全景图像摄影测量:如何计算范围? [英] Panoramic Image Photogrametry: How to calculate range?
问题描述
假设我拍摄了两幅垂直偏移为H的全景图像,每张图像都以尺寸为Xm和Ym的equirectangular投影呈现。为此,我将全景相机放在A位置并拍摄图像,然后移动相机H米并拍摄另一张图像。
Assume that I took two panoramic image with vertical offset of H and each image is presented in equirectangular projection with size Xm and Ym. To do this, I place my panoramic camera at position say A and took an image, then move camera H meter up and took another image.
我知道坐标为X1,Y1的图像1中的点是图像2上坐标为X2和Y2的相同点(假设X1 = X2,因为我们有只有垂直偏移)。
I know that a point in image 1 with coordinate of X1,Y1 is the same point on image 2 with coordinate X2 and Y2(assuming that X1=X2 as we have only vertical offset).
我的问题是如何计算所选点的范围(知道其X1和Y1在图像1上的点及其位置图像2是来自A点的X2和Y2(相机在拍摄图像时为1)。
My question is that How I can calculate the range of selected of point (the point that know its X1and Y1 is on image 1 and its position on image 2 is X2 and Y2 from the Point A (where camera was when image no 1 was taken.).
推荐答案
是的,你可以做到 - 坚持!!!
Yes, you can do it - hold on!!!
关键的事情 y
=镜头的焦距 - 现在我可以做到!!!
Key thing y
= focal length of your lens - now I can do it!!!
所以,我认为你的问题可以更简单地说,如果你移动你的相机(在图中的右侧)上涨 H
米,一个点向下移动 p
从新位置拍摄的图像中的像素。
So, I think your question can be re-stated more simply by saying that if you move your camera (on the right in the diagram) up H
metres, a point moves down p
pixels in the image taken from the new location.
如果您想象从侧面看,在拍摄照片时,就像这样。
Like this if you imagine looking from the side, across you taking the picture.
如果您知道相机CCD的微米间距与其规格有关,则可以转换 p
从像素到米来匹配 H
的单位。
If you know the micron spacing of the camera's CCD from its specification, you can convert p
from pixels to metres to match the units of H
.
从相机到场景平面的范围由 x
+ y
给出(两者都是红色的底部),和
Your range from the camera to the plane of the scene is given by x
+ y
(both in red at the bottom), and
x=H/tan(alpha)
y=p/tan(alpha)
所以你的范围是
R = x + y = H/tan(alpha) + p/tan(alpha)
和
alpha = tan inverse(p/y)
其中y是镜头的焦距。因为 y
可能是50毫米,它可以忽略不计,所以,到一个非常合理的近似值,你的范围是
where y is the focal length of your lens. As y
is likely to be something like 50mm, it is negligible, so, to a pretty reasonable approximation, your range is
H/tan(alpha)
和
alpha = tan inverse(p in metres/focal length)
或者,通过相似的三角形
Or, by similar triangles
Range = H x focal length of lens
--------------------------------
(Y2-Y1) x CCD photosite spacing
非常小心地把所有东西都放在米里。
being very careful to put everything in metres.
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