d e s t h e r e c o g n i z e r o a d b o u n d a r i e s a n d o b s t a c l e s . r e c o g n i t i o n t i m e , r e s p o n s e t i m e a n d a c t i v e b r a k i n g o r s t e e r i n g t i m e . T h e T h e i y s t e m is b a s e d o n s t e r e o s c o p y , a n d it c a n d e t e c t t w o w h i t e la n e m a r k s , t w o fences along t h e road and as m a n y a s s i x o b s t a c l e s s i m u l t a n e o u s l y w i t h i n 0.1

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crops and ridges are required. The appearances of these objects change due to sunlight, viewing perspective, soil condition and other factors in outside fields, meaning it is not easy to detect them robustly, based on their appearances and using two-dimensional images alone.The key characteristic of crops and ridges are their three-dimensional shapes within a space. Accordingly, a technology which processes three-dimensional information, such as stereo vision, seems more effective. Research 5 exists, which detects crop rows using a stereo camera device and controls a tractor by tracking the crop rows. This features a stereo camera mounted on the front of the tractor and allows the investigation of the overall three-dimensional shape of luxuriant crop rows. However, a technique to detect a wider range of objects, such as ridges and marker traces, is required. A stereo vision system 1 was developed by a tractor maker, and has already been practically applied. Stereo vision is a useful technology to understand a three-dimensional environment. However, the design method for the stereo camera, reflecting each purpose or mounting place, and techniques exploiting three-dimensional data have not been dis- IntroductionIn recent years, due to the aging workforce and with a lack of successors in the agricultural sector, there is a need for technical development that can ease the burden of those operating agricultural tractors, and enable highly efficient and accurate operation, even by unskilled operators. Based on these requirements, systems for operational assistance must be developed immediately.In seeding and ridge forming work, an operator drives a tractor parallel to the traces of the previous path, while weeding or harvesting involves the operator running along crops or preformed ridges. Technology to detect crops and ridges is important to develop operational assistance system. Vision technology is considered promising because human operators recognize such objects with the naked eye and there has been considerable research into object detection. A device used to detect green crops by distinguishing them from the field surface soil with a color camera 2 has been practically applied. However, techniques capable of detecting various other JARQ 46 (4), 287 -293 (2012) AbstractA stereo vision system for agricultural tractors was developed. Two kinds of stereo camera unit were manufactured: one of which is mounted on the front of the tractor and the other on the cabin roof. The system can detect various formed or shaped objects, such as crop rows, ridges, uneven surfaces after tilling and marker traces in front of the tractor in agricultural fields. The system generates distant images with a 0.1-second cycle, while an internal algorithm installed in the system analyzes this distant image data three-dimensionally, and detects the positions of objects. The positional data was transferred to a steering controller of the tractor and tilling work was performed automatically by tracking these objects.