JP2010198346A - Apparatus and method for processing image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing apparatus capable of controlling a sharpening processing or a coring processing in accordance with the change of an image. <P>SOLUTION: The image processing apparatus includes: a detection means for detecting a contrast variation between a plurality of frames included in image data; a sharpening control means for setting a sharpening parameter for controlling sharpening effect gain for the image data according to the detected contrast variation; and a sharpening processing means for executing the sharpening processing for the image data based on the sharpening parameter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image processing apparatus and an image processing method for executing a sharpening process for sharpening an image. The present invention also relates to an image processing apparatus that executes a coring process for reducing noise components in an image.

  In recent years, opportunities to view video content on a display for a personal computer having a resolution exceeding the SD (Standard Definition) standard are increasing. In addition, printer performance has been improved, and high-density printing has become possible. Furthermore, with the full-scale high-definition broadcasting, television receivers that are compliant with HD (High Definition) standards have become popular in ordinary households.

  Compared with such an output device having a high resolution, video data acquired by a photographing device such as a video camera, a television broadcast conforming to the SD standard, a DVD, or the like has a low resolution. For this reason, it is necessary to increase the resolution of the video data by some means. In addition, it is necessary to increase the resolution when displaying a part of a video or an image in an enlarged manner or when using a video camera to shoot with a digital zoom beyond the optical zoom.

  Conventionally, linear interpolation and interpolation by three-dimensional convolution (Cubic Convolution) have been used for high resolution, but there is a problem that sufficient sharpness cannot be obtained. Therefore, research on super-resolution technology that generates new pixel value data between pixels, creates high frequency components, and sharpens them to generate images that exceed the original resolution of image data. (See Patent Documents 1 and 2). In addition, development for incorporating a super-resolution function into the video input / output device as described above is also in progress.

JP 2008-067110 A JP 2008-146190 A

  However, when such sharpening processing is mounted on an actual output device such as a digital television, it has been found that depending on the state of the image, the sharpening processing may reduce the image quality. For example, when the input source image includes a rapid brightness change such as fade-in or fade-out, the image quality may be deteriorated by the sharpening process. Similarly, the image quality may deteriorate due to the coring process.

  An object of the present invention is to provide an image processing apparatus and an image processing method capable of controlling a sharpening process or a coring process in accordance with an image change.

  An image processing apparatus according to an embodiment of the present invention includes a detection unit configured to detect a change in brightness between a plurality of frames included in image data, and sharpening of the image data according to the detected change in brightness. Sharpening control means for setting a sharpening parameter for controlling the effect gain, and sharpening processing means for executing a sharpening process on the image data based on the sharpening parameter.

  An image processing method according to an embodiment of the present invention detects a light / dark change amount between a plurality of frames included in image data, and sets a sharpening effect gain for the image data in accordance with the detected light / dark change amount. A sharpening parameter to be controlled is set, and a sharpening process is performed on the image data based on the sharpening parameter.

  ADVANTAGE OF THE INVENTION According to this invention, the image processing apparatus and image processing method which can control a sharpening process or a coring process according to the change of an image can be provided.

1 is a diagram illustrating a schematic configuration of an image processing apparatus according to an embodiment of the present invention. It is a figure which shows an example of the change of the luminance histogram at the time of fade-out. It is a figure which shows an example of the weighting process with respect to histogram distribution. It is a flowchart which shows an example of the image quality deterioration prevention process which variably controls the effect of a super-resolution coring process and an image sharpening process according to the sudden brightness change, such as fade-in or fade-out. It is a figure for demonstrating the outline | summary of the light-dark change amount (difference value) between several frames. It is a figure which shows an example of the input-output conversion for acquiring the correction parameter for controlling the effect of a super-resolution coring process. It is a figure which shows an example of the input-output conversion for acquiring the correction parameter for controlling the effect of an image sharpening process. It is a figure which shows schematic structure of the television signal receiver incorporating the image processing apparatus shown in FIG. It is a figure which shows schematic structure of a super-resolution coring process module. It is a figure which shows schematic structure of a vertical noise reduction circuit (coring).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an image processing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the image processing apparatus includes a histogram acquisition module 104, a histogram value frame buffer 105, a luminance level transition state determination module 108, adders 110 and 117, a super-resolution coring processing module 120, and an image sharpening. A processing module 127 is provided.

