/// <summary>
/// Detect keypoints in an image set.
/// </summary>
/// <param name="images">Image collection.</param>
/// <param name="masks">Masks for image set. masks[i] is a mask for images[i].</param>
/// <returns>Collection of keypoints detected in an input images. keypoints[i] is a set of keypoints detected in an images[i].</returns>
public KeyPoint[][] Detect(IEnumerable <Mat> images, IEnumerable <Mat> masks = null)
{
if (images == null)
{
throw new ArgumentNullException("images");
}
Mat[] imagesArray = Util.ToArray(images);
IntPtr[] imagesPtr = new IntPtr[imagesArray.Length];
for (int i = 0; i < imagesArray.Length; i++)
{
imagesPtr[i] = imagesArray[i].CvPtr;
}
using (var keypoints = new VectorOfVectorKeyPoint())
{
if (masks == null)
{
NativeMethods.features2d_FeatureDetector_detect(
ptr, imagesPtr, imagesArray.Length, keypoints.CvPtr, null);
}
else
{
IntPtr[] masksPtr = EnumerableEx.SelectPtrs(masks);
if (masksPtr.Length != imagesArray.Length)
{
throw new ArgumentException("masks.Length != images.Length");
}
NativeMethods.features2d_FeatureDetector_detect(
ptr, imagesPtr, imagesArray.Length, keypoints.CvPtr, masksPtr);
}
return(keypoints.ToArray());
}
}
/// <summary>
/// select the 512 "best description pairs"
/// </summary>
/// <param name="images">grayscale images set</param>
/// <param name="keypoints">set of detected keypoints</param>
/// <param name="corrThresh">correlation threshold</param>
/// <param name="verbose">print construction information</param>
/// <returns>list of best pair indexes</returns>
public int[] SelectPairs(IEnumerable <Mat> images, out KeyPoint[][] keypoints,
double corrThresh = 0.7, bool verbose = true)
{
if (images == null)
{
throw new ArgumentNullException(nameof(images));
}
IntPtr[] imagesPtrs = EnumerableEx.SelectPtrs(images);
using (var outVec = new VectorOfInt32())
using (var keypointsVec = new VectorOfVectorKeyPoint())
{
NativeMethods.features2d_FREAK_selectPairs(ptr, imagesPtrs, imagesPtrs.Length,
keypointsVec.CvPtr, corrThresh, verbose ? 1 : 0, outVec.CvPtr);
keypoints = keypointsVec.ToArray();
return(outVec.ToArray());
}
}
/// <summary>
/// Compute the descriptors for a keypoints collection detected in image collection.
/// </summary>
/// <param name="images">Image collection.</param>
/// <param name="keypoints">Input keypoints collection. keypoints[i] is keypoints detected in images[i].
/// Keypoints for which a descriptor cannot be computed are removed.</param>
/// <param name="descriptors">Descriptor collection. descriptors[i] are descriptors computed for set keypoints[i].</param>
public virtual void Compute(IEnumerable <Mat> images, ref KeyPoint[][] keypoints, IEnumerable <Mat> descriptors)
{
if (images == null)
{
throw new ArgumentNullException("images");
}
if (descriptors == null)
{
throw new ArgumentNullException("descriptors");
}
IntPtr[] imagesPtrs = EnumerableEx.SelectPtrs(images);
IntPtr[] descriptorsPtrs = EnumerableEx.SelectPtrs(descriptors);
using (var keypointsVec = new VectorOfVectorKeyPoint(keypoints))
{
NativeMethods.features2d_DescriptorExtractor_compute2(
ptr, imagesPtrs, imagesPtrs.Length, keypointsVec.CvPtr,
descriptorsPtrs, descriptorsPtrs.Length);
keypoints = keypointsVec.ToArray();
}
}
