METHOD AND SYSTEM FOR AN ADAPTIVE AND AUTOMATIC
BRIGHTNESS CONTROL MECHANISM
FIELD OF THE INVENTION
The present invention pertains to a method and system for a fuzzy adaptive
brightness control mechanism for an electronic device having a display screen
and particularly to computer display devices.
BACKGROUND OF THE INVENTION
Electronic devices and technical gadgets are fast replacing conventional
equipment in varied aspects ranging from useful work to entertainment. They are
being used as simple devices in homes to complex ones in industries and offices.
Their growth trend in the past few years with the advancement in technology has
been remarkable.
The computer is perhaps the most popular and widely used electronic device.
These versatile machines are capable of performing a huge range of tasks. As a
result, they are present in homes as well as offices and industries. In most jobs
the usage of computers stretches from 8 to 9 hours a day.
Also several other devices are being increasingly used for different purposes. In
order to be more user friendly and interactive these gadgets have a display
screen. Also, these devices are used in a dynamic environment with varying light
conditions. As a result, the brightness of the screen if not set correctly can
produce glare. This glare can further cause eye irritation and strain, stress and
even headaches. Also, use of more illumination i.e. more brighntess than
required is expensive and energy inefficient.
There have been several solutions to this problem devised in the past. One of
them is anti - glare screens. These screens have an anti - reflective optical
coating designed to reduce the amount of external light reflecting from the
surface without affecting light emanating from the display thus reducing glare.
They are mounted onto the display unit of the device. But as a disadvantage,
anything between the user and the screen compromises the quality of the image.
Hence, they do not serve a useful purpose.
Another conventional approach to solve this problem is by adjusting the
brightness of the display with respect to the ambient light by including photo
detectors to adjust the brightness or to turn a backlight on or off. But the
drawback of this approach is that there is a fixed brightness range, which does
not always provide a comfortable viewing experience for the user.
Another different approach is to give the user manual control of repeated
adjustment of the display device's brightness. But the setback of this approach is
that it is bothersome and hectic and is satisfactory only for conscientious users
who regularly monitor the brightness settings and manually adjust them
accordingly.
US patent number 6947017 states a system and method to set dynamic
brightness range for portable computer displays based on ambient conditions. It
describes dynamically adjustable brightness range settings and a brightness
control mechanism for providing improved user readability and prolonged
component lifetime of the display screen. It can change the range settings based
on ambient light conditions or the user can perform the changes. The brightness
level of the display changes according to a user selected setting within the range
selected. The time required to implement the brightness change can beset to a
value which can be configured by the user.
US patent number 5760760 describes an intelligent LCD brightness control
system. It includes a method and apparatus for automatically adjusting the
brightness level of an LCD based on the ambient lighting conditions of the
environment in which the LCD is being operated. The ambient light signals are
corelated to predetermined automatic brightness control values for use in
controlling the brightness level of the LCD. Once the ambient light signals have
been used automatically to set the brightness level of the LCD, user-selection of
a different brightness level, either higher or lower, will override the automatic
brightness control setting. It may make use of more than one light sensors to
receive the input values pertaining to the ambient light signals. It also may
comprise of some form of artificial intelligence for "learning" a user's preferred
brightness level, or range of brightness levels, in various ambient lighting
conditions.
US patent number 5933130 states an anti-eye strain apparatus and method. The
invention automatically adjusts the brightness of a display to cause the muscles
of the eyes of the user to adjust and refocus such that eye fatigue or tiredness is
reduced or eliminated. The brightness is varied within a particular range and the
brightness within this range is occasionally or periodicaly adjusted. The changing
brightness preferably follows a predetermined pattern or cycle. These brightness
changes may be perceptible or imperceptible to the viewer. The brightness of the
display may be adjusted electronically or mechanically. Howvere, this invention
does not take into account the ambient light conditions or the task window colour.
It purely changes the brightness level based on some predetermined pattern.
US patent number 6094185 describes an apparatus and method for
automatically adjusting computer display parameters in response to ambient light
and user preferences. The apparatus automatically adjusts, in accordance with a
set of user preferences, a computer display parameter, such as brightness or
contrast, in response to ambient light conditions. The apparatus includes an
ambient light sensor to obtain an ambient light signal. A mapping mechanism,
connected to the ambient light sensor, maps the ambient light signal to a user
preference value in a user preference table. Computer display control circuitry,
connected to the mapping mechanism, then adjusts the selected computer
display parameter of the computer display in response to the user preference
value.
None of the above-cited patenst take the colour of the application window in the
display screen into consideration. The colour of the application window of the
display screen is an important factor that effects the brightness and glaring effect.
Hence, there is a need for a system that takes into consideration both the room
lighting and the colour of the background of the display screen as factors to set
the brightness of the screen. In this manner, optimal eye comfort and strain free
viewing of the display device can be achieved. Also, the brightness setting
feature must be user adaptive so that the user should be able to override the
auto - adjusted brightness setting if he is not satisfied with it. Further, this
change should be recorded for updating the settings for this set of inputs.
