Updating the datagen README with instructions to generate the noise

Author: ErickOF

tools/datagen/README.md

@@ -22,19 +22,25 @@ There are two versions of the script, a JupyterNotebook and a normal Python
 script. For both of them, in the main function, the variables `img_name` and
 `img_ext` must be updated. The `img_name` is only the name of the image that
 is saved in `tools/datagen/src/imgs` and the `img_ext` is the extension of the
-image. For instance:
+image. The `salt_probability` is used to set the probability of getting a salt
+pixel in the image, while `pepper_probability` is used for the pepper pixels.
+These two variables can be set to 0.0 to generate an image without noise. For
+instance:
 
 ```python
+salt_probability: float = 0.1
+salt_probability: float = 0.1
 img_name: str = 'car'
 img_ext: str = 'jpg
 ```
 
 will load `tools/datagen/src/imgs/car.jpg` image and generate:
 
 * tools/datagen/src/imgs/car\_grayscale\_image.jpg
-* tools/datagen/src/imgs/car\_sobel\_combined\_result.jpg
+* tools/datagen/src/imgs/car\_noisy\_image.jpg
 * tools/datagen/src/imgs/car\_sobel\_x\_result.jpg
 * tools/datagen/src/imgs/car\_sobel\_y\_result.jpg
+* tools/datagen/src/imgs/car\_sobel\_combined\_result.jpg
 
 These generated images are ignored and must not be committed to the repository.