U.S. patent application number 10/966073 was filed with the patent office on 2005-04-21 for karaoke system with built-in camera.
This patent application is currently assigned to The Singing Machine Company, Inc.. Invention is credited to Lau, Kwok Piu, So, Kin San.
Application Number | 20050084835 10/966073 |
Document ID | / |
Family ID | 34465285 |
Filed Date | 2005-04-21 |
United States Patent
Application |
20050084835 |
Kind Code |
A1 |
Lau, Kwok Piu ; et
al. |
April 21, 2005 |
Karaoke system with built-in camera
Abstract
A karaoke system with built-in camera includes a decoder, a
camera system, and a video selector. The decoder (e.g., a CDG
decoder) receives data from a disc and provides a first video
signal having graphics, e.g., for lyrics of a selected song. The
camera system captures an image of a live scene and provides a
second video signal. The video selector combines the first and
second video signals to obtain a third video signal and can provide
the first, second, or third video signal (e.g., based on user
control) as an output video signal. A color eliminator can filter
out a designated frequency (e.g., for a designated color such as
blue) in the first video signal to provide a better output image
for the third video signal. The decoder and camera system are
synchronized with a common vertical timing signal and further use a
common oscillator signal.
Inventors: |
Lau, Kwok Piu; (Nt, HK)
; So, Kin San; (Nt, HK) |
Correspondence
Address: |
Truong Dinh
Dinh & Associates
2506 Ash Street
Palo Alto
CA
94306
US
|
Assignee: |
The Singing Machine Company,
Inc.
Coconut Creek
FL
|
Family ID: |
34465285 |
Appl. No.: |
10/966073 |
Filed: |
October 15, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60511851 |
Oct 16, 2003 |
|
|
|
Current U.S.
Class: |
434/307A ;
84/610 |
Current CPC
Class: |
A61P 43/00 20180101;
A61P 35/02 20180101; C07D 401/14 20130101; C07D 401/12 20130101;
A61P 15/00 20180101; A61P 35/00 20180101; C04B 35/632 20130101;
A61P 13/08 20180101 |
Class at
Publication: |
434/307.00A ;
084/610 |
International
Class: |
G10H 007/00 |
Claims
What is claimed is:
1. A karaoke system comprising: a decoder operative to receive data
from a disc and provide a first video signal having graphics
defined by the data; a camera system operative to capture an image
of a live scene and provide a second video signal; and a video
selector operative to combine the first and second video signals to
obtain a third video signal and to provide the third video signal
as an output video signal.
2. The karaoke system of claim 1, wherein the video selector is
operative to provide the first, second, or third video signal as
the output video signal based on a control signal.
3. The karaoke system of claim 1, further comprising: a color
eliminator operative to receive the first video signal, filter out
a designated frequency, and provide a filtered first video signal,
and wherein the video selector is operative to combine the filtered
first video signal with the second video signal to obtain the third
video signal.
4. The karaoke system of claim 3, wherein the designated frequency
corresponds to a designated color.
5. The karaoke system of claim 4, wherein the designated color is
blue.
6. The karaoke system of claim 1, wherein the decoder and the
camera system are synchronized based on a common frame
synchronization input signal that provides vertical timing for the
first and second video signals.
7. The karaoke system of claim 1, wherein the decoder and the
camera system use a common oscillator signal to generate color
subcarriers for the first and second video signals.
8. The karaoke system of claim 1, further comprising: a control
unit operative to enable the camera system to adjust white balance
of the image and disable the camera system from adjusting the
brightness of the image.
9. The karaoke system of claim 8, wherein the control unit enables
the camera system to adjust the white balance of the image when the
karaoke system is powered on and not playing a CDG disc.
10. The karaoke system of claim 1, further comprising: a first
amplifier operative to amplify the first video signal and provide
an amplified first video signal; and a second amplifier operative
to amplify the second video signal and provide an amplified second
video signal, and wherein the video selector is operative to
combine the amplified first and second video signals to obtain the
third video signal.
11. The karaoke system of claim 1, wherein the camera system is
implemented on a CMOS (complementary metal oxide semiconductor)
integrated circuit.
12. The karaoke system of claim 1, wherein the graphics on the
first video signal if for lyrics of a song.
