JP2000358150A - Zoom processor and zoom processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a zoomed-area signal that represents the kind of data after zooming. SOLUTION: A zooming section 7 is provided with a generating circuit 70A for generating data after zooming, which generates zoomed data from data before zooming sequentially received and a zoomed area signal generating circuit 70B including an area signal selection section 78 that generates a zoomed area signal representing the kind of the zoomed data. The area signal selection section 78 outputs an area signal Sn as a zooming area signal Sx' when a smoothing coefficient relating to zoomed data IDx' is smaller than a 1st comparison value A. The area signal selection section 78 outputs an area signal Sn+1 as the zoomed area signal Sx' when the smoothing coefficient relating to the zoomed data IDx' is larger than a 2nd comparison value B. Furthermore, the area signal selection section 78 outputs a setting area signal as the zoomed area signal Sx' when the smoothing coefficient relating to the zoomed data IDx' is larger than the 1st comparison value A or over and smaller than the 2nd comparison value B or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom processing apparatus and a zoom processing method applied to a facsimile apparatus, a digital copying machine, etc., for enlarging or reducing an output image with respect to an input image.

[0002]

2. Description of the Related Art For example, in a facsimile apparatus, when a read original image is enlarged or reduced and output,
Zoom processing for interpolating pixels in the main scanning direction (reading direction of the image sensor) or thinning out pixels is performed. Further, in a device such as a facsimile device that expresses an optically read document image by a binary image,
For the scanned document image data, filter processing for smoothing the image or sharpening the outline of the image, and gamma correction processing for correcting the sensitivity characteristics to match the characteristics of the human eye, etc. Processing is performed. Further, prior to the filtering process, an area separation process is performed to determine whether the original image data is photograph data obtained by reading a halftone image or character data obtained by reading characters. .

Each of these processes is performed before and after the zoom process, such that the region separation process and the filter process are performed before the zoom process, and the γ correction process is performed after the zoom process. More specifically, data (image data) of a read document image is separated into photograph data and character data by a region separation process, and then subjected to a filtering process according to the type of the region-separated data. You. That is, when the image data is photographic data, an integration filter process (smoothing process) is performed to smooth the image. When the image data is character data, a differential filter process (edge emphasis process) is performed to enhance the outline of the image. The image data that has been subjected to the integration filter processing or the differential filter processing is subjected to zoom processing with an arbitrarily set scaling factor, and then to γ correction processing according to a γ correction table prepared in advance.

[0004]

However, in the conventional apparatus, the gamma correction processing using the same gamma correction table is performed on the photograph data subjected to the integration filter processing and the character data subjected to the differentiation filter processing. It had been. Therefore, an image reproduced based on the image data after the γ correction processing is not always a good image.

More specifically, since the filtering process is performed before the zooming process, as described above, the filtering process can be performed in accordance with the type of data that has been area-separated by the area separation processing. However, when the zoom process is performed, it is not known whether the data newly created by the zoom process is photograph data or character data. Therefore, in the conventional apparatus, it is not possible to perform the γ correction processing according to the type of data on the data after the zoom processing.

[0006] Therefore, an object of the present invention is to provide an image processing after the zoom processing together with the pixel data after the zoom processing so that an appropriate processing according to the type of data can be performed in the image processing after the zoom processing. It is an object of the present invention to provide a zoom processing device and a zoom processing method capable of generating a post-zoom area signal representing the type of the zoom processing.

[0007]

According to a first aspect of the present invention, there is provided a zoom process for performing a zoom process for enlarging or reducing an output image with respect to an input image. A data generating means for generating post-zoom data of one pixel based on pre-zoom data of two pixels, a preceding pixel and a succeeding pixel, which are inputted in succession; Determine whether the post-zoom data created by is the type of data of character data or photo data,
And a region signal generating means for generating a post-zoom region signal indicating the result of the determination.

[0010] According to this configuration, one-pixel post-zoom data is generated from pre-zoom data of two pixels, a preceding pixel and a succeeding pixel, which are input in succession. Then, it is determined whether the generated zoom processing data belongs to photograph data or character data, and based on the determination result, a post-zoom area signal indicating the type of the post-zoom data is generated. Thus, in the image processing performed after the zoom processing, image processing according to the type of the data after the zoom processing can be performed based on the area signal after the zoom processing. Therefore, a good image can be output based on the data after the image processing.

