Hello,
Will we have a Q&A session or office before the exam? It would really help a lot to solve some questions.
Hi Xinyu, feel free to ask questions on the forum!
Hi,
I am confused about the Slide Delineation-Page27. There is a polygonal approximation equation. The second term is the average sum of squared 2nd derivatives. As far as I understand the second term is the smoothness term. So my question is: 1. why do we use the 2nd derivatives instead of the 1st derivatives? 2. why is there a '-' sign before the second term? If we want it to be smooth, the second term should be as small as possible, which means the sign should be '+'.
Thanks in advance for answering.
I am confused about the Slide Delineation-Page27. There is a polygonal approximation equation. The second term is the average sum of squared 2nd derivatives. As far as I understand the second term is the smoothness term. So my question is: 1. why do we use the 2nd derivatives instead of the 1st derivatives? 2. why is there a '-' sign before the second term? If we want it to be smooth, the second term should be as small as possible, which means the sign should be '+'.
Thanks in advance for answering.
The second derivative measures the curvature or the rate of change of the slope of a function. When the second derivative is small, the function (or the curve in this case) changes direction slowly, implying smoothness. The first derivative measures the slope or the rate of change of the function itself. Minimizing the first derivative would aim to make the curve as flat as possible, which is not necessarily the goal.
However, there seems indeed to be an inconsistency for the sign between Page 27(-) and Page 28(+). We would confirm this soon.
Thanks
However, there seems indeed to be an inconsistency for the sign between Page 27(-) and Page 28(+). We would confirm this soon.
Thanks
About your second question, Prof Fua confirmed there is a typo in the slides, there should be no minus. Thanks for spotting it!
Yes, thanks you for spotting it. In the next iteration of the class, the slide will be fixed. See attached image.
Cheers
Pascal