13. The karaoke system of claim 1, wherein the graphics on the
first video signal are for graphics, pictures, symbols, or any
combination thereof.
14. The karaoke system of claim 2, wherein the control signal is
indicative of user-selection for the first, second, or third video
signal as the output video signal.
15. The karaoke system of claim 1, wherein the disc is a CDG
(compact disc+graphics) disc.
16. A method of providing an output video signal from a karaoke
system, comprising: processing data from a disc to obtain a first
video signal having graphics defined by the data; capturing an
image of a live scene with a camera system to obtain a second video
signal; combining the first and second video signals to obtain a
third video signal; and providing the third video signal as the
output video signal.
17. The method of claim 16, further comprising: filtering out a
designated frequency from the first video signal to obtain a
filtered first video signal, and wherein the filtered first video
signal is combined with the second video signal to obtain the third
video signal.
18. The method of claim 16, further comprising: enabling the camera
system to adjust white balance of the image for a particular
operating scenario; and disabling the camera system from adjusting
the white balance of the image after the particular operating
scenario.
19. The method of claim 16, further comprising: receiving a
user-selection for the first, second, or third video signal; and
providing the first, second, or third video signal as the output
video signal based on the user-selection.
20. An apparatus comprising: means for processing data from a disc
to obtain a first video signal having graphics defined by the data;
means for capturing an image of a live scene to obtain a second
video signal; means for combining the first and second video
signals to obtain a third video signal; and means for providing the
third video signal as an output video signal.
21. The apparatus of claim 20, further comprising: means for
filtering out a designated frequency from the first video signal to
obtain a filtered first video signal, and wherein the filtered
first video signal is combined with the second video signal to
obtain the third video signal.
22. The apparatus of claim 20, further comprising: means for
enabling the camera system to adjust brightness of the image for a
particular operating scenario; and means for disabling the camera
system from adjusting the brightness of the image after the
particular operating scenario.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of provisional U.S.
application Ser. No. 60/511,851, entitled "Karaoke System with
Built-in Camera," filed Oct. 15, 2003, which is incorporated herein
by reference in its entirety for all purposes.
BACKGROUND
[0002] The present invention relates generally to consumer
electronics, and more specifically to a karaoke system.
[0003] Karaoke singing has become a popular entertainment activity
in homes and commercial establishments throughout the world. A
karaoke system generates background music for a user-selected song
from a disc and allows one or more users to sing along with the
music via one or more microphones. The karaoke system mixes the
vocals from the users with the background music and provides an
output audio signal that contains a mixture of the user vocals and
the music. The output audio signal is typically played via a
speaker for listening pleasure of the users as well as any audience
that may have gathered for karaoke.
[0004] The karaoke system normally also has a video unit as well as
the audio unit. The video unit generates lyrics for the
user-selected song and displays the lyrics on a screen. This allows
the users to sing along, even if the users do not know the words to
the song, by scrolling the lyrics across the screen. The lyrics are
often highlighted in a manner to cue the users as to when each word
of the lyrics should be sung. The video unit may also receive or
generate pre-recorded graphics, video images, and/or video for
display along with the lyrics.
[0005] Since karaoke singing is a form of entertainment, it is
highly desirable to capture the excitement and enhance the
experience of users and audience gathered together for karaoke.
SUMMARY
[0006] A karaoke system with built-in camera is described herein.
This karaoke system can capture the excitement of a live scene with
the camera to enhance the experience of those gathered for
karaoke.
[0007] In a specific embodiment, the karaoke system comprises a
decoder, a camera system, and a video selector. The decoder (e.g.,
a CDG decoder) receives data from a disc and provides a first video
signal having graphics defined by the data. This graphics can be
for lyrics of a song selected by a user. The camera system, which
may be implemented on a Complementary Metal Oxide Semiconductor
(CMOS) integrated circuit (IC), captures an image of a live scene
and provides a second video signal. The video selector combines the
first and second video signals to obtain a third video signal and
can provide the first, second, or third video signal (e.g., based
on user control) as an output video signal. The decoder and camera
system are synchronized based on a common frame synchronization
input signal that provides vertical timing for the first and second
video signals. The decoder and camera system further use a common
oscillator signal to generate color subcarriers for their video
signals.