According to a second aspect of the present invention, the area signal generating means divides a preset constant by a scaling factor of zoom processing to calculate a scaling factor. A multiplication value of the pixel position corresponding to the data after the zoom processing generated by the data generation unit, divided by the above constant, and a smoothing coefficient generation unit that sets a remainder generated by the division as a smoothing coefficient; A first comparing means for comparing the magnitude with the comparison value; a second comparing means for comparing the magnitude of the smoothing coefficient with the second comparison value; and a comparison result by the first and second comparison means. If the smoothing coefficient is smaller than the first comparison value, it is determined that the pixel data after the zoom processing is of the same type as the data of the preceding pixel. If the smoothing coefficient is larger than the second comparison value, it is determined that the pixel data after the zoom processing is of the same type as the data of the succeeding pixel. When the comparison value is equal to or smaller than 2, the determination unit includes a determination unit that determines that the data is a predetermined type of data, and a generation unit that generates a post-zoom processing area signal representing a determination result by the determination unit. The zoom processing apparatus according to claim 1, wherein

According to the present invention, when the smoothing coefficient obtained by the arithmetic processing is smaller than the predetermined first comparison value, the data after the zoom processing is of the same type as the data of the preceding pixel before the zoom processing. Is determined. Also,
If the smoothing coefficient is larger than the second comparison value, the data after the zoom processing is determined to be the same type as the data of the subsequent pixel before the zoom processing. If the smoothing coefficient is greater than or equal to the first comparison value and less than or equal to the second comparison value, it is determined that the post-zoom processing data is data of a predetermined type. As a result, the type of the post-zoom data can be satisfactorily determined, and based on the result of the determination, an area signal appropriately representing the type of the post-zoom data can be generated.

According to a third aspect of the present invention, there is provided a zoom processing method for enlarging or reducing an output image with respect to an input image, the zoom processing method comprising: A data generation step of generating post-zoom data of one pixel based on the pre-zoom data; and the post-zoom data generated in this data generation step is a text data or a photo data. A region signal generating step of determining whether there is a region and generating a region signal after zoom processing representing the determination result.

According to this method, the same effect as that of the first aspect can be obtained. According to a fourth aspect of the present invention, in the area signal generating step, a step of calculating a magnification ratio constant by dividing a preset constant by a magnification ratio of zoom processing, a step of calculating the calculated magnification ratio constant and the data generation means. Dividing the multiplied value of the pixel position corresponding to the data after the zoom processing generated by the above by the constant, and setting a remainder generated by the division as a smoothing coefficient; and determining the magnitude of the smoothing coefficient and the first comparison value. A first comparing step of comparing, a second comparing step of comparing the magnitude of the smoothing coefficient with the second comparative value, and the smoothing coefficient being based on a comparison result of the first comparing step and the second comparing step. If smaller than the first comparison value, it is determined that the pixel data after the zoom processing is of the same type as the data of the preceding pixel, and If the smoothing coefficient is larger than the second comparison value, it is determined that the pixel data after the zoom processing is of the same type as the data of the subsequent pixel. When the difference is equal to or less than two comparison values, the method includes a determining step of determining that the data is a predetermined type of data, and a step of generating a post-zoom processing area signal representing a determination result of the determining step. A zoom processing method according to claim 3.

According to this method, the same effect as that of the second aspect can be obtained.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an electrical configuration of a portion related to image processing of a facsimile apparatus to which an embodiment of the present invention is applied. The document set on the facsimile machine is read by the scanner 1. The scanner 1 includes an image sensor for reading an image, such as a CCD image sensor. The image sensor may be an area sensor that reads two-dimensional data, or a line image sensor that reads line data. Usually, a line image sensor is used to make the device inexpensive.

The image data of the document read by the scanner 1 is supplied to an input interface unit 2, and the input interface unit 2 performs a signal sample and hold process and the like. In this embodiment, the input interface unit 2 is configured by an analog circuit, and the above processing is performed in an analog manner. The image data processed by the input interface unit 2 is output to a digital AGC circuit 3
To perform gain control to keep the level of the signal (image data) within a desired range, and to convert an analog signal to a digital signal.