Additionally, to avoid user discomfort, the switching between the two brightness
values on each adjustment should be smooth enough to avoid sudden brightness
change.
The system should further take inputs based on criteria most comfortable to the
user. For instance, the HSV (Hue, Saturation, Value) model, also known as HSB
(Hue, Saturation, Brightness) defines a colour space. HSV is preferred over RGB
or CMYK, because of its similarities to the way humans tend to percieve colour.
RGB and CMYK are additive and subtractive models, respectively, defining
colour in terms of the combination of primaries, whereas HSV encapsulates
information about a colour in terms that are more familiar to humans. Hue (H)
represents colour space, Saturation (S) represents amount of whiteness i.e.,
purity of colour and Value (V) represents brightness. For brightness to be
adjusted, the Saturation and Value values are required from the HSV space. If
the V value of the display is high, the purity is high and accordingly, the
brightness should be lessened to avoid sharp colours.
Further, the system must also use a technique to set the brightness which is
close to human behaviour. As human beings make decisions based on rules,
fuzzy machines, which always tend to mimic the behaviour of man, work the
same way. However, the decision and the means of choosing that decision is
replaced by fuzzy sets and the rules are replaced by fuzzy rules. Fuzzy rules also
operate using a series of if - then statements.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the instant invention to obviate the above drawbacks and
provide a method and system for an automatic and adaptive mechanism for
controlling the brightness of a display device. ,_
It is another object of the instant invention to provide a means to override the
auto - adjusted brightness setting.
It is further an object of the instant invention to provide a means to enable or
disable this feature or to manipulate the settings deciding the factors to adjust the
brightness.
It is yet another object of the instant invention to provide a smooth mechanism for
switching between two brightness values to avoid sudden brightness change and
user discomfort caused therefore.
To achieve the aforementioned objectives, the instant invention provides a
method and system to automatically alter the brightness setting of the display
device by continuously monitoring the ambient light conditions and the
background colour. These factors form the basis of the brightness setting and are
applied to a fuzzy adaptive program to calculate it.
The user as required can override this setting by using the increment and
decrement buttons provided to him in the graphical user interface. These
changes are recorded by the system to accordingly update the corresponding
fuzzy rule making the system user adaptive. This auto - adjustment feature may
be enabled or disabled as required or enabled with specific settings such as
setting the brightness depending only on the ambient light conditions and not on
the background colour. Also, the system makes sure that user discomfort is
avoided by making a smooth transition between two brightness values thereby
preventing sudden brightness change.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG 1 is a block diagram explaining the system and the working of the
instant invention
• FIG. 2 defines a flowchart depicting the basic operation of the instant
invention
• FIG. 3 defines a flowchart depicting the operation of overriding an auto
adjusted brightness value
DETAILED DESCRIPTION OF THE INVENTION
The instant invention provides a dynamic adaptive auto-adjustment of brightness
through a fuzzy adaptive program that can be implemented on any electronic
device having a display screen such as a cell phone, remote control device or a
mobile computer system. The invention has been explained here with the help of
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a personal computer system. However, it is not restricted to this implementation.
It can be used with any display device after modifying the configuration settings.
For the instant invention, a light intensity measuring device such any equipment
witFi a light dependent resistor (LDR) as a sensor to read the ambient light
intensity information is provided connected to the computer's input port via a
standard interface cable. The lux values from the light intensity-measuring device
are received via the interface cable coupled to the input port of the computer.
The said light intensity-measuring device is coupled to the cable via an analog to
digital converter (ADC) to convert the analog signal from the device to digital
output to send to the computer.
Figure 1 shows the system for implementing the instant invention. The system
includes a light intensity-measuring device (101). An analog to digital converter
(102), a port reader module (103), a screenshot analyzer module (104), a fuzzy
classifier module (105) and a display device (106).
The light intensity-measuring device (101) includes a sensor that is used to read
the ambient light intensity information from the surroundings. It continuously
monitors the ambient light conditions and generates a signal in response thereto.
It sends this signal to the ADC (102).
The analog to digital converter (102) receives the light intensity signal, i.e. analog
lux value from the light intensity measuring device (101) and converts this analog
input to digital output i.e. digital lux value to be given to the device containing the
display unit via an interface cable such as a bus coupled to the parallel port of a
computer. The digital lux is received is received as input at the interface cable
and given to the port reader module (103) via the parallel port.
The port reader module (103) is responsible for reading the values fed into the
parallel port and converting it to values usable by the processor. This digital lux
value received is then an input to the fuzzy classifier module (105).
The screenshot analyzer module (104) periodically analyzes the HSV (Hue,
Saturation, Value) colour space values for a set of pixels present in the
screenshot of the dynamic display device. The brightness is set on the basis of
the master HSV colour space values corresponding to the HSV of a pixel
intensity mostly distributed on the screenshot and the background colour.
Screenshots are captured pragmatically at regular intervals of time accompanied
by the computation of HSV values corresponding to RGB values for a set of
pixels.
