ArrayFire: harris (original) (raw)
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.
◆ af_harris()
| 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.
Parameters
| [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, | ||
| 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.
Parameters
| [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) |
Returns
features object 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