Is The Optical Mouse Suitable For All Surfaces Computer Science Essay

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At first the scope of the investigation was limited to only the coefficient of reflectance at the theoretical angle of the reflected ray, however, after numerous test experiments this was found to be impractical. Surfaces of the materials never completely represented a perfect plane as there were small imperfections on the surface. So it was later decided, after more trial runs, to investigate the 'relationship between the level of specular reflectance of a surface and the sensitivity of an optical mouse functioning on that surface'. This investigation will determine the suitability for use of the optical mouse on a selection of surfaces or even mapping motion of paths generated from moving objects.

To investigate the relationship, the sensitivity of the mouse was tested on different surfaces with controlled variables such as the color, thickness, temperature and shape of the surface. The optical mouse was displaced by certain distance using a constant source of motion; together with software the displacement of the virtual cursor on the computer screen could be calculated.

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In order to investigate the reflectance properties of a surface a point laser was shone on the different surfaces. The light intensities at different angles were measured; allowing the calculation of the degree of specular reflectance. The specular reflectance was then compared to the virtual displacement of the mouse.

It was concluded that there was no direct relationship between the level of specular reflectance and the sensitivity of the mouse. This was supported by subsurface scattering, a property hard to control as it reflection in the subsurface of the material. Therefore the CMOS sensor in an optical mouse is unsuitable to be used a device for surfaces with multiple properties. However, research did demonstrate that most reflective surfaces are specular and that these are generally not suitable for optical mice.

2 - TABLE OF CONTENTS

1 - ABSTRACT 1

2 - TABLE OF CONTENTS 2

3 - INTRODUCTION 3

4 - THEORY AND BACKGROUND 4

4.1 - FUNCTIONING OF THE OPTICAL MOUSE 4

4.2 - REFLECTIVE PROPERTIES OF A SURFACE 6

5 - HYPOTHESIS 7

6 - DEVELOPMENT OF METHODOLOGY 8

6.1 - TESTING OF THE SURFACE 8

6.2 - TESTING OF THE OPTICAL MOUSE 10

7 - VARIABLES 11

8 - METHOD 12

8.1 - TESTING OF SURFACE DIFFUSION AND REFLECTANCE 12

8.2 - TESTING OF MOUSE SENSITIVITY 15

9 - DATA ANALYSIS AND PROPOGATION OF ERRORS 18

9.1 - SURFACE ANALYSIS 18

9.2 - MOUSE DISPLACEMENT ANALYSIS 20

10 - CONCLUSION 21

11 - EVALUATION 24

12 - ACKNOWLEDGEMENTS 25

13 - APPENDICES 26

13.1 - APPENDIX I 26

13.2 - APPENDIX II 27

13.3 - APPENDIX III 28

13.4 - APPENDIX IV 29

13.5 - APPENDIX V 30

14 - BIBLIOGRAPHY 31

3 - INTRODUCTION

Exploitation of the photoelectric effect has allowed countless users to displace an optical mouse in a certain direction on a flat 2-dimensional surface and see the cursor on the computer screen displace by a proportional number of pixels in the same direction, this is the function of the optical mouse. The increase in mobile computing, as well as the growth in use of the optical mouse, has revealed to a number of users the common problem for individuals who use optical mice on many different surfaces. Problems range from difficulties in precise cursor control to even the ability of moving the pointer on the graphical user interface (GUI). This suggested the fact that optical mice must be affected by surface properties.

If the relationship between the surface and the mouse is analyzed and properly applied there could be revolutionary change in the implementation of Complementary metal-oxide-semiconductors (CMOS) sensors in many technologies. This can range from the simple use of the optical mouse in controlled motion experiments, for example mapping the path of a toy car, to advanced innovative use in the development of cameras where CMOS sensors already lead CCD sensors [1] . The displacement of the optical mouse in physical reality and displacement of the cursor in virtual reality is proportional; otherwise it would prove extremely difficult to control an optical mouse. [2] However, it would also be interesting if one could find the proportions for an array of different surfaces.