Next, the gain-controlled image data is applied to a shading correction circuit 4 to reduce or eliminate shading distortion. The shading distortion refers to uneven illumination of a reading light source when reading an original with the scanner 1 and uneven density between pixels due to other causes. The image data from which the shading distortion has been reduced or removed is next provided to the area separating circuit 5. In the region separating circuit 5, the input image data is image data (photo data) obtained by reading a halftone image such as a photograph or image data (character data) obtained by reading a binary image such as a character. Is determined. If the input image data includes photo data,
When character data and halftone data are mixed, area separation of each data is performed.

The photographic data also includes image data (halftone data) of halftone dots obtained by reading printed photographic images of newspapers and magazines. The output side of the area separation circuit 5 is connected to a filter processing unit 6 for performing different processing according to the type of area-separated data. The filter processing unit 6 receives the area signal Sn indicating the type of data of each pixel from the area separation circuit 5 and performs appropriate filter processing on each pixel. That is, the photographic data is subjected to integral filter processing for smoothing the image. Differential filter processing is performed on the character data to sharpen the outline.

The filtered data output from the filter processing unit 6 is supplied to a zoom processing unit 7. When the image is enlarged or reduced, the zoom processing unit 7 performs an enlargement or reduction process and a process of correcting image distortion accompanying the enlargement or reduction process. The zoom processing unit 7 receives a region signal from the region separation circuit 5, and the zoom processing unit 7 performs a zoom process indicating the type of data after the zoom process based on the region signal and the like. A rear area signal is created. In this embodiment, the zoom processing unit 7
Is characterized by its configuration and processing.

The image data that has undergone processing up to the zoom processing unit 7 is supplied to a gamma correction circuit 8, where the sensitivity characteristics of the data are corrected so as to match the characteristics of human eyes. The γ correction circuit 8 includes a character γ correction table 81 to be used when performing γ correction processing on character data, and a photographic γ correction table 82 to be used when performing γ correction processing to photographic data. The γ correction circuit 8 receives the post-zoom processing area signal created by the zoom processing unit 7, selects a γ correction table corresponding to the type of data, and performs appropriate γ correction on the image data.

The data after the γ correction is supplied to a binary processing circuit 9 when data to be input to a transmission circuit or a printing circuit (not shown) is binary data. Binarization processing circuit 9
Performs a simple binarization process for binarizing character data with a predetermined threshold value, and performs a binary error diffusion process for expressing the shading of an image with the density of dots for photographic data. Apply. The data processed by the binarization processing circuit 9 is output to the transmission circuit, the printing circuit, and the like.

On the other hand, when the data to be input to a transmission circuit or a printing circuit (not shown) is multi-value data, the data after the γ correction is given to the multi-value processing circuit 10. The multi-level processing circuit 10 does not perform any processing on the character data, and performs a multi-level error diffusion processing on the photographic data and the halftone data to realize a good halftone expression. Then, the image data output from the multi-level processing circuit 10 is provided to the above-described printing circuit and the like.

FIG. 2 is a block diagram showing the configuration of the zoom processing section 7. As shown in FIG. The zoom processing unit 7 includes a post-zoom data generation circuit 70A that generates post-zoom data from pre-zoom image data sequentially input from the filter processing unit 6, and a post-zoom data generation circuit 7A.
And a post-zoom processing area signal generation circuit 70B that generates a post-zoom processing area signal that represents the type of pixel data after the zoom processing generated by 0A.

The post-zoom processing data generation circuit 70A includes:
A register RP for holding a constant P and a register RM for holding a scaling factor M in zoom processing are provided. Data P held in register RP (constant P)
Is set to, for example, P = 1024. On the other hand, the data M (variable magnification M) held in the register RM can be variably set, for example, by operating an input key (not shown) provided in the operation unit of the facsimile machine.

The constant P held in the register RP and the scaling factor M held in the register RM are given to a scaling factor calculator 71. The scaling constant calculation unit 71 calculates the scaling constant Q by dividing the constant P by the scaling factor M. The calculated scaling factor Q is given to the multiplier 72 and multiplied by the pixel position X (X: an integer of 1 or more) corresponding to the post-zoom processing data IDx ′ to be created.
It is provided to a divider 73. In the divider 73, the multiplier 72
Is divided by the constant P held in the register RP. The "quotient" generated by the division is used as the memory reference address n, and the "remainder" is used as the smoothing coefficient m.

