JP2001157209A - Image processing unit and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing unit that enhances an encoding efficiency of an entire image by designating an image area on the basis of object information of image information and applying different encoding to the designated image area from that applied to other areas. SOLUTION: An image drawing object is discriminated (1101) on the basis of object information attached to the image drawing object and the image drawing object is expanded for the image drawing (1106). A prescribed image area is designated on the basis of the object information corresponding to the image drawing object that is expanded, after bits of image data in the prescribed image area are shifted up, the prescribed image area of the image drawing object that is expanded and the other image area are encoded at different compression rates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing apparatus and method for encoding image data having object information such as attribute information.

[0002]

2. Description of the Related Art Generally, image information has, as bit information, object information indicating an attribute of the image, and such object information is important information when the image information is developed and drawn. It is used.

[0003]

When encoding image information, it is desirable to encode the image information in accordance with image characteristics specified by attribute information or the like of the image information. For this reason, when encoding image information, an attempt has been made to designate an image area having a certain characteristic in the image, and to encode the area by a method different from other areas. However, in order to specify such an image area,
It had to be fixed manually or in a predetermined area.

[0004] The present invention has been made in view of the above conventional example, and specifies an image area based on object information included in the image information, and encodes the specified image area differently from other areas. It is therefore an object of the present invention to provide an image processing apparatus and a method for improving the coding efficiency of the entire image by performing the processing.

[0005]

In order to achieve the above object, an image processing apparatus according to the present invention has the following arrangement.
That is, a determination unit that determines the drawing object based on object information attached to the drawing object, a development unit that renders and develops the drawing object,
Designating means for designating a predetermined image area based on object information corresponding to a drawing object developed and developed by the developing means; and shifting up bits of image data of the predetermined image area, and then Encoding means for encoding the predetermined image area and the other image areas at different compression ratios.

In order to achieve the above object, the image processing method of the present invention comprises the following steps. That is, a determination step of determining the drawing object based on object information attached to the drawing object, a development step of rendering and developing the drawing object, and an object information corresponding to the rendering object rendered and developed in the development step A specifying step of specifying a predetermined image area based on the predetermined image area, and shifting up the bits of the image data of the predetermined image area, and then compressing the predetermined image area of the drawn and unrendered drawing object and the other image areas with different compression ratios. And an encoding step of encoding with

[0007]

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

The features according to the present embodiment include, for example, data format, image type, color /
Based on the information indicating black and white, etc., the region of interest in the image information is determined, and the compression ratio of the region of interest is suppressed to be lower than that of the other regions and encoded, thereby increasing the compression ratio of the entire image information. Another object of the present invention is to provide an image processing apparatus and method capable of preventing a decrease in image quality in encoding a region of interest. The details will be described below.

FIG. 1 is a block diagram showing a configuration of an image coding apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 101 denotes an image input unit for inputting image data, which includes, for example, a scanner for reading a document image, an image pickup device such as a digital camera, or an interface unit having an interface function with a communication line. I have. Reference numeral 102 denotes a discrete wavelet transform unit that executes a two-dimensional discrete wavelet transform (Discrete Wavelet Transform) on an input image. Reference numeral 103 denotes a quantization unit that quantizes the coefficients subjected to the discrete wavelet transform by the discrete wavelet transform unit 2. An entropy encoding unit 104 entropy-encodes the coefficients quantized by the quantization unit 103. A code output unit 105 outputs the code encoded by the entropy encoding unit 104. 10
Reference numeral 6 denotes an area designating unit which designates a region of interest of the image input from the image input unit 101.

The apparatus according to the first embodiment is similar to the apparatus shown in FIG.
The present invention can be applied to a case where a program for realizing this function is loaded into a general-purpose PC or workstation and operated, instead of a dedicated device as shown in FIG.

In the above configuration, first, the image input unit 1
01, a pixel signal constituting an image to be encoded is input in raster scan order, and its output is input to the discrete wavelet transform unit 102. In the following description, an image signal input from the image input unit 101 will be described as a monochrome multi-valued image. However, if a plurality of color components such as a color image are encoded, each of RGB color components or The luminance and chromaticity components may be compressed as the single color components.

