Journal of the Institute of Electronics Engineers of Korea SD (대한전자공학회논문지SD)

The Institute of Electronics and Information Engineers (대한전자공학회)
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Low-power Focus Value Calculation Algorithm using modified DCT for the mobile phone

개선된 이산 코사인 변환을 이용한 모바일 폰 용 저전력 초점 값 계산 알고리즘

  • Lee Sang-Yong (Department of Electronics Engineering, Korea University) ;
  • Park Sang-Soo (Department of Electronics Engineering, Korea University) ;
  • Kim Soo-Won (Department of Electronics Engineering, Korea University)
  • Published : 2005.11.01
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Abstract

This paper proposes the low power MDCT algorithm for precise FV with minimum size of sub-window in mobile phone. Proposed algerian uses the coefficient at the middle of whole result process requiring the least number of calculations, since it has a good characteristic when used as standard of the FV and needs minimum amount of operation. In addition, using the DCT result related to the middle frequency makes the characteristic of FV more superior because it suppresses the impulsive noise and difference of focus values is larger than any others. The proposed algorithm is implemented using Verilog HDL and verified using Excalibur-ARM board.

본 논문에서는 최소의 sub-window를 사용하여 정확한 초점 값을 측정할 수 있는 모바일 폰 용 저전력 MDCT 초점 값 연산 방식을 제안하였다. 제안된 알고리즘은 기존의 DCT 연산 계수 중 초점 값의 척도로 사용하기에 특성이 가장 우수하고, 하드웨어로 구현하였을 경우 연산량이 최소가 되는 중간 결과 계수를 초점 값으로 사용한다. 또한 중간 주파수에 연관된 DCT 결과를 초점 값으로 사용하므로 임펄스 성 노이즈의 영향을 줄일 수 있고, 영상의 흐린 정도에 따른 초점 값의 변화가 커서기존의 Gradient 방식보다 초점 값 특성이 우수하다. 제안된 알고리즘은 Verilog HDL언어를 사용하여 구현되었으며, Excalibur-ARM보드에 내장하여 그 성능을 검증하였다.

Keywords

References

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