[0008] The karaoke system may further include a color eliminator,
amplifiers, and a control unit. The color eliminator receives the
first video signal, filters out a designated frequency (e.g., for a
designated color such as blue), and provides a filtered first video
signal. The amplifiers amplify the filtered first video signal and
the second video signal and provide amplified video signals, which
are combined by the video selector to obtain the third video
signal. The control unit provides various controls for video and
audio units within the karaoke system. For example, the control
unit may enable the camera system to adjust the brightness of the
image under certain conditions and otherwise disables the camera
system from adjusting the brightness.
[0009] Various aspects, embodiments, and features of the invention
are described in further detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 shows a perspective view of a karaoke system with
built-in camera;
[0011] FIG. 2 shows a functional block diagram of the karaoke
system;
[0012] FIG. 3 shows a schematic diagram of a noise filter and
amplifier and a color eliminator;
[0013] FIG. 4 shows a block diagram of a camera system;
[0014] FIG. 5 shows a schematic diagram of video buffers and a
video selector; and
[0015] FIG. 6 shows horizontal timing for a video signal generated
by the karaoke system.
DETAILED DESCRIPTION
[0016] The word "exemplary" is used herein to mean "serving as an
example, instance, or illustration." Any embodiment or design
described herein as "exemplary" is not necessarily to be construed
as preferred or advantageous over other embodiments or designs.
[0017] FIG. 1 shows a perspective view of an embodiment of a
karaoke system 100 with a built-in camera. Karaoke system 100 is
encapsulated in a casing that is dimensioned to be of a convenient
size and shape for ease of transport and placement. This allows
karaoke system 100 to be placed, for example, on top of a home
television, next to a computer monitor, in an entertainment system,
and so on. In general, karaoke system 100 may be of any form
factor, size, and shape.
[0018] Karaoke system 100 includes a CDG system 120 that can read a
CD (compact disc) disc or a CDG (CD+graphics) disc. A CD disc
contains only music. A CDG disc contains music as well as graphics,
which may be for lyrics of the songs contained in the CDG disc. The
lyrics may be read from the CDG disc and displayed on a blue (or
any other color) background in synchronization with the music. The
lyrics are also often highlighted in a manner to signal when the
words should be sung. A CDG disc, however, contains no moving video
in the background.
[0019] Karaoke system 100 further includes a camera system 130 that
can capture an image of a live scene. This live scene may be of a
person singing in front of the karaoke system, a gathering of
people in a room where the karaoke system is located, and so on.
Camera system 130 may be implemented in various manners. For the
embodiment shown in FIG. 1, camera system 130 is encapsulated in a
unit that may be flipped up to activate the camera system and
flipped down to hide and protect the camera system. Camera system
130 may also be mounted in other manners, and this is within the
scope of the invention. For example, camera system 130 may be
mounted (1) on a swivel so that the camera can be rotated to
capture scenes around the room or (2) on a ball joint so that the
camera can be pointed in any direction.
[0020] Karaoke system 100 has easily accessible knobs 142 for
various audio and video controls such as audio volume control,
left/right balance control, and so on. A display 146 provides a
simple display of the track number of the CD or CDG being played.
Input and output jacks 148 are provided on the side, in the back,
and possibly in the front (not shown in FIG. 1) for input and
output audio signals and input and output video signals. For
example, two microphone inputs may be provided on the side, and
output audio/video signals may be provided in the back.
[0021] FIG. 2 shows a functional block diagram of an embodiment of
karaoke system 100 with built-in camera. A controller 210 receives
various inputs (e.g., from knobs 142 and buttons 144) and provides
various controls for the processing units within karaoke system
100. A memory unit 212 provides storage for code and data used by
controller 210 and possibly other processing units within karaoke
system 100.
[0022] Within CDG system 120, a CD mechanism 220 reads data from a
CD disc or a CDG disc via a CD lens and provides disc data to a CD
servo system 222. CD servo system 222 processes the disc data and
provides various signals to other circuit blocks. For example, CD
servo system 222 provides CDG sub-code data to a CDG decoder 224.
