如何根据距离分配图像大小

Question

我根据预定义的（例如）距离和图像宽度和高度来分配图像大小。我参考了这些链接：link1link2

height_of_frame = ((obj_distance) * measured_object_height_in_mm / 1000.0))/focal;

width_of_frame = ((obj_distance) * measured_object_width_in_mm / 1000.0))/focal;

int imagesize_height = ((152.4)*1990/1000)/0.33;

int imagesize_width = ((152.4)*3500/1000)/0.33;

距离以厘米为单位 = 152.4，ipadMini 相机焦距为 3.3mm = 0.33cm

但是，如果我这样做，它会减小图像大小而不是靠近或靠近。

基于纵横比的图像大小：

CGFloat widthRatio = self.view.frame.size.width / enteredRoomSize.width;
 CGFloat heightRatio = self.view.frame.size.height / enteredRoomSize.height;

  CGSize imageSize = CGSizeMake(350 * widthRatio, 199 * widthRatio);

 mmageView=[[UIImageView alloc]init];

 CGRect frame = mmageView.frame; frame.size = imageSize; mmageView.frame = frame;

Answer 1

这是基础数学。公式为：

object_distance = (focal * real_object_height)/object_height;

因此你应该有：

height_of_frame = (focal * measured_object_height_in_mm / 1000.0))/obj_distance;

width_of_frame = (focal  * measured_object_width_in_mm / 1000.0))/obj_distance;

另外，height_of_frame 与focal 具有相同的单位（通常是像素），obj_distance 的单位应该是米，而不是厘米。