This discrete wavelet transform unit 102
The input image signal is subjected to a two-dimensional discrete wavelet transform process, and its transform coefficient is calculated and output.

FIGS. 2A to 2C are diagrams illustrating the basic configuration and operation of the discrete wavelet transform unit 102 according to the present embodiment.

An image signal input from the image input unit 101 is stored in the memory 201, sequentially read out by the processing unit 202, subjected to a conversion process, and written in the memory 201 again.

FIG. 2B shows the configuration of the processing in the processing section 202 in the present embodiment. In the figure,
The input image signal is separated into a signal of an even address and a signal of an odd address by a combination of a delay element 204 and a down sampler 205, and is subjected to filter processing by two filters p and u. s and d represent a low-pass coefficient and a high-pass coefficient when one-dimensional decomposition is performed on a one-dimensional image signal, respectively, and are calculated by the following equations. And

D (n) = x (2n + 1) -floor [{x (2n) + x (2n + 2)} / 2] (Equation 1) s (n) = x (2n) + floor [{ d (n-1) + d (n)} / 4] (Expression 2) where x (n) is an image signal to be converted. In the above formula, floor {X} represents a maximum integer value not exceeding X.

With the above processing, one-dimensional discrete wavelet transform processing is performed on the image signal from the image input unit 101. In the two-dimensional discrete wavelet transform, the one-dimensional discrete wavelet transform is sequentially performed in the horizontal and vertical directions of an image, and details thereof are publicly known, and thus description thereof is omitted here.

FIG. 2C is a diagram showing an example of the structure of a two-level transform coefficient group obtained by the two-dimensional discrete wavelet transform process. The image signal is a sequence of coefficients HH1, HL1, LH1 in different frequency bands. , LL. In the following description, these coefficient sequences are called subbands. Each sub-band obtained in this way is output to the subsequent quantization unit 3.

An area specifying unit 106 determines an area (ROI: Region Of Interesting) to be decoded with higher image quality compared to the surrounding area in the image to be encoded, and performs discrete wavelet transform on the target image. At this time, mask information indicating which coefficient belongs to the specified area is generated.

FIG. 3A shows an example when generating mask information. As shown on the left side of the figure, when a star-shaped area is designated in the image by a predetermined instruction input,
When performing discrete wavelet transform on an image including the specified area, the area specifying unit 106 calculates a portion occupied by the specified area in each subband. The area indicated by the mask information is
This is a range including surrounding conversion coefficients necessary for restoring an image signal on the boundary of the designated area.

An example of the mask information calculated in this way is shown on the right side of FIG. In this example, mask information when a two-level discrete wavelet transform is performed on the image on the left side of the figure is calculated as shown in the figure. In the figure,
The star-shaped portion is the designated area, and the bits of the mask information in this area are “1”, and the other bits of the mask information are “0”. Since the entire mask information is the same as the configuration of the transform coefficient by the two-dimensional discrete wavelet transform, it is possible to identify whether or not the coefficient at the corresponding position belongs to the designated area by inspecting the bits in the mask information. it can. The mask information generated in this way is output to the quantization unit 103.

Further, the area designating section 106 inputs parameters for designating image quality for the designated area from an input system (not shown). This parameter may be a numerical value representing the compression ratio assigned to the designated area or a numerical value representing the image quality. The area specifying unit 106 calculates the bit shift amount B for the coefficient in the specified area from the parameter, and outputs the calculated amount to the quantization unit 103 together with the mask.

The quantizing section 103 quantizes the inputted coefficient by a predetermined quantization step, and outputs an index for the quantized value. Here, the quantization is performed by the following equation.

Q = sign (c) floor {abs (c) / Δ} (Equation 3) sign (c) = 1; c ≧ 0 (Equation 4) sign (c) = − 1; c <0 (Equation 5) Here, c is a coefficient to be quantized. abs (c) is c
The absolute value of Further, in the present embodiment, it is assumed that “1” is included as the value of the quantization step Δ. In this case, no quantization is actually performed.

Next, the quantization unit 103 includes an area designating unit 106
The quantization index is changed by the following equation based on the mask and the shift amount B input from.

