borders-detection

Native C++ module helps to detect objects bounds in 1-bit bmp image

Install

Tested on MacOS 10.14, NodeJs v9.2.0

$ npm install @wmakeev/borders-detection

Usage

Supports only 1-bit bmp images

const { pixelsGroups } = require('borders-detection')

pixelsGroups('/path/to/img.bmp', { maxGap: 0.01 }).then(res => {
  if (err) throw err
  console.log('borders:', res)
})

API

pixelsGroups(path: string, options: object): Promise

• path - full path to bmp image

• options.maxGap - max distance between pixels in group (percents of largest image side)

Returns

{
  imgWidth: 10,
  imgHeight: 10,
  groups: [
    { minX: 0, minY: 0, maxX: 0.2, maxY: 0.2, pixelsCount: 4 },
    { minX: 0.2, minY: 0.7, maxX: 0.3, maxY: 0.8, pixelsCount: 3 },
    { minX: 0.7, minY: 0.1, maxX: 0.8, maxY: 0.1, pixelsCount: 2 },
    { minX: 0.7, minY: 0.3, maxX: 0.8, maxY: 0.3, pixelsCount: 2 },
    { minX: 0.8, minY: 0.9, maxX: 0.9, maxY: 0.9, pixelsCount: 2 }
  ]
}

• imgWidth - input image width (pixels)

• imgHeight - input image height (pixels)

• groups[] - pixels groups bounds

• groups[].minX - top left x bound coordinate (percents of image width)

• groups[].minY - top left y bound coordinate (percents of image height)

• groups[].maxX - bottom right x bound coordinate (percents of image width)

• groups[].maxY - bottom right y bound coordinate (percents of image height)

• groups[].pixelsCount - pixels count inside bound

Known issues

• Incorrect bound detection with hi-res images

TODO

• Switch to BPM file format?