  The super-resolution coring processing module 120 receives input video signals 101 (luminance: Y), 102 (color signal: Cb / Pb), 103 (color signal: Cr / Pr). Similarly, the input video signals 101, 102, and 103 are also input to the histogram acquisition module 104. The super-resolution coring processing module 120 executes the super-resolution coring processing, and the super-resolution coring processing here means processing for suppressing noise components that may be generated by the super-resolution processing. The histogram acquisition module 104 acquires a histogram indicating the luminance distribution of the input video image in units of frames.

  When fading out, as shown in FIG. 2, the histogram of each image gradually changes so that the dark portion becomes stronger. On the contrary, when fading in, the histogram of each image gradually changes so that the bright part becomes stronger.

  FIG. 3 is a diagram illustrating an example of weighting processing for the histogram distribution. As can be seen from FIG. 3, the weighting coefficient increases as the luminance level decreases. This is because, during fade-in / fade-out, the stripe pattern due to the gradation difference in the plain region is easily noticeable in the region where the luminance level is low. That is, the stripe pattern due to the gradation difference in the plain area is easily noticeable on the dark side screen, so that the histogram value is enhanced as the dark side screen is obtained. Further, the weighting coefficient characteristic has a smaller coefficient value at a higher luminance level, and therefore the data amount is reduced for a bright screen. This also reduces the burden of data processing.

  As shown in FIG. 3, the histogram acquisition unit 104 multiplies the frequency of each level of the acquired histogram distribution by a weighting coefficient set for each level, and acquires the sum of the frequencies of all levels. The calculated value (histogram value) of the current frame is output to the histogram value frame buffer 105. In the case of fading out, the calculated value of the current frame is reduced from the calculated value of the previous frame. Conversely, in the case of fading out, the calculated value of the current frame increases from the calculated value of the previous frame. The obtained calculated value is output to the histogram value frame buffer 105 as the calculated value of the current frame.

  The histogram value frame buffer 105 buffers histogram values of a plurality of frames including the current frame, and changes the histogram values 107 of the plurality of frames including the current frame used for calculation in the luminance level transition state determination module 108 to the luminance level transition. It transmits to the state determination module 108.

  The luminance level transition state determination module 108 detects a light / dark change amount (difference value described below) between a plurality of frames based on the histogram value 107, and detects a fade-in or fade-out interval based on the detection result of the light / dark change amount. The fade-in or fade-out interval can be detected based on whether or not the same polarity (plus or minus) is continuous based on the difference in histogram values between a plurality of frames. When the luminance level transition state determination module 108 detects a fade or fade-out interval, the luminance level transition state determination module 108 outputs the first correction parameter (offset data) corresponding to the luminance change slope (brightness / darkness change amount) to the adder 110 in the interval. Then, the second correction parameter (offset data) corresponding to the luminance change slope (brightness / darkness change amount) is output to the adder 117 in the section. The luminance level transition state determination module 108 may output the corrected first or second correction parameter so that the first or second correction parameter does not change suddenly or frequently.

  The adder 110 adds the super-resolution coring initial parameter 111 and the first correction parameter to generate a super-resolution coring parameter, and outputs the super-resolution coring parameter to the super-resolution coring processing module 120. To do. That is, the adder 110 sets the super-resolution coring parameter corrected according to the luminance change slope (brightness / darkness change amount) in the super-resolution coring processing module 120.

  The adder 117 adds the image sharpening initial parameter 118 and the second correction parameter to generate an image sharpening parameter, and outputs the image sharpening parameter to the image sharpening processing module 127. That is, the adder 117 sets the image sharpening parameter corrected according to the luminance change slope (brightness / darkness change amount) to the image sharpening processing module 127.

  Thereby, the super-resolution coring processing module 120 can control the super-resolution coring effect according to the luminance change slope (brightness / darkness change amount). That is, the super-resolution coring processing module 120 can enhance the super-resolution coring effect in response to a sudden brightness change (fade-in or fade-out of a certain level or more) such as fade-in or fade-out. . Thereby, deterioration of MPEG noise can be prevented, and the user can enjoy a video to which the super-resolution coring process optimum for the input image is applied.

