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Topics - yashardel

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1
General Discussion / Bandpass filter for Wiimote Camera
« on: July 12, 2009, 02:38:41 PM »
Hi !

I am writing a report about a project I have recently done on Wii Remote-based head tracking. I need some information about the bandpass filter that is used in Wiimote's camera, information like the peak frequency, the bandwidth of the filter etc.

Are there some documentations on this or any ideas about  filter approximate properties?

Thanks.

Best Regards,
Yashar

2
Hi everybody.

I have an idea how to estmate the camera's vertical field of view.

It is said that the Wii IR camera has an ideal Field Of View (FOV) horizontally (pi/4)=45 degrees .

Assuming that the camera has 1:1 ratio of the pixel size meaning px=py then and knowledge of the
resolution  1024*768 pixels gives us :



           px
        .      .      .      .      .
    py
        .      .      .      .      .

        .      .      .      .      .

        .      .      .      .      .



    px=(FOVx)/1024 = (pi/4)/1024    [rad/pixel]      ------> this is the length of one unit of pixel in x direction

    py=(FOVy)/768  


    px=py ----> FOVy/768=(pi/4)/1024 ----> FOVy=(3/4)*(pi/4) [rad] =33.75 degrees



Does anybody have any idea about this method!?

BR,
Yashar















3
Project Ideas / Does anybody know the pixel size and focal length?
« on: February 25, 2009, 10:26:14 AM »
Hi! I am wroking for wii-remote tracking project and now we are standing in a point which we need the pixelsize and focal length in Milimeter; The point is we are able to estimate these values in respect to each other as :

assume : pixel size (1.0,1.0)
focal length h=1280-1300 pixel size

But as you see they are related to each other. We need to know each os these two parameters soly interm of pixel?
Please help us if you can!

Thanks ...



4
Hi!
 I am working on wii-remote based headtracking . There have been a small problem in the measurment of angles which is bothering me! To simlpify my words, each time when my LED alighemnts is in a way that two adjacent LEDs are so closed to each other (and so the angle between the vectors from the focal point to the points is SMALL) the error ofthe measurement incredibly increases and the angles are evaluated wrongly and so I cannot trust my mesurement anymore.  Has anybody als ofaced before such a problem?


5
Project Ideas / Advantage of 2 wiimotes over 1?
« on: February 07, 2009, 05:46:44 PM »
Hi!

I have been contemplating using 1 wiimote for headtracking applications. But seems that with 1 wiimote , getting full 6DOF info is rather difficult due to the big mathermatics behind. Does anybody know if using 2 wiimote have any advantage over 1 wiimote ? Do we get any further information combing two wiimotes or no it's just concidered as two seperate measurement from different angles which are combined together and the result is a more robust and accurate estimate?!!

Thanks for assistance!

6
General Hardware Talk / Request for LED array
« on: January 29, 2009, 10:57:46 AM »
Hi!
I am looking for some LED array like the one John lee is using in his VR-Desktop headttracking. Do you know where it is possible to order one ? (No doubts the LEDs  should be IR-leds that are used for wiimote.)

Thanks!

7
Other / Does 45 field of degree for wii mean totally 90 degress?
« on: January 29, 2009, 04:19:51 AM »
 Hi!
I was just wondering when in the documentation it says  the camera's field of view is 45 degree, is it half of a sysmetirc angle meaning 90 dergree in total or not in totat it is 45 degree? If it's 45 degree in total then it should be such a small range!
What do you think!?

8
Project Ideas / Question about radiansPerPixel in John lee's code
« on: January 27, 2009, 07:03:44 AM »
  Hi!
There is a point in John lee's code that I can't understand well.

radiansPerPixel
    is defined as (pi/4)/(1024) for both verstical and horizontal case. We know that the camera's resolution is 1024*768 so shouldn't in vertical case we use (pi/4)/(768) instead!!!?


9
Project Ideas / Question about Camera's vertical position - Please help!
« on: January 27, 2009, 05:54:59 AM »
Hi !
There are few important question in John Lee's code that I can't understand ! Can you help me with them ?!...

