Article Fast Image Edge Detection based on Faber Schauder Wavelet an...
Conference Paper A Fast FPGA Based Architecture for Sobel Edge Detection
As far as I know : Sobel , direct convolution operators are first oder and hence low complexity while LoG ,Canny are second order hence greater is the complexity
There are many standard edge detection algorithms such as Sobel', 'Prewitt', 'Roberts', 'Canny'. Canny's method is considered very robust. Sobel edge detection works quite fast, it returns a binary image (Black and White) containing 1s where the it finds edges in the input image and 0s elsewhere.
If you are using MATLAB software (suggested), then please have a look at