  The image sharpening processing module 127 can also control the image sharpening effect according to the luminance change slope (brightness / darkness change amount). That is, the image sharpening processing module 127 can also control the image sharpening effect in response to a sudden change in brightness such as fade-in or fade-out (fade-in or fade-out of a certain level or more). As a result, deterioration of MPEG noise can be prevented, and the user can enjoy a video to which an image sharpening process optimal for the input image is applied.

  Here, the super-resolution processing by the super-resolution coring processing module 120 and the image sharpening processing module 127 will be supplemented. For example, the image sharpening processing module 127 estimates the original pixel value from the low-resolution image signal that is the first resolution and increases the number of pixels, thereby restoring the high-resolution image signal that is the second resolution. Process. Here, the “original pixel value” is, for example, an image obtained when an image of the same subject as that obtained when a low resolution (first resolution) image signal is captured with a high resolution (second resolution) camera. A value indicated by each pixel of the signal. In addition, “estimate and increase the number of pixels” refers to capturing the characteristics of the target image, estimating the original pixel value from an image highly correlated within the same frame or between frames, and creating a new pixel. This means that the corresponding pixel value is used. That is, the correlation between images is used.

  More specifically, first, a temporary full HD high-resolution video is created from the original input video by up-conversion processing. That is, the interpolated pixels are interpolated based on the information of adjacent pixels to create a provisional full HD high-resolution video. The interpolated pixels are not necessarily in the original video. That is, noise or edge disturbance due to calculation errors may occur.

  Next, based on the imaging model function, a video that is down-converted to the same resolution as the original video is created from the temporary full HD high-resolution video. The imaging model function is a function that reproduces the same processing that a general camera converts information of an imaging element into a video signal by calculation.

  The down-converted video should be the same as the original input video, but a difference occurs between the down-converted video and the original input video due to a calculation error in the up-conversion process. This difference is detected, and correction is made so that a calculation error does not occur with reference to information on peripheral pixels and the like, and an output video subjected to super-resolution processing close to the original input video is generated.

  That is, the super-resolution processing is a technique for comparing a down-converted video with an original input video and restoring a signal that the original input video should originally have. In addition, the accuracy of the super-resolution processing improves as the comparison and restoration processes are repeated. Accordingly, the process of performing the comparison and restoration process only once is also a super-resolution process, and the process of repeating the comparison and restoration process a plurality of times is also a super-resolution process. When time is available, for example, when viewing recorded video later, super-resolution processing that repeats comparison and restoration processing a plurality of times can be used.

  Note that the super-resolution processing of this embodiment includes known and publicly-known techniques disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2007-310837, 2008-98803, and 2000-188680. As the super-resolution processing of the present embodiment, for example, a technique for restoring an image having a frequency component higher than the Nyquist frequency determined by the sampling period of the input image can be used.

  For example, when using the super-resolution processing disclosed in Japanese Patent Application Laid-Open No. 2007-310837, a change pattern of pixel values in a target image area including a target pixel in a frame for each of a plurality of medium resolution frames Select a plurality of corresponding points corresponding to a plurality of target image areas closest to the reference frame from the reference frame, set the sample value of the luminance at the corresponding point to the pixel value of the target pixel corresponding to the corresponding point, and Calculating a pixel value of a high-resolution frame corresponding to the reference frame, which is a high-resolution frame having a number of pixels larger than the number of pixels of the reference frame, based on the size of the sample value and the arrangement of a plurality of corresponding points. Thus, the original pixel value is estimated from the low resolution image signal and the number of pixels is increased to restore the high resolution image signal.

  In addition, when using the super-resolution processing using self-congruent position search in the same frame image disclosed in Japanese Patent Application Laid-Open No. 2008-98803, the error of each pixel in the search area of the medium resolution frame is compared. A minimum first pixel position is calculated, and a search is performed based on the first pixel position, the first error, the second pixel position around the first pixel, and the second error. The position where the error is minimum in the area is calculated with decimal precision. Then, a decimal precision vector having the position as the end point and the target pixel as the start point is calculated, and using the decimal precision vector, an extrapolation vector of the decimal precision vector having the pixel on the screen not included in the search area as the end point Is calculated. Then, based on the decimal precision vector, the extrapolation vector, and the pixel value acquired from the image signal, the pixel value of the high-resolution image having a larger number of pixels than the number of pixels included in the image signal is calculated. In the super-resolution processing of the present embodiment, by performing such processing, the original pixel value is estimated from the low-resolution image signal and the number of pixels is increased, thereby restoring the high-resolution image signal.

