Double thresholding in canny edge detection

1. What is double thresholding in Canny edge detection?
2. Why does the Canny detector have two thresholds?
3. What are thresholds in Canny edge?
4. How do you find the threshold for Canny edge detection?

What is double thresholding in Canny edge detection?

The Canny edge detection algorithm uses double thresholding. Edge pixels stronger than the high threshold are marked as strong; edge pixels weaker than the low threshold are suppressed and edge pixels between the two thresholds are marked as weak.

Why does the Canny detector have two thresholds?

High threshold is used to identify the strong pixels (intensity higher than the high threshold) Low threshold is used to identify the non-relevant pixels (intensity lower than the low threshold)

What are thresholds in Canny edge?

Canny does use two thresholds (upper and lower): If a pixel gradient is higher than the upper threshold, the pixel is accepted as an edge. If a pixel gradient value is below the lower threshold, then it is rejected.

How do you find the threshold for Canny edge detection?

The 'Canny' method uses two thresholds. For example, if the threshold is [0.1 0.15] then the edge pixels above the upper limit(0.15) are considered and edge pixels below the threshold(0.1) are discarded. Now, you may have a question "what about the pixels in between upper and lower threshold"?