JPH09327010A - Digital image scramble controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital image scramble controller in which control of scramble strength is conducted flexibly with high accuracy and a few descriptions. SOLUTION: A coordinate transformation unit 2 transforms a coordinate on an image into a value by which a coordinate on an image is transformed into a value to identify a position in a local area in the unit of scramble. A local scramble strength setting device 1 receives a value from the unit 2 and provides an output of local scramble strength in the corresponding scramble unit. A global scramble strength setting device 3 receives a coordinate on the image and provides an output of global scramble strength corresponding to the coordinate. A scramble strength calculation device 4 in the unit of scramble on the image decides the scramble strength with respect to the scramble unit on the image based on the local scramble strength with respect to the scramble unit outputted from the local scramble strength setting device 1 and the global scramble strength outputted from the global scramble strength setting device 3 and provides an output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital image scramble control device for precisely and flexibly controlling the scramble strength of digital image data with a small number of descriptions.

[0002]

2. Description of the Related Art A digital image to be transmitted is called M
Randomization using a pseudo-random signal such as a sequence code is called scrambling, achieving uniform transmission characteristics,
It is used for suppressing jitter. The means for controlling the scramble strength in such image scrambling is an image scramble control device. The conventional image scramble control device specifies a scramble strength for an image or a certain area on the image and applies it to all scramble units to be scrambled.

[0003]

Therefore, when the above-mentioned conventional image scramble controller is used, there is a problem that the setting of the scramble intensity is limited to a small number of steps. In addition, when the scramble unit is individually set as an area and the scramble intensity is adjusted, there is a problem that the setting description amount becomes large.

The present invention is intended to solve these problems, and an object thereof is to control a scramble intensity of digital image data precisely and flexibly with a small number of descriptions. To provide.

[0005]

In order to achieve the above object, a digital image scramble control apparatus according to the invention of claim 1 of the present invention uses a parameter for controlling the scramble intensity on the image data in another part. Of a local region containing a small number of scramble units that can be specified independently of
And a means for specifying a local scramble strength for specifying a scramble pattern created by the scramble unit, and a means for determining the scramble strength of each scramble unit in the image by using the scramble strength specifying means. It is characterized by

According to a second aspect of the present invention, the digital image scramble control device can control the image data by
A means for specifying a local scramble strength for specifying a scramble pattern created by the scramble unit in a local region containing a small number of scramble units in which a parameter for controlling the scramble strength can be specified independently of other parts; , A means for designating a global scramble strength by using a position in the image as a parameter, and a means for deciding a scramble strength of each scramble unit in the image by using the means for designating the two scramble strengths. Characterize.

According to a third aspect of the present invention, the digital image scramble controller controls the image data by
A means for specifying a local scramble strength for specifying a scramble pattern created by the scramble unit in a local region containing a small number of scramble units in which a parameter for controlling the scramble strength can be specified independently of other parts; , A means for designating an area to be scrambled on the image, and means for determining the scramble strength of each scramble unit in the image by using the two designating means.

The invention according to claim 4 of the present invention is the invention according to claim 1 or claim 2 or claim 3,
A device for controlling scrambling of an image coded for each pixel, wherein a block made up of n pixels is used as a scramble unit and a local area made up of a smaller number of blocks than the number of blocks forming the entire image. In order to specify the scramble pattern created by the scramble unit, a device for specifying the local scramble strength for each block in one local area is used as a means for specifying the local scramble strength for the local area. Characterize.

Further, the invention of claim 5 of the present invention is the invention of claim 1 or claim 2 or claim 3,
A device for controlling scrambling of an image coded by a block coding method in which an image is divided into blocks and coded, wherein each block is a scramble unit and is composed of a smaller number of blocks than the number of blocks of the entire image. A device for designating a scramble strength for each block in one local region for designating a scramble pattern made by a scramble unit of the local region is a means for designating a local scramble strength of the local region,
It is characterized by the following.

