beholder-detection v1.3.3

Beholder Detection

This is the marker detection component of Beholder. Current Version 1.3.3

Installation

npm install beholder-detection

or you can use UNPKG

<script src="https://unpkg.com/beholder-detection@1.3.3/dist/beholder-detection.js"></script>

Usage

The Markers

Beholder currently esclusively uses a Javascript port of the Aruco fiducial marker detection library. The source for the port can be found here and the Original Project can be found here. To use Beholder you must use the marker set from the Original Aruco implementation. You can get some from here and in the dictionary dropdown select "Original Aruco"

Basic Import

To use Beholder in your project, simply include it with your preferred method at the top of your code

// with require
const Beholder = require('beholder-detection');

// with UNPKG
const Beholder = window['beholder-detection'];

General Functions

A '*' indicates an optional parameter.

Custom Config

The config passed in on the initialize function can be used to set various parameters of the Beholder popup in default states. To change these parameters you must pass and object that mirrors the following structure.

{
    camera_params: {
        videoSize: 1, // The video size values map to the following [320 x 240, 640 x 480, 1280 x 720, 1920 x 1080]
        rearCamera: false, // Boolean value for defaulting to the rear facing camera. Only works on mobile
        torch: false, // Boolean value for if torch/flashlight is on. Only works for rear facing mobile cameras. Can only be set from init
    },
    detection_params: {
        minMarkerDistance: 10,
        minMarkerPerimeter: 0.2,
        maxMarkerPerimeter: 0.8,
        sizeAfterPerspectiveRemoval: 49,
   },
   feed_params: {
        contrast: 0,
        brightness: 0,
        grayscale: 0,
        flip: false,
   },
   overlay_params: {
       present: true, // Determines if the Beholder overlay will display or be invisible entirely via display: none
       hide: true, // Determines if the overlay should be hidden on the left of the screen or visible
   }
}

Individual Marker

Example Usage

var demoMarker = Beholder.getMarker(0);

if( demoMarker.present ) {
    var demoCenter = demoMarker.center;
    var demoRotation = demoMarker.rotation;
    
    console.log(demoCenter.x, demoCenter.y, demoRotation);
}

Marker Pairs

Example Usage

var demoMarkerPair = Beholder.getMarkerPair(0, 1);
var realWorldPosition = demoMarkerPair.getRelativePosition(25);

console.log(realWorldPosition.distance, realWorldPosition.heading, realWorldPosition.rotation);