Q ′ = q × 2 ^ B; m = 1 (Equation 6) q ′ = q; m = 0 (Equation 7) Here, m is the value of the mask at the position of the quantization index. By the above processing, the area specifying unit 106
Only the quantization indices belonging to the spatial region specified in are shifted up by B bits.

FIGS. 3B and 3C show the change of the quantization index due to the shift up. In FIG. 3B, when three quantization indices exist in each of the three subbands, the value of the mask in the networked quantization index is “1”, and the shift number B is “2”. , And the quantized index after the shift is as shown in FIG.

The quantization index changed in this way is output to the entropy encoding section 104 that follows.

The entropy coding unit 104 decomposes the input quantization index into bit planes, performs binary arithmetic coding for each bit plane, and outputs a code stream.

FIG. 4 is a diagram for explaining the operation of entropy coding section 104 according to the present embodiment. In this example, non-zero values are set in a subband having a size of 4 × 4.
There are three quantization indices, each having a value of “+13”, “−6”, and “+3”. The entropy encoding unit 104 scans this area to find the maximum value M, and calculates the number of bits S required to represent the maximum quantization index by the following equation.

S = ceil [log2 {abs (M)}] (Equation 8) where ceil (x) represents the smallest integer value among integers equal to or greater than x.

In FIG. 4, the maximum coefficient value is "13".
Therefore, the number of bits S is "4", and the 16 quantization indices in the sequence are processed in units of four bit planes as shown in FIG. First, the entropy coding unit 104 performs binary arithmetic coding on each bit of the most significant bit plane (represented by the MSB in the figure),
Output as a bit stream. Next, the bit plane is lowered by one level, and similarly, each bit in the bit plane is encoded until the target bit plane reaches the least significant bit plane (represented by LSB in the figure), and the code output unit 10
5 is output. At this time, the code of each quantization index is entropy-coded immediately after the first non-zero bit is detected in the bit plane scanning.

FIG. 5 is a schematic diagram showing the structure of a code string generated and output in this manner.

FIG. 3A shows the entire structure of a code string, where MH is a main header, TH is a tile header, and BS is a bit stream. Main header MH
Is the size of the image to be encoded (the number of pixels in the horizontal and vertical directions), the tile size when the image is divided into tiles as a plurality of rectangular areas, and the number of each color component, as shown in FIG. It has component information indicating the number of components to be represented, the size of each component, and bit precision. In the present embodiment, since the image is not divided into tiles, the tile size and the image size take the same value, and when the target image is a monochrome multi-valued image, the number of components is “1”.

Next, the structure of the tile header TH is shown in FIG.
Shown in The tile header TH includes a tile length including a bit stream length and a header length of the tile, an encoding parameter for the tile, mask information indicating a designated area, and a bit shift number for a coefficient belonging to the area. Here, the coding parameters include the level of the discrete wavelet transform, the type of filter, and the like.

FIG. 4D shows the configuration of the bit stream according to the present embodiment. In the figure, bit streams are grouped for each sub-band, and are arranged in order of increasing resolution starting with the sub-band having the smaller resolution. Further, in each subband, codes are arranged in units of bit planes from the upper bit plane (S-1) to the lower bit plane.

With such a code arrangement, it is possible to perform hierarchical decoding as shown in FIG. 9 described later.

In the above-described embodiment, the compression ratio of the entire image to be encoded can be controlled by changing the quantization step Δ.

As another method, in the present embodiment, lower bits of a bit plane to be coded in entropy coding section 104 are restricted (discarded) according to a required compression ratio.
It is also possible. In this case, all bit planes are not coded, and the bit planes from the upper bit plane to the number of bit planes corresponding to the desired compression ratio are coded,
It is included in the final code string.

When the function of limiting the lower bit plane is used, only bits corresponding to the designated area shown in FIG. 3 are included in the code string, that is, only the designated area has a low compression rate and high image quality. It can be encoded as a simple image.

Next, a method of decoding a bit stream coded by the above-described image coding apparatus will be described.

FIG. 6 is a block diagram showing the configuration of an image decoding apparatus according to the present embodiment, in which 601 is a code input unit, 602 is an entropy decoding unit, 603 is an inverse quantization unit, and 604 is an inverse discrete unit. A wavelet transform unit 605 is an image output unit.

