Firefly Eindhoven - Remaining Sensors: Difference between revisions

From Control Systems Technology Group
Jump to navigation Jump to search
Line 9: Line 9:
'''Working Principle'''
'''Working Principle'''


If <math>I(x,y,t)</math> is a pixel in an image then after some time <math>dt</math>, as the pixel moves some distance <math>dx</math> and <math>dy</math> then as the pixel intensity is consistent, it can be said that;
If <math>I(x,y,t)</math> is the intensity of a pixel in an image then after some time <math>dt</math>, as the pixel moves some distance <math>dx</math> and <math>dy</math> then as the pixel intensity is consistent, it can be said that;


<math>I(x,y,t) = I(x+dx,  y+dy,  t+dt)</math>
<math>I(x,y,t) = I(x+dx,  y+dy,  t+dt)</math>
Line 16: Line 16:


<math> \frac{\partial I}{\partial x} \frac{\partial x}{\partial t} + \frac{\partial I}{\partial y} \frac{\partial y}{\partial t} + \frac{\partial I}{\partial t} = 0 </math>
<math> \frac{\partial I}{\partial x} \frac{\partial x}{\partial t} + \frac{\partial I}{\partial y} \frac{\partial y}{\partial t} + \frac{\partial I}{\partial t} = 0 </math>
In the above equation, the space differentials of intensity are refereed to as image gradients and the above equation is termed as Optical flow Equation.


==Sensor fusion==
==Sensor fusion==

Revision as of 12:11, 26 May 2018

IMU

Lidar

Optical flow

Optical flow refers to estimation of apparent velocities of certain objects in an image. This is done by measuring the optical flow of each frame using which velocities of objects can be estimated. It is 2D vector field where each vector is a displacement vector showing the movement of points from first frame to second. By estimating the flow of points in a frame, the velocity of the moving camera can be calculated.

Working Principle

If [math]\displaystyle{ I(x,y,t) }[/math] is the intensity of a pixel in an image then after some time [math]\displaystyle{ dt }[/math], as the pixel moves some distance [math]\displaystyle{ dx }[/math] and [math]\displaystyle{ dy }[/math] then as the pixel intensity is consistent, it can be said that;

[math]\displaystyle{ I(x,y,t) = I(x+dx, y+dy, t+dt) }[/math]

Using taylor series, it is possible to write

[math]\displaystyle{ \frac{\partial I}{\partial x} \frac{\partial x}{\partial t} + \frac{\partial I}{\partial y} \frac{\partial y}{\partial t} + \frac{\partial I}{\partial t} = 0 }[/math]

In the above equation, the space differentials of intensity are refereed to as image gradients and the above equation is termed as Optical flow Equation.

Sensor fusion