getOrigin() {
    const tiePoints = this.fileDirectory.ModelTiepoint;
    const modelTransformation = this.fileDirectory.ModelTransformation;
    if (tiePoints && tiePoints.length === 6) {
      return [
        tiePoints[3],
        tiePoints[4],
        tiePoints[5],
      ];
    }
    if (modelTransformation) {
      return [
        modelTransformation[3],
        modelTransformation[7],
        modelTransformation[11],
      ];
    }
    throw new Error('The image does not have an affine transformation.');
  }
Returns the image origin as a XYZ-vector. When the image has no affine
transformation, then an exception is thrown.
@returns {Array<number>} The origin as a vector