The post-zoom processing data generation circuit 70A
Is provided with a line memory 74 capable of storing the image data for one line input from the filter processing unit 6 and the area signal input from the area separation circuit 5 in association with each pixel. ing. The image data and the area signal of the processing target line stored in the line memory 74 are held until the zoom processing on the processing target line ends.

The image data and the area signal stored in the line memory 74 are read out when a memory control signal generated based on the memory reference address n output from the divider 73 is supplied from the memory control unit 75. . More specifically, when the memory reference address n is input from the divider 73 to the memory control unit 75, the memory control unit 75 sets the data IDn and the area signal Sn of the n-th pixel from the first pixel to (n + 1) A memory control signal for reading the data IDn + 1 and the area signal Sn + 1 of the pixel is supplied to the line memory 74. As a result, the data IDn, IDn + 1 and the area signals Sn, Sn + 1 before the zoom processing are read from the line memory 74.

The data IDn, IDn + 1 before zoom processing read from the line memory 74 and the area signals Sn,
Sn + 1 is given to the zoom data generation unit 76. Further, the constant P stored in the register RP and the smoothing coefficient m output from the divider 73 are given to the zoom data generator 76. The zoom data generation unit 76 calculates the data IDn + 1 of the (n + 1) -th pixel.
Is subtracted from the data IDn of the n-th pixel, and a value obtained by multiplying the obtained value by m / P and the data IDn of the n-th pixel are added to the X-th pixel of the X-th pixel after the zoom processing. Output as data IDx '. That is, the zoom data generating unit 76 outputs the data IDx ′ obtained by the arithmetic processing according to the following equation (1) as the data of the X-th pixel after the zoom processing.

[0028]

(Equation 1)

The post-zoom processing area signal generation circuit 70B has a register RA for holding a first comparison value A for area determination.
And a register RB for holding a second comparison value B larger than the first comparison value A for area determination. The first comparison value A held in the register RA is compared with the comparison operation unit 77A
Is input to The comparison arithmetic unit 77A compares the magnitude of the first comparison value A with the smoothing coefficient m input from the divider 73. That is, it is determined whether the smoothing coefficient m is larger than the first comparison value A. Then, the comparison arithmetic unit 77A outputs the determination signal “1” when the smoothing coefficient m is larger than the first comparison value A, and outputs the determination signal “0” when the smoothing coefficient m is equal to or smaller than the first comparison value A. Output. The determination signal output from the comparison arithmetic unit 77A is:
The signal is input to the area signal selection unit 78.

Second comparison value B held in register RB
Is input to the comparison calculator 77B. Comparison arithmetic unit 77B
Then, the magnitude of the second comparison value B and the smoothing coefficient m input from the divider 73 are compared. That is, it is determined whether the smoothing coefficient m is smaller than the second comparison value B. Then, the comparison calculator 77B outputs the determination signal “1” when the smoothing coefficient m is smaller than the second comparison value B, and outputs the determination signal “0” when the smoothing coefficient m is equal to or larger than the second comparison value B. Output. The determination signal output from the comparison operation unit 77B is also input to the area signal selection unit 78.

The area signal selector 78 includes a comparison operator 77
A and 77B, the area signal Sn of the n-th pixel and the area signal Sn + 1 of the (n + 1) -th pixel in the image before the zoom processing are output from the post-zoom processing data generation circuit 70A. Is given. The region signal selection unit 78 is supplied with a setting region signal held in the register RC. The set area signal is changed according to, for example, the output mode of the facsimile apparatus set by operating the input key (not shown). That is, when the output mode of the facsimile apparatus is a photograph mode for outputting a photograph image, the setting area signal is set to a signal indicating that the data is photograph data, and when the output mode is a character mode for outputting a character image. In, the setting area signal is set to a signal indicating that it is character data.

The area signal selection section 78 is provided with a comparison arithmetic unit 77
A, 77B, the zoomed data I output from the zoom data generator 76 based on the determination signal
It is determined whether Dx 'is photograph data or character data, and the area signal Sx' after zoom processing corresponding to the determination result is obtained.
Is output. That is, when the judgment signal “0” is input from the comparison operation unit 77A and the judgment signal “1” is input from the comparison operation unit 77B, the area signal Sn is selected, and the area signal Sn is It is output as a region signal Sx '. When the judgment signal “1” is input from the comparison operation unit 77A and the judgment signal “0” is input from the comparison operation unit 77B, the area signal Sn + 1 is selected, and the area signal Sn + 1 is zoomed. The processed area signal Sx 'is output. When the judgment signal “1” is input from both of the comparators 77A and 77B, the set area signal set in the register RC is output as the post-zoom processing area signal Sx ′.

