Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫  π  -¹ ² ³ °

You are not logged in.

## #1 Re: Help Me ! » distance from camera to object » 2012-07-12 15:28:02

Hy thanks Bob:)

Well i tried to solve that.

if you see this figure :http://i1069.photobucket.com/albums/u472/tina12354/anglefind-1.png

then cos(60) = base /hypo
1/2      = 100 / y
y = 200 cm

and sin(60)     = perpendicular / gypo
sqrt(3) /2 = x / 200
sqrt(3)*100 = x
x = 173 cm.

Is it correct ?
So in think distance from cam to object is 173 cm.
Please correct me if i am wrong .
thanks

## #2 Re: Help Me ! » distance from camera to object » 2012-07-12 05:18:10

hmm yes you can say focal length .

## #3 Help Me ! » distance from camera to object » 2012-07-12 05:07:55

model
Replies: 8

Hy guys ,

I want to find distance from camera to object .
A picture is given in this link: http://i1069.photobucket.com/albums/u472/tina12354/anglefind.png

thanks

## #4 Help Me ! » Graph of electricity » 2012-06-25 00:29:57

model
Replies: 6

Hy guys,

Can any one please explain me this graph :

I did not understand graph by unit of electricity .
Could any one please explain me . thanks

## #5 Re: Help Me ! » Need help in understanding haar wavelet transformation » 2012-06-11 06:28:42

Hy Bob:

Thanks .
Actually i need to understand it mathematically .

Hy Bob, I need your help to understand it mathematically .
I am not capturing sense of Haar wavelet basis in figure

## #6 Help Me ! » Need help in understanding haar wavelet transformation » 2012-06-10 17:22:27

model
Replies: 4

hy guys ,

I am trying to understand haar wavelet transform.

I have 3 images given below .

1. http://i1268.photobucket.com/albums/jj562/ridasana/2.jpg
2. http://i1268.photobucket.com/albums/jj562/ridasana/3.jpg
3. http://i1268.photobucket.com/albums/jj562/ridasana/1-1.jpg

My problem is i do't understand figure in 3rd link.
I did not understand that how did he consider values of B , V , H and D.

## #7 Help Me ! » convert to scientific notation » 2012-05-27 19:20:30

model
Replies: 2

how  can i convert 1,228,000 in scientific notation ?

## #8 Help Me ! » Rotation in Homogeneous coordinate » 2012-04-07 05:14:51

model
Replies: 4

Hy All,

I am not understanding this eq in link : http://www.cs.mtu.edu/~shene/COURSES/cs3621/NOTES/geometry/geo-tran.html

, rotating a line Ax + By + C = 0 about the origin a degree brings it to a new equation:

(Acosa - Bsina)x' + (Asina + Bcosa)y' + C = 0

How did he get the equation ? ? ?

Also how did he use this equation  in the above link .
as shown in figure this : http://imageshack.us/photo/my-images/853/2drottran.jpg/

How did he combine it to make it translation and rotation ?

Could any one tell me ?
thanks

## #9 Help Me ! » Homogeneous Coordinates » 2012-04-07 04:15:40

model
Replies: 0

Hy all,

Question : Homogeneous Coordinates System

Its  said that

Without the use of homogeneous coordinates system, it would be difficult to design certain classes of very useful curves and surfaces in computer graphics and computer-aided design

Which meant if we convert Cartesian coordinate to Homogeneous system then we could handle infinity.

Ok then let say we have two point (x ,y) , by converting to homogeneous we will get x/w , y/w then let say w = 0 then it would be infinity . then how  are we dealing with infinity here ?
How are converting infinity . its same as cartesian form.  but yes if the eq is in polynomial form then we could handle infinity .

How is it homogeneous then ?

## #10 Re: Help Me ! » Area and perimeter of shapes » 2012-03-18 20:32:24

Let say i have square like as shown in this link,.
http://www.mathsisfun.com/geometry/perimeter.html

In the square we have 4 sides . that meant perimeter is 3 + 7+ 3+ 7 = 15
My question is : what is the area of that square in the link .

In my understanding ,i think that square have 3 columns and 7 rows  which mean the area is 3*7  = 21 pixels is area of that square .

Am i right ?

## #11 Help Me ! » Area and perimeter of shapes » 2012-03-18 20:18:54

model
Replies: 2

Hy all ,

I have two question about area and perimeter .

So first Area :

* Area is the number of pixels within a region.
* And Area can be find as quadtree . but how ?
Say  i have an image 10 * 10 . how  can we find area by representating an image in form of quadtree ?