The code input unit 601 inputs a code string coded by the above-described coding apparatus, analyzes a header included in the code string, extracts parameters necessary for the subsequent processing, and performs processing if necessary. Control the flow or send out the relevant parameters to the subsequent processing units. Also, the bit stream included in the code string is transmitted to the entropy decoding unit 60.
2 is output.

The entropy decoding unit 602 decodes and outputs the bit stream output from the code input unit 601 in bit plane units. FIG. 7 shows the decoding procedure at this time.

The left side of FIG. 7 shows a flow of sequentially decoding one area of the sub-band to be decoded in units of bit planes and finally restoring the quantization index. The bit plane is decoded. The restored quantization index is used as the inverse quantizer 603.
Is output to

The inverse quantizer 603 restores discrete wavelet transform coefficients from the input quantization index based on the following equation.

C ′ = Δ × q / 2 ^ U; q ≠ 0 (Equation 9) c ′ = 0; q = 0 (Equation 10) U = B; m = 1 (Equation 11) U = 0; m = 0 (Equation 12) Here, q is a quantization index, Δ is a quantization step, and the quantization step Δ is the same value as that used at the time of encoding. B is the number of bit shifts read from the tile header, and m is the value of the mask at the position of the quantization index. c ′ is a restored transform coefficient, which is a restored coefficient represented by s or d at the time of encoding. The transform coefficient c ′ is output to the subsequent inverse discrete wavelet transform unit 604.

FIG. 8 is a block diagram showing the configuration and processing of the inverse discrete wavelet transform unit 604 according to this embodiment.

In FIG. 9A, the input transform coefficients are stored in a memory 801. The processing unit 802 performs a two-dimensional inverse discrete wavelet transform by performing a one-dimensional inverse discrete wavelet transform, sequentially reading transform coefficients from the memory 801 and performing processing. The two-dimensional inverse discrete wavelet transform is performed in a procedure reverse to that of the forward transform. FIG. 9B shows a processing block of the processing unit 802. The input transform coefficients are subjected to two filter processes of u and p, and after being upsampled and superimposed, superimposed on the image signal x. 'Is output. These processes are performed by the following equations.

X ′ (2n) = s ′ (n) −floor [{d ′ (n−1) + d ′ (n)} / 4] (Expression 13) x ′ (2n + 1) = d ′ (n ) + Floor [{x ′ (2n) + x ′ (2n + 2)} / 2] (Equation 14) Here, the forward and reverse directions by (Equation 1), (Equation 2), and (Equation 13) and (Equation 14) Since the discrete wavelet transform in the direction satisfies the perfect reconstruction condition, if the quantization step Δ is “1” in this embodiment and all the bit planes have been decoded in the bit plane decoding, the The image signal x ′ matches the signal x of the original image.

The image is restored by the above processing and output to the image output unit 605. The image output unit 605 may be an image display device such as a monitor or a storage device such as a magnetic disk.

An image display mode when an image is restored and displayed by the above-described procedure will be described with reference to FIG.

FIG. 7A shows an example of a code string, and the basic configuration is based on FIG. Here, the entire image is set as a tile, and therefore, only one tile header and bit stream are included in the code string.
In this bit stream BS0, as shown in the drawing, codes are arranged in order of increasing resolution from LL, which is a subband corresponding to the lowest resolution, and further, in each subband, a higher bit plane is shifted from a lower bit plane to a lower bit. The codes are arranged toward the plane.

The decoding device sequentially reads the bit stream and displays an image when the code corresponding to each bit plane is decoded. FIG. 9B shows the correspondence between each subband and the size of the displayed image, and the change of the image accompanying decoding of the code string in the subband.
In the figure, it can be seen that the code sequence corresponding to LL is sequentially read out, and the image quality is gradually improved as the decoding process of each bit plane progresses. At this time, the star-shaped part which has become the designated area at the time of encoding is restored with higher image quality than other parts.

This is because the quantization unit shifts up the quantization index belonging to the specified area at the time of encoding, so that the quantization index becomes earlier than other parts at the time of bit plane decoding. This is because it is decoded by The reason why the designated area portion is decoded with high image quality is the same for other resolutions.

