Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1998-05-07
2002-06-18
Nguyen, Huy (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000, C386S349000
Reexamination Certificate
active
06408127
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image processing apparatus, and more particularly to digital signal processing from image processing apparatus.
2. Related Background Art
FIGS. 8A and 8B
are block diagrams of conventional constructions of apparatuses for processing sequential color difference line signals, e.g., signal processing circuits in a still video system, respectively showing the construction for brilliance signals and the construction for chrominance signals. In
FIG. 8A
reference numeral
800
designates an input terminal for a brilliance signal reproduced from a magnetic sheet which is a magnetic recording medium;
802
, a delay line of 1H (1 horizontal scanning time);
804
, a switch for selecting a reproduced brilliance signal of the input terminal
800
or a delay signal of the delay line
802
;
806
, an adder for adding the output of the switch
804
and the output of the delay line
802
and for taking an average;
808
, a delay line of 1/2H;
810
, a switch for selecting the output of the delay line
802
or the output of the delay line
808
; and
812
, an output terminal for the signal selected by the switch
810
.
In
FIG. 8B
,
814
designates an input terminal for reproduction line sequential chrominance signals reproduced from the magnetic sheet;
816
, a delay line of 1/2H;
818
, a switch for selecting the reproduction line sequential chrominance signals or the output of the delay line
816
;
820
,
822
, delay lines of 1H;
824
, a switch for selecting the output of the switch
818
or the output of the delay line
822
;
826
, an adder for adding the output of the switch
824
and the output of the delay line
822
and for taking an average;
828
,
830
, switches for selecting the output of the delay line
820
or the output of the adder
826
; and
832
,
834
, output terminals for the signals selected by the switches
828
,
830
.
The reproduced brilliance signals to be inputted to the input terminal
800
are represented by Y
0
, Y
1
, Y
2
, Y
3
, Y
4
, Y
5
, . . . orderly raster by raster. The switch
804
normally selects the input terminal
800
, and it shifts to the output of the delay line
802
when a drop-out occurs in the reproduction signal. The adder
806
adds the output of the switch
804
and the output of the delay line
802
and takes an average, and outputs (Y
0
+Y
1
)/2, (Y
1
+Y
2
)/2, (Y
2
+Y
3
)/2, (Y
3
+Y
4
)/2, (Y
4
+Y
5
)/2, . . . When a frame picture on the magnetic sheet is to be reproduced, the switch
810
normally selects the output of the delay line
802
; when a field picture is to be reproduced, the switch
810
shifts field by field.
The reproduction line sequential chrominance signals to be inputted to the input terminal
814
are represented by RY
0
, BY
1
, RY
2
, BY
3
, RY
4
, BY
5
, RY
6
, By
7
, . . . orderly raster by raster. The switch
824
normally selects the output of switch
818
, and it shifts to select the output of the delay line
822
when a drop-out occurs. The adder
826
adds the output of the delay line
822
and the output of the switch
824
and takes an average, and outputs (RY
0
+RY
2
)/2, (BY
1
+BY
3
)/2, (RY
2
+RY
4
)/2, (BY
3
+BY
5
)/2, (RY
4
+RY
6
)/2, (BY
5
+BY
7
)/2, . . . By the shifting of the switches
828
,
830
, RY
0
, (RY
0
+RY
2
)/2, RY
2
, (RY
2
+RY
4
)/2, RY
4
, (RY
4
+RY
6
)/2, RY
6
, . . . are outputted to the output terminal
832
, and 1H later from this, BY
1
, (BY
1
+BY
3
)/2, BY
3
, (BY
3
+BY
5
)/2, BY
5
, (BY
5
+BY
7
)/2, BY
7
, . . . are outputted to the output terminal
834
. When a frame picture on the magnetic sheet is to be reproduced, the switch
818
normally selects the input terminal
814
; when a field picture is to be reproduced, the switch
818
shifts field by field.
However, with this conventional arrangement, since many delay lines
802
,
808
,
816
,
820
,
822
are included, the number of parts to be adjusted at the stage of production or assembly would be increased. Secularly, the temperature characteristics, frequency characteristics, and S/N ratio of these delay lines would be varied and impaired. Further, the system furnished with image memories requires relatively large-sized circuits.
Conventionally, in an image recording and reproducing system having an image memory, when memorizing in the image memory an input image as reduced, the frequency of a clock, for forming a horizontal address signal to be impressed in the image memory, is divided by N (N is a positive integer), and the frequency of a horizontal synchronizing signal, for generating a vertical address signal, is divided by M/M (M is a positive integer). By this process, the input signal is reduced to 1/N horizontally and to 1/M vertically, and as a result, a reduced image of a 1/N×1/M size is memorized in the image memory.
However, in the conventional apparatus, an input image is memorized in the image memory simply by cutting out. Accordingly, in a still video system for processing chrominance signals in line sequence, when reducing the input image to a ¼×¼ size, for example, if the input image starts with R-Y components, i.e. RY
0
, BY
1
, RY
2
, BY
3
, RY
4
, BY
5
, RY
6
, BY
7
, RY
8
, BY
9
, RY
10
, BY
11
, . . . every fourth raster is sampled. As a result, only R-Y components, i.e. RY
0
, RY
4
, RY
8
, . . . are stored in the image memory, while B-Y components are completely omitted.
Further, when reducing the input image to a ⅕×⅕ size, every fifth rasters, i.e. RY
0
, BY
5
, RY
10
, . . . is memorized in the image memory and, as a result, other color different information is omitted in part. However, in the case where a lot of image information as reduced was stored in the image memory for the purpose of multi-screen display, because there is no priority between chrominance signals to be inputted, a single raster necessarily contains R-Y components and B-Y components in combination, which is very difficult to read out to output normally.
Especially when memorizing an input image, as reduced, in the image memory, the input image is written in the image memory with image areas of the input image reduced. Therefore, as shown in
FIG. 10
, if the reduced image is stored in a checked fashion, the image can be displayed only incompletely on a monitor screen; that is, part of the reduced image is omitted.
Another problem with the conventional arrangement is that when overlapping the reduced and memorized image over an input image, it requires, in addition to a signal indicative of an image zone of the reduced image, a signal indicative of a frame zone where the reduced image is to be framed.
Moreover, in the conventional image recording and reproducing system, when a framed image of a reproduction video signal from the magnetic recording medium is to be memorized in the image memory while a stationary image is being read out as the framed image from the image memory, the relationship between the field of an image outputted from the image memory and the field of an image inputted into the image memory has not been considered. Thus the reproduction video signal is merely written in the image memory.
However, if the field of an image outputted from the image memory does not coincide with the field of an input image (reproduction video signal) when a framed image from the magnetic recording medium is to be reproduced to store in the image memory, a skew distortion in the output image would occur during that time.
Yet if the two same fields of image signals are inputted in a frame memory and then are read out the field video signals one after another, a skew distortion would still occur due to the inconsistence of the fields.
Heretofore, as a means for processing video signals, a clamping circuit generally called “clamp” is known.
Generally, in the apparatus furnished with an image memory, any DC component of an input video signal is cut off by a condenser prior to using this video signal. But, for e
Horii Hiroyuki
Kubo Ryoji
Yamagishi Yoichi
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Nguyen Huy
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