JP2004110355A - Image processor, outline correction circuit, outline correction method and recording medium recorded with image processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor, an outline correction circuit, an outline correction method and a recording medium in which an image processing program is recorded, by which an image outline correction is applied to image data which not thinned out in image reduction, and a reduced image high in sharpness by preventing the deteroration of image quality. <P>SOLUTION: THe image processor 10 is provided with an outline signal generating circuit 1, an adjusting circuit 2, an outline correcting circuit 11 for correcting the outline of an image based on the data of the position of the outline part of a thinned-out image, a position data detecting circuit 12 for detecting the position of the outline part of a horizontally thinned out image, delay circuits 3 and 13, an adder 4, an image reducing circuit 14 for horizontally thinning out the image data, and for reducing the image size and a microcomputer 15. The image data are horizontally or vertically thinned out, the image size is reduced, the position of the outline part of the thinned out image is detected, and outline correction for correcting the outline of an image at a thinning out position is executed to the image data prior to reduction. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image processing apparatus, an outline correction circuit, and an outline correction method used for image signal processing in an image input device such as a camera, and more particularly, to an image for preventing deterioration in sharpness of an image caused when the size of the image is reduced. The present invention relates to a processing device, a contour correction circuit, a contour correction method, and a recording medium on which an image processing program is recorded.
[0002]
[Prior art]
In an image input device such as a camera, an image signal processing technique for reducing an image size and displaying the image is indispensable. As a method for improving the image sharpness of a reduced image, there is, for example, an image reduction display method and apparatus described in JP-A-2002-77724. The technique described in this publication is a method of performing image contour correction after reducing an image. As shown in FIG. 7, there is a method of performing image reduction after performing image contour correction.
[0003]
FIG. 7 is a block diagram illustrating a conventional image processing apparatus that performs contour correction and image reduction of an image.
In FIG. 7, an image processing apparatus includes an outline signal generation circuit 1 for generating an outline signal from an image input signal, a gain adjustment circuit 2 for adjusting a gain of an edge portion of a luminance signal, a delay circuit 3, an adder 4, an image reduction circuit. 5 and a microcomputer 6.
[0004]
An image signal is input from an image input device such as a camera, and an edge portion of a luminance signal of the image input signal is extracted by the contour signal generation circuit 1. The extracted edge portion is gain-adjusted to an edge signal of an appropriate size by the gain adjustment circuit 2 and output to the adder 4. The luminance signal of the image signal is delayed for a predetermined time by the delay circuit 3 and output to the adder 4. This delay is for matching the timing of the input signal to the adder 4. In the adder 4, the delayed luminance signal and the edge signal are added and combined, and the combined signal becomes a contour-corrected luminance signal.
[0005]
The contour-corrected luminance signal is input to an image reduction circuit 5, which receives a control signal for reduction signal processing from a microcomputer 6 and thins out the signal from the image signal at an arbitrary interval. Is reduced. At this time, the contour-corrected luminance signal is thinned out for image reduction, resulting in a signal in which the balance of the contour-corrected signal is lost, and image quality is degraded.
[0006]
[Problems to be solved by the invention]
However, such a conventional image reduction display device has the following problems.
The apparatus described in Japanese Patent Application Laid-Open No. 2002-77724 has a disadvantage that the image is reduced first, so that the contour of the deteriorated image after thinning is corrected, resulting in an image with insufficient sharpness.
[0007]
Further, as described with reference to FIG. 7, the method of reducing the image after performing the outline correction of the image has a disadvantage that a part of the outline correction is missing when thinning the image. .
This disadvantage will be specifically described.
[0008]
FIG. 8 is a signal waveform diagram according to the image contour correction and image reduction method of FIG.
As shown in FIG. 8A, when a trapezoidal wave signal is input as a luminance signal, the contour signal generation circuit 1 obtains a contour correction signal having an edge component signal (see FIG. 8B). Then, the signal whose gain has been adjusted by the gain adjustment circuit 2 and the signal whose input luminance signal has been delayed by the delay circuit 3 are added by the adder 4. FIG. 8C shows the added luminance signal.
[0009]
In the image reduction circuit 5, when the reduction ratio is decimated at an arbitrary interval in response to the reduction control signal from the microcomputer 6, the image is reduced at the timing of the signal number (1) shown in FIG. When it is subtracted, the output of the output luminance signal becomes as shown in FIG. 8D, and the contour correction portion of the edge component is missing. In the above description, the timing of the number (1) has been described as an example, but similar image quality degradation occurs even if other edge portions are thinned out.
