feat: upd readme

README.md

-# Aidge CPU library
+# Aidge backend OpenCV library
 
 You can find in this folder the library that implements :
 - Computer vision databases 
 - The OpenCV tensor, operators and stimulis
 
 So far be sure to have the correct requirements to use this library
-- GCC
-- OpenCV >= 3.0
-- Make
-- CMake
-- aidge_core
-- aidge_backend_cpu
-- Python (optional, if you have no intend to use this library in python with pybind)
+[TOC]
 
-## Pip installation
+## Installation
+### Dependencies
+- `GCC`
+- `OpenCV` >= 3.0
+- `Make`
+- `CMake`
+- `Python` (optional, if you have no intend to use this library in python with pybind)
 
-You will need to install first the aidge_core and aidge_backend_cpu libraries before installing aidge_backend_opencv.
-Then run in your python environnement : 
+#### aidge dependencies
+ - `aidge_core`
+ - `aidge_backend_cpu`.
+
+### Pip installation
 ``` bash
 pip install . -v
-```
\ No newline at end of file
+```
+> **TIPS :** Use environment variables to change compilation options :
+> - `AIDGE_INSTALL` : to set the installation folder. Defaults to /usr/local/lib. :warning: This path must be identical to aidge_core install path.
+> - `AIDGE_PYTHON_BUILD_TYPE` : to set the compilation mode to **Debug** or **Release** 
+> - `AIDGE_BUILD_GEN` : to set the build backend with 
+