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The Research Question of this essay is to investigate any 'relationship between the level of specular reflectance of a surface and the sensitivity of an optical mouse functioning on that surface'

4 - THEORY AND BACKGROUND

4.1 - FUNCTIONING OF THE OPTICAL MOUSE

The optical mouse like most other digital technologies relies on input and output. The input for the standard optical mouse is the red LED light which must be illuminated at an angle to the surface (Figure 1). The LED of the mouse is red because the CMOS sensor is most sensitive to red light. [3] Firstly, the light from the LED is shone onto a prism where it is reflected twice before reaching the surface where it is reflected again. The light that is reflected from the surface can be scattered by diffuse or specular reflection that occurs from irregularities in the material.

Light reflected from the surface, otherwise known as the input, is received by the CMOS sensor which sends the image recorded at that point in time to the digital signal processor (DSP) for analysis.

On a CMOS sensor, similar to a CCD sensor, there are many pixels which each can perform photon to electron conversion and then an electron to voltage conversion (Figure 2) [4] . The number of electrons produced is a function of the wavelength and the intensity of light striking the semiconductor [5] .The DSP compares these recorded images relative to another, finds the displacement between them, and moves the cursor respectively. The higher the sensitivity of the mouse the further the virtual cursor moves for every unit of distance moved by the real (physical) optical mouse. The words cursor and pointer are used interchangeably in this essay, but both mean the virtual 'Arrow' which is present in most GUIs.

4.2 - REFLECTIVE PROPERTIES OF A SURFACE

In order to comprehend the functioning of an optical mouse must also appreciate the phenomena resulting from the interaction of light on surfaces, mainly reflectance.

In total specular reflection the reflecting surface acts like an absolutely efficient mirror. This means that the surface will completely follow the law of reflection. The law of reflection states that the angle of incidence of a light ray is always equal to the angle of reflection when measured from the normal (), as can be seen in Figure 3.

In diffuse reflection the opposite effect occurs, instead when the light rays hits the surface the surface scatters them in random directions (Figure 4). As one would expect, rough surfaces with more irregularities and imperfections would be more diffuse than those with uniformly smooth surfaces. [6] 

5 - HYPOTHESESE

HYPOTHESIS I

Research on optical mice had presented to me that the displacement of the optical mice was related to the number of imperfections on a surface [7] . With a larger number of imperfections the CMOS sensor should be able to detect with a higher efficiency as it provides hotspots to compare an images. Therefore the more diffuse the surface the more efficient and sensitive the mouse should be. This is because imperfections in the surface are the main reason for diffuse reflection.

HYPOTHESIS II

However, the phenomena of surface diffusion showed that most surfaces do scatter light, as it is almost impossible to obtain a 100% efficient mirror. The scattered light might easily interfere with the reliability of the CMOS sensor's captured images. Therefore it can also be predicted that with a higher level of diffusion one can expect the mouse to work less efficiently as there is disruption in the input light rays.

6 - DEVELOPMENT OF METHODOLOGY

To ensure experimentation took place efficiently specialized equipment was carefully selected to accurately reproduce the phenomena which occur during the standard operation of the optical mouse. Throughout the experiment many aspects of experimental design were changed as they were encountered, these were to make the experiment reliable and accurate.

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6.1 - TESTING OF THE SURFACE

To test the intensity of light rays reflected from a surface, and thus determine the level of specular reflectance of the surface, there were some specifications made to ensure the imitation of an optical mouse.

Firstly, there needed to be a light source which acted like a red LED in a mouse. A Helium Neon Laser was obtained this released a beam of light with a suitable wavelength of 632.8nm [8] which is in the same range of wavelengths as a mouse LED [9] .