The CDG sub-code data may include (1) a clock signal used by CDG
decoder 224 for decoding/decompression, (2) data for graphics in a
video signal, and (3) an SFSY signal that contains control data and
other information used for decoding/decompression. CD servo system
222 also provides left and right audio signals, A.sub.Lcdg and
A.sub.Rcgd, to an auto voice control (AVC) mute circuit 276.
[0023] CDG decoder 224 receives the CDG sub-code data from CD servo
system 222, decodes the CDG sub-code data, and generates a graphics
video signal, V.sub.cdg. The graphics video signal may contain, for
example, lyrics for a song in the CDG disc. In an embodiment, CDG
decoder 224 is implemented with integrated circuit (IC) chips and
additional circuitry. For example, these IC chips may include
Toshiba TC-9411F and Oki 514256C IC chips, which are commercially
available.
[0024] A noise filter and amplifier (Amp) 240 receives the
V.sub.cdg video signal from CDG decoder 224 and provides a filtered
and amplified graphics video signal, V.sub.lpf. The noise filter
removes digital noise in the V.sub.cdg video signal, which may be
generated by CDG decoder 224. The amplifier enhances the filtered
graphics video signal, which is reduced in amplitude after the
noise filtering.
[0025] A color eliminator 242 receives the V.sub.lpf video signal
and, when enabled by a CEenb control signal, removes (i.e.,
suppresses or eliminates) a designated color (e.g., blue) in the
V.sub.lpf video signal and provides a color-eliminated graphics
video signal, V.sub.ce. The V.sub.ce video signal has most of the
designated color removed. The V.sub.ce video signal is subsequently
merged with a camera video signal, V.sub.cam, from camera system
130 to obtain a composite video signal, V.sub.comp, as described
below. Removing the designated color from the V.sub.ce video signal
results in a better output image on a television screen for the
composite video signal. Color eliminator 242 provides a buffered
version of the V.sub.lpf video signal if it is not enabled by the
CEenb control signal. Thus, color eliminator 242 provides a
V.sub.ce/lpf video signal, which may be either the V.sub.ce video
signal (with the designated color removed) or the V.sub.lpf video
signal (without the designated color removed) depending on the
CEenb control signal.
[0026] A video buffer 244 receives the V.sub.ce/lpf video signal
from color eliminator 242, amplifies the V.sub.ce/lpf video signal
to obtain the proper signal level, and further buffers the
amplified video signal to provide the proper signal drive and
impedance level for a conventional television. Video buffer 244
also provides isolation and prevents video signals from flowing
backward. More specifically, when a first video signal is combined
with a second video signal, the video buffer for the first video
signal prevents the second video signal from flowing back to the
source of the first video signal, and vice versa. Video buffer 244
provides to a video selector 246 an amplified graphic video signal,
V.sub.buf, which may or may not have the designated color removed
depending on the CEenb control signal.
[0027] A buffer 226 receives an oscillator (OSC) signal and a frame
synchronization input (FSI) signal from CDG decoder 224. The OSC
signal is the clock signal used by CDG decoder 224 to generate the
color subcarrier and color bursts for the graphics video signal,
V.sub.cdg. The FSI signal is a vertical timing signal used by CDG
decoder 224 to generate the vertical video lines for the graphics
video signal. Since the graphics video signal from CDG decoder 224
and the camera video signal from camera system 130 are subsequently
combined into one video signal, these two units should be
synchronized with the same color carrier phase and line timing so
that the color and lines from these two units are aligned. For the
embodiment shown in FIG. 2, CDG decoder 224 is the master unit and
its OSC and FSI signals are also used by camera system 130 for
synchronization with CDG decoder 224. Buffer 226 amplifies each
signal to obtain the proper signal level, buffers each amplified
signal, and provides the buffered FSI and OSC signals, FSI' and
OSC', to camera system 130. In alternative embodiments, camera
system 130 may be the master unit and CDG decoder 224 may be slaved
to camera system 130, or another master unit may drive both CDG
decoder 224 and camera system 130.