Here, the operation of the area signal selection unit 78 is shown in Table 1.
It is put together in. However, Table 1 shows that the area signal selection unit 7
8 shows the relationship between the combination of the determination signals input to 8 and the area signal after zoom processing Sx 'selectively output by the area signal selection unit 78. Note that the smoothing coefficient m is equal to the first
Since there is no case where it is determined that the value is smaller than the comparison value A and larger than the second comparison value B, the area signal selection unit 7
No judgment signal “0” is input to 8 from both of the comparators 77A and 77B.

[0034]

[Table 1]

FIG. 3 shows a region signal generating circuit 7 after the zoom processing.
It is a figure for explaining processing in 0B. In the following description, it is assumed that, for example, 85.7% zoom processing is performed on the image data before the zoom processing input from the filter processing unit 6 to the zoom processing unit 7. Also, the constant P is set to 1024, and the first comparison value A
= 400 and the second comparison value B = 700.

Under the above assumption, the magnification ratio M = 0.857.
Since the constant P = 1024, the scaling constant Q calculated by the scaling constant calculating unit 71 is Q = P / M = 10
24 / 0.857 = 1194. The smoothing coefficient m is the remainder when the multiplication value of the scaling factor Q and the position X of the pixel corresponding to the zoomed data IDx 'is divided by the constant P. For the pixel ′, 1194 × 1/1024 = 1 remainder 170, and the smoothing coefficient m becomes 170.
Similarly, the smoothing coefficient m for the second and subsequent pixels "" is m = 340, 510, 68
0, 850, ....

Therefore, for example, for the first pixel ′ of the image after zoom processing, the smoothing coefficient m =
At 170, the smoothing coefficient m is the first comparison value A = 400
Therefore, the determination signal “0” is input to the area signal selection unit 78 from the comparison operation unit 77A, and the comparison operation unit 7
The determination signal “1” is input from 7B. As a result, it is determined that the data ID1 'for the pixel' is the same type of data as the data ID1 of the first pixel (preceding pixel) before the zoom processing, and the area signal S1 of the pixel is changed to the area signal S1 after the zoom processing. 'Is output from the area signal selection unit 78.

For the third pixel ′ of the image after zooming, the smoothing coefficient m is 510, and the smoothing coefficient m is not less than the first comparison value A = 400 and not more than the second comparison value B = 700. The determination signal “1” is input to the area signal selection unit 78 from both of the comparison operators 77A and 77B. As a result, the set area signal set in the register RC is output from the area signal selecting unit 78 as the post-zoom processing area signal S3 'indicating the type of the data ID3' for the pixel '.

Further, with respect to the fifth pixel ′ of the image after the zoom processing, the smoothing coefficient m = 850 and the smoothing coefficient m is larger than the second comparison value B = 700. The determination signal “1” is input from the arithmetic unit 77A, and the determination signal “0” is input from the comparison arithmetic unit 77B. As a result, the data ID5 'for the pixel' is determined to be the same type of data as the data ID6 of the sixth pixel (subsequent pixel) before the zoom processing, and the area signal S6 of the pixel is changed to the area signal S6 after the zoom processing. 'Is output from the area signal selection unit 78.

As described above, the zoom processing unit 7 generates the post-zoom data IDx ′ from the pre-zoom image data sequentially input from the filter processing unit 6, and generates the generated post-zoom data IDx ′. It is determined whether IDx ′ belongs to photograph data or character data, and the data ID after zoom processing is determined based on the determination result.
A post-zoom processing area signal Sx 'representing the type of x' is generated.
Thereby, in the γ correction processing by the γ correction circuit 8,
Based on the post-zoom processing area signal Sx ', a gamma correction table corresponding to the type of the post-zoom data IDx' can be selected, and appropriate gamma correction can be performed on the post-zoom data IDx '. Therefore, it is possible to satisfactorily reproduce the document image.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the configuration in which the zoom process is performed after the filter process has been described as an example. However, the filter process may be performed after the zoom process. Also in this case, it is possible to perform an appropriate filtering process on the data after the zoom process according to the type of the data.

