Description : You need to implement a program to detect edges in an input image using Sobel method.

$-$ Input : The following value from keyboard.

$-$ Input image file name $($square size, and $.$ppm format $($P$6)).$

$-$ threshold value for edge detection $($integer$).$

$-$ You can use one of the Sobel filters in the lecture slide.

$-$ Your program needs to do the following basically:

$-$ Get input values above.

$-$ Perform 'ReadPPM' for input image.

$-$ Perform 'CreatPPM' for output image.

$-$ Initialize all pixel values of output image as white $(255).$

$-$ Convolute input image with the Sobel filter $($Gx$)$ you selected, and save the results as an array, and convolute input image with the Sobel filter $($ Gy $)$ you selected, and save the results as a different array. You need to apply this step to gray scale values of all pixels.

$-$ Apply an equation $($i$.$e$,$ Detect edges $\backslash (=\backslash )$ sqrt $(($outputs by Gx$)\backslash (\{\}^\{2\}+\backslash )($outputs by Gy$)\backslash (\{\}^\{2\}\backslash ))$ to the above arrays.

$-$ If the result of this formula is larger than the input threshold value, put a black pixel into the output image created by 'CreatPPM' above using 'PutRPixel, PutGPixel, and PutBPixel'.

$-$ Perform 'WritePPM' for output images.