My second prototype built on the first one but improved a lot of the ideas and techniques used in it. It also included 6 video frames in one large window, simply because I wanted to improve a lot of the previous ideas before specialising in one specific technique. Generally, this prototype mainly focused on optimising the background subtraction and threshold to get the best blob contours as possible. To smoothen the contours, I added an adjustable blur effect. Also, the threshold could be changed manually in the running application. I played with colour effects, like having a random colour for each blob. I also added a transparency attribute for the blob filling. I experimented with the history of blob contours and with the blob centroids (the central point of each blob). In terms of programming I think for this prototype I played a lot with loops.

Below are the source files of prototype 02 written in pseudo code for easier understanding.


include stuff

// Main
open window of size 1050,800
run main c++ file (testApp.cpp)


Include addons like ofxOpenCv, ofxVectorMath, ofxBox2d, ofxContourUtil and ofxBlobTracker

customBall class which sets size and colour of balls

name physics worlds
name the linestrip for the contours
name the linestrip for drawing line
name the contact handler for the physics worlds
name the vector for the customBalls
name the vector for the balls

name variables for simplification, threshold, font, image, mouse location, and various others

name colour images to store the video pixels in
name grayscale images to store the foreground and background pixels in

name contour finders to store the contours in

name video grabber for the webcam or video player for movie

name the vector to store the points of the drawing line in

name the blobTracker for the history of contours and blobs


// Setup
set background colour

initialise video grabber
(or load movie)

allocate memory for the original video, the foreground video and background video

set gauss parameters
create gauss background

load font

set number of points of drawing to 0 to begin with

allocate memory for original video and contour frame
initialise physics world
enable gravity
set bounds to contour frame only

setup blob listener

// Update
set window title to current framerate for reference

store pixels of input video (camera or movie) into respective frames
update background and foreground models including blur and threshold values
find contours using the foreground model

track blobs

// Draw
draw foreground video at 20,40 (top left)
draw background for contours
draw contours at 360,40 (top middle)

write text

draw original video at 700,40 (top right)
draw history of contours at 700,40 (top right)

draw background for pixel video
draw pixel effect of video or live feed at 20,320 (bottom left)

draw background for contours
draw and fill contours with random colours at 360,320 (bottom middle)

draw background for centroids
draw centroids and their history at 700,320 (bottom right)

draw customBalls

draw line on mouseclick at mouse location

// KeyPressed
increase or decrease simplification of contour by clicking left or right
increase or decrease blur by clicking up or down
increase or decrease threshold by clicking pageup or pagedown
draw big balls by clicking space
draw small balls by clicking b

// MouseDragged
add current point of mouse to drawing array and linestrip

// MousePressed
clear drawing array and linestrip on right click

// MouseReleased
stop adding points to the drawing array and linestrip