  Also, super-resolution processing using mapping between a plurality of frame images disclosed in Japanese Patent Laid-Open No. 2000-188680 can be used.

  In the super-resolution processing of the present embodiment, a unique algorithm is added to the stretched video to convert it to a low-resolution video once, and the video is compared with the original input video to detect a difference and further correct the processing. By applying the above, high image quality processing may be performed.

  However, the super-resolution processing method of the present embodiment is not limited to the above, and the high-resolution image signal is restored by estimating the original pixel value from the low-resolution image signal and increasing the number of pixels. Or any method can be applied.

  Hereinafter, a process for variably controlling the effects of the super-resolution coring process and the image sharpening process will be described in more detail.

  FIG. 4 is a flowchart illustrating an example of an image quality deterioration prevention process that variably controls the effects of the super-resolution coring process and the image sharpening process according to a sudden brightness change such as fade-in or fade-out. In the present embodiment, an image quality deterioration prevention process in which two processes of a super-resolution coring process and an image sharpening process are variably controlled according to a sudden change in brightness will be described. However, the present invention is not limited to this. For example, the image quality deterioration prevention process described below may variably control the effect of only one of the super-resolution coring process and the image sharpening process according to a sudden change in brightness. Further, the image quality deterioration prevention process described below can be applied to image processing other than the super-resolution coring process and the image sharpening process.

  As shown in FIG. 4, in step SA1, histogram values (DIN (1) -DIN (m)) for m frames are acquired. Next, in Step SA2, Step SA3, and Step SA4, the difference value (DΔ (1 to n) between the histogram value of the past d frames and the histogram value of each frame (i = 1) to frame (i = n). )). Note that m = n + d or m> n + d.

  FIG. 5 shows a difference value (DΔ using the histogram values (DIN (1) −DIN (m)) for m frames buffered and the histogram values of frames (i = 1) to (i = n). (1-n)) is shown.

  When the difference value (DΔ (1 to n)) is acquired, it is determined in step SA5 in FIG. 4 whether or not the polarities of the difference values are continuously matched. The fact that all the polarities are the same means that the screen is continuously darker from the brighter (fade out) or brighter from the darker (fade in) over several frames. At this time, all the absolute values of the difference values (DΔ (1 to n)) are added, and the added value is set as DΔall (step SA6). If the polarities do not match, 0 is set as DΔall (step SA7).

  Subsequently, based on DΔall, the first correction parameter is output through the input / output conversion C1 shown in FIG. 6 (step SA8). Similarly, based on DΔall, the second correction parameter is output through input / output conversion C2 shown in FIG. 7 (step SA9).

  FIG. 6 is a diagram illustrating an example of the input / output conversion C1 in step SA8. In the input / output conversion C1, a conversion function with two input-output threshold levels (threshold values) is cited. As shown in FIG. 6, OUT1 is set for IN1, and OUT2 is set for IN2. Note that the relationship between the input threshold level and the output level shown in FIG. 6 is an example, and can be freely changed in order to bring out the effect of preventing deterioration in image quality.

  As shown in FIG. 6, with respect to an input value between IN1 and IN2 (IN1 or more and IN2 or less), a value that transits from OUT1 to OUT2 is output by performing linear interpolation. When the input value is less than IN1, OUT1 is always output. If the input value exceeds IN2, OUT2 is always output.

  The value obtained by the input / output conversion C1 (step SA8) is output to the adder 110 as the first correction parameter to the super-resolution coring processing module 120. The adder 110 adds the super-resolution coring initial parameter 111 and the first correction parameter to generate a super-resolution coring parameter (super-resolution coring offset parameter). It outputs to the resolution coring processing module 120 (step SA10).

  That is, the super-resolution coring parameters input to the super-resolution coring processing module 120 are as follows.

  (1) At the time of detecting the first light / dark change amount less than IN1, the first super-resolution coring parameter for obtaining the first coring effect is set.

  (2) At the time of detecting the second light / dark change amount larger than IN2, the second super-resolution coring parameter for obtaining the second coring effect larger than the first coring effect is set.

  (3) Coring parameters for obtaining a third coring effect that is larger than the first coring effect and smaller than the second coring effect based on detection of the third light-dark change amount that is greater than or equal to IN1 and less than or equal to IN2. In addition, a third coring parameter for obtaining a third coring effect that increases as the third light / dark change amount increases is set.

