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双目测距-初识

news 2025/10/11 9:39:04

双目测距流程

1 相机标定（获取内外参数）

2 双目矫正（矫正镜头变形图像）

3 双目立体匹配（视差图）

4 计算深度信息（深度图）

5 计算距离

其中立体匹配是整个流程中比较重要的一环，往往在这里做研究和优化

流程

标定

参考标定+矫正 MATLAB

矫正

匹配（传统算法或深度学习算法）

双目测距原理

其中_Xr_是负数，解释如下：
xr** represents a negative value.**

Here’s a step-by-step explanation of why:

1. The Coordinate System

To make the math work, we need to establish a consistent coordinate system for each camera’s image sensor. The standard convention is:

The origin (0) is at the center of the image (the principal point, where the optical axis intersects the sensor).
The x-axis increases to the right.
Therefore, any point to the right of the center has a positive x-coordinate, and any point to the left has a negative x-coordinate.

2. Analyzing the Diagram

Let’s apply this coordinate system to the diagram:

For the Left Camera (Ol): The point P is to the right of the camera’s central axis. Its projection on the image sensor, xl, is therefore also to the right of the center. So, xl** is a positive number**.
For the Right Camera (Or): The point P is to the left of this camera’s central axis. Its projection on the image sensor, xr, is therefore to the left of the center. So, xr** is a negative number**.

3. Why This is Crucial for the Formula

Now, let’s look at the formula for disparity (d):

d = xl - xr

If we substitute the signs we just determined:

d = (a positive number) - (a negative number)
d = (a positive number) + (another positive number)

This means the disparity d will be a positive value, which makes perfect sense. Disparity represents a distance (in pixels) and should be positive.

The Final Calculation

The final formula for calculating the distance Z is:

Z = f * T / d

Since the focal length f, the baseline T, and the disparity d are all positive values, the calculated distance Z will also be positive, which is correct.

In summary: Although the diagram draws xr as a length, the formula d = xl - xr treats it as a coordinate. For this formula to be correct in this geometric setup, xr must be a negative value.