[0028] When the camera is enabled, an automatic (auto) white
balance adjustment algorithm 230 within camera system 130
automatically adjusts the white balance of the image in the
V.sub.cam video signal generated by camera system 130. The auto
white balance adjustment may also be referred to as brightness
adjustment, intensity adjustment, and so on. This auto white
balance adjustment may be desirable if the camera video signal is
displayed by itself. However, the camera video signal may
subsequently be merged with the graphics video signal. If the auto
white balance adjustment is not disabled, then camera system 130
will perform the auto white balance adjustment continuously. In
that case, when the color of the graphics video signal changes, the
white balance of the image on the television screen will also
change and may cause the screen to become unstable. Since users are
normally annoyed by fluctuation in the intensity on the screen, the
auto white balance adjustment is disabled, for example, once the
karaoke system starts playing the CDG tracks.
[0029] A control unit 228 receives a CDG signal from CDG decoder
224 and controls the operation of color eliminator 242 and camera
system 130. The CDG signal indicates whether or not CDG decoder 224
is reading a CDG disc. CDG decoder 224 sets the CDG signal to a low
amplitude when CDG servo system 222 is reading a CDG disc and to a
high amplitude otherwise. If control unit 228 receives a low CDG
signal, indicating that a CDG disc is being read, then control unit
228 allows buffer 226 to provide the FSI signal to camera system
130, disables the auto white balance function of camera system 130,
and enables color eliminator 242 to remove the designated color
from the V.sub.cdg video signal. If control unit 228 receives a
high CDG signal, indicating that a CD disc or no disc is being
read, then control unit 228 prevents buffer 226 from providing the
FSI signal to camera system 130, enables the auto white balance
function of camera system 130, and disables color eliminator 242 so
that the designated color is not removed from the V.sub.cdg video
signal. When reading a CD disc that contains no graphics, the
camera output is provided as the video output and is not
superimposed on any graphics. When reading a CDG disc, the camera
output is superimposed with the graphics from the CDG disc, and the
auto white balance adjustment is disabled to prevent the screen
from changing rapidly and/or becoming too light or too dark. The
auto white balance adjustment function is enabled when karaoke
system 100 is first turned on until and unless a CDG disc is
read.
[0030] Auto white balance adjustment algorithm 230 adjusts and
calibrates the image device sensitivity on the primary (RGB) colors
to match the color cast of the light source. The auto white balance
adjustment is one of the built-in function of the CMOS IC for
camera system 130. The auto white balance adjustment algorithm
operates as follows. After karaoke system 100 is turned on or is
reset, the CMOS IC performs the auto white balance until it reaches
balance level. The CMOS IC continues to perform the auto white
balance when it is powered on and adjusts to changes in the light
level of the ambient area. The auto white balance function is
disabled if a CDG disc is played. If control unit 228 receives a
low CDG signal from CDG decoder 224, then control unit 228 sends
the appropriate control to disable the auto white balance function
within the CMOS IC. On the other word, when karaoke system 100 is
turned on and before a user starts to play a CDG disc, the auto
white balance function is enabled. Once the user starts to play a
CDG disc, the auto white balance function is disabled. When the
user stop to play the CDG disc, the auto white balance is enabled
again.
[0031] Camera system 130 includes a built-in camera and associated
video processing circuitry. The built-in camera has a lens that
captures an image of the scene in front of the camera. The video
processing circuitry then processes the image and provides the
V.sub.cam video signal, which contains the image captured by the
built-in camera. The V.sub.cam video signal is a composite video
signal with just the image captured by the built-in camera. Camera
system 130 may be implemented with a camera CMOS IC such as, for
example, an OV7910 or an OV7930 color CMOS analog camera chip from
Omni Vision (.TM.). The use of a CMOS camera chip for camera system
130 provides various benefits such as low cost, smaller area,
greater reliability, less power consumption, and so on.
[0032] A video buffer 234 receives and buffers the camera video
signal from camera system 130 and provides an amplified camera
video signal, V'.sub.cam. Video buffers 234 and 244 also provide
isolation between the V.sub.cam video signal and the V.sub.ce/lpf
video signal so that (1) the V.sub.ce/lpf video signal does not
feed through to the V.sub.cam video signal, when these two signals
are combined by video selector 246, and bleed into a Camera Out
output, and (2) vice versa.