Further, the invention of claim 6 of the present invention is the same as the invention of claim 1 or claim 2 or claim 3, in which an image encoded by a method of encoding an image in units of a series of pixels is used. A device for controlling scrambling, wherein the encoding unit is a scramble unit, and a local region including a small number of m rows of pixels compared to the entire image,
In order to specify the scramble pattern generated by the scramble unit, the device for specifying the local scramble strength for the scramble unit of each row in m rows is a means for specifying the local scramble strength of the local region. And

When the value of the parameter for controlling the scramble strength can be specified independently of other image data parts in units of a code word sequence encoding a set of some pixels on the image. Is called a scramble unit. At this time, the local scramble strength, which is the scramble pattern of the scramble unit in the local region composed of several scramble units, is specified independently of the global scramble strength. When scrambling the same area, by changing only the scramble strength designation of the local area, the scramble strength within the area can be finely controlled. In addition, the local scramble strength of the local area is kept constant,
Since the scramble area on the image or the scramble strength of the scramble area can be changed, the scramble strength and the scramble location at a certain position on the image can be finely controlled with a small description. These are simplified in description as compared with directly describing the scramble intensity of the entire image.

For example, in scrambling a partial area of a high-resolution image, increasing the ratio of the scrambled area in the local area is not a change in the scramble target area, but a change in the scramble target area globally. Appears as an increase in scramble strength.

Such control of the scramble strength is easier than the control of the scramble strength by making the scramble strength of all the scramble units in the area the same.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a digital image scramble controller for explaining a first embodiment which is an embodiment of the invention of claim 2 of the present invention.

In this embodiment, the coordinates on the image are input, and the scramble intensity corresponding to the scramble unit is output.

Reference numeral 1 denotes a local scramble strength setting device, which receives a value for identifying a position of a scramble unit in a local region as an input and outputs a local scramble strength for a scramble unit corresponding to the value. An apparatus for converting a coordinate on an image into a value for identifying a position in a local region in a scramble unit, 3 is a global scramble strength setting device,
An apparatus for inputting coordinates on an image and outputting a global scramble strength corresponding to the coordinates, 4 is a scramble strength calculating means for calculating a scramble strength of each scramble unit on the image, and a local scramble strength setter. This is a device for determining the scramble strength for the scramble unit on the image from the local scramble strength for the scramble unit output by 1 and the global scramble strength output by the global scramble strength setting unit 3.

The output of such a digital image scramble controller is input to an image scrambler (not shown), and the image scrambler scrambles each scramble unit based on the scramble strength indicated by the input.

FIG. 2 is a block diagram of a digital image scramble controller for explaining a second embodiment which is an embodiment of the invention of claim 1 of the present invention.

The apparatus of the present embodiment shown in FIG. 2 does not have the global scramble strength setting unit of 3 in the apparatus of FIG. 1, but in the scramble strength calculation apparatus of 4 ′ scramble unit, the local scramble strength for each scramble unit is The scramble strength for each scramble unit on the image is determined only from this.

FIG. 3 is a block diagram of a digital image scramble controller for explaining a third embodiment which is an embodiment of the invention of claim 3 of the present invention.

The apparatus of the present embodiment shown in FIG. 3 has a scramble area setting unit 3'designating an area to be scrambled on an image, instead of the global scramble intensity setting apparatus 3 in the apparatus of FIG. , In the scramble strength calculating device 4 ″, the local scramble strength for the scramble unit output from the local scramble strength setting unit 1 and the area to be scrambled on the image output from the scramble area setting unit 3 ′. The scramble strength for each scramble unit on the image is determined from the information indicating the outside.

The details of each component in each of the first, second and third embodiments will be described below.

First, the local scramble strength setting device 1 in each of the first, second and third embodiments will be described.

The setting of the local scramble strength of the local area by the local scramble strength setting device 1 is as follows.

[A] For an image coded pixel by pixel, a rectangular block of n pixels × m pixels is used as a scramble unit, and the local scramble strength setting unit 1 has a rectangular block of p blocks × q blocks. A local scramble strength is set for each block in the local area (example embodiment of the invention of claim 4 of the present invention).

[B] In the case of an image represented by block coding in which an image is divided into rectangular blocks of n pixels × m pixels and coded, the blocks are scrambled by the local scramble strength setting unit 1. , P blocks × q blocks, a local scramble strength for each block in a rectangular local region is set (example embodiment of the invention of claim 5 of the present invention).

[C] In the case of an image coded by a method of coding with a sequence of pixels as a unit, the coding unit is a scramble unit, and the local scramble strength setting unit 1 uses The local scramble strength applied to the scramble unit is set (embodiment example of the invention of claim 6 of the present invention).