  As a result, the super-resolution coring processing module 120 determines the brightness based on the super-resolution coring parameter (super-resolution coring offset parameter) corrected according to the change in brightness in the fade-in or fade-out interval. The super-resolution coring process according to the change in the number can be executed (step SA12). In other words, the effect of super-resolution coring can be enhanced in accordance with the change in brightness such as the fade-in or fade-out period, and deterioration of MPEG noise can be prevented. As shown in FIG. 1, the super-resolution coring processing module 120 has super-resolution coring-processed video signals 103 (luminance: Y ′) and 104 (color signals: corresponding to the input video signals 101, 102, 103). Cb ′ / Pb ′) and 105 (color signal: Cr ′ / Pr ′) are output.

  FIG. 7 is a diagram illustrating an example of the input / output conversion C2 in step SA9. In the input / output conversion C2, a conversion function with two input-output threshold levels (threshold values) is cited. As shown in FIG. 7, OUT1 is set for IN1, and OUT2 is set for IN2. Note that the relationship between the input threshold level and the output level shown in FIG. 7 is an example, and can be freely changed in order to bring out the effect of preventing deterioration in image quality.

  As shown in FIG. 7, for an input value between IN1 and IN2 (IN1 or more and IN2 or less), a value that changes from OUT1 to OUT2 is output by performing linear interpolation. When the input value is less than IN1, OUT2 is always output. When the input value exceeds IN2, OUT1 is always output.

  The value obtained by the input / output conversion C2 (step SA9) is output to the adder 117 as the second correction parameter to the image sharpening processing module 127. The adder 117 adds the image sharpening initial parameter 118 and the second correction parameter to generate an image sharpening parameter (image sharpening offset parameter), and outputs the image sharpening parameter to the image sharpening processing module 127. (Step SA11).

  That is, the image sharpening parameters input to the image sharpening processing module 127 are as follows.

  (1) At the time of detecting a first light / dark change amount less than IN1, a first sharpening parameter for obtaining a first sharpening effect gain is set.

  (2) At the time of detecting the second light / dark change amount larger than IN2, the second sharpening parameter for obtaining the second sharpening effect gain smaller than the first sharpening effect gain is set.

  (3) Sharpness for obtaining a third sharpening effect gain that is smaller than the first sharpening effect gain and larger than the second sharpening effect gain based on detection of the third brightness change amount that is greater than or equal to IN1 and less than or equal to IN2. And a third sharpening parameter for obtaining a third sharpening effect gain that decreases as the third amount of change in brightness is increased.

  As a result, the image sharpening processing module 127 performs an image corresponding to the change in brightness based on the image sharpening parameter (image sharpening offset parameter) corrected according to the change in brightness in the fade-in or fade-out section. A sharpening process can be executed (step SA13). That is, it is possible to prevent the MPEG noise from deteriorating by reducing the image sharpening gain in accordance with the change in brightness in the fade-in or fade-out section. As shown in FIG. 1, the image sharpening processing module 127 includes image sharpening processed video signals 120 (luminance: Y ″), 121 (corresponding to the super-resolution coring processed video signals 103, 104, 105. Color signals: Cb ″ / Pb ″) and 122 (color signals: Cr ″ / Pr ″) are output.

  The above-described image processing apparatus can detect a situation in which MPEG noise is likely to occur (fade-in or fade-out period), and at the time of detection, the effect of super-resolution coring can be enhanced and the image sharpening gain can be reduced. Thereby, MPEG noise generated in the fade-in or fade-out period can be reduced without affecting other images.

  If the image processing apparatus described above is not applied, for example, the super-resolution coring parameter and the image sharpening parameter remain fixed, and MPEG noise is emphasized in a situation where MPEG noise is likely to occur. .

  FIG. 8 is a diagram showing a schematic configuration of a television signal receiving apparatus in which the image processing apparatus shown in FIG. 1 is incorporated.

  As shown in FIG. 8, the television signal receiving apparatus includes a signal processing module 34. The signal processing module 34 includes the image processing apparatus shown in FIG. 1 as an image processing module. The digital television broadcast signal received by the digital television broadcast receiving antenna 22 is supplied to the tuner 24 via the input terminal 23. The tuner 24 selects and demodulates a signal of a desired channel from the input digital television broadcast signal. The signal output from the tuner 24 is supplied to the decoder 25 and subjected to MPEG (moving picture experts group) 2 decoding processing by the MPEG decoder 41 and the like.