Secondly, a Phillip Harris Light Sensor Meter was chosen to measure the light intensity of the reflected rays. The Sensor Meter is able to detect wavelengths of 623.8mm from the Helium Neon Laser; this makes it suitable for the experiment. [10] 

Lastly, up to 12 surfaces were chosen to be tested. This was because of the unpredictable nature of the surfaces, as there is a high possibility that some of these surfaces will be excluded. The range of surfaces will also allow a range of results with reasonable intervals, that is enough to suggest a trend.

Initially, these were the only two pieces of equipment which were to be used to find the coefficient of reflectance of a surface (Figure 5).

However, after testing many materials this method proved to be fallible. Surfaces such as glass appeared to have a lower coefficient than paper, which was unexpected. Later it was found out that the reflected ray rarely was reflected at the theoretical angle, showing that adjusting the surface to act like a plane was difficult. Therefore the research question was changed to investigate the intensities at different angles (which is the current title) since a specified range of angles could be measured and this covers a larger area making the results more reliable.

In the end a spectrograph was chosen to be used for measuring the specular reflectance. This piece of equipment, although engineered for a completely different purpose, allows the light meter to be panned at different angles at equidistant positions.

Throughout the experiment other unanticipated factors such as light fluctuations throughout the experiment were firstly thought to be insignificant and negligible as the background radiation was to be subtracted from the recorded value. However after weather and time of day changed this did not make the experiment fair as the Sensor Meter was highly sensitive. Action was taken to black out the room by sticking black card onto the windows.

6.2 - TESTING OF THE OPTICAL MOUSE

To test the sensitivity of an optical mouse it was decided that the design of the experiment must allow the measurement of virtual displacement compared to the physical displacement of the optical mouse.

A Rosto T2 TravelPac optical mouse was selected for experimentation due to its relatively high 2400 dpi setting and low cost, the higher the dpi setting the more reliable the results will be as the CMOS will be able to detect minute imperfections [11] .

A foreseen problem when testing the sensitivity of the optical mouse was the reflected light from underneath the surface which could have resulted from unpredictable translucency of the material e.g. when placing plastic over wood some of the light escapes. However, it was known air an unreflective gas could not be detected by a CMOS sensor. This allowed air to be an ideal medium for which light rays could pass through without reflecting back. Referring back to Figure 1 on page 4 we can see that once the optical mouse is far above the surface all the reflected light will not reach the sensor. From the paper earlier we also know that mouse only needs to be displaced 1.25mm from the surface to not function, however a 2cm distance was used to ensure no light was reflected back into the CMOS sensor.

If the optical mouse were allowed to be displaced diagonally controlling the experiment would be problematic. To stop diagonal displacement direction controls were added. These were made from polished wood which helped reduce friction; they also helped create tension in surfaces to stop any deformation when a mass was present.

Friction from these controls and the surface were compensated by a 100g mass which was used to reproduce consistent motion, keeping the experiment fair. The recoil which occurred was solved by attaching a small sponge to a blocking mass in order to stop the mouse displacing in any unwanted directions.

7 - VARIABLES

The following variables and controls were used in the experiment. These were either deduced before the experiment or found from multiple trial experiments.

The independent variable of this experiment is the level of specular reflectance of a surface, the range of surfaces is what allows a range of independent variables. The dependent variable is the displacement of the pointer that occurs when the optical mouse is displaced.

7.1 - TESTING OF THE SURFACE

To keep the experiment fair the light levels in the room had to be controlled, this was done by using the same HeNe laser to emit light. The lights in the room were also turned off and black card was also taped onto all windows to prevent any light fluctuations.

The surface was controlled by keeping the thickness at 2cm as well as a constant shape and temperature. All the surfaces were also kept flat to make sure it replicated a perfect plane; otherwise it would significantly alter the angle of maximum intensity and create further problems. Furthermore, the light meter was also panned around the same angle range, ±45 degrees from the theoretical ray of reflection with 3 degree intervals.

