Changes to Edge Lecture

• 2023-09-26 13:14:40 UTC (Hans Georg Schaathun): Line equation for edges
• 2022-08-31 07:11:17 UTC (Hans Georg Schaathun): notes on edge detection
• 2022-08-31 05:57:41 UTC (Hans Georg Schaathun): notes
• 2021-09-21 07:42:10 UTC (georg): stub