Tham khảo tài liệu 'vision systems - applications part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Extraction of Roads From Out Door Images 111 calculates the moments of the region of interest to extract the centroid and the orientation of the path. In the last step Transmission the information concerning the path centroid and the orientation is transmitted by a RS-232 serial interface to a navigation module. Besides these functions other considerations had to be taken to run the algorithm in the embedded system New data types were created in C in order to be compatible with ADSP EZKIT- LITE BF533. These data structures manage the information in the image and handle all the parameters that the algorithm uses. All the variables are defined according with the size and physical position that each one will take in the physical memory in the development kit. This execution allows a better use of the hardware resource and enables simultaneous processing of two images one image is acquired by the DMA and other is processed in the CPU. Finally The Blackfin s ALU only handles fixed-point values so floating-point values have to be avoided in order to maintain the performance of the whole system. 6. Conclusion Even when there has been an extensive development of works on road detection and road following during the last two decades most of them are focused on well structured roads making difficult its use for humanitarian demining activities. The present work shows a way to use the natural information in outdoor environment to extract the roads or paths characteristics which can be used as landmarks for the navigation process. Other important observation is that the information combines of two colors . the projection R B Cb or Cr channels hence reducing the harmful effect of the changing illumination in natural environment. Good results were also achieved in the path planning process. The robot executes a 2 D trajectory planning which facilitates the work of the vision system because only the close range segmentation has to be correct to be successful in the path .
