My Computer Vision with Python talk given at Pycon Singapore 2014

1. Mark Rees
CTO
Century Software

2. What is Computer Vision – 1980’s
Then it was called Machine Vision
"the automatic acquisition and analysis of images to
obtain desired data for interpreting
a scene or controlling an activity" (Schaffer, 1984).
cnt dw $0000
src dw $0000
dst dw $0000
memcpy public
ldab cnt+1 ;Set B = cnt.L
beq check ;If cnt.L=0, goto check
loop ldx src ;Set IX = src
ldaa ix ;Load A from (src)
inx ;Set src = src+1
stx src
ldx dst ;Set IX = dst
staa ix ;Store A to (dst)
inx ;Set dst = dst+1
stx dst
decb ;Decr B
bne loop ;Repeat the loop
stab cnt+1 ;Set cnt.L = 0
check tst cnt+0 ;If cnt.H=0,
beq done ;Then quit
dec cnt+0 ;Decr cnt.H
decb ;Decr B
bra loop ;Repeat the loop
done rts ;Return

3. What is Computer Vision - 2014
“Computer vision is a field that includes methods for acquiring,
processing, analyzing, and understanding images and, in general, high-
dimensional data from the real world in order to produce numerical or
symbolic information, e.g., in the forms of decisions. A theme in the
development of this field has been to duplicate the abilities of human
vision by electronically perceiving and understanding an image. This
image understanding can be seen as the disentangling of symbolic
information from image data using models constructed with the aid of
geometry, physics, statistics, and learning theory. Computer vision has
also been described as the enterprise of automating and integrating a
wide range of processes and representations for vision perception.”
(Wikipedia 2014 http://en.wikipedia.org/wiki/Computer_Vision)

4. What is Computer Vision - 2014

5. Computer Vision – My Reality

6. CV is a lot more than grabbing an image
CV
Object Illumination
Image
Capture
Sensors/Cameras Digitisation/Conversion
Image
Processing
Algorithm
Development
Implementation
Display Control

7. Python Imaging Library
Pillow – The friendly PIL fork python 2.6+, 3.2+
http://python-pillow.github.io/
PIL – The “original” PIL python 1.52+, 2.0+
last release 11/2009
http://effbot.org/downloads
Demo: PIL.ipynb

8. Scipy ndimage
N dimensional array image processing
http://docs.scipy.org/doc/scipy/reference/ndimage.html
Demo: Multi-demensional image processing.ipynb

9. SimpleCV
SimpleCV is an open source framework for building
computer vision applications. With it, you get access to
several high-powered computer vision libraries such as
OpenCV – without having to first learn about bit depths,
file formats, color spaces, buffer management,
eigenvalues, or matrix versus bitmap storage.
http://simplecv.org/
Demo: SimpleCV - The Basics.ipynb
Pygamedependency caused me some problems
Not all image manipulation worked in ipython. Simplecv
shell is where all functionality works.

10. PyOpenCV
Official python wrapper for OpenCV C/C++ libraries
Two namespaces cv & cv2. Use cv2, cv deprecated
Basis of SimpleCV and other python CV libraries
Demo: OpenCV - The Basics.ipynb
Demo: OpenCV Motion Detection.ipynb
Demo: OpenCV Face Detection.ipynb

11. Raspberry Pi CV
OpenCV available but USB cameras slow
Rpi camera faster, uses GPU, doesn’t work with OpenCV
apt-get install python-picamera solves that.
http://picamera.readthedocs.org/en/release-1.5/

12. Resources
http://www.packtpub.com/opencv-computer-
vision-with-python/book
http://programmingcomputervision.com/
There also is a Python CV module PCV
http://szeliski.org/Book/
Computer Vision: Algorithms and Applications

13. Mark Rees
mark@censof.com
+Mark Rees
@hexdump42
hex-dump.blogspot.com
https://bitbucket.org/hexdump42/seeing-in-python-pycon-sg-
2014
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