Page 19 - 3DF Zephyr

Keypoints Density: keypoints represent the matched pixels in the pictures. This parameter allows to set the amount of keypoints that 3DF Zephyr will have to extract for each photo; nevertheless a substantial amount of keypoints does not lead to a better result, since the more the elements involved the higher the ambiguity during correspondences detection between the keypoints themselves. Very low: extracts up to 2,500 keypoints per image Low: extracts up to 5,000 keypoints per image Medium: extracts up to 7,500 keypoints per image High: extracts up to 10,000 keypoints per image Very High: extracts up to 15,000 keypoints per image It is recommended to decrease keypoints density when: - it is required a high computing speed; - the distance between cameras and subject/scene on survey does not change;