<< Chapter < Page Chapter >> Page >

Change in pixel values indicates motion

A simple method of subtracting one movie frame from another will provide information about which parts of the scene have changed (generally due to motion). This method was performed on each frame of the movie, with consecutive frames being subtracted from each other.

Frame subtraction

First, the scene is converted to an array of pixel values. These pixel values are the averaged Red, Green, and Blue (RGB) values for each pixel. The pixel values of the previous frame are then subtracted from the current frame’s pixel values, and the absolute value of the values is taken. The result is an array of values that represent how much each pixel has changed between the two frames, with higher values representing more change. The amount of change in a region of pixels can be interpreted as the amount of motion that is taking place in that region. These data can then be used to determine where in the scene the most motion is taking place.

Illustrative example

The images below show the results of subtracting two frames from Punch Drunk Love. Note that these are NOT consecutive frames, as the changes between consecutive frames can be very small. The frames presented below were chosen to clearly illustrate the results of frame subtraction. In the “difference” frame, higher values (more change) are represented by white.

Figure 1: the current frame

Figure 1: the previous frame (not consecutive frames)

Figure 3: the “difference” frame

White regions indicate more change in pixel values. Very little change has occurred in much of the scene. Only the movement of the main character has resulted in a large amount of change in pixel values. Note that in this scene, the motion is taking place not in the center of the frame, but slightly offset to the left.

Questions & Answers

If potatoes cost Jane $1 per kilogram and she has $5 that could possibly spend on potatoes or other items. If she feels that the first kilogram of potatoes is worth $1.50, the second kilogram is worth$1.14, the third is worth $1.05 and subsequent kilograms are worth $0.30, how many kilograms of potatoes will she purchase? What if she only had $2 to spend?
Susan Reply
cause of poverty in urban
DAVY Reply
QI: (A) Asume the following cost data are for a purely competitive producer: At a product price Of $56. will this firm produce in the short run? Why Why not? If it is preferable to produce, what will be the profit-maximizing Or loss-minimizing Output? Explain. What economic profit or loss will the
Falak Reply
what is money
DAVY Reply
what is economic
Stephen Reply
economics is the study of ways in which people use resources to satisfy their wants
Falak
what is Price mechanism
Dhany Reply
introduction to economics
Uday Reply
welfare definition of economics
Uday
examine the wealth and welfare definitions of economics
Uday
read book by ml jhingan
Anand
What do we mean by Asian tigers
Aeesha Reply
Dm me I will tell u
Shailendra
Hi
Aeesha
hi
Pixel
What is Average revenue
KEMZO
How are u doing
KEMZO
it is so fantastic
metasebia
uday
Uday
it is a group of 4 countries named Singapore, South Korea, Taiwan and Hong Kong because their economies are growing very faster
Anand
what's a demand
Edward Reply
it is the quantity of commodities that consumers are willing and able to purchase at particular prices and at a given time
Munanag
quantity of commodities dgat consumers are willing to pat at particular price
Omed
demand depends upon 2 things 1wish to buy 2 have purchasing power of that deserving commodity except any from both can't be said demand.
Bashir
Demand is a various quantity of a commodities that a consumer is willing and able to buy at a particular price within a given period of time. All other things been equal.
Vedzi
State the law of demand
Vedzi
The desire to get something is called demand.
Mahabuba
what is the use of something should pay for its opportunity foregone to indicate?
Random Reply
Why in monopoly does the firm maximize profits when its marginal revenue equals marginal cost
astrid Reply
different between economic n history
Falma Reply
If it is known that the base change of RM45 million, the statutory proposal ratio of 7 per cent, and the public cash holding ratio of 5 per cent, what is the proposed ratio of bank surplus to generate a total deposit of RM 300 million? 
Jeslyne Reply
In a single bank system, a bank can create a deposit when it receives a new deposit in cash. If a depositor puts a cash deposit of RM10,000 into the bank, assume the statutory reserve requirement is 7% and the bank adopts a surplus reserve of 8%. a. Calculate the amount of deposits made at the end o
Jeslyne
the part of marginal revenue product curve lies in the _ stage of production is called form demand curve for variable input.
Bashir Reply
The cost associated with the inputs owned by the farmer is termed as
Bashir
the cost associated with inputs owned by the farmer is termed as ____
Bashir
why do we study economic
Nwobodo Reply
we study economics to know how to manage our limited resources
Eben
တစ်ဦးကျဝင်​ငွေ
myo
we study economics the know how to use our resources and where to put it
Mamoud
what is end
Nwobodo
we study economics to make rational decision
Gloria
we study economics only to know how to effectively and efficiently allocate our limited resource in other to meet our unlimited wants
Kpegba
We study economics inorder for us to know the difference of the needs and wants and aslo how to use the limited resources that are available
Bongani
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play




Source:  OpenStax, Adaptive region of interest for video. OpenStax CNX. Dec 14, 2010 Download for free at http://cnx.org/content/col11256/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Adaptive region of interest for video' conversation and receive update notifications?

Ask