7.1 - TESTING OF THE MOUSE

To control the testing of the mouse the same optical mouse was used in all experiments (TravelPac Rosto T2). The physical distance and direction in which the optical mouse was displaced was uniform, as well as the reproducible force.

By keeping the above variables controlled the correlation, if any, which exists, should be more easily recognized as these controls should inhibit any systematic or random error which might hinder the reliability and accuracy of the data.

8 - METHOD

After numerous trials and careful consideration of the variables and background influences a final method was drawn up.

8.1 - TESTING OF SURFACE DIFFUSION AND REFLECTANCE

APPARATUS

Spectrograph - this piece of apparatus should have cylindrical tunnels or other form of support firmly keep the light sensor meter and laser held firmly. All lenses should also be removed to stop interference with the light rays.

Helium Neon Laser - the helium neon laser should preferably have a wavelength of 630-650nm [12] and minimal fluctuations in recording.

Light Intensity Meter - this piece of apparatus should be able to measure all wavelengths and light intensities which can be produced by the laser.

METHOD

A spectrograph, helium neon laser (HeNe laser) and light intensity sensor should be obtained.

This HeNe laser should be carefully aligned so that the incident ray passes through the center of the spectrometer (Figure 6). Firstly, the center of the disc should be found, this can be located by drawing two chords joined from angles which are at opposite sides of the plate (180 degrees apart). Any small cylindrical object should then be placed at the intersection of these chords. The laser should then be adjusted accordingly and secured tightly so that the ray hits this small cylindrical object.

After calibration of the laser a plane surface of a certain material should be selected and placed in a precise position to allow the incident ray of the laser to penetrate it at a 45 degree angle (Figure 7). For example of the HeNe Laser is located at the 0 degree angle the material should be placed so that its edges are aligned with the 45 degree and 225 degree angle of the circle respectively. (The experiment conducted used the following materials: Corrugated Plastic, Glass, Plastic Block, Plastic Sheets, Plastic Bags, Mouse Pad, Paper, Cloth, Wood, Leather, Cardboard and a Folder)

The light sensor can then be placed directly 90 degrees anticlockwise from the laser to measure the light intensity at the theoretical angle.

The light sensor should then be panned at 3 degree intervals with light intensity being recorded at each interval. The panning should be completed for angles 45 degrees clockwise and anti-clockwise from the theoretical angle.

The process should be repeated for all twelve surfaces indicated. Movement of apparatus is significant and should be minimized unless necessary.

When the data is collected a value of the background radiation should also be collected to subtract from the intensity values obtained.

This experiment should ideally be conducted in a dark room or a room where light intensity does not fluctuate.

8.2 - TESTING OF MOUSE SENSITIVITY

APPARATUS

Optical Mouse - a TravelPac T2 Rosto was used, but essentially any optical mouse. Still, the mouse should not have standby mode also the higher the DPI the more reliable the results.

Frame - essentially can be made from anything as long as it is of similar shape, is at least 2cm thick and has a hole with larger dimensions than the optical mouse.

100g Mass

String, Tape

Table - or any other elevated surface.

Pulley

Padding - cloth, sponge, cotton as long as it withstands the impact.

A computer that can run HTML.

Another touchpad or optical mouse

METHOD

A setup, identical those shown in Figure 8 and Figure 9 should be assembled. (Further instructions below).

A frame like that in Figure 10 should be obtained.

The surface should be placed on the area of the frame where there is an air space present; this is indicated by the grey area on Figure 10. The surface should be suspended above the air space by means such as tape or masses which will stop it from deformation during the experiment.

String and tape should be used to attach the optical mouse and 100g mass together, the string should be around 70cm long (adjust if necessary)

A blocking mass of reasonable mass to withstand the force from the optical mouse. Padding should be attached to act as a shock absorber and prevent any recoil from the mouse.

A pulley should be placed perpendicular to the edge of the frame so that the string from the optical mouse is straight and does not undergo unnecessary friction.