In the cases [A] and [B], the local scramble strength setting device 1 is a value for identifying one position from the p × q blocks in the local area, for example, the coordinates (x,
y), (x = 0, 1, ..., P-1, y = 0, 1, ..., q
-1) as input and outputs the local scramble strength for the scramble unit for this value.
The local scramble strength in the local area is expressed by, for example, a p-row q-row matrix having the local scramble strength for the scramble unit as a component, and for the coordinates (x, y), (x + 1, y + 1) in the matrix. ) Component should be output.

In the case of the above [C], the local scramble strength setting unit 1 is a value for identifying one row out of m rows of pixels in the image, for example, a one-dimensional coordinate x (x = 0, 1, ..., M). -1) is received as an input, and the local scramble strength for the scramble unit corresponding to this value is output. The local scramble strength of the local region is, for example, m whose component is the local scramble strength for the scramble unit.
It may be represented by an array having elements and the x + 1th component may be output with respect to the coordinate x.

The simplest local scramble strength for a scramble unit is a binary value indicating whether scrambling is performed or not.

Further, the parameter for scrambling the scramble unit can be directly described as a matrix element. For example, for an image coded using the discrete cosine transform, the frequency band for scrambling becomes a parameter, and at the same time, the maximum shift due to scrambling of each frequency component becomes a parameter.

For example, JPE which is an image compression coding system
In G and MPEG, an image is decomposed into two-dimensional frequency components by a two-dimensional discrete cosine transform, serialized, and then compression-encoded. It is expressed by a set of binary numbers, and as a parameter in this case, the frequency itself for expressing the frequency pair to be scrambled, or the index indicating the order in the series when serialized, and the transition width of each frequency As the maximum value, the value itself or the bit position to be converted in the binary number is set.

For an image in which pixel values are directly encoded,
The maximum displacement due to scrambling of pixels is a parameter.

In run-length coding, which is a typical method for coding a series of pixels, the pixel value of the run and the maximum width of the transition of the run length are parameters.

The parameters of these maximum displacements are concretely expressed by actual numerical values or by the number of scrambled bits of binary numbers representing the values.

It is also possible to prepare a set of typical combinations of the values of the parameters and use an identifier for selecting one of them as a local scramble strength for a scramble unit.

Next, the coordinate converter 2 in the first, second and third embodiments will be described.

Coordinates input to the local scramble strength setting device 1 of FIGS. 1, 2 and 3, the global scramble strength setting device 3 of FIG. 1 and the scramble area setting device 3'of FIG. In the case of a coded image (embodiment example of claim 4 of the present invention), it is the coordinates of pixels on the image, and in the case of an image represented by block coding (claim 5 of the present invention). (Embodiment example of the invention) is a coordinate of a block of an image in units of blocks. When the scramble unit is a block in an image coded pixel by pixel, a block-based coordinate system may be used as in the case of the block coding. In the case of an image coded with a pixel sequence as a unit (claim 6 of the present invention
Embodiment of the invention), the input coordinates are the coordinates of the pixel (for example, the first pixel) of the representative point in the coding unit.

In the coordinate conversion in the coordinate converter 2, the coordinates on the image are converted into the coordinates in the local area according to the following rules. The conversion rule is the local scramble strength setter 1
The method of image coverage with local regions used in.

The point P on the image overlaps the point P'in the local area when the image is covered with the local area used by the local scramble strength setting device 1. At this time, the coordinates of the point P are converted into the coordinates of the point P ′ in the local area.

When the local area used in the local scramble strength setting unit 1 is a rectangular area of p blocks × q blocks, the above method is executed by the following calculation. When the remainder obtained by dividing the integer a by b is represented by a mod b, when the input coordinates are represented in block units, when the position of the block on the image is the x-th horizontal block and the y-th vertical block. In the local region, the block in the horizontal direction x ′ = x mod p-th block and the vertical direction in the local y ′ = y mod q-th block corresponds to this. Therefore, the coordinate converter 2 outputs the coordinates (x ', y') in the local area.