The fuzzy classifier module (105) obtains an optimum brightness value
depending upon the inputs it receives. It allows for dynamic and adaptive autoadjustment
of display brightness. It follows the fuzzy rules as defined such as if
the room is dark, the brightness should be less and vice versa. Also, if the
background is bright the brightness should be less and vice versa. The lux value
and/or master HSV values are fed into the fuzzy classifier module (105) to obtain
an optimum brightness value to be set. If the user is not satisfied with the autoadjusted
brightness, this value can be overridden using the controls provided.
Accordingly, the fuzzy rule corresponding to the said input lux value and/or
master HSV value is updated making the system user adaptive. Hence the next
time for the same inputs the user-adjusted brightness is set.
The computed brightness is then set for the display screen. The user can choose
to auto-adjust the brightness according to the ambient light surroundings or the
background colour or both. He may further alter the auto-set brightness, which
will also update the system's technique of setting the brightness.

We claim:
1. A method for automatic adjustment of the display brightness of a dynamic
display device by responding to changes in ambient light conditions and
background colour, said method comprising the steps of:
- obtaining periodically the lux value and the master HSV (hue,
saturation, value) colour space values from the screenshot of the
display device
- obtaining an optimum brightness value by applying the obtained lux
value and master HSV values to the fuzzy classifier; and
- setting the optimum brightness value for the display device
2. A user adaptive method as claimed in claim 1, wherein the optimum
brightness level set by the system, can be modified by the user,
comprising the steps of:
- allowing the user to override the auto adjusted brightness setting using
increment and decrement graphic buttons on the graphical user
interface
- altering the brightness level as specified by the user; and
- updating the fuzzy rule corresponding to the input lux value and / or
master HSV value range to revise the overridden brightness value so
that next time for the same inputs user adjusted brightness is set
3. A method as claimed in claim 1, to obtain the master HSV colour space
values, consisting the steps of
- capturing screenshots pragmatically at regular intervals of time
- obtaining the pixel intensity mostly distributed on the screenshot by
analyzing the pixels of the screenshot
- computing the HSV values corresponding to RGB values for a set of
pixels
4. A method as claimed in claim 1, wherein the optimum brightness value is
obtained via a fuzzy classifier comprising the steps of:
- applying the obtained lux values and / or the master HSV colour space
values to the defined fuzzy rules
- obtaining thereby a fuzzy set using the fuzzy rules defined
- obtaining thereby a single brightness value using a defuzzification
technique such as standard set of gravity (COG) method
5. A method as claimed in claim 1 is device independent
6. A method as claimed in claim 1, wherein the switching between the two
brightness values on each adjustment is smooth enough to avoid sudden
brightness change
7. A method as claimed in claim 1, wherein the brightness of the display
device is auto adjusted within the brightness range of the display device
8. A method as claimed in claim 1, wherein a text file is maintained in the
memory of the gadget consisting the display device to store the fuzzy
rules with each row representing a fuzzy rule and the corresponding
output brightness value
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9. A method as claimed in claim 2, wherein the auto adjusted brightness
setting can be overridden using the increment and decrement graphic
buttons on the graphical user interface and the brightness is increased or
decreased by specified units each time the corresponding button is clicked
10.A method as claimed in claim 2, wherein the user is provided with the
option to enable or disable the automatic brightness setting feature or to
enable it depending only on the ambient light conditions or only on the
background colour, as a drop down menu in the graphical user interface
as claimed in claim 2 and setting the chosen option
11. A method as claimed in claim 5, wherein the fuzzy rules are defined on
fuzzy sets which are defined on lux value, saturation value and V value of
the dominant pixels in the current task window snapshot
12. A system for automatic adjustment of the display brightness of a dynamic
display device by responding to changes in ambient light conditions and /
or background colour, comprising:
- an interface cable coupled to the input port of the gadget comprising
the display device to connect the light intensity measuring device to the
gadget comprising the display unit and give the lux values pertaining to
the surrounding ambient conditions
- a light intensity measuring device to read the ambient light intensity
- the gadget comprising the display unit whose brightness is to be set
- the fuzzy classifier which takes inputs and accordingly sets the
brightness of the display unit
13.A system as claimed in claim 12, wherein the light intensity measuring
device comprises:
- an analog to digital converter (ADC) to convert analog output from the
light sensor to digital output
- a light sensor coupled to the ADC for providing light intensity signal to
the gadget
14.A system as claimed in claim 12, wherein the lux value is obtained from
the light intensity measuring device through the interface cable coupled to
the input port of the gadget comprising the display device
15.A system as claimed in claim 12, wherein the system is user adaptive
since the user is able to override an auto adjusted brightness setting if he
is not satisfied with it
16.A system as claimed in claim 12, wherein only the Saturation and Value
values of the HSV values of the pixels are used from the captured
screenshots
17. A system as claimed in claim 12, wherein the brightness value is set using
fuzzy logic
18. A system as claimed in claim 12, wherein the fuzzy rules are stored in a
text file maintained in the memory of the gadget comprising the display
device