Television – Bandwidth reduction system – Data rate reduction
Reexamination Certificate
1997-06-27
2001-06-05
Sniezek, Andrew L. (Department: 2651)
Television
Bandwidth reduction system
Data rate reduction
C386S349000, C386S349000, C382S232000
Reexamination Certificate
active
06243139
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image processing apparatus, and more particularly to an apparatus for block encoding of an input image signal.
2. Related Background Art
In the field of such apparatus, there has already been known a digital VTR (video tape recorder) for digitizing image signals and effecting the recording and reproduction there of after block encoding.
In such a digital VTR, the correlation of the fields within a frame is usually discriminated at the compression and encoding of the digital image signal, and a frame process and a field process are switched according to the correlation, in order to reduce the amount of code at the encoding by a process of higher correlation, thereby controlling the code amount so as to conform to the code amount defined by the format of each digital VTR.
In such a digital VTR, the dubbing operation in digital signal form from another equipment such as a VTR is usually conducted, as shown in
FIG. 1
, by reproducing the image signal in digital format from a digital VTR
1
, and recording said signal in a digital VTR
2
. Also in such a dubbing operation of the image signal already recorded and reproduced in a digital VTR, the frame and field processes are switched by discrimination of the correlation of the fields, as in the first recording.
Such a dubbing operation between the digital VTR's can be most simply achieved with digital data, but, for the protection of copyright, there is conceived a method of avoiding the digital interface and conducting the dubbing after the digital data are returned to analog form.
Such analog connection provides an additional advantage of compatibility with conventional analog equipment, such as a title/illustration inserting equipment or an effecter
3
for achieving a wiping/fading effect, as shown in FIG.
2
.
However, in the aforementioned dubbing between the digital VTR's, the switching of the frame/field process at the digital recording of the image signal is conducted in the recording VTR, based on the correlation of the fields, so that the re-encoding process at the recording VTR may become different from the initial encoding process (prior to dubbing). As a result, there may occur significant deterioration of the image.
More specifically, in such a dubbing operation, because of transmission errors in the analog transmission channel, representative values of the quantization at the re-encoding in the recording VTR may be different from those in the initial or preceding quantization. As a result, the representative values of quantization are aberrated from the original values as the dubbing operation is repeated, thus eventually resulting in significant deterioration of the image quality.
Also in the dubbing of the signal reproduced from an analog VTR, the formation of the optimum pixel blocks may be hindered by the loss of image correlation, resulting from variable time-base components, such as jitter (principally caused by mechanical reasons), generally contained in the reproduced signal.
SUMMARY OF THE INVENTION
In consideration of the foregoing, an object of the present invention is to resolve the drawbacks mentioned above.
Another object of the present invention is to provide an apparatus, capable of preventing deterioration of the image quality, in the dubbing from a digital VTR or in the recording of the image signal.
The above-mentioned objects can be attained, according to an aspect of the present invention, by an image processing apparatus, comprising image input means for entering an image signal, block forming means for dividing said image signal into blocks, each containing a predetermined number of pixels, and information input means for entering block forming information relating to said block forming process applied previously to said image signal, wherein said block forming means is adapted to effect said block forming process according to the block forming information from said information input means.
Still another object of the present invention is to provide an apparatus capable of preventing the deterioration in image quality, resulting from a level variation in the analog transmission channel or a level variation by connection with another equipment.
The above-mentioned object can be attained, according to another aspect of the present invention, by an image processing apparatus, comprising level control means for controlling the level of an input image signal, compression means for compressing the amount of information of the image signal from said level control means, expansion means for expanding the amount of information of the image signal compressed by said compression means, detection means for detecting the deterioration in image quality of said input image signal, resulting from said compression and expansion, and control means for controlling said level control means according to the output of said detection means.
Still other objects of the present invention, and the features thereof, will become fully apparent from the following detailed description of the embodiments, to be taken in conjunction with the attached drawings.
REFERENCES:
patent: 4792851 (1988-12-01), Mochizuki
patent: 5055927 (1991-10-01), Keesen et al.
patent: 5065259 (1991-11-01), Kubota et al.
patent: 5091782 (1992-02-01), Krause et al.
patent: 5198940 (1993-03-01), Nagasawa et al.
patent: 5274442 (1993-12-01), Murakami et al.
patent: 5353063 (1994-10-01), Yagisawa et al.
patent: 5544266 (1996-08-01), Koppelmans et al.
patent: 5557417 (1996-09-01), Ishii
patent: 5561529 (1996-10-01), Tanaka et al.
Kashida Motokazu
Takahashi Koji
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Sniezek Andrew L.
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