FAST feature detector.  
More...
|  | 
| AFAPI features | fast (const array &in, const float thr=20.0f, const unsigned arc_length=9, const bool non_max=true, const float feature_ratio=0.05, const unsigned edge=3) | 
|  | C++ Interface for FAST feature detector.  More... 
 | 
|  | 
| AFAPI af_err | af_fast (af_features *out, const af_array in, const float thr, const unsigned arc_length, const bool non_max, const float feature_ratio, const unsigned edge) | 
|  | C Interface for FAST feature detector.  More... 
 | 
|  | 
FAST feature detector. 
A circle of radius 3 pixels, translating into a total of 16 pixels, is checked for sequential segments of pixels much brighter or much darker than the central one. For a pixel p to be considered a feature, there must exist a sequential segment of arc_length pixels in the circle around it such that all are greather than (p + thr) or smaller than (p - thr). After all features in the image are detected, if nonmax is true, the non-maximal suppression is applied, checking all detected features and the features detected in its 8-neighborhood and discard it if its score is non maximal. 
      
        
          | AFAPI af_err af_fast | ( | af_features * | out, | 
        
          |  |  | const af_array | in, | 
        
          |  |  | const float | thr, | 
        
          |  |  | const unsigned | arc_length, | 
        
          |  |  | const bool | non_max, | 
        
          |  |  | const float | feature_ratio, | 
        
          |  |  | const unsigned | edge | 
        
          |  | ) |  |  | 
      
 
C Interface for FAST feature detector. 
- Parameters
- 
  
    | [out] | out | struct containing arrays for x and y coordinates and score, while array orientation is set to 0 as FAST does not compute orientation, and size is set to 1 as FAST does not compute multiple scales |  | [in] | in | array containing a grayscale image (color images are not supported) |  | [in] | thr | FAST threshold for which a pixel of the circle around the central pixel is considered to be greater or smaller |  | [in] | arc_length | length of arc (or sequential segment) to be tested, must be within range [9-16] |  | [in] | non_max | performs non-maximal suppression if true |  | [in] | feature_ratio | maximum ratio of features to detect, the maximum number of features is calculated by feature_ratio * in.elements(). The maximum number of features is not based on the score, instead, features detected after the limit is reached are discarded |  | [in] | edge | is the length of the edges in the image to be discarded by FAST (minimum is 3, as the radius of the circle) |  
 
- Examples: 
- fast.cpp.
 
 
      
        
          | AFAPI features af::fast | ( | const array & | in, | 
        
          |  |  | const float | thr = 20.0f, | 
        
          |  |  | const unsigned | arc_length = 9, | 
        
          |  |  | const bool | non_max = true, | 
        
          |  |  | const float | feature_ratio = 0.05, | 
        
          |  |  | const unsigned | edge = 3 | 
        
          |  | ) |  |  | 
      
 
C++ Interface for FAST feature detector. 
- Parameters
- 
  
    | [in] | in | array containing a grayscale image (color images are not supported) |  | [in] | thr | FAST threshold for which a pixel of the circle around the central pixel is considered to be greater or smaller |  | [in] | arc_length | length of arc (or sequential segment) to be tested, must be within range [9-16] |  | [in] | non_max | performs non-maximal suppression if true |  | [in] | feature_ratio | maximum ratio of features to detect, the maximum number of features is calculated by feature_ratio * in.elements(). The maximum number of features is not based on the score, instead, features detected after the limit is reached are discarded |  | [in] | edge | is the length of the edges in the image to be discarded by FAST (minimum is 3, as the radius of the circle) |  
 
- Returns
- features object containing arrays for x and y coordinates and score, while array orientation is set to 0 as FAST does not compute orientation, and size is set to 1 as FAST does not compute multiple scales 
- Examples: 
- fast.cpp.