  The output of the tuner 24 is also supplied to the selector 26. It is also possible to separate video / audio information from the signal and record the video / audio information in the storage unit via the control unit 35.

  Further, the analog television broadcast signal received by the analog television broadcast receiving antenna 27 is supplied to the tuner 29 via the input terminal 28. The tuner 29 selects and demodulates a signal of a desired channel from the input analog television broadcast signal. The signal output from the tuner 29 is digitized by an A / D (analog / digital) converter 30 and then output to the selector 26.

  The analog video and audio signals supplied to the analog signal input terminal 31 are supplied to the A / D converter 32 and digitized, and then output to the selector 26. Further, the digital video and audio signals supplied to the digital signal input terminal 33 are supplied to the selector 26 as they are.

  When the A / D converted signal is recorded in the storage unit, the MPEG encoder 42 attached to the selector 26 performs compression processing in a predetermined format, for example, MPEG (moving picture experts group) 2 system. After that, it is recorded in the storage unit.

  The selector 26 selects one of the four input digital video and audio signals and supplies it to the signal processing module 34. The signal processing module 34 performs predetermined signal processing on the input digital video signal and provides it for video display on the video display 14. As the video display unit 14, for example, a flat panel display such as a liquid crystal display or a plasma display is adopted. In addition, the signal processing module 34 performs predetermined signal processing on the input digital audio signal, converts it into an analog signal, and outputs it to the speaker 15 for audio reproduction.

  Here, in the television signal receiving apparatus, various operations including the various receiving operations described above are comprehensively controlled by the control unit 35. The control unit 35 is a microprocessor with a built-in CPU (central processing unit) and the like, and receives operation information from the operation unit 16 and an operator (not shown) or operation information transmitted from the remote controller 17. By receiving and processing the light receiving unit 18, each unit is controlled so that the operation content is reflected.

  In this case, the control unit 35 uses the memory 36. This memory 36 mainly includes a ROM (read only memory) storing a control program executed by the CPU, a RAM (random access memory) for providing a work area to the CPU, various setting information and control information. And the like are stored in a nonvolatile memory.

  Next, the super-resolution coring process will be described with reference to FIGS. 9 and 10. For example, as shown in FIG. 9, the super-resolution coring processing module 120 is configured. The input video signal is input to the horizontal noise reduction circuit 1202, the frame delay circuit 1205, and the inter-frame difference information counting circuit 1206.

  The horizontal noise reduction circuit 1202 is a filter using, for example, a clock delay element and a coefficient unit, and performs noise reduction processing on the horizontal line in the horizontal direction. The output of the horizontal noise reduction circuit 1202 is input to the 5-tap line delay circuit 1203. The 5-tap line delay circuit 1203 synchronizes five horizontal lines using a plurality of line delay circuits. The synchronized line signals are input to the vertical noise reduction circuit 1204, subjected to vertical noise reduction processing, and output to the output terminal.

  Here, the above-described super-resolution coring parameters are input to the horizontal noise reduction circuit 1202 and the vertical noise reduction circuit 1204 in order to control the amount of noise reduction. The horizontal noise reduction circuit 1202 controls the noise reduction level based on the super-resolution coring parameter, and reduces the noise by coring processing of the high frequency component in the horizontal direction. The vertical noise reduction circuit 1204 also controls the noise reduction level based on the super-resolution coring parameter, and reduces noise by coring processing of the high frequency component in the vertical direction.

  FIG. 10 is a diagram showing an example of the vertical noise reduction circuit 1204 shown in FIG. The signal from the 5-tap line delay circuit 1203 is input to the vertical bandpass filter 1204a. The vertical bandpass filter 1204a performs a filtering process using the input signal, and extracts a vertical high frequency component including a noise component. This vertical high-frequency component is input to the limiter 1204b, and is input to the subtractor 1204c after being subjected to amplitude limitation, for example, by the super-resolution coring parameter. The subtractor 1204c subtracts the output of the limiter 1204b from the center tap signal of the line delay output signal to reduce noise that is a vertical high frequency component. Thereby, the subtractor 1204c can obtain a video signal with reduced noise by the high frequency coring method. The magnitude of the output amplitude of the limiter 1204c is the degree of noise reduction.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention in the implementation stage. In addition, the embodiments may be appropriately combined as much as possible, and in that case, the combined effect can be obtained. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be obtained as an invention.