[0033] A video selector 246 receives the V.sub.buf video signal
from video buffer 244 and the V'.sub.cam video signal from video
buffer 234. Video selector 246 provides an output video signal
(V.sub.out or Video Out) which may be (1) the graphics video signal
with the lyrics (i.e., the V.sub.buf video signal), (2) the camera
video signal with the image captured by built-in camera 130 (i.e.,
the V'.sub.cam video signal), or (3) the composite video signal
with both the lyrics and image (i.e., a V.sub.comp video signal).
The V.sub.comp video signal is generated by merging the V.sub.buf
and V'.sub.cam video signals. The determination of which video
signal to provide as the output video signal may be determined by a
user, by pre-configuration, and so on. Depending on a video
selection control signal, C.sub.sel, the output video signal may be
relatively static or may jump dynamically from video signal to
video signal.
[0034] The output video signal is typically connected to a
television so that the user can see on the television screen what
has been selected (e.g., lyrics, image, or both lyrics and image).
The camera video signal (or Camera Out) may also be provided to a
VCR (or DVD recorder) and used to record the image without the
lyrics.
[0035] Karaoke system 100 can superimpose the graphics video signal
from CDG decoder 224 on top of the camera video signal from camera
system 130. This allows the lyrics from a CDG disc to be displayed
on the image captured by camera system 130. The camera video signal
can capture the excitement of users and audience gathered within a
room for karaoke. Showing this captured image on a television
screen can enhance the experience of those in the gathering.
Superimposing the lyrics over the camera image can (1) allow the
singer(s) to see how he/she/they perform without missing the
lyrics, (2) allow the singer to read the lyrics and the audience to
see the live scene on the same screen at the same time, which can
bring extra fun to the karaoke experience.
[0036] The video and audio portions of karaoke system 100 is
described below. The video processing units within karaoke system
100 may be implemented in various manners. Exemplary designs for
these units are described below.
[0037] FIG. 3 shows a schematic diagram of an embodiment of noise
filter and amplifier 240 and color eliminator 242. Noise filter and
amplifier 240 includes an input buffer 310, a noise filter 320, and
an amplifier 350. The graphics video signal, V.sub.cdg, is provided
to the base of an NPN transistor 312. Noise filter 320 is
implemented with resistors 322 and 330, capacitors 324 and 328, and
an inductor 326, as shown in FIG. 3. Noise filter 320 removes
digital noise generated by CDG decoder 224. Two-stage amplifier 350
is implemented with an NPN transistor 352, a PNP transistor 362,
and resistors 354, 356, 358, 364 and 366, which are coupled as
shown in FIG. 3. The first stage has a gain determined by the ratio
of resistors 354 to 356. The second stage has a gain determined by
the ratio of resistors 366 to 364. Resistor 358 provides feedback
for the two stages to improve linearity.
[0038] Color eliminator 242 eliminates or suppresses the designated
color (e.g., blue) from the graphics video signal so that a clearer
picture with both the lyrics and image is displayed on the
television screen for the composite video signal, V.sub.comp. Color
eliminator 242 is implemented with an inductor 378 and capacitors
380 and 382, which are coupled as shown in FIG. 3. Inductor 378 and
capacitors 380 and 382 form a trap filter having a very low
impedance (almost ground) for certain frequency (e.g., the
designated color) and a nominal impedance for other frequencies
(other colors). The designated color may be blue or some other
color which may either be pre-set or adjusted by the user. The
resonant frequency of the trap filter is determined by the values
of inductor 378 and capacitors 380 and 382 and may be adjusted with
variable capacitor 380. The trap filter may be enabled by closing a
switch 376 and disabled by opening the switch with the CEenb
control signal. NPN transistor 372 and resistor 374 also provide
buffering for the V.sub.ce/lpf video signal, which may or may not
have the designated color removed.
[0039] FIG. 4 shows a block diagram of an embodiment of camera
system 130. A 2-dimensinonal array 410 of photodiodes converts
incoming light into charge. A row decoder 412 selects one row of
photodiodes at a time based on a control signal from a clock/timing
generator 440. Column sense amplifiers 414 convert the charges in
the selected photodiodes into voltages. An analog processing unit
420 processes the signals from sense amplifiers 414 and provides
component signals. For example, analog processing unit 420 may
perform color separation, automatic gain control (AGC), gamma
correction, black level calibration, aperture correction, luminance
and chrominance processing, filtering, and so on. A video encoder
430 converts the component signals from analog processing unit 420
into a composite video signal, which is provided as the camera
video signal, V.sub.cam.
