Fast9 -- FAST Corner Detection

Fast9 is a pure javascript implementation of 'FAST Corner Detection'.

This is port of 'C soure code' to JavaScript.

The original C source code can be found here.

Install

``
npm install fast9
`

Usage

$3

Params
`
im : grayscale byte array
width : image width
height : image height
threshold : threshold
nonmax : non-maximum suppression
`

Result
`
Array
{
x:x position,
y:y position,
score:corner score
}
`

Source
`javascript
// detect corners
var threshold = 20;
var corners = fast9.detect(im, width, height, threshold, true);
`

Example

`javascript
var fast9 = require('fast9');
var fs = require('fs');
var PNG = require('pngjs').PNG;

var pngfile = 'example.png';

fs.createReadStream(pngfile)
.pipe(new PNG({
filterType: -1,
}))
.on('parsed', function() {
var data = this.data;
var width = this.width;
var height = this.height;

// data is 'RGBA buffer'

// make grayscale buffer (byte array)
var gs = new Array(width * height);
//var gs = new Uint8Array(width * height); //es6
var gs_index = 0;
for (var y=0; y for (var x=0; x var idx = (width * y + x) << 2;
// data[idx] is red
// data[idx+1] is green
// data[idx+2] is blue
// data[idx+3] is alpha
var gray = parseInt(data[idx] 0.3 + data[idx+1] 0.6 + data[idx+2] * 0.11);
//var gray = (data[idx] >> 2) + (data[idx+1] >> 1) + (data[idx+2] >> 2); // faster
gs[gs_index++] = gray;
}
}

var threshold = 20;
var corners = fast9.detect(gs, width, height, threshold, true);

// sort by score
//corners.sort((a,b)=>b.score-a.score); //lamda
corners.sort(function(a,b) {
return b.score-a.score;
});

// print corners
console.log(corners.slice(0, 100));

})
.on('error', function(e) {
console.log(e);
});
``

License

BSD license