Figure 16.
The edge detection results using the Sobel operator (threshold = 2); (a) Front side of the first specimen, (b) Back side of the first specimen, (c) Front side of the second specimen, (d) Back side of the second specimen.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.