Further, when all the bit planes have been decoded, the designated area and the other parts have the same image quality. However, if the decoding is discontinued in the middle, the designated area is more than the other areas. Also, an image restored with high image quality can be obtained.

In the above-described embodiment, the amount of coded data to be received or processed is reduced by limiting (ignoring) the lower bit plane to be decoded in the entropy decoding unit 602, and as a result, the compression ratio is controlled. It is possible. By doing so, it is possible to obtain a decoded image of a desired image quality only from encoded data of a necessary data amount. Also, the quantization step Δ at the time of encoding
Is "1" and all the bit planes are decoded at the time of decoding, it is also possible to realize lossless encoding / decoding in which the restored image matches the original image.

If the function of limiting the lower bit plane is used, the code string to be decoded contains only bits corresponding to the designated area shown in FIG. 3 more than other areas. In other words, the same effect can be obtained as in the case where data encoded as a high-quality image with a low compression ratio only in the specified area is decoded.

In the above description, an example in which spatial scalable is used has been described. However, it is needless to say that a similar effect can be obtained by using SNR scalable.

In this case, FIG. 5 for the description of the encoder is replaced with FIG. 10, and FIG. 9 for the description of the decoder is replaced with FIG. This will be described below with reference to FIGS.

FIG. 10 is a schematic diagram showing the structure of a code string generated and output in SNR scalable manner.

FIG. 9A shows the entire structure of a code string, where MH is a main header, TH is a tile header, and BS is a bit stream. Main header MH
Is the size of the image to be encoded (the number of pixels in the horizontal and vertical directions), the tile size when the image is divided into tiles as a plurality of rectangular areas, and the number of each color component, as shown in FIG. It has component information indicating the number of components to be represented, the size of each component, and bit precision. In this embodiment, since the image is not divided into tiles,
The tile size and the image size take the same value, and when the target image is a monochrome multivalued image, the number of components is “1”.

Next, the structure of the tile header TH is shown in FIG.
It is shown in (c). The tile header TH includes a tile length including a bit stream length and a header length of the tile, an encoding parameter for the tile, mask information indicating a designated area, and a bit shift number for a coefficient belonging to the area. ing. The coding parameters include the level of the discrete wavelet transform, the type of filter, and the like. The configuration of the bit stream according to the present embodiment is shown in FIG. In the figure, the bit streams are grouped in units of bit planes, and are arranged from the upper bit plane (S-1) to the lower bit plane. In each bit plane, the result of encoding the bit plane of the quantization index in each subband is sequentially arranged in subband units.
In the figure, S is the number of bits required to represent the maximum quantization index. The code string generated in this way is output to the code output unit 105.

With such a code arrangement, it is possible to perform hierarchical decoding as shown in FIG. 11, which will be described later.

FIG. 11 is a diagram for explaining a display form of an image when the code string shown in FIG. 10 is restored and displayed.

FIG. 9A shows an example of a code string.
The basic configuration is based on FIG. 10, but here the entire image is set as a tile, and only one tile header and bit stream are included in the code string.
In the bit stream BS0, as shown in the figure, codes are arranged from the highest bit plane to the lower bit plane.

The above-described decoding apparatus sequentially reads the bit stream and displays an image when the code of each bit plane is decoded. In the figure, the image quality is gradually improved as the decoding process of each bit plane progresses, but the star-shaped portion which has become the designated area during encoding is restored to a higher image quality than the other portions.

This is because, as described above, the quantization section shifts up the quantization index belonging to the designated area at the time of encoding, so that the quantization index is not compared with other parts at the time of bit plane decoding. , Because they are decoded earlier.

Further, when all the bit planes are decoded, the designated area and the other parts have the same image quality, but when the decoding is stopped in the middle, the designated area is higher than the other areas. An image restored to the image quality is obtained.

Next, a characteristic configuration according to the present embodiment will be described in the case of a printing apparatus.

FIG. 12 is a diagram for explaining processing of a print target object in the printing apparatus according to the present embodiment.