[0010]
The present invention has been made in view of such a problem, and it is possible to perform contour correction of an image at a place where no thinning is performed by reducing an image, to prevent deterioration in image quality, and to obtain a reduced image with high sharpness. It is an object of the present invention to provide an image processing apparatus, an outline correction circuit, an outline correction method, and a recording medium on which an image processing program is recorded.
[0011]
[Means for Solving the Problems]
An image processing apparatus according to the present invention is an image processing apparatus for processing image data, wherein the image data is thinned out in the horizontal or vertical direction to reduce the image size, and an outline of the thinned image is provided. It is characterized by comprising position data detecting means for detecting the position of the portion, and wheel correcting means for correcting the contour of the image at the thinned position detected by the position data detecting means.
[0012]
More preferably, the position data detecting means detects a position of a contour portion of the image to be thinned out.
More preferably, the contour correcting means corrects the image data before reduction.
The contour correcting means may correct the contour of the image based on the pixel of the contour part and one or a plurality of pixels adjacent to the pixel (including those adjacent to the pixel).
[0013]
More preferably, the contour correction means obtains a correction direction of the pixel based on a signal level of a pixel in a contour portion and a signal level of a pixel adjacent to the pixel, and determines a predetermined direction for the pixel in the correction direction. Is corrected.
[0014]
More preferably, the contour correcting means determines the inclination of the contour signal based on a signal level of a pixel of the contour part and a signal level of a pixel adjacent to the pixel. Slope detecting means for detecting, pattern discriminating means for discriminating a pattern between the detected inclination of the contour signal and a plurality of correction patterns, and compensating the contour signal based on a correction direction of the pixel obtained based on the pattern discrimination result. Signal correction means.
[0015]
Further, as a more preferable specific mode, the contour correction means replaces a pixel of the contour part with a pixel adjacent to the pixel or adds a pixel adjacent to the pixel to a pixel of the contour part. It is.
[0016]
In a more preferable specific mode, the contour correcting means weights according to a signal level of a pixel in a contour portion and a signal level of a pixel adjacent to the pixel.
[0017]
The pixel of the outline portion may be a pixel that disappears due to image reduction.
The image processing apparatus according to the present invention is further characterized by further comprising an instructing unit for instructing the image reducing unit to thin out the image according to an image size.
[0018]
Further, the contour correction circuit of the present invention is a contour correction circuit for enhancing the sharpness of the reduced image, wherein the image reduction means for thinning out the image data in the horizontal or vertical direction to reduce the image size. Position data detecting means for detecting the position of the contour portion of the thinned image, and contour correcting means for correcting the contour of the image at the thinned position with respect to the image data before reduction. .
[0019]
The contour correction method according to the present invention is a contour correction method for correcting a contour of a reduced image, wherein the image data is thinned out in a horizontal direction or a vertical direction to reduce an image size, and The image processing apparatus further includes a step of detecting a position of a contour portion of the image, and a correcting step of correcting the contour of the image at the thinned position with respect to the image data before reduction.
[0020]
Further, as a more preferable specific mode, in the correction step, a step of determining a pixel of the contour portion, a contour signal based on a signal level of a pixel of the contour portion and a signal level of a pixel adjacent to the pixel are performed. Detecting the inclination of the contour signal, performing the pattern discrimination between the detected inclination of the contour signal and the plurality of correction patterns, and correcting the contour signal based on the correction direction of the pixel obtained based on the pattern discrimination result. Are sequentially executed.
[0021]
Further, the present invention provides an image processing apparatus for processing image data, wherein the image data is thinned in the horizontal or vertical direction to reduce the image size, and the position of the thinned image data is determined. A computer having recorded thereon a program for functioning as an image processing apparatus comprising: position data detecting means for detecting; and contour correcting means for correcting a contour of an image at a thinned position detected by the position data detecting means. This is a readable recording medium.
[0022]
The present invention also provides an image processing apparatus for processing image data, wherein the image data is thinned out in the horizontal or vertical direction to reduce the image size, and the position of the thinned image data is determined. This is a program for functioning as an image processing apparatus including: a position data detecting unit to be detected; and an outline correcting unit that corrects an outline of an image at a thinned-out position detected by the position data detecting unit.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of an image processing apparatus, a contour correction circuit, and a contour correction method according to the present invention will be described in detail with reference to the accompanying drawings.