[0040] Clock/timing generator 440 receives the buffered OSC and FSI
signals from buffer 226 and generates various controls for row
decoder 412, analog processing unit 420, and video encoder 430. A
control unit 450 receives the auto white control signal C.sub.abc
and possibly other input control signals and controls the operation
of analog processing unit 420 and video encoder 430. Control unit
450 implements auto white balance adjustment algorithm 230 and
adjusts the white balance under the specific IC pin setting. As
noted above, camera system 130 may be implemented with a CMOS
camera chip.
[0041] FIG. 6 shows the horizontal timing for a video signal
generated by karaoke system 100. In general, the video signal may
be an NTSC or PAL signal. For an NTSC signal, each horizontal line
of active video has the timing shown in FIG. 6. The vertical timing
for the video lines in the video signals from CDG decoder 224 and
camera system 130 is determined by the FSI signal. The color
subcarrier and color bursts are generated from the OSC signal and
has a frequency that is one quarter of the frequency of OSC
signal.
[0042] FIG. 5 shows a schematic diagram of an embodiment of video
buffers 234 and 244. Video buffer 234 is implemented with a PNP
transistor 522, resistors 512, 514, 524, and 528, and a capacitor
526, which are coupled as shown in FIG. 5. Resistor 514 provides
termination for the camera video signal from camera system 130,
which is designed to drive a standard television or video monitor.
PNP transistor 522 and resistor 524 implement an emitter follower
that buffers the camera video signal and drives subsequent
circuitry. Since the emitter of PNP transistor 522 is a low
impedance source, the V.sub.buf video signal is prevented from
flowing backward and affecting the V.sub.cam video signal.
Capacitor 526 and resistor 528 provides a source impedance for
video buffer 234.
[0043] Video buffer 244 is implemented with a PNP transistor 552,
capacitors 542 and 556, and resistors 544, 554, and 558, which are
coupled as shown in FIG. 5. Capacitors 542 and 556 provide AC
coupling. PNP transistor 552 and resistor 554 implement an emitter
follower that buffers the input video signal and drives subsequent
circuitry. Since the emitter of PNP transistor 552 is a low
impedance source, the V'.sub.cam video signal is prevented from
flowing backward and affecting the V.sub.ce/lpf video signal.
Resistor 558 provides a source impedance for video buffer 540.
[0044] FIG. 5 also shows an embodiment of video selector 246. Video
selector 246 receives the V.sub.buf video signal from video buffer
244 and the V'.sub.cam video signal from video buffer 234. Within
video selector 246, a summer 562 combines (or merges) the V.sub.buf
and V'.sub.cam video signals to obtain the composite video signal,
V.sub.comp. The V.sub.buf and V'.sub.cam video signals may also be
combined in other manners. For example, the V.sub.buf video signal
may be multiplexed as the output video signal for certain video
lines and the V'.sub.cam video signal may be multiplexed as the
output video signal for other video lines. A multiplexer 564
receives the V.sub.buf, V.sub.comp, and V'.sub.cam video signals
and the C.sub.sel video selection control signal from controller
210. Based on the C.sub.sel control signal, multiplexer 564
provides one of the three video signals as the output video signal,
V.sub.out.
[0045] Referring back to FIG. 2, karaoke system 100 also includes
an audio portion. A microphone amplifier 270 receives input audio
signals from two microphones, A.sub.m1 and A.sub.m2, amplifies each
input microphone signal, combines the two amplified microphone
signals, and provides a combined microphone signal, A.sub.m.
Microphone amplifier 270 may also be designed to receive one input
audio microphone signal, or to receive and combine more than two
input audio signals.
[0046] An echo system 272 simulates echo effect in the combined
microphone signal. This may be achieved by (1) delaying the
combined microphone signal by different amounts of delay to obtain
different delayed versions of the combined microphone signal, (2)
scaling the different delayed versions by different gains (e.g.,
lower gain for greater amount of delay) to obtain scaled and
delayed versions of the combined microphone signal, and (3)
combining the scaled and delayed versions to obtain an echo signal,
A.sub.e. Echo system 272 provides the echo signal having echo
effect. The echo effect may be turned off or reduced by getting the
gains for greater delays to zero or low values.
