/// <summary>
/// Compute the descriptor given the image and the point location
/// </summary>
/// <param name="image">The image where the descriptor will be computed from</param>
/// <param name="mask">The optional mask, can be null if not needed</param>
/// <param name="keyPoints">The keypoint where the descriptor will be computed from. Keypoints for which a descriptor cannot be computed are removed.</param>
/// <returns>The descriptors founded on the keypoint location</returns>
private Matrix <byte> ComputeDescriptorsRawHelper(CvArray <Byte> image, Image <Gray, byte> mask, VectorOfKeyPoint keyPoints)
{
if (mask != null)
{
keyPoints.FilterByPixelsMask(mask);
}
int count = keyPoints.Size;
if (count == 0)
{
return(null);
}
Matrix <byte> descriptors = new Matrix <byte>(count, DescriptorSize * image.NumberOfChannels, 1);
CvInvoke.CvOrbDetectorComputeDescriptors(_ptr, image, keyPoints, descriptors);
return(descriptors);
}
/// <summary>
/// Compute the descriptor given the image and the point location
/// </summary>
/// <param name="image">The image where the descriptor will be computed from</param>
/// <param name="mask">The optional mask, can be null if not needed</param>
/// <param name="keyPoints">The keypoint where the descriptor will be computed from. Keypoints for which a descriptor cannot be computed are removed.</param>
/// <returns>The descriptors founded on the keypoint location</returns>
private Matrix <Byte> ComputeDescriptorsRawHelper(CvArray <Byte> image, Image <Gray, byte> mask, VectorOfKeyPoint keyPoints)
{
const float epsilon = 1.192092896e-07f; // smallest such that 1.0+epsilon != 1.0
keyPoints.FilterByImageBorder(image.Size, 48 / 2 + 9 / 2); //this value comes from opencv's BriefDescriptorExtractor::computeImpl implementation
keyPoints.FilterByKeypointSize(epsilon, float.MaxValue);
if (mask != null)
{
keyPoints.FilterByPixelsMask(mask);
}
int count = keyPoints.Size;
if (count == 0)
{
return(null);
}
Matrix <Byte> descriptors = new Matrix <Byte>(count, DescriptorSize * image.NumberOfChannels, 1);
CvInvoke.CvBriefDescriptorComputeDescriptors(_ptr, image, keyPoints, descriptors);
Debug.Assert(keyPoints.Size == descriptors.Rows);
return(descriptors);
}