THETA V 360 is Output Dual-Fisheye , not EquiRectangular

Jiasheng_Wang · 2017-10-16 16:48:33 UTC

I have watch this video.
And How does it do that Output Dual-Fisheye?

codetricity · 2017-10-16 16:56:19 UTC

It’s a video from file, not a live stream.

When you save the video to the camera, it’s in dual-fisheye

Jiasheng_Wang · 2017-10-16 17:04:16 UTC

How can I get this file?
I get the file which is equirectangular format.
The file is from Android “Theta S” APP.

codetricity · 2017-10-16 17:05:08 UTC

plug your THETA V into your laptop or desktop computer with a USB cable, then open the camera as storage device.

Jiasheng_Wang · 2017-10-16 17:37:45 UTC

So…I have a question

The Equirectangular image transfer to dual-fisheye image.
It must have fisheye coordinate parameter of r.
r is named radius.
And it is a constant? What is it value?

codetricity · 2017-10-16 17:39:54 UTC

Are you looking for the precise lens parameter information, or a rough number?

codetricity · 2017-10-16 17:52:27 UTC

this might be useful for you for the rough approximation. Ricoh does not release the specific lens parameter information…

github.com

theta360developers/video-streaming-sample-app/blob/master/samples/common/thetaview.js

/* global THREE */
'use strict';

/**
 * Copyright (c) 2016 Ricoh Company, Ltd. All Rights Reserved.
 * See LICENSE for more information
 */

class ThetaView {

  _cyln2world(a, e) {
    return (new THREE.Vector3(
      Math.cos(e) * Math.cos(a),
      Math.cos(e) * Math.sin(a),
      Math.sin(e)));
  }

  _world2fish(x, y, z) {
    let nz = z;
    if (z < -1.0) nz = -1.0;

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github.com

theta360developers/THETA-S-LiveViewer-P5/blob/master/ThetaLive/ThetaSphere.pde


class ThetaSphere {
  // k : latitude
  // s : longitude

  PVector[][] vertices3D;   // 3D vertices of hemisphere
  PVector[][] t_vertices1;  // 2D texture vertices of hemisphere (1 of 2)
  PVector[][] t_vertices2;  // 2D texture vertices of hemisphere (2 of 2)

  // constructor(initialize)
  ThetaSphere(int k_div, int s_div, int sphere_r, int xc1, int yc1, int xc2, int yc2, int img_r) {
    vertices3D =  calcHemisphereVertices( k_div, s_div, sphere_r );
    t_vertices1 = calcHemisphereTextureVertices( k_div, s_div, xc1, yc1, img_r );
    t_vertices2 = calcHemisphereTextureVertices( k_div, s_div, xc2, yc2, img_r );
  }


  // draw textured sphere
  void draw(PImage t_img) {
    drawHemisphere( vertices3D, t_vertices1, t_img );

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Jiasheng_Wang · 2017-10-16 17:54:16 UTC

Yes, it is the fisheye lens parameter of focal length.
I want this value number which is Ricoh define.

Jiasheng_Wang · 2017-10-16 18:02:30 UTC

When I get .mp4 file which is dual-fisheye format.
Which app can turn this .mp4 file to equirectangular format?
I will try to decompiler this app and find this value.
It sound so crazy…

Svendus · 2017-10-16 18:06:36 UTC

@Jiasheng_Wang

check this out https://theta360.com/en/about/application/pc.html

codetricity · 2017-10-16 18:23:17 UTC

The lens parameter information is not publicly available. If you are involved in a large project, you may be able to contact Ricoh directly and negotiate access to the information under NDA.

Is this a potentially large project?

codetricity · 2017-10-16 18:26:16 UTC

This person used JPEXS Flash Decompiler to access XMP data. I don’t think he accessed the data you’re looking for. The desktop app is made with Adobe Air.