Television – Image signal processing circuitry specific to television – Noise or undesired signal reduction
Reexamination Certificate
1999-10-18
2002-07-23
Miller, John W. (Department: 2714)
Television
Image signal processing circuitry specific to television
Noise or undesired signal reduction
C348S616000, C348S620000, C348S701000
Reexamination Certificate
active
06424382
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an error picture image data correction apparatus for correcting error data of the picture image signals outputted from a video camera etc. that employs a solid image capturing device. transmission and signal data processing are included in the picture image data of the audio visual apparatus such as a VCR, a video disk, a scanner and a camera, even though the error is about only one pixel, the picture quality may be remarkably deteriorated.
2. Description of the Art
When error data unintentionally generated in the process such as data transmission and signal data processing are included in the picture image data of the audio visual apparatus such as a VCR, a video disk, a scanner and a camera, even though the error is about only one pixel, the picture quality may be remarkably deteriorated.
Especially in case that the camera includes defective pixels in the image capturing device, the picture quality will be remarkably deteriorated because those error data are always generated and included in the output picture signals in the same fixed position corresponding to the defective pixels.
Especially in case that the camera includes defective pixels in the image capturing device, the picture quality will be remarkably deteriorated because those error data are always generated and included in the output picture signals in the same fixed position corresponding to the defective pixels.
In recent years, a solid image capturing device, especially a charge coupled device (hereinafter referred to as “CCD”) is widely used as an image capturing device. However, the CCD has difficulty in the manufacturing process. Defective pixels are easily generated in the CCD pixels. Therefore, it is difficult to achieve enough high yields in the current CCD manufacturing technology. Considering the manufacturing cost, even though a manufactured CCD has some defective pixels, it will be employed as a product with an error picture image data correction apparatus for correcting the error data corresponding to the defective pixels.
As the conventional error picture image data correction apparatus, the apparatus disclosed by the unexamined Japanese patent application Tokkai-Hei 9-284783 is known.
FIG. 5
is a block diagram that shows the configuration of the error picture image data correction apparatus of the above-mentioned application. In
FIG. 5
,
100
a
,
100
b
and
100
c
are input terminals in which each digital video signal corresponding to each R, G and B color channel is inputted respectively,
5011
,
5021
and
5031
are delay elements that delay the inputted R, G and B signal data from input terminal
100
a
,
100
b
and
100
c
for one data period, and the delay elements are composed of D flip flop. Each output signal of these delay elements
5011
,
5021
and
5031
is inputted to the output switch circuit
111
and the selector
108
respectively.
5012
,
5022
and
5032
are delay elements that delay the output signal data from the delay element
5011
,
5021
and
5031
for one data period, and the delay elements are composed of D flip flop.
5013
,
5023
and
5033
are adders for adding each R, G and B signal inputted from input terminals
100
a
,
100
b
and
100
c
and each output signal outputted from delay elements
5012
,
5022
and
5032
respectively.
5014
,
5024
and
5034
are amplifiers for amplifying the inputted signal value by ½ by the bit shift and outputting the amplified signal data. These delay elements
5011
,
5012
, the adder
5013
and the amplifier
5014
compose the average mean value calculation circuit
501
corresponding to the R channel. The delay elements
5021
,
5022
, the adder
5023
and the amplifier
5024
compose the average mean value calculation circuit
502
corresponding to the G channel. The delay elements
5031
,
5032
, the adder
5033
and the amplifier
5034
compose the average mean value calculation circuit
503
corresponding to the B channel. Each average mean value is inputted to the channel switching circuit
104
. The delay elements
5011
5021
and
5031
not only compose the average mean value calculation circuit but also work for adjusting the phase of the input signal of the output switch circuit
111
to the predetermined phase.
The circuit
104
is a channel switch circuit for selecting color channel signals specified by the channel signal chj, chk and chl outputted from the control circuit
508
and outputting these selected color channel signals as sj, sk and sl respectively. Herein, the signal chk is a signal for specifying the defect channel which includes the defect error data. The signal sk is a defect channel signal, and the chj channel and the chl channel are the correct channels. The signal sj and sl correspond to these chj and chl channels.
105
and
106
are the adders for generating the differential signal Dj=sk−sj, Dl=sk−sl.
107
is a selector for selecting the smaller value between the differential signal value Dj or Dl according to the control signal cd outputted from the controller circuit
508
and outputting the selected smaller value.
108
is a selector for selecting one color channel signal among R, G and B channel signals according to the channel signal ch
2
and outputting the selected color channel signal.
109
is an adder for adding the output signal of the selector
107
and the output signal of the selector
108
.
110
is a clip circuit for outputting the output signal of the adder
109
as it is when the output signal level is within the predetermined range, and clipping the output signal of the adder
109
between the maximum value and minimum value when the output signal level is beyond the predetermined range. Generally, the peak level of the picture signal is set as the maximum value and the block level is set as the minimum value. The output switch circuit
111
can input each R, G and B input signal and the correction data Dc which is the output signal of the clip circuit
110
and can select one signal among the inputted data according to the chk which is the output signal of the control circuit
508
.
Hereinafter, the operation of the conventional error picture image data correction apparatus configured above is described below.
FIG. 4
is a drawing for explaining the input signals of the conventional error picture image data correction apparatus when the error picture image data is included in high frequency input signal data. In this example, the error picture image data is only one pixel data of high frequency input signal data included in the G channel. Herein the G channel data G(i) is a defective data wherein i represents time and t represents a certain time width, the average mean value output signal RAV, GAV and BAV shown respectively by Equation 1 are calculated in the average mean value calculation circuit
501
,
502
and
503
.
RAV={R
(
i+t
)+
R
(
i−t
)}/2
GAV={G
(
i+t
)+
G
(
i−t
)}/2
BAV={B
(
i+t
)+
B
(
i−t
)}/2 (Equation 1)
The channel switch circuit
104
outputs the average mean value RAV, GAV and BAV as the output signal Sj, Sk and Sl respectively. The adder
105
and
106
output the differential signal GAV−RAV, GAV−BAV as the output signal Dj and Dl. In this example, it is apparently understood from the signal level of each channel as shown in
FIG. 4
, the Dl is larger than Dj (Dj<Dl). Therefore, the differential signal Dj is selected and outputted by the selector
107
according to the output control signal cd of the control circuit
508
. The selector
108
outputs signal R(i) according to channel signal ch
2
, and the adder
109
generates signal G′(i) shown by Equation 2.
G
′(
i
)=
R
(
i
)+{
G
(
i+t
)+
G
(
i−t
)−
R
(
i+t
)−
R
(
i−t
)}/2 (Equation 2)
Then, the clip circuit
110
outputs the correction data Dc, and the output switch circ
Fukushima Yasushi
Hanaoka Tetsurou
Ono Hiroyuki
Yasui Toshiyuki
Yoshida Tadahiro
Merchant & Gould P,C,
Miller John W.
Yenke Brian P.
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