英语翻译
A human face can be modeled using PhotoModeler Scanner (PM Scanner) using one or more pairs of stereo photos.Sometimes it is possible with a single camera,but due to the subtle movement of a human face (despite all efforts of your model to keep still!),you will usually get a better result with two or more synchronized cameras.
The following sequence of steps is based on the assumption that you know the basics of marking and referencing points (target and non-target points),that you are familiar with the basic steps of creating DSM’s with PM Scanner,and that you have a well calibrated camera.
For more basic instructions the PM Scanner tutorial projects and videos are a good place to start.
This article is closely related to the article here.There are links to particular sections of the article throughout this one.
Scene Setup and Photography
1.Place a series of targets on a wall or a rig so that targets surround the face.Ensure as many of the targets are visible in as many of the photos as possible.Coded targets make orientation and setup phase very efficient.
2.Have your face model sitting comfortably and still.If using just one camera,the model will need to be extremely still during photography.
The following shows a typical setup (one photo of a 4-synchronized cameras setup):
3.If using synchronized cameras,set up your cameras on tripods and test your synchronization (using a remote control or other remote triggering system).
Arrange your cameras in a configuration similar to this (if not using synchronized cameras,move your camera to these positions as quickly as possible before your model moves!) and take the photos:
The angles between these positions will be small and close to parallel.There should not be any more than a few degrees of toe-in angle.
Usually 4 photos will be enough to model the face and parts of the sides of the head.If you want to model the front,sides,and back,you’ll need to make sure your photo pairs cover the entire area of interest,and you’ll need to make sure that you have enough targets in view to adequately orient your photos.
You may want to include another photo from the side or above at a greater angle to assist in camera orientation.The camera in red above suggests this.Adding this photo will help increase the angle of your referenced points and will help strengthen the solution.