Patent ID: 8520955

Claim:
An object detection apparatus for detecting a predetermined object from an image, comprising one or more strong classifiers each including one or more weak classifiers each including a feature extracting section and a function mapping section, of which the feature extracting section extracts a feature of the image, and the function mapping section determines a weak classification of the image in accordance with the feature extracted by the feature extracting section; wherein the feature extracting section comprises: a feature point extracting section, for extracting a combination of predetermined feature point pairs from the image; a pixel value obtaining section, for obtaining a pixel value of each feature point in the combination of feature point pairs; a feature point comparing section, for comparing, in accordance with the pixel values obtained by the pixel value obtaining section, two feature points in each feature point pair to obtain a logical value; and a feature obtaining section, for determining the feature of the image in accordance with the logical value, wherein the feature point comparing section obtains the logical value b i for an i-th feature point pair using any one of the following formulae: b i = sign ⁡ ( ∑ s = 1 i ⁢ ( g s ⁢ ⁢ 1 - g s ⁢ ⁢ 2 ) ) b i = sign ⁡ ( ∑ s = 1 i ⁢ 2 s - 1 ⁢ ( g s ⁢ ⁢ 1 - g s ⁢ ⁢ 2 ) ) where g s1 and g s2 represent pixel values of two feature points in s-th feature point pair, respectively, and the function sign( ) is defined as follows: sign ⁡ ( v ) = { 1 , if ⁢ ⁢ υ ≥ 0 0 , if ⁢ ⁢ υ < 0 .