Reduced energy-ratio measure for robust autofocusing in digital camera

Sang Yong Lee, Jae Tack Yoo, Soo-Won Kim

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

A robust and power efficient focus measure applicable in digital cameras is proposed. This measure, namely reduced energy-ratio (RER), uses the dc component and the lowest order five AC components of the discrete cosine transform (DCT) and is expressed as the ratio of the AC and DC components. The low-frequency AC and DC components contain the most energy (information) of an image as well as the detailed edge and base edge information. Autofocus score calculation method is used to assess the performance of the proposed measure and to compare it with other measures. Experimental results under various conditions verify the robustness of the proposed focus measure for the Gaussian as well as impulsive noises.

Original languageEnglish
Pages (from-to)133-136
Number of pages4
JournalIEEE Signal Processing Letters
Volume16
Issue number2
DOIs
Publication statusPublished - 2009 Feb 5

Fingerprint

Auto-focusing
Impulse noise
Discrete cosine transforms
Digital Camera
Digital cameras
Energy
Autofocus
Impulsive Noise
Discrete Cosine Transform
Gaussian Noise
Low Frequency
Lowest
Verify
Robustness
Experimental Results

Keywords

  • Autofocus
  • Digital camera
  • Discrete cosine transform (DCT)
  • Focus measure

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Signal Processing
  • Applied Mathematics

Cite this

Reduced energy-ratio measure for robust autofocusing in digital camera. / Lee, Sang Yong; Yoo, Jae Tack; Kim, Soo-Won.

In: IEEE Signal Processing Letters, Vol. 16, No. 2, 05.02.2009, p. 133-136.

Research output: Contribution to journalArticle

Lee, Sang Yong ; Yoo, Jae Tack ; Kim, Soo-Won. / Reduced energy-ratio measure for robust autofocusing in digital camera. In: IEEE Signal Processing Letters. 2009 ; Vol. 16, No. 2. pp. 133-136.
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