* update config manual white balance doc

Author: lxowalle

docs/doc/en/vision/camera.md

@@ -157,10 +157,18 @@ cam.gain(100)
 ```
 
 ### Setting the white balance
+Currently, only manual white balance via gain adjustment is supported. Use set_wb_gain() to pass in an array of four values corresponding to the gain for `R`, `Gr`, `Gb`, and `B` channels, with each value ranging from [0.0, 1.0].
+
+The recommended default manual white balance gains are:
+For MaixCam: [0.134, 0.0625, 0.0625, 0.1239]
+For MaixCam2: [0.0682, 0, 0, 0.04897]
+To fine-tune image appearance, it is usually sufficient to adjust only the `R` and `B` channels, while keeping `Gr` and `Gb` unchanged.
 
 ```python
 cam = camera.Camera()
-cam.awb_mode(1)     # 0,turn on white balance;1,turn off white balance
+cam.awb_mode(1)  # 0 to enable auto white balance, 1 to enable manual white balance
+cam.set_wb_gain([0.134, 0.0625, 0.0625, 0.1239])  # Set gains for R, Gr, Gb, B channels
+
 ```
 
 ### Setting brightness, contrast and saturation

docs/doc/zh/vision/camera.md

@@ -171,10 +171,14 @@ cam.gain(100)
 ```
 
 ### 设置白平衡
+目前只支持通过设置增益来手动设置白平衡, 通过set_wb_gain()传入一个长度为4的数组，分别对应`R`,`Gr`,`Gb`,`B`的增益值, 范围为[0.0, 1.0]
+建议maixcam默认手动白平衡增益为`[0.134, 0.0625, 0.0625, 0.1239]`, maixcam2默认手动白平衡增益为`[0.0682, 0, 0, 0.04897]`
+如果需要调整画面效果, 通常只需要调整`R`通道和`B`通道, `Gr`和`Gb`通道可以保持不变
 
 ```python
 cam = camera.Camera()
-cam.awb_mode(1)			# 0,开启白平衡;1,关闭白平衡
+cam.awb_mode(1)			# 0,开启自动白平衡, 1,开启手动白平衡;
+cam.set_wb_gain([0.134, 0.0625, 0.0625, 0.1239])  # 设置r, gr, gb, b四个通道的增益
 ```
 
 ### 设置亮度、对比度和饱和度