Code:
relativeVerticalAngle = (avgY - 384) * radiansPerPixel;//relative angle to camera axis

            if(cameraIsAboveScreen)
               headY = .5f+(float)(movementScaling * Math.Sin(relativeVerticalAngle + cameraVerticaleAngle)  *headDist);
            else
               headY = -.5f + (float)(movementScaling * Math.Sin(relativeVerticalAngle + cameraVerticaleAngle) * headDist);


- The headDist calculated in Vertical position differs with that in Horizontal position. John is using the same headDist in both cases? Isn't he doing that wrong...?! headDist_Y^2=DheadY^2+headDist_X^2 where headDist_X is the head distance calcualted in the Horizontal poistion.Why is he ignoring this simple fact!!!!?

- What is the effect adding +/- 0.5 f to the formula?

- Why do we need to write (AvgY-384) and NOT only Avg Y? is the subtraction necessary?

Hope some body can assist me alittle!



10
  Hi!

I have been thinking about John Lee's VR dekstop project over the last few days. In my project I am using a Stationary Wiimote with 2 IR LEDs. In John's code, he is able to do a full localization leading to figuring the values for x,y & z. There are also some angles calculated in his project . Now, I am wondering if we could also do a full Orienation estimation using this method?

Personally I guess only one of the rotation types namely Yaw (defiened as rotation along  z axis) could be calculated since it is related to teta(headx) but about the other two i am not sure if it is possible? What do you think people!? Does anybody have idea on how to do a full oreination (Yaw,Roll,Pitch)calculation?

THANKS!


11
 Hi !
I was just wondering if the Wi remote camera have the same resolution in both x and yu directions? In other words does it have the same Field Of View (FOV) of 45 degress in both x and y directions or they differ? Where can I find this information?

I have also another question  and that if the resolution of 1024*768 causes any difference in the field of view? Can anybody exaplain me alittle ?

Thanks!


12
Project Ideas / Perspective tranformtion method used for 3d Localization
« on: January 21, 2009, 08:23:17 AM »
 Hi.
I have been studying carefully the method that John Lee is using for 3D Localization having 2D info recieved by wiimote and I found that he is using an advanced method namely Perpective Transformtion. I am not familiar with this method and I need some explainations in simple language about the idea of the method and the parametes thata re needed to be fed to the method as input (example x-y and etc) to produce 3D output information (x-y-z) . (Maybe similarizing with john Lees method)

Any ideas is greatly appreciated.

THANKS.
 

13
Programmers Den / What is IR Size?
« on: January 21, 2009, 04:49:50 AM »

Hi!
There is variable in IR data structure in wiiuse code namely IR_size (0-15);
Can you please tell me what it is and hiow we can have acess to this information from wiimote?

I think it has got to do with the IR dot intensities but I am not sure.
If so, is this the way the 3D infmration is found using a 2D IR camera?

Any ideas is greatly appreciated in advanced.

Thanks...


14
Wiimote Desktop VR/Head Tracking / How to estimate z coordinate ?
« on: January 20, 2009, 11:06:09 AM »
  Hi!
I am doing a headtracking project in c++ using wiiuse code. I was wondering if the IR-Camera is only capable of detecting x and y coordinates , how one can find the other coordinate z based on the available data. For sure there should be method (maybe a geometrical approach) to do so otherwise the headtracking solution is not possible! If by any means , one can find relations that leads to the derivation of z , he/she can then use the (x,y,z) for tracking.
I would greatly appreciate ideas !

Thanks ...

15
Programmers Den / About John Chenny C# code
« on: January 20, 2009, 03:21:24 AM »
 Hi!
I am a new programmer in C# and I am making my own c++ code for headtracking.
I was trying to look at john Chenny VR C# code and I came up with the folowwing error.
Can anybody tell me what the problem is and how can I fix it?
The problem occurs while I try opening WiiDesktopVR...


The class WiiDesktopVR can be designed, but is not the first class in the file. Visual Studio requires that designers use the first class in the file. Move the class code so that it is the first class in the file and try loading the designer again.


Thanks,

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