TORCS: Track and Segments

I came across fiddling with torcs for a while for self-driving tests. In some case, I need to reset the car to the middle of the track when stuck. After some trial and error and studying into the code, I found out that the tCar struct always records the closest main part of the track in trkPos, albeit the car might be in the rside and lside segments attached to the track. So generally, one section of a track consists of main road, left side and right side, left border and right border. Their composition is as follows,

Image Processing - Histogram Equalization - Part 2

Draw Histograms

# draw flattened histogram
import matplotlib.pyplot as plt
import numpy as np
from PIL import Image
%matplotlib inline

im = Image.open("sample.jpg")
im_arr = np.array(im)
print im_arr.shape

plt.figure(figsize=(15,5))
plt.subplot(1,2,1)
plt.imshow(im_arr)
plt.axis('off')

plt.subplot(1,2,2)
im_r = im_arr[:,:,0].flatten() # 3d (r,g,b) to 1d (stacked)
im_g = im_arr[:,:,1].flatten()
im_b = im_arr[:,:,2].flatten()
imhist, bins = np.histogram(im_r, 256, normed=True) #bins are a sequence of data range
plt.plot(imhist, label="Red")
imhist, bins = np.histogram(im_g, 256, normed=True)
plt.plot(imhist, label="Green")
imhist, bins = np.histogram(im_b, 256, normed=True)
plt.plot(imhist, label="Blue")
plt.legend(loc=1)

Histogram Equalization on Grayscale Image

# histogram equalization
def histeq(im, nbr_bins=256):
    imhist,bins = np.histogram(im.flatten(),nbr_bins,normed=True)
    cdf = imhist.cumsum() # cumulative distribution function (cumulative sum)
    cdf = 255 * cdf / cdf[-1] # normalization (brilliant! cdf[-1] is the sum of all)
    im2 = np.interp(im.flatten(), bins[:-1], cdf) # (x', x, fx) linear interpolate x' accordingg to x -> f(x)
    return im2.reshape(im.shape), cdf

im_gray = np.array(im.convert('L')) # interpolate in grayscale
im2, cdf = histeq(im_gray) # increase the dark area

plt.figure(figsize=(15,10))
plt.subplot(2,2,1)
plt.imshow(im_gray,cmap='gray')

plt.subplot(2,2,2)
plt.imshow(im2,cmap='gray')

plt.subplot(2,2,3)
plt.plot(cdf, label="Cumulative Distribution Function")
plt.legend(loc=2)

imhist2, bins2 = np.histogram(im2, 256, normed=True)
plt.subplot(2,2,4)
plt.plot(imhist2, label="Equalized Historgram")
plt.legend(loc=1)

Histogram Equalization on Colored Image

im = Image.open("Luncheon.jpg")
im_arr = np.array(im)

img_r = im_arr[:,:,0]
img_g = im_arr[:,:,1]
img_b = im_arr[:,:,2]

im_r_eq, cdf = histeq(img_r)
im_g_eq, cdf = histeq(img_g)
im_b_eq, cdf = histeq(img_b)

im_eq = np.zeros(im_arr.shape, 'uint8')
print im_r_eq.shape
im_eq[:,:,0] = im_r_eq
im_eq[:,:,1] = im_g_eq
im_eq[:,:,2] = im_b_eq
print im_eq.shape

plt.figure(figsize=(15,10))
plt.subplot(2,3,1)
plt.imshow(im_r_eq, cmap="gray")
plt.axis('off')

plt.subplot(2,3,2)
plt.imshow(im_g_eq, cmap="gray")
plt.axis('off')

plt.subplot(2,3,3)
plt.imshow(im_b_eq, cmap="gray")
plt.axis('off')

ime = Image.fromarray(im_eq)
plt.subplot(2,3,4)
plt.imshow(ime)
plt.axis('off')

plt.subplot(2,3,5)
plt.imshow(im)
plt.axis('off')

Matplotlib: Image Processing - Part 1

Remapping Images

from PIL import Image
import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline

n_row, n_col = 1, 5
plt.figure(figsize=(n_col*3,n_row*3),dpi=100)

img = Image.open("sample.jpg")
plt.subplot(n_row, n_col, 1)
plt.imshow(img)
plt.axis('off')