The direction controllers should then be placed parallel with the optical mouse with only a 1mm margin to allow the mouse to move. These should be held securely to stop the mouse being displaced diagonally.

The mouse should be placed at its starting position where it is not moving, ideally where it is being stopped by the blocking mass. The position of the mouse should be marked. A ruler should then be used to mark a line 5cm from the starting position.

The mouse setting on the computer should be set to minimum speed and enhanced pointer precision should be disabled.

The code obtained from a JavaScript Coding site [13] should be used to identify the position of the mouse on the screen. The optical mouse should be moved to the desired position 5cm from the starting position and the X Y coordinates should be recorded. By using a touchpad or another mouse the virtual pointer should then be moved to a position where it can displace a large screen area. After the mouse is let go and displaces the new X Y should be recorded again.

This process should be repeated 10 times for each surface.

9 - DATA ANALYSIS AND PROPOGATION OF ERRORS

9.1 - SURFACE ANALYSIS

A table in Appendix II shows the light intensities at different angles for the range of surfaces. This data was plotted on Logger Pro, together with the integrator tool it was possible to calculate the sum of the light intensities for any material, and in this case it is the plastic bag (Figure 11).

The integral tool is then used again to find the light reflected at the peak or angle of maximum intensity with errors considered (±0.5 degrees) as shown below in Figure 12.

The level of specular reflectance (percentage) is then obtained by comparing the amount of light reflected at the peak angle of maximum light intensity to the total light reflected from the surface. This can be notated by the equation specular reflectance and values for reflected light at the peak angle and total light reflected.

To find the coefficient of reflectance at the theoretical angle the equation is used, where is the coefficient of reflectance and are the intensities of the reflected and incident rays respectively. Although most coefficients were relatively small, since the incident ray is fixed at 150,000 lux [14] , they are of similar magnitude and can be compared relative to each other.

The errors and uncertainties appreciated in this method are based on the Philip Harris Light SensorMeter which has an accuracy of 15%. Therefore for all results a 15% error will be considered.

The results from surface testing are shown in Appendix II.

9.2 - MOUSE DISPLACEMENT ANALYSIS

The displacement of the cursor on the screen was calculated using Pythagoras's theorem. Using the X and Y coordinates recorded on the screen the displacement was calculated using the formula below.

This is illustrated by Figure 13.

To propagate the errors resulting from the uncertainties of pointer position the smallest unit of measurement was used, i.e. 1 pixel. Though, when finding displacement there needs to be two positions which are considered, both of these positions have a possible uncertainty of 1 pixel. If there are two positions then the displacement can have an uncertainty of ±2 pixels.

This uncertainty is used to find a percentage error for each result by using the equation.

The percentage uncertainties of the ten results are then averaged as well as the values for displacement. The final value for displacement will be the <Average Displacement> ± <Average Percentage Uncertainty>

10 - CONCLUSION

Data obtained from the graph of 'Graph showing the displacement in pixels of the optical mouse on different materials' gave the general observational idea that materials which were transparent in nature, i.e. the glass and plastics, were not ideal for the functioning of an optical mouse, this is because of the relatively low displacement of the mouse on those surfaces. Other unexpected anomalies included the corrugated plastic board which appeared white and opaque in nature however the mouse displacement on this surface was minimal; this can probably be explained by its uniform surface. Another significant difference was noticed in the small dip in the displacement of the mouse pad which should have been engineered for good performance. Surfaces which were opaque in nature all performed similarly well, which further hints that there will be no linear relationship.

After analysis was conducted on the Graph showing the relationship between the level of specular reflectance of a surface and the virtual mouse displacement it can be concluded that there is no direct relationship between the level of diffusion of the material and the displacement of an optical mouse. Even when the error bars are considered or some data points are excluded( mouse pad, cloth and plastic bag) there is only a weak correlation that is present. Furthermore, the correlation produced is also not at a suitable range, in other words the data points are in clusters and need to be spread out more at multiple intervals to be considered as a trend. Since there is no direct relationship this implies that motion sensing on surfaces with multiple properties is not possible.

