Sift segfaults

[doublex]

Steps to reproduce, image: segfault.jpg

seeta::FaceDetection detector( "/path/to/model_fd" );
detector.SetMinFaceSize( 22 );
detector.SetScoreThresh( 3.85 );
detector.SetImagePyramidScaleFactor( 0.8 );
detector.SetWindowStep( 4, 4 );

std::vector<seeta::FaceInfo> faces = detector.Detect( "/path/to/segfault.jpg" );
for( Integer i=0; i < faces.size(); ++i )
{
    const seeta::FaceInfo &detectedface = faces[i];
    if( i != 78 )
        continue;

    // Initialize face alignment model
    seeta::FaceAlignment point_detector( "/path/to/model_fa" );

    // Detect 5 facial landmarks
    seeta::FacialLandmark points[5];
    memset( &points, 0, sizeof(points) );
    bool landmarks = point_detector.PointDetectLandmarks( img_data, detectedface, points );
}

This patch worksaround this issue:

*** ./sift.cpp-old      2017-06-07 18:17:55.181142668 +0200
--- ./sift.cpp  2017-08-08 12:20:52.940184068 +0200
*************** void SIFT::ImageOrientation(double* gray
*** 357,362 ****
--- 357,364 ----
                  double tmpV = im_vert_edge[i * param.image_width + j];
                  double tmpH = im_hori_edge[i * param.image_width + j];
                  double tmpMagnitude = sqrt(pow(tmpV, 2) + pow(tmpH, 2));
+                 if (tmpMagnitude == 0.0)
+                       tmpMagnitude = 1.0;
                  im_magnitude[i * param.image_width + j] = tmpMagnitude;
                  im_cos_theta[i * param.image_width + j] = tmpV / tmpMagnitude;
                  im_sin_theta[i * param.image_width + j] = tmpH / tmpMagnitude;