New README.md changes

Author: adamiao

README.md

@@ -4,7 +4,7 @@ Let's create a tool to detect edges of an image! To do so we'll use the Sobel op
 
 <img src="https://latex.codecogs.com/gif.latex?G_x=\begin{bmatrix}&space;1&space;&&space;0&space;&&space;-1&space;\\&space;2&space;&&space;0&space;&&space;-2&space;\\&space;1&space;&&space;0&space;&&space;-1&space;\end{bmatrix}\quad\text{and}\quad&space;G_y=\begin{bmatrix}&space;1&space;&&space;2&space;&&space;1&space;\\&space;0&space;&&space;0&space;&&space;0&space;\\&space;-1&space;&&space;-2&space;&&space;-1&space;\end{bmatrix}" title="G_x=\begin{bmatrix} 1 & 0 & -1 \\ 2 & 0 & -2 \\ 1 & 0 & -1 \end{bmatrix}\quad\text{and}\quad G_y=\begin{bmatrix} 1 & 2 & 1 \\ 0 & 0 & 0 \\ -1 & -2 & -1 \end{bmatrix}" />
 
-Think of Gx and Gy as maps of the form <img src="https://latex.codecogs.com/gif.latex?\mathbb{R}^{3\,\times\,3}\rightarrow\mathbb{R}" />, where we take in a 3 by 3 patch of image (denoted by <img src="https://latex.codecogs.com/gif.latex?$$A\in\mathbb{R}^{3\,\times\,3$$" />), do some operation (using matrices associated with Gx and Gy), and returns a real number (the pixel value of the output).
+Think of Gx and Gy as maps of the form <img src="https://latex.codecogs.com/gif.latex?\mathbb{R}^{3\,\times\,3}\rightarrow\mathbb{R}" />, where we take in a 3 by 3 patch of image (denoted by <img src="https://latex.codecogs.com/gif.latex?$$A\in\mathbb{R}^{3\,\times\,3$$" />), do some operation on it (using the matrices shown above), and return a real number (the value of the pixel for the output image).
 
 So, for example, if we are given the following patch of grayscale image:
 
@@ -29,7 +29,7 @@ To apply the Sobel operation to that patch of image we want to calculate:
 
 <img src="https://latex.codecogs.com/gif.latex?\sqrt{\big[G_x(A)\big]^2+\big[G_y(A)\big]^2}\quad\text{which&space;in&space;the&space;case&space;of&space;this&space;example&space;is&space;equal&space;to&space;}\,174.917" />
 
-For now it's ok to have values which are out of the [0,255] range because at the very end we will normalized the image values.
+This number will be the pixel contained in the output image. For now it's ok to have values which are out of the [0,255] range because at the very end we will normalized the image values. Notice that the output will be always greater than or equal to zero.
 
 We do this operation for the entire input image and create a new image based on these outputs just describe above.