[0047] An AVC system 274 controls the combining of the combined
microphone signal, A.sub.m, from microphone amplifier 270 with the
left audio signals, A.sub.Rcdg, from CD servo system 222. When AVC
system 274 is activated and a microphone signal is received, AVC
system 276 mutes (partial mute, depended on the VR knob) the right
audio signal from CD servo system 222 so that the combined
microphone signal can be provided on the right audio channel. The
user can control the amount of muting by turning a knob (e.g., one
of knobs 142 in FIG. 1). AVC system 274 provides a mute control
signal, C.sub.avc, for muting the right audio channel for AVC.
[0048] AVC mute circuit 276 receives the echo signal, A.sub.e, from
echo system 272 and the left and right audio signals, A.sub.Lcdg
and A.sub.Rcdg, from CD servo system 222. AVC mute circuit 276
combines the echo signal with each of the left and right audio
signals and further mutes the right audio channel if directed by
the mute control signal. AVC mute circuit 276 provides A.sub.Ll and
A.sub.Rl audio signals.
[0049] A volume balance unit 278 receives the A.sub.Ll and A.sub.Rl
audio signals, adjusts the amplitude of each of the two audio
signals based on a balance control signal, C.sub.bal, and provides
adjusted left and right audio signals, A.sub.Lb and A.sub.Rb. The
user may manipulate the balance control signal (e.g., with one of
knobs 142 in FIG. 1) so that the left/right balance is suitably
adjusted.
[0050] A system mute circuit 280 receives the A.sub.Lb and A.sub.Rb
audio signals from volume balance unit 278 and mutes both audio
channels if indicated by a reset control signal, C.sub.reset. For
example, the audio signals may be temporarily muted when karaoke
system 100 is first powered on or reset. Mute circuit 280 provides
final right and left audio signals, A.sub.Lf and A.sub.Rf.
[0051] An audio buffer 282 receives and buffers the final left and
right audio signal from mute circuit 280 and provides an output
audio signal, Aux Out, for the left and right channels. A power
amplifier 284 also receives and amplifies the final left and right
audio signal from mute circuit 280 and provides a speaker output
signal, Speaker Out, for a speaker and an output audio signal,
Headphone, for a headphone jack. The amplification may be in
accordance with a loudness setting that may be adjusted by the
user.
[0052] The karaoke system described herein may be used with various
disc formats such as CD, CDG, SCDG, MP-3, DVD, and so on. Different
disc formats may be supported through the use of different
decoders. The other video processing units within karaoke system
100 (e.g., noise filter and amplifier 240, color eliminator 242,
buffers 234 and 244, and video selector 246) can perform the same
processing to provide the desired output video signal, regardless
of the disc format.
[0053] The karaoke system described herein may be implemented by
various means. For example, the video and audio processing units
for the karaoke system may be implemented in hardware, software, or
a combination thereof. For a hardware implementation, the
processing units may be implemented within one or more application
specific integrated circuits (ASICs), digital signal processors
(DSPs), digital signal processing devices (DSPDs), programmable
logic devices (PLDs), field programmable gate arrays (FPGAs),
processors, controllers, micro-controllers, microprocessors, other
electronic units designed to perform the functions described
herein, or a combination thereof.
[0054] Portions of the karaoke system may also be implemented in
software. For example, the controls for various processing units
may be implemented with modules (e.g., procedures, functions, and
so on) that perform the functions described herein. The software
codes may be stored in a memory unit (e.g., memory unit 212 in FIG.
2) and executed by a processor (e.g., controller 210).
[0055] The previous description of the disclosed embodiments is
provided to enable any person skilled in the art to make or use the
present invention. Various modifications to these embodiments will
be readily apparent to those skilled in the art, and the generic
principles defined herein may be applied to other embodiments
without departing from the spirit or scope of the invention. Thus,
the present invention is not intended to be limited to the
embodiments shown herein but is to be accorded the widest scope
consistent with the principles and novel features disclosed
herein.
* * * * *