Canny-Edge-Implementation

(My own implementation on Canny Edge runs on both CPU & GPU: CUDA)

In Edge.h, there are two class member functions to do canny edge detection: cannyEdge() & cannyEdge2()

cannyEdge2() is an optimized version of cannyEdge() in 2D convolution process, it separates the sobel kernel into two smaller kernels for faster convolution process and reduces one for-loop.

Update 6/30

• Provided a docker image: docker pull wchern/dev:opencv
• Added Makefile (make clean supported) for ubuntu. Just make to compile.
• Added argument support for selecting benchmark parameteres (smalle or large image, number of iterations, instructions below)
• Edited define marco for gcc (version 7.4.0) compiler & microsoft's compiler (SIMD vectorization available on g++)
• Factorized a lot of codes
• Removed atan() & sqrt(gx^2 + gy^2) for speed boost
• Added thread control function to select number of threads according to image size
• vectorized some for-loops
• optimized nonMaxSuppression() & hysteresis_threshold() to reduce if statements
  

Update on 7/1

• Vectorized a for-loop using omp inbranch for flow control
  

Update on 7/9

• Revised hysteresis threshold's algorithm, using recursive DFS now with same performance

Input size	Time (ms) (Avg. of 1000 runs)	OpenMP Enable?	Env
637 x 371	0.593 ms (before: 3.647 ms)	Yes, 4 threads	gcc 7.4.0, ubuntu 18.04 (docker), -O2 optimization, omp simd
3840 x 2160	20.65 ms (before: 106.775 ms)	Yes, 8 threads	gcc 7.4.0, ubuntu 18.04 (docker), -O2 optimization, omp simd

Parameter Usage: ./app_name -firstPara -secPara thirPara

• -firstPara = valid inputs are -small or -large
  
• -secPara = valid input is -iter
  
• -thirPara = valid input is any positve integer number for iteration
  

CUDA implementation added 7/22 (See Edge_Cuda.cuh, tested on Windows with Cuda 10.1)

Can be further optimized and factorized tho!