First embodiment
FIG. 1 is a block diagram showing an image processing apparatus for performing contour correction and image reduction of an image according to a first embodiment of the present invention. This is an example in which the present invention is applied to an outline correction circuit that corrects the outline of an image thinned out in the horizontal direction when the image is reduced. The same components as those in FIG. 7 are denoted by the same reference numerals.
[0024]
In FIG. 1, an image processing apparatus 10 includes an outline signal generation circuit 1 for generating an outline signal from an image input signal, a gain adjustment circuit 2 for adjusting a gain of an edge portion of a luminance signal, and a position of an outline portion of a thinned image. A contour correction circuit (contour correction means) 11 for correcting the contour of the image based on the data, a position data detecting circuit (position for detecting the position of the contour portion of the image which is thinned out in the horizontal and / or vertical directions when the image is reduced) Data detecting means) 12, a delay circuit 3, a delay circuit 13, an adder 4, an image reducing circuit 14 (image reducing means) for thinning out image data in the horizontal and / or vertical direction to reduce the image size, and A microcomputer 15 (instruction means) for controlling the entire apparatus is provided.
[0025]
The microcomputer 15 controls the entire image processing apparatus 10 and outputs a control signal for instructing the image reduction circuit 14 to thin out the image according to the image size.
The image reduction circuit 14 receives a control signal for reduction signal processing from the microcomputer 15 and reduces the image by thinning out the signal from the image signal at an arbitrary interval. The position data detection circuit 12 specifies the position of the contour correction in the contour correction circuit 11 based on the thinning information from the image reduction circuit 14.
[0026]
FIG. 2 is a block diagram showing a detailed configuration of the contour correction circuit 11.
In FIG. 2, a contour correction circuit 11 includes a comparison circuit 20 (determination means) for comparing the luminance signal delayed and adjusted by the delay circuit 3 with the position data from the position data detection circuit 12, and a contour pixel and its surrounding pixels. A slope detection circuit 21 (slope detection means) for detecting the slope of the contour signal based on how much the signal level of the pixel has changed, and pattern discrimination between the detected slope of the contour signal and a plurality of correction patterns prepared in advance And a signal correction circuit 23 (signal correction unit) that corrects the contour signal so as to be shifted to the previous or subsequent position based on the pixel correction direction obtained based on the pattern determination result. ).
[0027]
The inclination detection circuit 21 can easily detect the difference by taking the difference between the signal level of the pixel in the contour portion and the signal levels of the pixels before and after it. If the pixel is a plurality of pixels having a certain width, it is a difference between the averages of the plurality of pixels. Note that the expression “adjacent to a pixel” is used in the present application, but the meaning of “adjacent” is not limited to a pixel before, after, adjacent to, or below, but is used for convenience as a concept including a pixel adjacent to a pixel. It is not limited by what was.
[0028]
The pattern discrimination circuit 22 discriminates the pattern of the inclination of the contour signal to determine a correction pattern having the best matching pattern, and outputs the correction direction of the pixel indicated by the correction pattern.
[0029]
The signal correction circuit 23 adds a predetermined amount of contour signal (detail signal) at positions before and after the pixel adjacent to the pixel concerned and at the position of the pixel in the correction direction (<correction direction>) (<correction amount). >) Make corrections. <Correction direction> and <Correction amount> will be described later with reference to FIG.
[0030]
As described above, the signal correction circuit 23 shifts the outline signal to the previous or subsequent position, and performs the outline correction to a place where no thinning is performed by image reduction. The specific operations of the comparison circuit 20, the inclination detection circuit 21, the pattern determination circuit 22, and the signal correction circuit 23 will be described later with reference to FIG.
Hereinafter, the outline correction and image reduction operations of the image processing apparatus 10 configured as described above will be described. First, the overall operation of the image processing apparatus 10 will be described.
[0031]
As shown in FIG. 1, an image signal is input from an image input device such as a camera, and an edge portion of a luminance signal of the image signal is extracted by a contour signal generation circuit 1. The extracted edge portion is gain-adjusted to an edge signal of an appropriate size by the gain adjustment circuit 2 and output to the contour correction circuit 11.
[0032]
The contour correction circuit 11 corrects the contour of the image based on the data of the position of the contour portion of the thinned image detected by the position data detection circuit 12, and outputs the corrected contour signal to the adder 4.
[0033]
On the other hand, the luminance signal of the image signal is delayed for a predetermined time by the delay circuit 3 and the delay circuit 13 and output to the adder 4. This delay is for adjusting the processing time of each circuit in the contour signal generation circuit 1, the gain adjustment circuit 2, and the contour correction circuit 11 so as to match the timing of the input signal to the adder 4. In the adder 4, the delayed luminance signal and the edge signal corrected by the contour correction circuit 11 are added and combined, and the combined signal becomes a contour-corrected luminance signal.
[0034]
The contour-corrected luminance signal is input to an image reduction circuit 14, which receives a control signal for reduction signal processing from a microcomputer 15 and thins out the signal from the image signal at an arbitrary interval. Is reduced. Further, the image reduction circuit 14 outputs a signal of an outline portion of the image to be decimated in the horizontal direction to the position data detection circuit 12, and the position data detection circuit 12 outputs the signal of the image to be decimated in the horizontal direction when the image is reduced. The position of the contour portion is detected and output to the contour correction circuit 11.
[0035]
Here, the contour correction circuit 11 can receive the thinning-out information from the image reduction circuit 14 to the position data detection circuit 12 by feedback, and can perform the outline correction of the image where no thinning is performed by the image reduction. Therefore, the luminance signal whose outline has been corrected by the outline signal generation circuit 1 is not thinned out for image reduction, and image quality deterioration can be prevented. Further, since the contour is corrected from the original image signal, it is possible to correct the image quality corresponding to the input image, and it is possible to obtain a reduced image having higher sharpness as compared with the related art.
Next, the contour correction operation by the contour correction circuit 11 will be described in detail.
[0036]
FIG. 3 is a diagram for explaining the principle of the contour correction method of the contour correction circuit 11, and is an example in which a contour signal is synthesized from a luminance signal to generate a contour-corrected luminance signal.
As shown in FIG. 3A, when a trapezoidal wave signal is input as a luminance signal, the contour signal generation circuit 1 obtains a contour correction signal having an edge component signal (see FIG. 3B). The adder 4 adds the signal whose gain has been adjusted by the gain adjustment circuit 2 and whose contour has been appropriately corrected by the contour correction circuit 11 and the signal whose input luminance signal has been delayed by the delay circuits 3 and 13. Is done. FIG. 3C shows the luminance signal after the contour correction, and the numbers (1) to (7) in the figure are the numbers assigned for explaining the correction position. These numbers (1) to (7) correspond to the inclination of the luminance signal and the correction patterns (1) to (7) shown in FIG. This embodiment is an example in which there are seven inclinations of the luminance signal and seven correction patterns corresponding to the inclination.
[0037]
In each correction pattern shown in FIG. 3D, point b is a pixel (position) that disappears due to image reduction, point a is the immediately preceding pixel (position) adjacent to point b, and point c is point b. This is a pixel (position) immediately adjacent to the next pixel. FIG. 3E shows the correction direction (refer to the arrow) of the b-point pixel in each of the correction patterns, and the disappearing b-point pixel is left by correction to the a-point pixel or the c-point pixel (shift). Do). FIG. 3F shows the contour signal corrected in the correction direction of the pixel at point b shown in FIG. 3E. For example, when it is determined that the correction pattern is (1) in FIG. 3D, the correction direction of the b-point pixel is the a-point pixel (as indicated by the arrow of the number (1) in FIG. 3E). Position), and the contour is corrected to the point a side (front side) as indicated by the number (1) in FIG. Similarly, when it is determined that the correction pattern is (2) in FIG. 3D, the correction direction of the point b pixel is the c point pixel as shown by the arrow of the number (2) in FIG. 3 (e). (Position), and the contour is corrected to the point c side (rear side) as indicated by the number {circle around (2)} in FIG.
[0038]
Here, when it is determined that the correction pattern is {circle around (5)} {circle around (6)} {circle around (7)} in FIG. 3 (d), it means that there is no edge portion (no significant change), and the number in FIG. No correction is performed as shown in (5), (6) and (7).
As a result, even if the point b is thinned out by image reduction, the contour correction portion is not missing due to the presence of the contour correction signal on the side of the point a or c.
[0039]
When the direction of correction is determined, a correction is performed by adding a predetermined amount of contour signal (detail signal) (<amount of correction>). For <amount of correction>, the pixel
1. Simple replacement (replace the contour signal at point b with point a or c)
2. Simple addition (point a or point c is added to point b)
3. Take the larger contour signal (replace point b with a larger signal at point a or c)
4. Average value (average of points a, b and c)
5. Weighting according to the degree of inclination (level adjustment according to the level difference from point b)
And so on.
Based on the above basic idea, a specific operation of the contour correction circuit 11 shown in FIG. 2 will be described with reference to FIGS.
[0040]
FIG. 4 is a waveform diagram of the contour correction of the contour correction circuit 11, and FIGS. 4 (a) to 4 (c) correspond to FIGS. 3 (a) to 3 (c), respectively. Point b shown in FIG. 4A is a pixel (position) that disappears due to image reduction, point a is a pixel (position) before the point b, and point c is a pixel (position) after the point b. It is an example of the correction pattern (2) in FIG.
[0041]
FIGS. 5A to 5C are timing charts for explaining the thinning-out position of the luminance signal by the image reduction. FIGS. 5A to 5C show the image reduction circuit 14 and the contour correction circuit 11 when the image is reduced in the horizontal direction. 5D to 5F show the positions of the image reduction circuit 14 and the outline correction circuit 11 when the image is reduced in the vertical direction.
[0042]
FIG. 5A shows the reference synchronization signal hd in the horizontal direction. The microcomputer 15 determines whether to thin out the image at an arbitrary clock after an arbitrary clock based on the horizontal synchronization signal hd, generates a reduced image control signal based on the determination result, and sends the reduced image control signal to the image reduction circuit 14. Output. The image reduction circuit 14 performs image reduction by thinning out an image according to a control signal from the microcomputer 15 and outputs a control signal from the microcomputer 15 to the position data detection circuit 12. FIG. 5B shows a thinned-out position of the image reduction circuit 14. The position data detection circuit 12 detects position data indicating which image in the horizontal direction has been thinned out, and outputs the position data to the contour correction circuit 11. In this case, since the delay time from the contour correction circuit 11 to the image reduction circuit 14 is a fixed time, it is possible to instruct the contour correction circuit 11 at a timing based on the horizontal synchronization signal hd. In the present embodiment, an example has been described in which the position data corresponding to the thinning-out of the image reduction is supplied from the microcomputer 15 to the contour correction circuit 11 via the image reduction circuit 14, but the microcomputer 15 capable of high-speed processing is used. May be directly supplied to the contour correction circuit 11 from the microcomputer 15. By the contour correction by the contour correction circuit 11, the point b which is a thinned-out position is corrected to the front side as shown in FIG.
[0043]
The above is the image reduction in the horizontal direction, but the same can be performed in the vertical direction. Examples of image reduction and contour correction in the vertical direction will be described later according to the second embodiment.
[0044]
The comparison circuit 20 of the contour correction circuit 11 shown in FIG. 2 receives from the position data detection circuit 12 the data of the position to be thinned out by the image reduction of the luminance signal, and the comparison circuit 20 calculates the position data and the position to be thinned out. And outputs the comparison result to the inclination detection circuit 21. The inclination detection circuit 21 detects the inclination of the luminance signal from the comparison of the signal levels.
[0045]
The pattern discriminating circuit 22 discriminates the correction pattern shown in FIG. 3D from the inclination of the luminance signal. When the correction pattern is determined, the correction direction of the contour signal shown in FIG.
The signal correction circuit 23 corrects the contour signal based on the correction direction of the pixel obtained by the pattern discrimination circuit 22 so as to shift the contour signal to a previous or subsequent position.
[0046]
FIG. 4 illustrates the correction of the contour signal by taking the correction pattern (2) of FIG. 3 as an example. FIG. 4C shows a luminance signal whose outline has been corrected before the image is reduced. FIG. 4D shows a state in which the pixel at point b is thinned out by image reduction for this signal waveform. In the conventional example, a part of the contour correction is missing as shown in this figure. In the present embodiment, as shown in FIG. 4E, the outline signal at point b, which is decimated by image reduction, is corrected to point c. 4F has a waveform shown in FIG. 4F, and there is no lack due to the presence of the contour correction signal at the point c, and there is no deterioration in image quality due to thinning for image reduction.
[0047]
As described above, the image processing apparatus 10 according to the present embodiment includes a contour signal generation circuit 1 that generates a contour signal from an image input signal, a gain adjustment circuit 2 that performs gain adjustment of an edge portion of a luminance signal, and a thinned image. An outline correction circuit 11 for correcting the outline of the image based on the data of the position of the outline part, a position data detection circuit 12 for detecting the position of the outline part of the image to be thinned out in the horizontal direction when the image is reduced, It comprises circuits 3 and 13, an adder 4, an image reduction circuit 14 for thinning out image data in the horizontal direction and reducing the image size, and a microcomputer 15, and thinning out the image data in the horizontal or vertical direction. To reduce the image size, detect the position of the outline portion of the image to be thinned, and correct the outline of the image at the thinned position with respect to the image data before reduction. Since the contour correction, can be performed image contour correction where not thinned out by the image reduction and becomes, the sharpness of the image degradation that occurs upon reducing the size of image can be prevented.
Further, since the contour correction is performed on the image signal before reduction (original image signal), the image quality can be corrected in accordance with the input image. A high reduced image can be obtained.
[0048]
Second embodiment
In the first embodiment, the image size is reduced in the horizontal direction, but the same can be performed in the vertical direction. The second embodiment is an example of image reduction and contour correction in the vertical direction.
[0049]
FIG. 6 is a block diagram illustrating an image processing apparatus that performs contour correction and image reduction of an image according to the second embodiment of this invention. The same components as those in FIG. 1 are denoted by the same reference numerals, and description of overlapping portions will be omitted.
6, an image processing apparatus 10 includes an outline signal generation circuit 1 that generates an outline signal from an image input signal, a gain adjustment circuit 2 that adjusts the gain of an edge portion of a luminance signal, and the position of an outline portion of a thinned image. A contour correction circuit 11 for correcting the contour of the image based on the data, a position data detection circuit 12 for detecting the position of the contour portion of the image which is decimated in the horizontal or vertical direction when the image is reduced, and a plurality of horizontal scanning periods. It comprises a line memory 31 for storing image signals, a delay circuit 13, an adder 4, an image reduction circuit 14, and a microcomputer 15.
[0050]
The line memory 31 is a memory for storing the pixel b which disappears due to the image reduction, and the points a and c adjacent to the pixel b above and below the pixel b every scanning period.
The image reduction circuit 14 receives a control signal for reduction signal processing from the microcomputer 15 and reduces a horizontal or vertical image by thinning out the signal from the image signal at an arbitrary interval.
[0051]
The position data detection circuit 12 designates the position of the contour correction in the horizontal or vertical direction in the contour correction circuit 11 based on the thinning information from the image reduction circuit 14. Note that the image reduction circuit 14 and the position data detection circuit 12 only need to be able to reduce the image in the horizontal or vertical direction and detect the position of the outline of the image, and may use the same circuit as in the first embodiment. Alternatively, the horizontal processing block and the vertical processing block may be independent.
[0052]
Hereinafter, the vertical contour correction and image reduction operation of the image processing apparatus 10 configured as described above will be described. Also in the case of the vertical direction, image reduction and contour correction can be performed by performing the same processing as in the horizontal direction described in detail in the first embodiment.
The thinning positions of the image reduction circuit 14 and the contour correction circuit 11 when the image is reduced in the vertical direction are shown in FIGS.
[0053]
FIG. 5D shows the reference synchronization signal vd in the vertical direction. The microcomputer 15 determines whether to thin out the image every arbitrary clock after an arbitrary clock based on the vertical synchronization signal vd, creates a reduced image control signal based on the determination result, and sends the reduced image control signal to the image reduction circuit 14. Output. For example, when the screen size is reduced to 75%, in the vertical direction, thinning is performed every horizontal scanning period by one horizontal scanning period.
[0054]
The image reduction circuit 14 performs image reduction by thinning out an image according to a control signal from the microcomputer 15 and outputs a control signal from the microcomputer 15 to the position data detection circuit 12. FIG. 5E shows a thinned-out position of the image reduction circuit 14. The position data detection circuit 12 detects position data indicating which image in the horizontal direction has been thinned out, and outputs the position data to the contour correction circuit 11. In this case, since the delay time from the contour correction circuit 11 to the image reduction circuit 14 is a fixed time, it is possible to instruct the contour correction circuit 11 at a timing based on the vertical synchronization signal vd. In the present embodiment, an example has been described in which position data is provided from the microcomputer 15 to the contour correction circuit 11 via the image reduction circuit 14, but the position data may be provided directly from the microcomputer 15 to the contour correction circuit 11. Further, the line memory 31 and the delay circuit 13 are set so that the delay amount for timing adjustment is one horizontal scanning period.
By the contour correction by the contour correction circuit 11, the point b, which is the thinned position, is corrected to the front side as shown in FIG.
[0055]
In this manner, in the vertical direction, similarly to the horizontal direction, the outline of the image can be corrected in a place where the image is not thinned out by image reduction, and a reduced image with high sharpness can be obtained while preventing image quality deterioration. In addition, since the contour is corrected from the original image signal, it is possible to perform high-quality correction and obtain a reduced image with high sharpness.
[0056]
In each of the above embodiments, the present invention can be applied to an image processing apparatus, an outline correction circuit, and an outline correction method for inputting / outputting an image in image signal processing in an image input device such as a camera, and is not limited to a still image. It can be applied to other image reproducing apparatuses. For example, the present invention can be applied not only to an information processing apparatus such as a personal computer but also to a recording / reproducing apparatus that records data on a recording medium such as an HDD or a DVD. The content read from a recording medium such as a disk may be in any format.
[0057]
In this embodiment, the names of the image processing device, the contour correction circuit, and the contour correction method are used, but this is for convenience of description, and the signal processing circuit, the information processing device, the reduced display device, the reduced display method, and the like are used. May be. The display device that displays the image reproduction signal may be a display screen of a television receiver as well as a monitor screen of an information processing device such as a personal computer.
[0058]
Furthermore, in the present embodiment, the pixel b which disappears due to the image reduction and the pixels a and c before and after the pixel b are set in one pixel unit, but may be a plurality of pixel units having a certain width. The adjacent pixels need only be adjacent pixels, and need not necessarily be adjacent pixels. Further, the number, arrangement, format, and the like of the correction patterns may be any.
[0059]
Further, it goes without saying that the number and types of circuits and members constituting the image processing apparatus are not limited to the above-described embodiment, and may be realized not only by software but also by hardware.
[0060]
Further, the image processing device, the contour correction circuit, and the contour correction method described above can be realized by a program for causing these image processing devices and the like to function. This program is stored in a computer-readable recording medium. In the present invention, as the recording medium, the main memory of the CPU itself may be a program medium, or a program reading device such as a CD-ROM drive may be provided as an external storage device, and the recording medium may be inserted therein. It may be a program medium such as a CD-ROM that can be read by a computer. In any case, the stored program may be configured to be accessed and executed by the CPU of the system control unit, or the program may be read in any case, and the read program is not shown. The program may be downloaded to the program storage area and the program may be executed. This download program is stored in advance in each device.
[0061]
Here, the program medium is a recording medium configured to be separable from the communication terminal device or the information processing device, and is a magnetic disk such as a magnetic tape or a cassette tape, a CD-ROM, a CD-R / RW, an MO, an MD. , DVD-ROM, DVD-RAM, DVD-RW and other optical disc systems, PC cards, compact flash cards, smart media, IC cards, SD cards, memory sticks, etc., or mask ROMs, EPROMs, EEPROMs, flashes It may be a medium that carries a fixed program including a semiconductor memory such as a ROM.
[0062]
Further, the medium may carry a program in a fluid manner such that the program is downloaded from a communication network through a communication connection unit capable of connecting to an external communication network such as an Internet connection provider or a mobile mail service. . When the program is downloaded from the communication network as described above, the download program may be stored in advance, or may be installed from another storage medium. The content stored in the recording medium is not limited to a program, but may be data.
[0063]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to perform image contour correction where no thinning is performed by image reduction, and to obtain a reduced image with high sharpness while preventing image quality deterioration.
Further, since the contour is corrected from the original image signal, the image quality can be corrected in accordance with the input image, and a reduced image with high sharpness can be obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an image processing apparatus that performs contour correction and image reduction of an image according to a first embodiment of this invention.
FIG. 2 is a block diagram illustrating a detailed configuration of a contour correction circuit of the image processing apparatus according to the present embodiment.
FIG. 3 is a diagram illustrating the principle of a contour correction method of a contour correction circuit of the image processing device according to the present embodiment.
FIG. 4 is a waveform diagram of contour correction by a contour correction circuit of the image processing apparatus according to the embodiment.
FIG. 5 is a timing chart for explaining a thinning-out position of the luminance signal of the image processing apparatus according to the present embodiment by image reduction.
FIG. 6 is a block diagram illustrating an image processing apparatus that performs contour correction and image reduction of an image according to a second embodiment of this invention.
FIG. 7 is a block diagram illustrating a conventional image processing apparatus that performs contour correction and image reduction of an image.
FIG. 8 is a signal waveform diagram according to a conventional image contour correction and image reduction method.
[Explanation of symbols]
1 Contour signal generation circuit
2 Gain adjustment circuit
3,13 delay circuit
4 Adder
10 Image processing device
11. Contour correction circuit (contour correction means)
12. Position data detection circuit (position data detection means)
14. Image reduction circuit (image reduction means)
15 Microcomputer (instruction means)
20 Comparison circuit (determination means)
21 Tilt detecting circuit (tilt detecting means)
22 Pattern discriminating circuit (pattern discriminating means)
23 signal correction circuit (signal correction means)

Claims (15)

In an image processing device that processes image data,
Image reducing means for reducing the image size by thinning out the image data in the horizontal or vertical direction,
Position data detecting means for detecting the position of the thinned image data,
An image processing apparatus comprising: a contour correcting unit that corrects a contour of an image at a thinning position detected by the position data detecting unit. 2. The image processing apparatus according to claim 1, wherein the position data detection unit detects a position of a contour portion of the image to be thinned out. 2. The image processing apparatus according to claim 1, wherein the contour correction unit corrects the image data before reduction. 4. The image processing apparatus according to claim 1, wherein the contour correction unit corrects a contour of an image based on a pixel of the contour part and one or more pixels adjacent to the pixel. 5. The contour correction unit determines a correction direction of a pixel based on a signal level of a pixel in a contour portion and a signal level of a pixel adjacent to the pixel, and performs predetermined correction on the pixel in the correction direction. The image processing apparatus according to any one of claims 1, 3 and 4, wherein The contour correction means includes:
Determining means for determining a pixel of an outline portion;
Slope detection means for detecting a slope of a contour signal based on a signal level of a pixel of the contour portion and a signal level of a pixel adjacent to the pixel;
Pattern determination means for performing a pattern determination of the detected inclination of the contour signal and a plurality of correction patterns,
6. The image processing apparatus according to claim 1, further comprising: a signal correction unit configured to correct a contour signal based on a correction direction of a pixel obtained as a result of the pattern determination. apparatus. The contour correction means includes:
Replace the pixel of the outline part with a pixel adjacent to the pixel, or
The image processing device according to claim 1, wherein a pixel adjacent to the pixel is added to a pixel of the contour portion. The contour correction means includes:
9. The method according to claim 1, wherein weighting is performed according to a signal level of a pixel in a contour portion and a signal level of a pixel adjacent to the pixel. An image processing apparatus according to claim 1. 9. The image processing apparatus according to claim 1, wherein the pixels in the outline portion are pixels that disappear by image reduction. 10. 2. The image processing apparatus according to claim 1, further comprising an instruction unit that instructs the image reduction unit to perform thinning according to an image size. In an image contour correction circuit for enhancing the sharpness of a reduced image,
Image reducing means for reducing the image size by thinning out the image data in the horizontal or vertical direction,
Position data detection means for detecting the position of the outline portion of the image to be thinned,
A contour correction circuit, comprising: contour correction means for correcting the contour of the image at the thinned position with respect to the image data before reduction. In an outline correction method for correcting the outline of a reduced image,
Thinning the image data horizontally or vertically to reduce the image size;
Detecting the position of the contour portion of the thinned image;
A correction step of correcting the outline of the image at the thinned position with respect to the image data before reduction. In the correction step,
Determining pixels of the outline part;
Detecting the slope of the contour signal based on the signal level of the pixel of the contour portion and the signal level of a pixel adjacent to the pixel;
Performing a pattern discrimination between the detected inclination of the contour signal and the plurality of correction patterns;
13. The method according to claim 12, wherein the step of correcting the contour signal is sequentially performed based on the correction direction of the pixel obtained as a result of the pattern determination. In an image processing apparatus for processing image data, image reduction means for thinning out image data in the horizontal or vertical direction to reduce the image size, and position data detection means for detecting the position of the image data to be thinned out A computer-readable recording medium on which is recorded a program for functioning as an image processing device comprising: a contour correcting means for correcting a contour of an image at a thinned position detected by the position data detecting means. In an image processing apparatus for processing image data, image reduction means for thinning out image data in the horizontal or vertical direction to reduce the image size, and position data detection means for detecting the position of the image data to be thinned out And a program for causing the image processing apparatus to function as an image processing device including: a contour correcting unit that corrects a contour of an image at a thinned position detected by the position data detecting unit.

Images