Harris corner detector. More...
Functions | |
AFAPI features | harris (const array &in, const unsigned max_corners=500, const float min_response=1e5f, const float sigma=1.f, const unsigned block_size=0, const float k_thr=0.04f) |
C++ Interface for Harris corner detector. More... | |
AFAPI af_err | af_harris (af_features *out, const af_array in, const unsigned max_corners, const float min_response, const float sigma, const unsigned block_size, const float k_thr) |
C Interface for Harris corner detector. More... | |
Harris corner detector.
Compute corners using the Harris corner detector approach. For each pixel, a small window is used to calculate the determinant and trace of such a window, from which a response is calculated. Pixels are considered corners if they are local maximas and have a high positive response.
AFAPI af_err af_harris | ( | af_features * | out, |
const af_array | in, | ||
const unsigned | max_corners, | ||
const float | min_response, | ||
const float | sigma, | ||
const unsigned | block_size, | ||
const float | k_thr | ||
) |
C Interface for Harris corner detector.
[out] | out | struct containing arrays for x and y coordinates and score (Harris response), while arrays orientation and size are set to 0 and 1, respectively, because Harris does not compute that information |
[in] | in | array containing a grayscale image (color images are not supported) |
[in] | max_corners | maximum number of corners to keep, only retains those with highest Harris responses |
[in] | min_response | minimum response in order for a corner to be retained, only used if max_corners = 0 |
[in] | sigma | the standard deviation of a circular window (its dimensions will be calculated according to the standard deviation), the covariation matrix will be calculated to a circular neighborhood of this standard deviation (only used when block_size == 0, must be >= 0.5f and <= 5.0f) |
[in] | block_size | square window size, the covariation matrix will be calculated to a square neighborhood of this size (must be >= 3 and <= 31) |
[in] | k_thr | Harris constant, usually set empirically to 0.04f (must be >= 0.01f) |
AFAPI features harris | ( | const array & | in, |
const unsigned | max_corners = 500 , |
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const float | min_response = 1e5f , |
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const float | sigma = 1.f , |
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const unsigned | block_size = 0 , |
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const float | k_thr = 0.04f |
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) |
C++ Interface for Harris corner detector.
[in] | in | array containing a grayscale image (color images are not supported) |
[in] | max_corners | maximum number of corners to keep, only retains those with highest Harris responses |
[in] | min_response | minimum response in order for a corner to be retained, only used if max_corners = 0 |
[in] | sigma | the standard deviation of a circular window (its dimensions will be calculated according to the standard deviation), the covariation matrix will be calculated to a circular neighborhood of this standard deviation (only used when block_size == 0, must be >= 0.5f and <= 5.0f) |
[in] | block_size | square window size, the covariation matrix will be calculated to a square neighborhood of this size (must be >= 3 and <= 31) |
[in] | k_thr | Harris constant, usually set empirically to 0.04f (must be >= 0.01f) |