In the above-described embodiment, a facsimile apparatus is taken as an example. However, the present invention is widely applied to apparatuses capable of performing a zoom process on a document image, such as an image scanner and a digital copying machine. be able to.
In addition, various design changes can be made within the scope of the technical matters described in the claims.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of a part related to image processing of a facsimile apparatus to which an embodiment of the present invention is applied.

FIG. 2 is a block diagram illustrating a configuration of a zoom processing unit.

FIG. 3 is a diagram for describing processing in a post-zoom area signal generation circuit.

[Explanation of symbols]

7 Zoom processing unit (zoom processing device) 70A Data processing circuit after zoom processing (data generation means) 70B Area signal generation circuit after zoom processing (area signal generation means) 71 Variable magnification constant calculation unit (means for calculating magnification constant) 72 Multiplier (smoothing coefficient generation unit) 73 Divider (smoothing coefficient generation unit) 77A Comparison operation unit (first comparison unit) 77B Comparison operation unit (second comparison unit) 78 Area signal selection unit (judgment unit, generation unit)

Claims (4)

[Claims] 1. A zoom processing device for performing a zoom process for enlarging or reducing an output image with respect to an input image, wherein the zoom process is performed on two pixels, a preceding pixel and a succeeding pixel, which are input in succession. Data generation means for generating post-zoom data for one pixel based on the previous data; and whether the post-zoom data generated by the data generation means is character data or photograph data. And a region signal generating means for generating a post-zoom region signal representing the result of the determination. 2. An area signal generating means for calculating a magnification constant by dividing a preset constant by a magnification of a zoom process, and a data generated by the calculated magnification constant and the data generating means. Dividing the multiplied value of the pixel position corresponding to the data after the zoom processing by the above constant, and using a remainder generated by the division as a smoothing coefficient; and determining the magnitude of the smoothing coefficient and the first comparison value. First comparing means for comparing; second comparing means for comparing the smoothing coefficient with a second comparison value; and a smoothing coefficient based on a comparison result by the first comparing means and the second comparing means. If smaller than the first comparison value, it is determined that the pixel data after the zoom processing is of the same type as the data of the preceding pixel, and the smoothing coefficient is determined. If the second comparison value is larger than the second comparison value, it is determined that the pixel data after the zoom processing is of the same type as the data of the subsequent pixel, and if the smoothing coefficient is equal to or greater than the first comparison value, the second comparison value In the following case, the method includes: a determination unit that determines that the data is a predetermined type of data; and a generation unit that generates a post-zoom processing area signal representing a determination result by the determination unit. Item 2. The zoom processing device according to Item 1. 3. A zoom processing method for enlarging or reducing an output image with respect to an input image, based on pre-zoom data of two pixels, a preceding pixel and a succeeding pixel, which are inputted successively. A data generation step of generating post-zoom data for one pixel; and determining whether the post-zoom data generated in the data generation step is character data or photo data, A region signal generating step of generating a post-zoom region signal representing the determination result. 4. The area signal generating step includes a step of calculating a magnification constant by dividing a preset constant by a magnification of zoom processing, and a step of generating the calculated magnification constant and the data generating means. Dividing the multiplied value of the pixel position corresponding to the data after the zoom processing by the constant, and setting a remainder generated by the division as a smoothing coefficient; and comparing the smoothing coefficient with a first comparison value. A first comparison step; a second comparison step of comparing the magnitude of the smoothing coefficient with a second comparison value; and a first comparison step based on a comparison result of the first comparison step and the second comparison step. If the value is smaller than the value, it is determined that the pixel data after the zoom processing is of the same type as the data of the preceding pixel, and the smoothing is performed. If the zoom coefficient is larger than the second comparison value, it is determined that the pixel data after the zoom processing is of the same type as the data of the subsequent pixel, and if the smoothing coefficient is equal to or greater than the first comparison value and the second When the comparison value is equal to or less than two comparison values, the method includes a determining step of determining that the data is of a predetermined type, and a step of generating a post-zoom processing area signal representing a determination result of the determining step. 4. The zoom processing method according to claim 3, wherein: