JP2010062879A - Device, method and program for processing image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device, a method and a program for processing an image, capable of reduction at an optional reduction ratio, and preventing degradation of image quality. <P>SOLUTION: The device for processing an image includes: an image input part 10 configured to input a first image comprising a plurality of pixels; a reduction filter storage part 22 configured to store data of a two-dimensional reduction filter used in reducing an image at fixed reduction ratio; a reduction filter-processing part 20 configured to repeatedly execute a reduction process using the two-dimensional reduction filter to the first image based on the data stored in the reduction filter storage part 22 one or more times; and an interpolation function processing part 30 configured to output a third image by executing a reduction process at an adjusted reduction ratio larger than the fixed reduction ratio to a second image after being subjected to the reduction process by the reduction filter processing part 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, method, and program for performing reduction or resolution conversion of an image composed of a plurality of pixels.

2. Description of the Related Art Conventionally, an image processing apparatus that performs a reduction process on an original image composed of a plurality of pixels arranged on a two-dimensional plane is known (for example, see Patent Document 1). In this image processing apparatus, reduction processing is performed on the input image data of the original image in each of the X direction and the Y direction. Specifically, this reduction process is performed by an interpolation operation using pixel values of four pixels adjacent in the X direction or the Y direction.
JP 11-353473 A (page 4-8, FIG. 1-10)

  By the way, in the conventional technique described in Patent Document 1 described above, interpolation calculation is performed using pixel values of four pixels along the X direction or the Y direction. There was a problem that could not be done. In addition, it is possible to reduce a magnification smaller than 1/4 by thinning out a plurality of pixels arranged in the X direction and the Y direction in accordance with the reduction magnification. When this is done, there is a problem that the ratio of the number of pixels to be deleted to the original image increases and the image quality is extremely deteriorated.

  The present invention was created in view of the above points, and an object of the present invention is to provide an image processing apparatus, method, and program capable of reducing an arbitrary magnification and suppressing deterioration in image quality. There is.

  In order to solve the above-described problem, an image processing apparatus according to the present invention includes a plurality of pixels arranged at equal intervals along each of a first direction and a second direction that is non-parallel to the first direction. And a reduction filter for storing data of a two-dimensional reduction filter used when the image is reduced at a fixed reduction magnification along each of the first and second directions. A first reduction processing unit that repeatedly performs a reduction process using a two-dimensional reduction filter on the first image one or more times based on data stored in the storage unit and the reduction filter storage unit; Second reduction processing means for reducing the second image after the reduction processing by the first reduction processing means at an adjustment reduction magnification larger than the fixed reduction magnification and outputting a third image; It has.

  The image processing method of the present invention is configured to input a first image composed of a plurality of pixels arranged at equal intervals along each of a first direction and a second direction that is not parallel to the first direction. The image input step to be performed and the data of the two-dimensional reduction filter used for reducing the image at a fixed reduction magnification along each of the first and second directions are read from the reduction filter storage means, and the first image is obtained. On the other hand, the first reduction processing step in which the reduction processing using the two-dimensional reduction filter is repeated once or a plurality of times, and the second image after the reduction processing in the first reduction processing step are fixed. And a second reduction process step of performing a reduction process at an adjustment reduction ratio larger than the reduction ratio and outputting a third image.

  An image processing program according to the present invention is a first image composed of a plurality of pixels arranged at equal intervals along each of a first direction and a second direction that is non-parallel to the first direction. An image input means for inputting the image, a reduction filter storage means for storing data of a two-dimensional reduction filter used when the image is reduced at a fixed reduction magnification along each of the first and second directions, and a reduction filter A first reduction processing means for performing a reduction process using a two-dimensional reduction filter on the first image one or more times based on data stored in the storage means; and a first reduction processing means The second image that has been subjected to the reduction process is subjected to a reduction process at an adjustment reduction ratio larger than the fixed reduction ratio, and functions as a second reduction processing unit that outputs a third image.

  By combining one or more reduction processes using a two-dimensional reduction filter with a fixed reduction ratio and one reduction process with an adjustment reduction ratio, a reduction process with an arbitrary reduction ratio smaller than 1/4 can be performed. Further, by performing the reduction process in a plurality of times, information on each pixel can be included in the information on each pixel after the reduction process, so that deterioration in image quality can be suppressed. Furthermore, the processing content can be simplified by repeatedly using a reduction filter with a fixed coefficient.

Further, it is desirable to further include a reduction number setting means for setting the number of times of reduction processing by the first reduction processing means based on the first image and the third image described above. Specifically, the fixed reduction ratio is A, the reduction ratio when the first image is reduced to the third image is B, the number of times of reduction processing by the first reduction processing means is N, and the second reduction processing means When the adjustment reduction magnification of the reduction process is set to C, the reduction number setting means sets B = A ^N × C and N value satisfying A <C <1.

Alternatively, it is desirable to further include a reduction number setting step for setting the number of times of reduction processing in the first reduction processing step based on the first image and the third image described above. Specifically, the fixed reduction ratio is A, the reduction ratio when the first image is reduced to the third image is B, the number of times of reduction processing by the first reduction processing means is N, and the second reduction processing means In the reduction count setting step, ^N = value satisfying B = A ^N × C and A <C <1 is set, where C is the adjustment reduction magnification of the reduction process according to the above.

  This makes it possible to set an appropriate number of reductions corresponding to the size and resolution of the image before and after the reduction process.

In addition, it is desirable to further include an adjustment reduction ratio setting unit that sets an adjustment reduction ratio of the reduction process performed by the second reduction processing unit based on the first image and the third image described above. Specifically, the fixed reduction ratio is A, the reduction ratio when the first image is reduced to the third image is B, the number of times of reduction processing by the first reduction processing means is N, and the second reduction processing means When the adjustment reduction magnification of the reduction process according to the above is C, the adjustment reduction magnification setting means sets a value of C that satisfies B = A ^N × C and A <C <1.

Alternatively, it is desirable to further include an adjustment reduction magnification setting step for setting an adjustment reduction magnification of the reduction processing in the second reduction processing step based on the first image and the third image described above. Specifically, the fixed reduction ratio is A, the reduction ratio when the first image is reduced to the third image is B, the number of reduction processes in the first reduction process step is N, and the second reduction process step. In the adjustment reduction magnification setting step, a value of C satisfying B = A ^N × C and A <C <1 is set.

  As a result, it is possible to set an appropriate adjustment reduction ratio corresponding to the size and resolution of the image before and after the reduction process.

  In addition, it is desirable to further include an overall reduction ratio setting unit that sets the value of B based on the number of pixels of the first image and the number of pixels of the third image. Alternatively, it is desirable to further include an overall reduction ratio setting step for setting the value B based on the number of pixels of the first image and the number of pixels of the third image. Thereby, it is possible to set a reduction ratio suitable for the input first image.

  The first and second directions described above are preferably orthogonal to each other. Thereby, it is possible to perform reduction processing with little deterioration in image quality at an arbitrary magnification for the most widely used image in which pixels are arranged horizontally and vertically.

  Further, it is desirable that the above-described fixed reduction ratio is 1/2. Thereby, the reduction process using the fixed reduction ratio can be further simplified.

  In the above-described two-dimensional reduction filter, it is desirable that a value obtained by adding a value obtained by multiplying each pixel value of 4 × 4 pixels by a predetermined coefficient is a pixel value of a new pixel. Specifically, the value multiplied by the pixel value of each pixel of 4 × 4 pixels is w11, w12, w13, w14, w21, w22, w23, w24, w31, w32, w33, w34, w41, in the order of arrangement. When w42, w43, and w44, w11 = w14 = w41 = w44 = −1 / 16, w22 = w23 = w32 = w33 = 9/16, and the others are set to 0.

  Hereinafter, an image processing apparatus according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of an image processing apparatus according to an embodiment. As shown in FIG. 1, the image processing apparatus according to the present embodiment includes an image input unit 10, an input image data storage unit 12, a total reduction ratio setting unit 14, a reduction filter processing unit 20, a reduction filter storage unit 22, and a reduction count setting. Unit 24, intermediate image data storage unit 26, interpolation function processing unit 30, interpolation function storage unit 32, adjustment reduction magnification setting unit 34, reduced image data storage unit 36, display processing unit 40, and display device 42. Yes.

  The image input unit 10 is for capturing image data having a predetermined resolution. This image data corresponds to an image (first image) composed of a plurality of pixels arranged at equal intervals along each of a first direction and a second direction that is non-parallel to the first direction. Is. For example, the first direction is set in the direction (horizontal direction) along the horizontal axis (x-axis), and the second direction is set in the direction (vertical direction) along the vertical axis (y-axis). Image data corresponding to an image constituted by a plurality of pixels arranged along a horizontal axis and a vertical axis orthogonal to each other is input using the image input unit 10.

  Specifically, a scanner that optically reads an image drawn on a paper document with a predetermined resolution can be used as the image input unit 10. Alternatively, when image data recorded on a removable storage medium such as a CD or DVD is captured, a drive device (reading device) for these storage media can be used as the image input unit 10. When capturing image data recorded in a semiconductor memory or a hard disk device, an input / output interface for connecting them can be used as the image input unit 10. In addition, when image data is captured by communication via the Internet, other networks, a telephone line, or the like, a communication device corresponding to the type of line can be used as the image input unit 10. In addition, when image data is captured by broadcast distribution, a receiving device corresponding to the broadcast form can be used as the image input unit 10.

  The input image data storage unit 12 stores the image data captured by the image input unit 10. The total reduction ratio setting unit 14 sets the total reduction ratio B based on the image (first image) captured by the image input unit 10 and the final image (third image) after reducing the image. Set the value. Specifically, when the image sizes (number of pixels) of the first image and the third image are determined, the ratio of these number of pixels is set as the “total reduction magnification”.

  The reduction filter processing unit 20 repeats reduction processing using a two-dimensional reduction filter for image data captured by the image input unit 10 and stored in the input image data storage unit 12 once or a plurality of times.

  The reduction filter storage unit 22 stores data of a two-dimensional reduction filter used when the image is reduced at a fixed reduction magnification A along each of the first and second directions (horizontal direction and vertical direction). This data is read out and reduced by the reduction filter processing unit 20. A specific example of the reduction process of the fixed reduction magnification A will be described later.

  The reduction count setting unit 24 uses the reduction filter processing unit 20 based on the image (first image) captured by the image input unit 10 and the final image (third image) after reducing the image. The number N of times of reduction processing is set. For example, the number N of reduction processes is determined based on the total reduction magnification B.

  The intermediate image data storage unit 26 stores image data of an image (second image) after the reduction process is performed by the reduction filter processing unit 20.

  The interpolation function processing unit 30 performs the reduction process on the second image after the reduction process by the reduction filter processing unit 20 with the adjustment reduction magnification C larger than the fixed reduction magnification A described above. Image data of the obtained image (third image) is output.

  The interpolation function storage unit 32 stores interpolation function data used in the reduction processing by the interpolation function processing unit 30. This data is read out, and interpolation processing by the interpolation function processing unit 30 is performed to generate a third image having a smaller number of pixels than the second image.

  The adjustment reduction ratio setting unit 34 is based on the image (first image) captured by the image input unit 10 and the final image (third image) after reducing the image, and the interpolation function processing unit 30. The adjustment reduction magnification C of the reduction processing by is set. For example, the adjustment reduction magnification C is determined based on the total reduction magnification B.

Specifically, the fixed reduction ratio is A, the total reduction ratio when the first image is reduced to the third image is B, the number of times of reduction processing by the reduction filter processing unit 20 is N, and the interpolation function processing unit 30 is used. When the adjustment reduction magnification of the reduction process is C, the reduction count setting unit 24 sets ^N = B that satisfies A = C <1 and B = A ^N × C. In addition, the adjustment reduction magnification setting unit 34 sets a value of C that satisfies B = A ^N × C and A <C <1.

  The reduced image data storage unit 36 stores image data of an image (third image) after the reduction process is performed by the interpolation function processing unit 30.

  The display processing unit 40 reads out the reduced image data after the reduction processing by the interpolation function processing unit 30 from the reduced image data storage unit 36 and reduces the image captured by the image input unit 10 at the total reduction magnification B. The image is displayed on the screen of the display device 42. In parallel with this display operation or in place of the display operation, the reduced image is printed using a printer or transmitted to other devices via the Internet, telephone line, wireless line, etc. Also good.

  The image input unit 10 described above is an image input unit, the reduction filter storage unit 22 is a reduction filter storage unit, the reduction filter processing unit 20 is a first reduction processing unit, and the interpolation function processing unit 30 is a second reduction processing unit. Further, the reduction count setting unit 24 corresponds to the reduction count setting unit, the adjustment reduction magnification setting unit 34 corresponds to the adjustment reduction magnification setting unit, and the total reduction magnification setting unit 14 corresponds to the total reduction magnification setting unit.

  The operation performed by the image input unit 10 described above is the operation of the image input step, the operation performed by the reduction filter processing unit 20 is the operation of the first reduction processing step, and the operation performed by the interpolation function processing unit 30. In the operation of the second reduction processing step, the operation performed by the reduction number setting unit 24 is the operation of the reduction number setting step, and the operation performed by the adjustment reduction magnification setting unit 34 is the operation of the adjustment reduction magnification setting step. The operation performed by the magnification setting unit 14 corresponds to the operation of the overall reduction magnification setting step.

  Further, the above-described image processing apparatus can be realized by a computer configuration including a CPU, a ROM, a RAM, and the like. In this case, the input image data storage unit 12, the reduced filter storage unit 22, the intermediate image data storage unit 26, the interpolation function storage unit 32, and the reduced image data storage unit 36 can be configured by a hard disk device or a semiconductor memory. . The total reduction magnification setting unit 14, the reduction filter processing unit 20, the reduction number setting unit 24, the interpolation function processing unit 30, and the adjustment reduction magnification setting unit 34 are provided with predetermined image processing programs stored in a ROM, a RAM, a hard disk device, or the like. It can be realized by executing it on the CPU.

  The image processing apparatus according to the present embodiment has such a configuration. Next, specific contents of the image reduction process performed by the image processing apparatus will be described. FIG. 2 is a flowchart showing an operation procedure of image reduction processing by the image processing apparatus of this embodiment. Image data is input using the image input unit 10 (step 200) and stored in the input image data storage unit 12 (step 201). Next, the total reduction ratio setting unit 14 determines the total reduction ratio B based on the image sizes of the input image and the reduced image (step 202). The reduction count setting unit 24 determines the number N of repetitions of the reduction processing performed by the reduction filter processing unit 20 based on the total reduction magnification B determined by the total reduction magnification setting unit 14 (step 203).

  Next, the reduction filter processing unit 20 reads the two-dimensional reduction filter stored in the reduction filter storage unit 22, and reduces the input image data stored in the input image data storage unit 12 by the reduction number setting unit 24. A reduction process is performed with the determined reduction number N as the number of repetitions (step 204). The intermediate image data finally obtained by the N reduction processes is stored in the intermediate image data storage unit 26 (step 205).

  FIG. 3 is an explanatory diagram illustrating a specific example of the reduction process performed by the reduction filter processing unit 20. FIG. 4 is an explanatory diagram showing an image after the reduction process by the reduction filter processing unit 20. In FIG. 3, each circle represents each pixel of the original image to be reduced. In FIGS. 3 and 4, x indicates each pixel of the image obtained by the reduction process.

  In the present embodiment, the number of pixels in the horizontal direction and the vertical direction is halved by a single reduction process by the reduction filter processing unit 20. The reduction process is performed using a 4 × 4 two-dimensional reduction filter having each pixel value of 4 × 4 pixels as a component. Specifically, paying attention to the pixel w shown in FIG. 3, the pixel value of the pixel w is calculated by using each pixel value of 4 × 4 pixels (16 pixels in total) surrounded by a dotted line. . However, in this embodiment, the pixel values of all 16 pixels are not used, but only the pixel values of 8 pixels indicated by a, b, c, d, e, f, g, and h in FIG. 3 are used. Thus, the pixel value of the pixel w is calculated.

  Specifically, the filter coefficients of the two-dimensional reduction filter are as follows.

  The filter coefficients corresponding to the four pixels a, b, c, and d are set to 9/16, and the filter coefficients corresponding to the other four pixels e, f, g, and h are set to −1. / 16 is set. The filter coefficient is set to 0 for the other 8 pixels.

That is, the value multiplied by the pixel value of each of the 4 × 4 pixels surrounded by the dotted line in FIG. 3 is w11, w12, w13, w14, w21, w22, w23, w24, w31 in the order of arrangement from the upper left pixel. , W32, w33, w34, w41, w42, w43, w44, w11 = w14 = w41 = w44 = −1 / 16, w22 = w23 = w32 = w33 = 9/16. In addition, other w12, w13, w21, w24, w31, w34, w42, and w43 are all 0. FIG. 5 is an explanatory diagram of these filter coefficient setting methods, and is used in this embodiment. A function (interpolation function) is shown. The sampling function φ (t) shown in FIG. 5 is a piecewise polynomial expressed by the following equation, and has two pixels on the left and right of the interpolation position in the center (two pixels (total) The pixel value of the interpolation target pixel w can be calculated using the pixel value of 4 pixels)).

φ (t) = − 1.75 | t | ² +1.0 (| t | ≦ 0.5)
1.25 | t | ² −3.0 | t | +1.75 (0.5 <| t | ≦ 1.0)
0.75 | t | ² −2.0 | t | +1.25 (1.0 <| t | ≦ 1.5)
−0.25 | t | ² + | t | −1.0 (1.5 <| t | ≦ 2.0)
0 (2.0 <| t |)
... (1)
In the present embodiment, there are no other pixels in the horizontal and vertical directions of the pixel w shown in FIG. 3, and eight pixels a, b, c, d, e, f, g, h exists. For this reason, the pixel value of the center pixel w is calculated using these eight pixels.

  By the way, if the pixel interval along the oblique 45 ° direction (for example, the distance between the pixel d and the pixel h) is 1, the distance from the pixel w to the pixels a, b, c, and d is 0.5. The value of the sampling function corresponding to this distance can be obtained by substituting t = 0.5 into the above equation, and the value is 9/16. Further, the distance from the pixel w to the pixels e, f, g, and h is 1.5. The value of the sampling function corresponding to this distance can be obtained by substituting t = 1.5 into the above equation, and the value is −1/16. The filter coefficient of the two-dimensional reduction filter shown in Equation 1 is determined in this way.

  By using this two-dimensional reduction filter, the pixel value w of the pixel w becomes the pixel values a, b, c, d of the eight pixels a, b, c, d, e, f, g, h described above. , E, f, g, and h are used to calculate the following formula.

w = (a + b + c + d) × 9 / 16− (e + f + g + h) / 16
In this way, for example, the 12 × 12 pixel image shown in FIG. 3 is reduced to the 6 × 6 pixel image shown in FIG. In step 204, such a reduction process with a reduction ratio of 1/2 is repeated N times.

  Next, the adjustment reduction magnification setting unit 34 determines an adjustment reduction magnification C that is a magnification of the reduction processing performed by the interpolation function processing unit 30 based on the total reduction magnification B determined by the total reduction magnification setting unit 14. (Step 206).

  Next, the interpolation function processing unit 30 reads the interpolation function data stored in the interpolation function storage unit 32, and adjusts the intermediate image data stored in the intermediate image data storage unit 26 by the adjustment reduction magnification setting unit 34. Reduction processing of the determined adjustment reduction magnification C is performed (step 207). The reduced image data obtained by the reduction process is stored in the reduced image data storage unit 36 (step 208).

The adjustment reduction magnification C, which is the magnification of the reduction processing performed in step 207, is performed when a target image is not obtained by the N reduction processing using the fixed reduction magnification in step 204. Therefore, when the relationship of B = A ^N is satisfied, the reduction process in step 207 is omitted.

  In addition, the reduction process using the adjustment reduction ratio C is not performed using a two-dimensional reduction filter as in the reduction process in step 204, but is a sampling function specified by the interpolation function data stored in the interpolation function storage unit 32. Are used separately along the horizontal and vertical directions. In the present embodiment, the reduction process by the interpolation function processing unit 30 is performed using the sampling function shown in FIG.

  6 and 7 are explanatory diagrams of the reduction process performed by the interpolation function processing unit 30. FIG. As described above, when the fixed reduction ratio A is 1/2, the adjustment reduction ratio C is set to a value between 1/2 and 1. 6 and 7, □ indicates each pixel before reduction, ☆ indicates each pixel after reduction, and Δ indicates an intermediate pixel used for obtaining the pixel after reduction. Compared to the horizontal and vertical intervals of the pixels before reduction, the intervals of the pixels after reduction become wider and the number of pixels decreases.

  Consider a case where the pixel value p of the reduced pixel p is calculated. For example, (1) First, pixel values h1, h2, h3, h4 of four intermediate pixels h1, h2, h3, h4 having the same position in the vertical direction as the pixel p are obtained (FIG. 6), (2) next The pixel value p is calculated based on these pixel values h1, h2, h3, and h4 (FIG. 7).

The calculation of the pixel value h1 of the intermediate pixel h1 is performed using the upper and lower two pixels a01, a05, a09, and a13 of the intermediate pixel h1 and the sampling function (FIG. 5) represented by equation (1). Specifically, when the horizontal and vertical intervals of the pixels a01 to a16 are 1, and the distances from the intermediate pixel h1 to the pixels a01, a05, a09, and a13 are t1, t2, t3, and t4, the intermediate pixel h1 The pixel value h1 of
h1 = a01 × φ (t1) + a05 × φ (t2)
+ A09 × φ (t3) + a13 × φ (t4)
It becomes. The same applies to the pixel values of the other intermediate pixels h2, h3, and h4.

  Next, using the pixel values of these four intermediate pixels h1 to h4 and the sampling function represented by the expression (1), the pixel value p of the pixel p is obtained by the same method. In addition, pixel values of other pixels indicated by ☆ are obtained in the same manner. The pixel value (reduced image data) of each pixel obtained in this way is stored in the reduced image data storage unit 36.

  Next, the display processing unit 40 reads the reduced image data stored in the reduced image data storage unit 36, and displays the reduced image obtained by reducing the image captured by the image input unit 10 with the overall reduction magnification B by the display device 42. Is displayed on the screen (step 209).

  As described above, in the image processing apparatus according to the present embodiment, by combining one or more reduction processes using the two-dimensional reduction filter with the fixed reduction ratio A and one reduction process with the adjustment reduction ratio C, 1 / Reduction processing with an arbitrary reduction ratio smaller than 4 is possible. Further, by performing the reduction process in a plurality of times, information on each pixel can be included in the information on each pixel after the reduction process, so that deterioration in image quality can be suppressed. Furthermore, the processing content can be simplified by repeatedly using a reduction filter with a fixed coefficient. In particular, by reducing the fixed reduction ratio A to 1/2, the reduction process of the fixed reduction ratio can be further simplified.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the above-described embodiment, the first direction is the horizontal direction and the second direction is the vertical direction, and the reduction process is performed on the input image composed of the pixels regularly arranged along these directions. Although described, the first direction and the second direction may be directions other than the horizontal direction and the vertical direction orthogonal to each other.

  Further, as shown in FIGS. 6 and 7, the reduction process of step 207 (reduction process of the adjustment reduction magnification C) first obtains the pixel values of the four intermediate pixels arranged in the horizontal direction, and then determines these four values. The pixel value of the final pixel is obtained from the pixel value of the intermediate pixel. Conversely, the pixel values of four intermediate pixels arranged in the vertical direction are first obtained, and then the pixel values of these four intermediate pixels are obtained. From this, the final pixel value of the pixel may be obtained.

  In the above-described embodiment, the case has been described in which the reduction processing in both steps 204 and 207 is performed using the sampling function shown in FIG. 5 and the expression (1). However, other sampling functions are used. It may be. Further, the sampling function used for obtaining the two-dimensional reduction filter used in the reduction process in step 204 may be different from the sampling function used in the reduction process in step 207.

  In the above-described embodiment, the fixed reduction magnification A is set to ½, but the fixed reduction magnification A may be set to a value other than ½. In the reduction process using the two-dimensional reduction filter, the pixel value is determined in consideration of the pixel value of 4 × 4 pixels (16 pixels) around the pixel of interest w (more precisely, the pixel value of 8 pixels therein). Although calculated, the pixel value of the pixel of interest w may be calculated in consideration of each pixel value in a range other than 4 × 4 pixels.

It is a figure which shows the structure of the image processing apparatus of one Embodiment. It is a flowchart which shows the operation | movement procedure of the image reduction process by the image processing apparatus of this embodiment. It is explanatory drawing which shows the specific example of the reduction process performed by the reduction filter process part. It is explanatory drawing which shows the image after the reduction process by the reduction filter process part. It is explanatory drawing of the setting method of a filter coefficient. It is explanatory drawing of the reduction process performed by the interpolation function process part. It is explanatory drawing of the reduction process performed by the interpolation function process part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image input part 12 Input image data storage part 14 Total reduction ratio setting part 20 Reduction filter processing part 22 Reduction filter storage part 24 Reduction frequency setting part 26 Intermediate image data storage part 30 Interpolation function processing part 32 Interpolation function storage part 34 Adjustment reduction Magnification setting unit 36 Reduced image data storage unit 40 Display processing unit 42 Display device

Claims (30)

An image input means for inputting a first image composed of a plurality of pixels arranged at equal intervals along each of a first direction and a second direction that is non-parallel to the first direction;
Reduction filter storage means for storing data of a two-dimensional reduction filter used when performing image reduction at a fixed reduction magnification along each of the first and second directions;
First reduction processing means for performing reduction processing using the two-dimensional reduction filter on the first image one or more times based on data stored in the reduction filter storage means;
Second reduction processing for outputting a third image by performing reduction processing at an adjustment reduction magnification larger than the fixed reduction magnification for the second image after reduction processing by the first reduction processing means Means,
An image processing apparatus comprising: In claim 1,
An image processing apparatus, further comprising: a reduction number setting unit that sets the number of times of reduction processing by the first reduction processing unit based on the first image and the third image. In claim 2,
The fixed reduction magnification is A, the reduction magnification when the first image is reduced to the third image is B, the number of times of reduction processing by the first reduction processing means is N, and the second reduction processing means. When the adjustment reduction ratio of reduction processing by C is C,
The image processing apparatus, wherein the reduction count setting means sets the value of N satisfying B = A ^N × C and A <C <1. In claim 1,
An image processing apparatus, further comprising: an adjustment reduction ratio setting unit that sets an adjustment reduction ratio of a reduction process by the second reduction processing unit based on the first image and the third image. In claim 4,
The fixed reduction magnification is A, the reduction magnification when the first image is reduced to the third image is B, the number of times of reduction processing by the first reduction processing means is N, and the second reduction processing means. When the adjustment reduction ratio of reduction processing by C is C,
The image processing apparatus, wherein the adjustment reduction magnification setting means sets the value of C satisfying B = A ^N × C and A <C <1. In claim 3 or 5,
An image processing apparatus, further comprising: an overall reduction ratio setting unit that sets the value of B based on the number of pixels of the first image and the number of pixels of the third image. In any one of Claims 1-6,
The image processing apparatus, wherein the first and second directions are orthogonal to each other. In any one of Claims 1-6,
The image processing apparatus according to claim 1, wherein the fixed reduction magnification is 1/2. In any one of Claims 1-6,
The image processing apparatus, wherein the two-dimensional reduction filter uses a value obtained by adding a value obtained by multiplying each pixel value of 4 × 4 pixels by a predetermined coefficient as a pixel value of a new pixel. In claim 9,
The value multiplied by the pixel value of each pixel of the 4 × 4 pixels is w11, w12, w13, w14, w21, w22, w23, w24, w31, w32, w33, w34, w41, w42, w43, in the order of arrangement. An image processing apparatus characterized in that when w44, w11 = w14 = w41 = w44 = -1 / 16, w22 = w23 = w32 = w33 = 9/16, and the others are set to 0. An image input step for inputting a first image composed of a plurality of pixels arranged at equal intervals along each of a first direction and a second direction that is non-parallel to the first direction;
Data of a two-dimensional reduction filter used when reducing the image at a fixed reduction magnification along each of the first and second directions is read from the reduction filter storage means, and the second image is read from the first image. A first reduction processing step in which reduction processing using a dimension reduction filter is repeated once or a plurality of times;
Second reduction processing for outputting a third image by performing reduction processing with an adjustment reduction magnification larger than the fixed reduction magnification on the second image after the reduction processing in the first reduction processing step Steps,
An image processing method comprising: In claim 11,
An image processing method, further comprising: a reduction count setting step for setting the number of times of reduction processing in the first reduction processing step based on the first image and the third image. In claim 12,
The fixed reduction magnification is A, the reduction magnification when the first image is reduced to the third image is B, the number of times of reduction processing by the first reduction processing means is N, and the second reduction processing means. When the adjustment reduction ratio of reduction processing by C is C,
In the reduction count setting step, the N value satisfying B = A ^N × C and A <C <1 is set. In claim 11,
An image processing method, further comprising: an adjustment reduction magnification setting step for setting an adjustment reduction magnification of the reduction processing in the second reduction processing step based on the first image and the third image. In claim 14,
The fixed reduction magnification is A, the reduction magnification when the first image is reduced to the third image is B, the number of times of reduction processing in the first reduction processing step is N, and the second reduction processing step. When the adjustment reduction magnification of the reduction processing in C is C,
In the adjustment reduction magnification setting step, the value of C satisfying B = A ^N × C and A <C <1 is set. In claim 13 or 15,
An image processing method, further comprising: an overall reduction ratio setting step of setting the value of B based on the number of pixels of the first image and the number of pixels of the third image. In any one of Claims 11-16,
The image processing method according to claim 1, wherein the first and second directions are orthogonal to each other. In any one of Claims 11-16,
The image processing method according to claim 1, wherein the fixed reduction magnification is 1/2. In any one of Claims 11-16,
The image processing method, wherein the two-dimensional reduction filter uses a value obtained by adding a value obtained by multiplying each pixel value of 4 × 4 pixels by a predetermined coefficient as a pixel value of a new pixel. In claim 19,
The value multiplied by the pixel value of each pixel of the 4 × 4 pixels is w11, w12, w13, w14, w21, w22, w23, w24, w31, w32, w33, w34, w41, w42, w43, in the order of arrangement. An image processing method, wherein w11 = w14 = w41 = w44 = -1 / 16, w22 = w23 = w32 = w33 = 9/16, and other values are set to 0 when w44 is assumed. Computer
An image input means for inputting a first image composed of a plurality of pixels arranged at equal intervals along each of a first direction and a second direction that is non-parallel to the first direction;
Reduction filter storage means for storing data of a two-dimensional reduction filter used when performing image reduction at a fixed reduction magnification along each of the first and second directions;
First reduction processing means for performing reduction processing using the two-dimensional reduction filter on the first image one or more times based on data stored in the reduction filter storage means;
Second reduction processing for outputting a third image by performing reduction processing at an adjustment reduction magnification larger than the fixed reduction magnification for the second image after reduction processing by the first reduction processing means Means,
Image processing program to make it function. In claim 21,
An image processing program for causing a computer to further function as a reduction number setting means for setting the number of times of reduction processing by the first reduction processing means based on the first image and the third image. In claim 22,
The fixed reduction magnification is A, the reduction magnification when the first image is reduced to the third image is B, the number of times of reduction processing by the first reduction processing means is N, and the second reduction processing means. When the adjustment reduction ratio of reduction processing by C is C,
The image processing program characterized in that the reduction number setting means sets the value of N satisfying B = A ^N × C and A <C <1. In claim 21,
An image processing program for causing a computer to further function as an adjustment reduction ratio setting means for setting an adjustment reduction ratio for reduction processing by the second reduction processing means based on the first image and the third image . In claim 24,
The fixed reduction magnification is A, the reduction magnification when the first image is reduced to the third image is B, the number of times of reduction processing by the first reduction processing means is N, and the second reduction processing means. When the adjustment reduction ratio of reduction processing by C is C,
The image processing program characterized in that the adjustment reduction magnification setting means sets the value of C that satisfies B = A ^N × C and A <C <1. In claim 23 or 25,
An image processing program for causing a computer to further function as an overall reduction ratio setting unit that sets the value of B based on the number of pixels of the first image and the number of pixels of the third image. In any of claims 21 to 26,
An image processing program characterized in that the first and second directions are orthogonal to each other. In any of claims 21 to 26,
An image processing program, wherein the fixed reduction magnification is 1/2. In any of claims 21 to 26,
An image processing program characterized in that the two-dimensional reduction filter uses a value obtained by adding a value obtained by multiplying each pixel value of 4 × 4 pixels by a predetermined coefficient as a pixel value of a new pixel. In claim 29,
The value multiplied by the pixel value of each pixel of the 4 × 4 pixels is w11, w12, w13, w14, w21, w22, w23, w24, w31, w32, w33, w34, w41, w42, w43, in the order of arrangement. An image processing program characterized in that when w44, w11 = w14 = w41 = w44 = -1 / 16, w22 = w23 = w32 = w33 = 9/16, and the others are set to 0.

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