In FIG. 12, reference numeral 1100 denotes a controller that controls the overall operation of the printing apparatus according to the present embodiment. A PDL analysis unit 1101 analyzes and interprets PDL data (print data) input from an external device such as a host computer. A print object 1102 is an object created by analyzing the input PDL data by the PDL analysis unit 1101. A graphic library 1103 converts the object 1102 into an instruction object 1104 that can be interpreted by the rendering engine 1106, and adds information 1105 to the object 1104.
With reference to later). Rendering engine 110
6 inputs an object 1104, and FIG.
5, bit information is manipulated to create bitmap image data 1107 for printing. This bitmap image data 1107 is RG
8 bit image data (1108) for each color, and 3
Bit information (bit / pixel) (1109) is included.

FIG. 13 is a view for explaining the meaning of each bit of the information 1105.

Here, the information 1105 is composed of 3 bits, and bit 0 is a bit (referred to as a Bitmap flag) indicating whether the bitmap is a bitmap or a vector (Vector) graphic. ", And" 1 "for a vector. Bit 1 is a bit (color flag) indicating whether the object is a color object or a monochrome object, and is “0” for color and “1” for monochrome. Bit 3 indicates whether the bitmap flag is “0” (= Bitmap data), a character (= 1) or non-character (= 0). If the Bitmap flag is “1” (vector data), This is a bit (called a character flag) indicating whether priority is given to gradation (= 0) or resolution (= 1).

FIGS. 14 and 15 are diagrams for explaining a method of synthesizing the source image (S) and the destination image (D).

In FIG. 14, reference numeral 1401 denotes an object to be combined with only S (only the source image, that is, when the object is overwritten) or NotS only (when the source image is inverted by 0/1 to overwrite the object). In this case, the 3-bit information (Sflag) of S is directly converted to 3-bit information 1109.
As shown. Reference numeral 1402 denotes a case where the object to be combined is only D (only the destination image, that is, when the background is used as it is) or Not.
D only (0/1 inversion of destination bit)
In this case, it indicates that the 3-bit information (Dflag) of D is left as 3-bit information 1109 as it is. Reference numeral 1403 denotes a method of combining S and D, including “S or D” (logical sum of S and D) and “S a
nd D ”(logical product of S and D),“ S xor D ”(exclusive OR of S and D),“ S α D ”(α operation of S and D = and and or of S and D having transparency) , Xor). In this case, the logical product of each bit of the 3-bit information of S and D shown in FIG. 13 is obtained, and this is determined as the information of the synthesized image.

FIG. 15 is a diagram for explaining another synthesizing method. Similar to 1401, reference numeral 1501 denotes only a synthesized object S (only a source, that is, when an object is overwritten) and only NotS (a negative operation of a source). Child = 0/1 inversion of the source bit to overwrite the object), and in this case, the 3-bit information of S is left as the information 1109 as it is. Also, 1502 is similar to 1402 only for D (only for destination.
A case where the base is used as it is, a case where only NotD is performed (a destination negation operator = inversion of 0/1 of the destination bit is performed), and in this case, the 3-bit information of D is left as information 1109 as it is.
Reference numeral 1503 denotes a method of synthesizing S and D, and “S
or D "(logical sum of S and D)," S and D "(S and D
), “S xor D” (exclusive OR of S and D),
There is “S α D” (α operation of S and D = and, or, xor of S and D having transparency). In this case, each of the 3-bit information of S and D shown in FIG. If S and D are the same, the bit information of S (Sfla
g) is left as it is, and if S and D are not the same, 0 (000) (other than bitmap, color, and character) is set as bit information.

FIG. 16 is a view for explaining the area designation in the print image data generated by the printing apparatus according to the present embodiment.

In FIG. 16, reference numeral 1501 denotes the RG of FIG.
This is image data corresponding to the B image data 1108. An image 1502 is an image data area having the attribute 1 (for example, (000: other than bitmap, color, and character)) defined by the information shown in Fig. 13. Similarly, the image 1503 is defined by the information shown in Fig. 13. (Attribute 2
(For example, (010: bitmap, black and white, other than characters)). Further, an image 1504 is an image data area having (attribute 3 (for example, (001: bitmap, color, character)) defined by the information in Fig. 13. Reference numeral 1505 corresponds to the image data 1501 in Fig. 12. Represents information corresponding to the flag 1109.