This weak trend can probably be explained with subsurface scattering. In subsurface scattering incident light penetrates into the material where it is scattered from within due to being reflected by the particles. This is not directly caused by irregularities in the surface, since the CMOS detection is dependent on detection of these irregularities. The subsurface scattering interferes with the diffusion resulting from the irregularities. [15] This partially agrees with Hypothesis II which predicts that diffusion will interfere with functionality of the mouse, but for the completely wrong reason.

Further analysis of the obtained data was conducted to determine any further relationships which could have possibly been related to the displacement of the optical mouse. This included the coefficient of reflectance, location of maximum intensity and total intensity however no suggestions of any relationships were found.

As can be seen from the possible surface properties, an optical mouse is not suitable for use on all surfaces.

11 - EVALUATION

Most of the problems in this investigation resulted from the systematic errors which occurred. One of the significant problems was color. Although only materials with white surfaces were chosen the required equipment to determine the color content of the surfaces was not available. This could have resulted in unknown amounts of light absorbance which could potentially have an effect, however, as stated before the number of electrons produced is a function of the wavelength and the intensity of light striking the semiconductor so are unlikely to be relevant [16] .

Random errors were only present in some materials with less non-uniform surfaces such as the plastic bag which often contained imperfections on the surface. This could be improved by selecting a better array of surfaces, flattening the surfaces with immense pressure or apply tension to the surfaces. This must be planned carefully as it the action itself could change the properties of the surface.

Although calculating the area under the graph was used to find the level of specular reflectance this method could be criticized because intensity was recorded at 3 degree intervals. The light intensity of the HeNe Laser itself also fluctuated at times which could have made results unreliable, this could be fixed by repeating the process. The laser beam was also not singular point but a 0.15mm radius circle which was measured using a precise ruler. The non-singular point laser can radically affect the specular reflectance, this is because there will be multiple reflected rays of light reflected from the surface. This might have caused a specular surface to imitate diffuse surface properties.

Another flaw in this experiment is the magnitude of equipment, CMOS sensors operate on a much smaller scale than rulers (which were used for measurement in this specific experiment) although a weak trend was established. If this measuring equipment and possibly the reproducible force were more precise then any relationship, if any, could be confirmed with higher assurance.

12 - ACKNOWLEDGEMENTS

This particular topic for the Extended Essay has been most challenging but truly worthwhile endeavor. I sincerely thank my Extended Essay supervisor Mr. Andrew Roff and other physics teachers who have given me advice and guidance to me throughout the way. My thanks are also given to my friends and family who have also supported me throughout the experimental process which has resulted in the great amount of data which has been collected.

13 - APPENDICES

13.1 - APPENDIX I - JavaScript Source Code

JavaScript Source Code from http://javascript.internet.com/page-details/mouse-coordinates.html used to identify the coordinates of the pointer on the computer screen.

<!-- ONE STEP TO INSTALL MOUSE COORDINATES:

1. Copy the coding into the BODY of your HTML document -->

<!-- STEP ONE: Paste this code into the BODY of your HTML document -->

<BODY>

<form name="Show">

X <input type="text" name="MouseX" value="0" size="4"><br>

Y <input type="text" name="MouseY" value="0" size="4"><br>

</form>

<script language="JavaScript1.2">

<!-- Original: CodeLifter.com (support@codelifter.com) -->

<!-- Web Site: http://www.codelifter.com -->

<!-- This script and many more are available free online at -->

<!-- The JavaScript Source!! http://javascript.internet.com -->

<!-- Begin

var IE = document.all?true:false;

if (!IE) document.captureEvents(Event.MOUSEMOVE)

document.onmousemove = getMouseXY;

var tempX = 0;

var tempY = 0;

function getMouseXY(e) {

if (IE) { // grab the x-y pos.s if browser is IE

tempX = event.clientX + document.body.scrollLeft;

tempY = event.clientY + document.body.scrollTop;