104 ... Histogram acquisition module, 105 ... Histogram value frame buffer, 108 ... Luminance level transition state determination module, 120 ... Super-resolution coring processing module, 127 ... Image sharpening processing module

Claims (9)

Detection means for detecting a change in brightness between a plurality of frames included in the image data;
Sharpening control means for setting a sharpening parameter for controlling a sharpening effect gain for the image data in accordance with the detected contrast change amount;
Sharpening processing means for executing a sharpening process on the image data based on the sharpening parameter;
An image processing apparatus comprising: Detection means for detecting a change in brightness between a plurality of frames included in the image data;
Coring control means for setting a coring parameter for controlling a coring effect on the image data according to the detected light / dark change amount;
Coring processing means for performing coring processing on the image data based on the coring parameters;
An image processing apparatus comprising: Coring control means for setting a coring parameter for controlling a coring effect on the image data according to the detected light / dark change amount;
Coring processing means for performing coring processing on the image data based on the coring parameters;
The image processing apparatus according to claim 1, further comprising: The sharpening control means sets a first sharpening parameter for obtaining a first sharpening effect gain based on detection of the first lightness / darkness change amount, and sets a second sharpness parameter larger than the first lightness / darkness change amount. Setting a second sharpening parameter for obtaining a second sharpening effect gain smaller than the first sharpening effect gain based on the detection of the brightness change amount;
The sharpening processing means executes a sharpening process on the image data based on the first or second sharpening parameter;
The image processing apparatus according to claim 1, wherein the image processing apparatus is an image processing apparatus. The coring control means sets a first coring parameter for obtaining a first coring effect based on detection of the first light / dark change amount, and sets a second light / dark larger than the first light / dark change amount. Setting a second coring parameter for obtaining a second coring effect larger than the first coring effect based on detection of a change amount;
The sharpening processing means performs a coring process on the image data based on the first or second coring parameter.
The image processing apparatus according to claim 2 or 3, The sharpening control means includes
Setting a first threshold and a second threshold greater than the first threshold;
Setting a first sharpening parameter for obtaining a first sharpening effect gain based on detection of a first light-dark change amount less than the first threshold;
Setting a second sharpening parameter for obtaining a second sharpening effect gain smaller than the first sharpening effect gain based on detection of a second light / dark change amount greater than the second threshold;
A third sharpening that is smaller than the first sharpening effect gain and larger than the second sharpening effect gain based on detection of a third brightness change amount that is greater than or equal to the first threshold and less than or equal to the second threshold. A sharpening parameter for obtaining an effect gain, and a third sharpening parameter for obtaining the third sharpening effect gain that decreases as the third light-dark change amount increases,
The sharpening means is
Performing a sharpening process on the image data based on the first, second, or third sharpening parameter;
The image processing apparatus according to claim 1, wherein the image processing apparatus is an image processing apparatus. The coring control means includes
Setting a first threshold and a second threshold greater than the first threshold;
Setting a first coring parameter for obtaining a first coring effect based on detection of a first light-dark change amount less than the first threshold;
Setting a second coring parameter for obtaining a second coring effect larger than the first coring effect based on detection of a second light-dark change amount larger than the second threshold;
Based on detection of a third light-dark change amount that is greater than or equal to the first threshold and less than or equal to the second threshold, a third coring effect that is greater than the first coring effect and smaller than the second coring effect. Generating a third coring parameter for obtaining the third coring effect, which is a coring parameter for obtaining and increases in accordance with an increase in the third light / dark change amount,
The coring processing means performs a coring process on the image data based on the first, second, or third coring parameter.
The image processing apparatus according to claim 2 or 3, A channel selection means for selecting a signal of a desired channel from a broadcast signal,
The detecting means detects a change in brightness between a plurality of frames included in the image data in the selected signal;
The image processing apparatus according to claim 1. Detect the amount of change in brightness between multiple frames included in the image data,
In accordance with the detected light / dark change amount, a sharpening parameter for controlling a sharpening effect gain for the image data is set,
Performing a sharpening process on the image data based on the sharpening parameters;
An image processing method comprising:

Images