In the present embodiment, the region of interest (R) is set in the region specifying unit 106 (ROI region specification) shown in FIG.
It is characterized in that the 3-bit information is used to determine OI). Specifically, information 1505 (corresponding to the flag 1109 in FIG. 12) shown in FIG.
An area that can be an ROI area is extracted based on the information (1506), and an area used by the rendering engine 1106 as the ROI is determined from the extracted areas.

In this method of selecting the ROI area, priority is given to the state of each bit of the 3-bit information shown in FIG. 13 to give priority to data having an attribute of giving priority to image quality (high quality cannot withstand quality). Decide in a way that you do. For example, the image area (vector, color, and resolution priority) where the 3-bit information is “101” is the most important high-quality image area, and the image area (vector, color, and gradation priority) is “100”. Is set as the next important high-quality image area.

Incidentally, regarding this prioritization,
It is necessary to take into account the characteristics of the print engine, etc.
No particular provision is made here.

FIG. 17 is a flowchart for explaining the area designation processing in the printing apparatus of this embodiment.

First, in step S1, print data is input from a host computer or the like. In step S2, the input print data is analyzed to generate an object that can be referred to in subsequent rendering processing. Next, step S
3 and according to the instruction of the print data, FIG.
As described with reference to FIG. 4 and FIG. 15, the processing of synthesizing images and generating 3-bit information is performed.

Next, the routine proceeds to step S4, where the flag 1109 is set.
Is checked to see if the 3-bit information indicates a predetermined attribute (for example, vector data, color and resolution priority as described above). If so, the process proceeds to step S6, and the flag is set. The current image region is set as a region of interest (ROI). And step S7
Steps S5 to S7 are repeatedly executed until all of the flags 1109 are checked. When the designated area is determined in this manner, the process proceeds to step S8, where rendering processing is performed, and bitmap image data 1107 including the image data 1108 and the flag 1109 shown in FIG.
Is generated, and the process ends. As another method, after rendering all the data, that is, after obtaining the bitmap image data 1107, the ROI is determined by examining the image data 1108 of each of the RGB 8 bits included in the image data 1107. The same effect can be obtained.

Note that such area designation processing is not limited to the processing executed in the printing apparatus, and as shown in FIG. 1 described above, an image captured by an X-ray camera, a digital camera, or the like, or a photographic image It is needless to say that the present invention can be applied to the encoding of an image and the like, and the method of specifying the area is not limited to the printing apparatus.

[Second Embodiment] In the first embodiment, the bit information is prioritized. However, a portion having the largest area of the 3-bit information is selected as the ROI and notified to the rendering engine 1106. By doing so, a high-quality image can be obtained as a whole.

[Embodiment 3] Embodiments 1 and 2 described above.
Has selected only one area as ROI,
If a plurality of regions can be designated as I, a plurality of ROIs may be designated based on the first and second embodiments.

In the first to third embodiments, RO
It goes without saying that the area designation method of the present invention can be applied to all compression methods having the same function as I.

[Embodiment 4] The above-described Embodiments 1 to 3
Although the example in which the ROI is obtained from the 3-bit information has been described above, in a printing apparatus using a plurality of compression methods having no ROI, this bit information can be used as a selection criterion of the compression method. As an example, if the printing device supports PackBits compression and JPEG compression, check the bit information and use JPEG compression for images with many color images, and use PackBits compression for images with many black and white characters. It is possible. It should be noted that the combination of the compression method and the bit information can be almost automatically determined by the characteristics of the compression method, and is not exhaustive here.

The present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, and the like), and can be applied to a single device (for example, a copier, a facsimile). Device).

Further, an object of the present invention is to supply a storage medium (or a recording medium) in which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and to provide a computer (a computer) of the system or the apparatus. Alternatively, this can be achieved by a CPU or an MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. By executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. This also includes a case where some or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. This also includes the case where the CPU provided in the function expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

As described above, according to the present embodiment, a region of interest in image information having bit information as attribute information is determined using the bit information, thereby achieving higher quality and higher compression. Image can be obtained.