* How can we find area using polygon vertices ?

Perimeter is the number pixels in the boundary  of  shape .

let  say i have an square of 4*4 . What's the perimeter of it  ?
and let say i have triangle
like
*
**
***   in the stared triangle, What is the perimeter ?
I need to know about these  as soon as possible until tomorrow .
Expecting a good response thanks

## #12 Help Me ! » Fourier transform and log polar coordinate system » 2012-03-11 15:49:18

model
Replies: 1

IS Fourier transform also  called log  polar coordinates system ?

## #13 Help Me ! » automated mean and deviation for color normalization » 2012-03-05 01:06:52

model
Replies: 2

How to calculate automated mean?

what does mean by deviation to color normalization ?

## #14 Help Me ! » Degree and movement condition statement understanding » 2012-02-27 18:19:44

model
Replies: 0

if thumb moves 0 to 90 degree and back two times fast.

What does mean by 2 times fast ?

Does it mean like

if(thumb move to 0 to 90 and thumb.x 2 and thumb.y*2)  ???

## #15 Re: Help Me ! » Please elaborate the given statement. thanks » 2012-02-27 03:35:43

bobbym wrote:

Hi model;

Any more to that quote?

no , just that is the statement.

## #16 Help Me ! » Please elaborate the given statement. thanks » 2012-02-27 01:35:27

model
Replies: 3

Statement:

"delete the vertex whose distance is less than 10 pixels when comparing with next vertex .then we will get one single point. "

What does it mean ?

Does it mean like

Say i have point A and point B

if(distance of A and B < 10) then delete which vertex A or B.?

What does mean by the above quoted statement ?

## #17 Re: Help Me ! » Count the number of fingers of hand » 2012-02-25 20:03:47

John E. Franklin wrote:

i dont understand how you get all the points in place in the first place.  Who put down the 3 colored points?
Is the hand flat on to the camera?  Are you neglecting the vanishing point or perspective and using the image as is?

Yes, I found convex hull of my hand contour or have image..
and those circles are convexity defects presented on hand.
And yes its hand from live video. and video is a sequence of images.

## #18 Re: Help Me ! » Count the number of fingers of hand » 2012-02-22 21:40:19

I have hand center  point . and points from convex hull like start , end and depth points .

I need to find the hand radius . How can i do that ?

## #19 Help Me ! » Count the number of fingers of hand » 2012-02-16 19:52:12

model
Replies: 4

Hy  All.

This is an image of convex hull of hand plus defect points : http://imageshack.us/photo/my-images/818/convexhullanddefect.png/

where
blue circles : start point
red circles : end point
green circles : depth points.

I want to define the finger counter from defect points .
Does any one have any idea to get the number of fingers .
if yes then please share ideas,
thanks

## #20 Help Me ! » find the other point on the circle with center point and radius of cir » 2012-02-15 03:34:13

model
Replies: 2

Hy ,

if we have radius of a circle and center value .
then how can we find the other point on the circle ?

## #21 Re: Help Me ! » Bayes' Theorem » 2012-02-12 17:47:17

bobbym wrote:

Hi model;

I think you meant by this is area of point A, right ?

## #22 Re: Help Me ! » Bayes' Theorem » 2012-02-11 21:08:38

bobbym wrote:

Hi model;

Unless we can get the problem down to something like post #6 we will not be able to say anything about the probabilty.

I will draw you a diagram that will hopefully explain what we need.

hmm ok i am waiting for your diagram then .
and yes thanks for helping me.

## #23 Re: Help Me ! » Bayes' Theorem » 2012-02-11 00:19:02

well initial location of  my hand is 0 when there is no hand appear  in the video  but when hand appear any where in the video then location will appear .  Hy  please consider #6 for my work as i shown in the image.

## #24 Re: Help Me ! » Bayes' Theorem » 2012-02-10 23:53:09

Hy,

my image area is : 76800

and hand area is : 4592

you can see in this image as link :  http://imageshack.us/photo/my-images/823/imgoy.png/

And now tell me what info do we need to get the probability of my hand as a point A ?

## #25 Re: Help Me ! » Bayes' Theorem » 2012-02-10 23:35:45

bobbym wrote:

If you were to draw an imaginary rectangle around the area where Point A could be placed where would it be?

hmm hold on. lemme post  here total image size in form of rectangle area . and a point A(i-e hand) with its coordinates x  and y .  ok