When the input coordinates are in pixel units and the scramble unit is n pixels × m pixels, the pixel unit coordinates (x, y) are in block units (INT (x
/ N), INT (y / m)). INT here
(A / b) represents the integer part of the quotient obtained by dividing a by b. The coordinates of the corresponding local area are calculated in the same manner as the block coding using the coordinates of the block unit.

When the sequence of pixels is a coding unit, only y representing the position of the inner line of the coordinates (x, y) of the image on the image is sent to the local scramble strength setting unit 1.

Next, the global scramble strength setting device 3 in the first embodiment will be described.

The global scramble strength setting unit 3 in FIG. 1 outputs the global scramble strength corresponding to the position on the image. For the global scramble intensity, for example, an area is designated on the image, it is determined whether the input coordinates are inside or outside the area, and different scramble strengths are output.

A method of outputting the resulting value by an arithmetic function having the coordinate value as an argument may be adopted.

The global scramble strength can use the same parameters as the local scramble strength for the scramble unit. However, both need not necessarily use the same type of parameters.

Next, the scramble area setting unit 3'in the third embodiment will be described.

The scramble area setting unit 3'can be realized by a binary value indicating whether or not scrambling is performed as an output in the configuration of the global scramble strength setting unit 3 described above.

Finally, the scramble strength calculation means 4, 4 ', 4 "in the first, second and third embodiments will be described.

The scramble strength calculating means 4 for the scramble unit on the image of FIG. 1 determines and outputs the actual scramble strength for the scramble unit from the local scramble strength and the global scramble strength for the input scramble unit. The scramble strength calculating means 4'on the scramble unit on the image of FIG. 2 determines and outputs the actual scramble strength for the scramble unit only from the local scramble strength for the input scramble unit. The scramble strength calculating means 4 ″ for the scramble unit on the image of FIG. 3 uses the local scramble strength for the input scramble unit and the information indicating whether it is inside or outside the scramble unit to determine the actual scramble strength for the scramble unit. Is output and this output is expressed in the form of a parameter for controlling the scramble strength for each scramble in the scrambler.

For example, for an image coded by using the discrete cosine transform, the frequency band for scrambling becomes a parameter, and at the same time, the maximum shift due to scrambling of each frequency component becomes a parameter.

For example, JPE which is an image compression coding system
In G and MPEG, an image is decomposed into two-dimensional frequency components by a two-dimensional discrete cosine transform, serialized, and then compression-encoded. Expressed as a set of binary numbers, the parameters in this case are the frequency itself to represent the scrambled frequency pair, or the index that represents the order in the series when serialized, and the maximum value of the transition width at each frequency. As, the value itself or the bit position or the like to be converted in the binary number is set.

For an image in which pixel values are directly encoded,
The maximum shift due to the scrambling of pixels is a parameter.

In run-length coding, which is a typical method for coding a sequence of pixels, the pixel value of the run and the maximum width of the transition of the run length are parameters.

The parameters of these maximum transitions are, for example,
It is concretely expressed by an actual numerical value or the number of scrambled bits of a binary number representing the value.

As a method of calculating the scramble strength in scramble units in the scramble strength calculating means 4, 4 ', 4 "of FIGS. 1, 2 and 3, for example, the following [1] to
According to any of [7]. It is also possible to use a calculation method other than this.

[1] When both the local scramble strength and the global scramble strength for a scramble unit take a binary value indicating whether or not to perform scrambling, when both scramble strengths are to be scrambled, The scramble strength set by the scramble strength calculation means 4, 4'4 "is output, and in other cases, a value indicating that scrambling is not performed is output.

[2] When both the local scramble strength and the global scramble strength for a scramble unit take a binary value indicating whether or not to perform scrambling, four combinations of the values of both scramble strengths are preliminarily calculated. The scramble strength calculating means 4, 4 ', 4 "sets the scramble strength and outputs a value corresponding to the input pattern.

[3] When the local scramble strength for each scramble unit has an N value and the global scramble strength has an M value, the combinations of both scramble strength values N × M are shown in advance in FIG. The scramble strength calculation means 4, 4, and 4'set the scramble strength in advance and output a value corresponding to the input pattern.

[4] The scramble strength calculation means 4 in which the local scramble strength for each scramble unit is shown in FIG.
It is expressed in the same format as the output of 4, 4, and when the global scramble strength is a binary value, the global scramble strength indicates a value indicating that scrambling is performed.
The local scramble strength for the scramble unit input from is output, and in other cases, a value indicating that scrambling is not performed is output.

