Sobel Operator Edge Detection

This is a command line utility which implements edge detection using the sobel filter.

Installation

Given that this is a go project, installation is simple. The only tool you'll need to run this implementation is go.

If go is installed, run:

 $ git clone https://github.com/bksworm/sobel && cd sobel
 $ go build 

Usage

Usage is relatively simple, there are just a few options. This tool supports both png and jpeg image input formats, and file type is determined automatically.

To run detection on a specific file, use:

$ ./examples/edgedetect -f <file.[png, jpg]>

You can optionally specify an output file:

$ ./examples/edgedetect -f <file.[png, jpg]> -o <output.[png, jpg]>

Default output is sobel.jpg or sobel.png

Note: this is not a conversion program. The output file will be of the same format as the inut file, so name files accordingly.

Usage as a go library

The internal package sobel can be used in any standard go program. It exposes a single function. Here is an example:

package main 

import (
  "image"
  "os"
  "github.com/bksworm/sobel" //package which implements the filter
 )
 
 var edge image.Image
 
 func main() {
    f, err := os.Open("example.jpg")
    if err != nil { panic(err) }
    defer f.Close()
    
    img, _, err := image.Decode(f)
    if err != nil { panic(err) }
    
    edge = sobel.FilterMath(img) //converts "img" to grayscale and runs edge detect. Returns an image.Image with changes.
    //do something with detected image...
 }

Function FilterMath() is pure go filter implementation. If you like things to go 8-9 times faster you may use FilterSimd(). This one is based on Simd library. But if you don't need it, you may clear the mess I have here :)

There are a few another implementations of the filter. You can use them in benchmark tests to get an idea about go code performance and memory management tricks.

Happy coding for everyone!