Final answer:
A PGT edge detector is an electronic circuit used to detect edges in an image. It involves convolving a Prewitt gradient template with the image to calculate the vertical and horizontal gradients. The resulting image highlights the edges with brighter regions.
Step-by-step explanation:
A PGT edge detector is an electronic circuit used to detect edges or boundaries in an image. It is commonly used in image processing applications to highlight transitions between different areas in an image. The basic operation of the PGT edge detector involves convolving a Prewitt gradient template with the image.
This template consists of two matrices that calculate the vertical and horizontal gradients, which are then combined to determine the magnitude of the gradient at each pixel.
For example, if we have a pixel with coordinates (x, y), the vertical gradient can be calculated by multiplying the pixel values in the following arrangement: (-1, 0, 1, -1, 0, 1, -1, 0, 1).
Similarly, the horizontal gradient can be calculated using the arrangement: (-1, -1, -1, 0, 0, 0, 1, 1, 1). These two matrices are convolved or multiplied with the corresponding pixel values in the image to calculate the gradients.
The magnitude of the gradient is then determined by taking the square root of the sum of the squares of the vertical and horizontal gradients at each pixel.
If the magnitude exceeds a certain threshold, that pixel is considered an edge pixel. The resulting image will have brighter regions where there are edges and darker regions where there are no edges.