[5] The local scramble strength for each scramble unit is the scramble strength calculating means 4 in the figure.
4, the output is the same as the output of '4', and when the global scramble strength is N, the local scramble strength for each scramble unit is scaled by the global scramble strength and output. When the intensity is represented by the maximum value D of the transition, (D × K / N) is output for the value K of the global scramble intensity.

[6] The roles of the local scramble strength and the global scramble strength in [4] are reversed.

[7] The roles of the local scramble strength and the global scramble strength in [5] are reversed.

In the above calculation method, the scramble strength calculating means 4'of the second embodiment uses the global scramble strength prepared as a fixed value in advance.
The third embodiment corresponds to the case where the global scramble strength in the above calculation method takes a binary value indicating whether or not scrambling is performed.

The above scramble control device may be realized as hardware or may be realized by a processing device controlled by a program.

[0068]

As described above, according to the present invention,
Specify the scramble strength for the scramble unit in the local area, or specify the scramble strength for the scramble unit in the local area and specify the scramble strength for the position on the scramble target image, or specify the scramble strength for the scramble unit in the local area. Since the scramble strength of each scramble unit in the image is determined by using the designation of the scrambled area, it is possible to make a complicated setting with a description having a small scramble strength. A change in the setting of the scramble strength in the scramble unit within the local area appears as a change in the scramble strength of the local area itself globally, and therefore the global scramble strength can be set finely and flexibly. For example,
At high resolution, scrambling half of the scramble units in the local region results in globally lower scrambling intensity when applied to the entire image than when scrambling all scramble units. Further, in order to obtain the scramble effect while preserving the color information, it is possible to set that some scramble units are not scrambled at all.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a second exemplary embodiment of the present invention.

FIG. 3 is a configuration diagram showing a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Local scramble intensity setting device 2 ... Coordinate converter 3 ... Global scramble intensity setting device 3 '... Scramble area setting device 4, 4', 4 "... Scramble intensity calculation means in scramble unit on image

Claims (6)

[Claims] 1. A scramble pattern created by a scramble unit in a local area including a small number of scramble units in which a parameter for controlling a scramble intensity can be specified independently of other parts on image data. And a means for determining the scramble strength of each scramble unit in the image using the scramble strength designating means. 2. A scramble pattern made by a scramble unit of a local region including a small number of scramble units in which a parameter for controlling scramble strength can be specified independently of other parts on image data. Means for specifying the local scramble strength, means for specifying the global scramble strength using the position in the image as a parameter, and means for specifying the two scramble strengths,
A digital image scramble control device comprising: a means for determining a scramble intensity of each scramble unit in an image; 3. A scramble pattern created by a scramble unit in a local area including a small number of scramble units in which a parameter for controlling a scramble intensity can be specified independently of other parts on image data. Means for specifying the local scramble strength of the image, means for specifying an area to be scrambled on the image, and means for determining the scramble strength of each scramble unit in the image using the two specifying means, A digital image scramble control device having. 4. A device for controlling scrambling of an image coded for each pixel, wherein a block composed of n pixels is used as a scramble unit, and the number of blocks is smaller than the number of blocks forming the entire image. Means for designating a local scramble strength of a local area for designating a scramble pattern of a local area created by a scramble unit, The digital image scramble control device according to claim 1, 2 or 3, characterized in that. 5. A device for controlling scrambling of an image coded by a block coding method for dividing an image into blocks and coding the blocks, wherein the number of blocks is smaller than the number of blocks of the entire image in scrambling units. A device for specifying the scramble strength for each block in one local area, in order to specify the scramble pattern made by the scramble unit of the local area composed of blocks, specifies the local scramble strength of the local area. The digital image scramble control device according to claim 1, 2 or 3, characterized in that it is means. 6. An apparatus for controlling scrambling of an image encoded by a method of encoding an image in units of a series of pixels, wherein the encoding unit is a scramble unit and the number is smaller than that of the entire image. To specify the scrambling pattern created by the scrambling unit for a local region containing m rows of pixels, a device for specifying the local scrambling strength for each scrambling unit of m rows is used. The digital image scramble control device according to claim 1, 2, or 3, wherein the scramble strength is designated.