}

else { // grab the x-y pos.s if browser is NS

tempX = e.pageX;

tempY = e.pageY;

}

if (tempX < 0){tempX = 0;}

if (tempY < 0){tempY = 0;}

document.Show.MouseX.value = tempX;

document.Show.MouseY.value = tempY;

return true;

}

// End -->

</script>

<p><center>

<font face="arial, helvetica" size"-2">Free JavaScripts provided<br>

by <a href="http://javascriptsource.com">The JavaScript Source</a></font>

</center><p>

<!-- Script Size: 1.33 KB -->

13.2 - APPENDIX II - Light intensity at different angles for all surfaces

13.3 - APPENDIX III

The following is an example of the table of results for the mouse displacement on the surface cardboard.

X1 (± 1 Pixel)

Y1 (± 1 Pixel)

X2 (± 1 Pixel)

Y2 (± 1 Pixel)

δX (± 2 Pixels)

δY (± 2 Pixels)

Projected Displacement (No Error)

149

421

152

609

3

188

188

142

452

147

644

5

192

192

140

551

147

740

7

189

189

138

614

145

794

7

180

180

138

700

144

890

6

190

190

135

720

140

908

5

188

188

135

782

141

973

6

191

191

129

819

138

1012

9

193

193

134

920

140

1111

6

191

191

152

856

158

1044

6

188

188

δX Minimum

δX Maximum

δY Minimum

δY Maximum

Displacement Minimum

Displacement Maximum

1

5

186

190

186

190

3

7

190

194

190

194

5

9

187

191

187

191

5

9

178

182

178

182

4

8

188

192

188

192

3

7

186

190

186

190

4

8

189

193

189

193

7

11

191

195

191

195

4

8

189

193

189

193

4

8

186

190

186

190

Average

187

191

Displacement =

189

±

1.1

%

13.4 - APPENDIX IV

The following is an example of the table of results for the light intensity at different angles for the surface leather.

Angle from Reflected Ray (degrees)

Light Intensity (lux) ± 15%

-45

0.9

-42

0.9

-39

0.9

-36

0.9

-33

0.9

-30

0.9

-27

1.0

-24

1.0

-21

1.2

-18

1.3

-15

1.4

-12

1.4

-9

1.4

-6

1.8

-3

1.8

0

2.3

3

2.8

6

3.6

9

4.4

12

3.7

15

3.6

18

2.8

21

2.7

24

2.3

27

1.7

30

1.4

33

1.0

36

0.9

39

0.9

42

0.9

45

0.9

13.5 - APPENDIX V

The following is a table which summarizes the significant processed data.

Surface

Intensity at Peak Angle ± 15%

Total Intensity ± 15%

Percentage (%) of Specular Reflectance

Displacement (Pixels)

Percentage (%) Error of Displacement

Absolute Pixel Error

Plastic Board

18.91

466.9

4.05

3

10.8

0.3

Glass

9.204

175.5

5.24

5

35.1

1.8

Hard Plastic

120.8

796.8

15.16

16

13.3

2.1

Soft Plastic

76.39

480.3

15.90

28

7.6

2.1

Plastic Bag

61.52

571.4

10.77

42

5.0

2.1

Mouse Pad

4.14

158.1

2.62

109

2.0

2.1

Paper

6.085

448.9

1.36

167

1.2

2.1

Cloth

5.666

310.8

1.82

181

1.2

2.1

Wood

17.85

606.9

2.94

183

1.1

2.1

Leather

8.808

370.1

2.38

184

1.1

2.1

CardBoard

4.734

371.2

1.28

189

1.1

2.1

Folder

5.532

389.4

1.42

190

1.1

2.1