# gray
img2 = np.array(img.convert('L'))
plt.subplot(n_row, n_col, 2)
plt.imshow(img2, cmap='gray')
plt.axis('off')

# inverse
img3 = 255 - img2
plt.subplot(n_row, n_col, 3)
plt.imshow(img3, cmap='gray')
plt.axis('off')

# map to 100 ... 200
img4 = (100.0/255)*img2 + 100
plt.subplot(n_row, n_col, 4)
plt.imshow(img4, cmap='gray')
plt.axis('off')

# squared
img5 = 255.0 * (img2/255.0) **2
plt.subplot(n_row, n_col, 5)
plt.imshow(img5, cmap='gray')
plt.axis('off')

Plot multiple functions together

from PIL import Image
import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline

f1 = np.array(range(255))
# f1 = np.linspace(0,255,255,endpoint=True)
f2 = 255 - f1
f3 = (100.0/255)*f1 + 100
f4 = 255.0*(f1/255.0)**2

plt.figure(figsize=(8,5))
plt.plot(f1,f1,label="f(x)=x")
plt.plot(f1,f2,label="f(x)=255-x")
plt.plot(f1,f3,label="f(x)=(100.0/255)*x + 100")
plt.plot(f1,f4,label="f(x)=255.0*(x/255.0)**2")
plt.axis([0,260, 0, 260])
plt.legend(loc=2)

print min(f1), max(f1)
print min(f2), max(f2)
print min(f3), max(f3)
print min(f4), max(f4)

XSLT: Structuring Data in Attributes or in Child Elements

We are free to select tags to our liking, so are to build an XML structure, whether it is element-based, where there is almost no attributes in the XML tree (see the following exmample) or attribute-based (converted by XSLT code to be shown below).

<?xml version="1.0" encoding="UTF-8"?>
<catalog>
 <cd>
  <title>Empire Burlesque</title>
  <artist>Bob Dylan</artist>
  <country>USA</country>
  <company>Columbia</company>
  <price>10.90</price>
  <year>1985</year>
 </cd>
 <cd>
  <title>Hide your heart</title>
  <artist>Bonnie Tyler</artist>
  <country>UK</country>
  <company>CBS Records</company>
  <price>9.90</price>
  <year>1988</year>
 </cd>
 <cd>
  <title>Greatest Hits</title>
  <artist>Dolly Parton</artist>
  <country>USA</country>
  <company>RCA</company>
  <price>9.90</price>
  <year>1982</year>
 </cd>
 <cd>
  <title>Still got the blues</title>
  <artist>Gary Moore</artist>
  <country>UK</country>
  <company>Virgin records</company>
  <price>10.20</price>
  <year>1990</year>
 </cd>
 <cd>
  <title>Eros</title>
  <artist>Eros Ramazzotti</artist>
  <country>EU</country>
  <company>BMG</company>
  <price>9.90</price>
  <year>1997</year>
 </cd>
 <cd>
  <title>One night only</title>
  <artist>Bee Gees</artist>
  <country>UK</country>
  <company>Polydor</company>
  <price>10.90</price>
  <year>1998</year>
 </cd>
 <cd>
  <title>Sylvias Mother</title>
  <artist>Dr.Hook</artist>
  <country>UK</country>
  <company>CBS</company>
  <price>8.10</price>
  <year>1973</year>
 </cd>
 <cd>
  <title>Maggie May</title>
  <artist>Rod Stewart</artist>
  <country>UK</country>
  <company>Pickwick</company>
  <price>8.50</price>
  <year>1990</year>
 </cd>
 <cd>
  <title>Romanza</title>
  <artist>Andrea Bocelli</artist>
  <country>EU</country>
  <company>Polydor</company>
  <price>10.80</price>
  <year>1996</year>
 </cd>
 <cd>
  <title>When a man loves a woman</title>
  <artist>Percy Sledge</artist>
  <country>USA</country>
  <company>Atlantic</company>
  <price>8.70</price>
  <year>1987</year>
 </cd>
 <cd>
  <title>Black angel</title>
  <artist>Savage Rose</artist>
  <country>EU</country>
  <company>Mega</company>
  <price>10.90</price>
  <year>1995</year>
 </cd>
 <cd>
  <title>1999 Grammy Nominees</title>
  <artist>Many</artist>
  <country>USA</country>
  <company>Grammy</company>
  <price>10.20</price>
  <year>1999</year>
 </cd>
 <cd>
  <title>For the good times</title>
  <artist>Kenny Rogers</artist>
  <country>UK</country>
  <company>Mucik Master</company>
  <price>8.70</price>
  <year>1995</year>
 </cd>
 <cd>
  <title>Big Willie style</title>
  <artist>Will Smith</artist>
  <country>USA</country>
  <company>Columbia</company>
  <price>9.90</price>
  <year>1997</year>
 </cd>
 <cd>
  <title>Tupelo Honey</title>
  <artist>Van Morrison</artist>
  <country>UK</country>
  <company>Polydor</company>
  <price>8.20</price>
  <year>1971</year>
 </cd>
 <cd>
  <title>Soulsville</title>
  <artist>Jorn Hoel</artist>
  <country>Norway</country>
  <company>WEA</company>
  <price>7.90</price>
  <year>1996</year>
 </cd>
 <cd>
  <title>The very best of</title>
  <artist>Cat Stevens</artist>
  <country>UK</country>
  <company>Island</company>
  <price>8.90</price>
  <year>1990</year>
 </cd>
 <cd>
  <title>Stop</title>
  <artist>Sam Brown</artist>
  <country>UK</country>
  <company>A and M</company>
  <price>8.90</price>
  <year>1988</year>
 </cd>
 <cd>
  <title>Bridge of Spies</title>
  <artist>T`Pau</artist>
  <country>UK</country>
  <company>Siren</company>
  <price>7.90</price>
  <year>1987</year>
 </cd>
 <cd>
  <title>Private Dancer</title>
  <artist>Tina Turner</artist>
  <country>UK</country>
  <company>Capitol</company>
  <price>8.90</price>
  <year>1983</year>
 </cd>
 <cd>
  <title>Midt om natten</title>
  <artist>Kim Larsen</artist>
  <country>EU</country>
  <company>Medley</company>
  <price>7.80</price>
  <year>1983</year>
 </cd>
 <cd>
  <title>Pavarotti Gala Concert</title>
  <artist>Luciano Pavarotti</artist>
  <country>UK</country>
  <company>DECCA</company>
  <price>9.90</price>
  <year>1991</year>
 </cd>
 <cd>
  <title>The dock of the bay</title>
  <artist>Otis Redding</artist>
  <country>USA</country>
  <company>Atlantic</company>
  <price>7.90</price>
  <year>1987</year>
 </cd>
 <cd>
  <title>Picture book</title>
  <artist>Simply Red</artist>
  <country>EU</country>
  <company>Elektra</company>
  <price>7.20</price>
  <year>1985</year>
 </cd>
 <cd>
  <title>Red</title>
  <artist>The Communards</artist>
  <country>UK</country>
  <company>London</company>
  <price>7.80</price>
  <year>1987</year>
 </cd>
 <cd>
  <title>Unchain my heart</title>
  <artist>Joe Cocker</artist>
  <country>USA</country>
  <company>EMI</company>
  <price>8.20</price>
  <year>1987</year>
 </cd>
</catalog>

With the help of XSLT, we can easily transform element-based data into attribute-based data. Several points to notice in the XSLT code:

• child selector child::
• element name name()
• element text text()
• dynamic attribute name {name()}

<?xml version="1.0" encoding="UTF-8" ?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:template match="/">
        <catalog>
        <xsl:for-each select="catalog/cd">
            <cd>
                <xsl:for-each select="child::*">
                    <xsl:attribute name="{name(.)}">
                        <xsl:value-of select="text()"/>
                    </xsl:attribute>
                </xsl:for-each>
            </cd>
        </xsl:for-each>
        </catalog>
    </xsl:template>
</xsl:stylesheet>

Result: the attribute-based data.

<catalog>
    <cd title="Empire Burlesque" artist="Bob Dylan" country="USA" company="Columbia" price="10.90" year="1985" />
    <cd title="Hide your heart" artist="Bonnie Tyler" country="UK" company="CBS Records" price="9.90" year="1988" />
    <cd title="Greatest Hits" artist="Dolly Parton" country="USA" company="RCA" price="9.90" year="1982" />
    <cd title="Still got the blues" artist="Gary Moore" country="UK" company="Virgin records" price="10.20" year="1990" />
    <cd title="Eros" artist="Eros Ramazzotti" country="EU" company="BMG" price="9.90" year="1997" />
    <cd title="One night only" artist="Bee Gees" country="UK" company="Polydor" price="10.90" year="1998" />
    <cd title="Sylvias Mother" artist="Dr.Hook" country="UK" company="CBS" price="8.10" year="1973" />
    <cd title="Maggie May" artist="Rod Stewart" country="UK" company="Pickwick" price="8.50" year="1990" />
    <cd title="Romanza" artist="Andrea Bocelli" country="EU" company="Polydor" price="10.80" year="1996" />
    <cd title="When a man loves a woman" artist="Percy Sledge" country="USA" company="Atlantic" price="8.70" year="1987" />
    <cd title="Black angel" artist="Savage Rose" country="EU" company="Mega" price="10.90" year="1995" />
    <cd title="1999 Grammy Nominees" artist="Many" country="USA" company="Grammy" price="10.20" year="1999" />
    <cd title="For the good times" artist="Kenny Rogers" country="UK" company="Mucik Master" price="8.70" year="1995" />
    <cd title="Big Willie style" artist="Will Smith" country="USA" company="Columbia" price="9.90" year="1997" />
    <cd title="Tupelo Honey" artist="Van Morrison" country="UK" company="Polydor" price="8.20" year="1971" />
    <cd title="Soulsville" artist="Jorn Hoel" country="Norway" company="WEA" price="7.90" year="1996" />
    <cd title="The very best of" artist="Cat Stevens" country="UK" company="Island" price="8.90" year="1990" />
    <cd title="Stop" artist="Sam Brown" country="UK" company="A and M" price="8.90" year="1988" />
    <cd title="Bridge of Spies" artist="T`Pau" country="UK" company="Siren" price="7.90" year="1987" />
    <cd title="Private Dancer" artist="Tina Turner" country="UK" company="Capitol" price="8.90" year="1983" />
    <cd title="Midt om natten" artist="Kim Larsen" country="EU" company="Medley" price="7.80" year="1983" />
    <cd title="Pavarotti Gala Concert" artist="Luciano Pavarotti" country="UK" company="DECCA" price="9.90" year="1991" />
    <cd title="The dock of the bay" artist="Otis Redding" country="USA" company="Atlantic" price="7.90" year="1987" />
    <cd title="Picture book" artist="Simply Red" country="EU" company="Elektra" price="7.20" year="1985" />
    <cd title="Red" artist="The Communards" country="UK" company="London" price="7.80" year="1987" />
    <cd title="Unchain my heart" artist="Joe Cocker" country="USA" company="EMI" price="8.20" year="1987" />
</catalog>

VBScript: Dynamically Create GUIDs

Function CreateGUID()
 Set TypeLib = CreateObject("Scriptlet.TypeLib") 
 myGuid = CStr(TypeLib.Guid)
 CreateGUID = Left(myGuid, Len(myGuid)-2)
 Set TypeLib = Nothing
End Function

Windows Installer: Migrating From InstallShield to WiX

Notice: I've prepared my scripts into this repository github: IS2WiX ^[5].

Preparation

Installing WiX Toolset will get you all the tools to compile all XML files in your WiX project. It will also install templates to Visual Studio and VS does automatically configure compilation options for you.

We need programming knowledge from XSLT/XPATH to operate on XML files, also some VB.NET knowledge to write customized custom actions.

Here is a list of all related tools and languages.

• WiX Toolset^[1], documentation
• Visual Studio 2012
• Microsoft SDK (Orca.exe, Wilogutl.exe etc.^[2])
• XSLT, XPath, XML
• VB.NET Custom Actions
• InstallShield, Help file
• Your InstallShield project file and Internet Explorer^[3]

The Idea

WiX and InstallShield are tools to make .msi packages, they all base on Microsoft Windows Installer technology. They all use .xml files to represent their project, where .xml is either handcrafted or auto-generated from parameters set from a graphic interface. So to build a bridge between the two, we seek XSLT for help.

Example

Your Binary table shall look similar to this.

<table name="Binary">
 <col key="yes" def="s72">Name</col>
 <col def="V0">Data</col>
 <col def="S255">ISBuildSourcePath</col>
 <row><td>ISLockPermissions.dll</td><td/><td>[ISProductFolder]\redist\Language Independent\i386\ISLockPermissions.dll</td></row>
 <row><td>ISSCHRPL.DLL</td><td/><td>[ISProductFolder]\redist\language independent\i386\isschrpl.dll</td></row>
 <row><td>ISSetup.dll</td><td/><td>[ISProductFolder]\redist\language independent\i386\ISSetup.dll</td></row>
 ...
</table>

Let's write a stylesheet to convert the above table to WiX format,

<?xml version="1.0" encoding="UTF-8" ?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output method="xml" indent="yes" />
    <xsl:template match="/">
        <xsl:for-each select="/table/row">
            <Binary>
                <xsl:attribute name="Id">
                  <xsl:value-of select="td[1]" /></xsl:attribute>
                <xsl:attribute name="SourceFile">
                  <xsl:value-of select="td[3]" /></xsl:attribute>
            </Binary>
        </xsl:for-each>
    </xsl:template>
</xsl:stylesheet>

The output shall look like,

<Binary Id="ISLockPermissions.dll" SourceFile="[ISProductFolder]\redist\Language Independent\i386\ISLockPermissions.dll" />
<Binary Id="ISSCHRPL.DLL" SourceFile="[ISProductFolder]\redist\language independent\i386\isschrpl.dll" />
<Binary Id="ISSetup.dll" SourceFile="[ISProductFolder]\redist\language independent\i386\ISSetup.dll" />

View the InstallShield Project

Your project is composed of tables. With the help of stylesheet written in is.xsl^[4], you could have a direct view of all these tables.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<?xml-stylesheet type="text/xsl" href="is.xsl" ?>

From InstallShiled MSI tables to WiX

One can search help files provided by WiX to study how it is really mapped. The following is an incomplete list collected while I was working on a migration project.

IS/MSI	WiX Element	Parent
ActionText	ProgressText	UI
AdminExecuteSequence	AdminExecuteSequence	Fragment
AdminUISequence	AdminUISequence	Fragment
AdvtExecuteSequence	AdvertiseExecuteSequence	Product
AppSearch	DirectorySearch	Property
Binary	Binary	Fragment
CheckBox	Control Type="CheckBox" CheckBoxValue=""	Dialog
Component	Component	Fragment, Directory
Control	Control	Dialog
ControlCondition	Condition	Control
ControlEvent	Publish	UI
CreateFolder	CreateFolder	Directory
CustomAction	CustomAction	Fragment
Dialog	Dialog	UI
Directory	Directory	Directoryref, Fragment
DrLocator	DirectorySearch	Property
Error	Error	UI
EventMapping	Subscribe	Control
Feature	Feature	FeatureGroup, Fragment
FeatureComponents	FeatureRef, ComponentRef, ComponentGroupRef	Fragment
File	File	Component
Font	File TrueType=yes	Component
ISString	String	WixLocalization
Icon	Icon	Shortcut
InstallExecuteSequence	InstallExecuteSequence	Product
InstallUISequence	InstallUISequence	UI
Property	Property	Product
RadioButton	RadioButton, RadioButtonGroup	Control
Registry	Registry	Component
ServiceControl	ServiceControl	Component
ServiceInstall	ServiceInstall	Component
Shortcut	Shortcut	Component
TextStyle	TextStyle	UI
UIText	UIText	UI
Upgrade	Upgrade, UpgradeVersion	Product

Footnote

1. WiX Toolset
2. Windows Installer Development Tools
3. Chrome will have problems viewing an .xml file referencing another .xsl file locally due to the cross-origin security issue.
4. By default, the stylesheet file should be at C:\Program Files (x86)\InstallShield\2011\Support\is.xsl
5. Github: IS2WiX