By giving a priority to the attribute and setting an image region having an attribute with a higher priority as a region of interest, for example, the compression ratio of the entire image can be reduced while the compression ratio of a region that emphasizes resolution is kept low. The image can be encoded without reducing the image quality.

[0097]

As described above, according to the present invention, an image area is designated based on object information included in the image information, and the designated image area is coded differently from other areas. Thus, there is an effect that the coding efficiency of the entire image can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image encoding device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a wavelet transform unit according to the present embodiment and subbands obtained by the transform.

FIG. 3 is a diagram illustrating conversion of a region of interest (designated region) in an image and bit shift of image data in the region.

FIG. 4 is a diagram illustrating an operation of an entropy encoding unit according to the present embodiment.

FIG. 5 is a schematic diagram showing a configuration of a code string generated and output by spatial scalability.

FIG. 6 is a block diagram illustrating a configuration of an image decoding device according to the present embodiment.

FIG. 7 is a diagram illustrating bit planes and an order of decoding for each bit plane by an entropy decoding unit according to the present embodiment.

FIG. 8 is a block diagram illustrating a configuration of a wavelet decoding unit according to the present embodiment.

FIG. 9 shows an example of a code string in the case of spatial scalability,
FIG. 7 is a diagram illustrating each sub-band, the size of an image displayed corresponding thereto, and a change in a reproduced image accompanying decoding of a code string of each sub-band when decoding the sub-band.

FIG. 10 is a diagram illustrating an example of a code string in the case of SNR scalability.

FIG. 11 shows a code string for SNR scalability,
It is a figure explaining the decoding processing.

FIG. 12 is a diagram illustrating processing of a print target object in the printing apparatus according to the present embodiment.

FIG. 13 is a diagram illustrating a configuration of 3-bit information according to the present embodiment.

FIG. 14 is a diagram illustrating a method of combining objects and a method of combining flags according to the present embodiment.

FIG. 15 is a diagram illustrating a method of combining objects and a method of combining flags according to the present embodiment.

FIG. 16 is a diagram illustrating an area designation process based on bit information according to the present embodiment.

FIG. 17 is a flowchart illustrating an area designation process in the printing apparatus according to the present embodiment.

Claims (9)

[Claims] A determining unit that determines the drawing object based on object information attached to the drawing object; a developing unit that develops the drawing object; and a drawing object that is developed by the developing unit. Specifying means for specifying a predetermined image area based on object information; and shifting up the bits of the image data of the predetermined image area, and then setting the predetermined image area and the other image areas of the drawn and developed drawing object. An image processing apparatus comprising: encoding means for encoding at different compression rates. 2. The image processing apparatus according to claim 1, further comprising: a combining unit configured to combine object information corresponding to the drawing object when the combining of the drawing objects is instructed, and the developing unit based on the drawing object combined by the combining unit. 2. The image processing apparatus according to claim 1, wherein the image processing is performed. 3. The image processing apparatus according to claim 1, wherein the encoding unit encodes the image data in the predetermined image area at a low compression rate. 4. The image processing apparatus according to claim 1, wherein the specifying unit specifies a predetermined image area according to a priority of object information corresponding to a drawing object. 5. A drawing step of determining the drawing object based on object information attached to the drawing object, a developing step of drawing and developing the drawing object, and a drawing object corresponding to the drawing object drawn and developed in the developing step. A designation step of designating a predetermined image area based on object information, and, after shifting up bits of image data of the predetermined image area, the predetermined image area of the drawn object developed and drawn and the other image areas An encoding step of encoding with different compression ratios. 6. A combining step of combining object information corresponding to the drawing object when the combination of the drawing objects is instructed, wherein the expanding step includes, based on the drawing object combined in the combining step. 6. The image is developed by drawing.
The image processing method according to 1. 7. The image processing method according to claim 5, wherein in the encoding step, the image data in the predetermined image area is encoded at a low compression rate. 8. The image processing method according to claim 5, wherein in the specifying step, a predetermined image area is specified according to a priority of object information corresponding to a drawing object. 9. A computer-readable storage medium storing a program for executing the image processing method according to claim 5. Description: