JP4304609B2 - Signal processing apparatus and method, recording medium, and program - Google Patents

Description

  The present invention relates to a signal processing apparatus and method, a recording medium, and a program, and more particularly, to a signal processing apparatus and method, a recording medium, and a program that can effectively enhance an input image signal.

  Conventional video cameras improve contrast (brightness / darkness difference) and sharpness (brightness of boundaries) of images captured by image sensors such as CCD (Charge Coupled Device) and CMOS (Complementary Metal-Oxide Semiconductor). As a method, a contrast enhancement method by gradation conversion and a high frequency component enhancement method for enhancing the contrast of a high frequency component in an image are considered.

  As a contrast enhancement method, tone curve adjustment for converting each pixel level of an image with a function having a predetermined input / output relationship (hereinafter referred to as a level conversion function), or frequency distribution of pixel levels A method called histogram equalization has been proposed in which the level conversion function is adaptively changed according to the above.

  As a high frequency component enhancement method, a method called an unsharp mask that performs edge enhancement that extracts edges from an image and emphasizes the extracted edges has been proposed.

  However, in contrast enhancement methods, in addition to the problem that the contrast can be improved only in a part of the luminance range in the entire dynamic range (difference between the maximum level and the minimum level) of the image, in addition, in the case of tone curve adjustment However, there is a problem that the contrast is lowered in the brightest and darkest parts of the image, and in the case of histogram equalization, in the vicinity of the luminance region where the frequency distribution is small. Further, in the high frequency component enhancement method, only the contrast of the high frequency component of the image is enhanced, thereby causing a problem that the vicinity of the edge of the image is unnaturally enhanced and the image quality is deteriorated.

  Therefore, conventionally, an image signal processing device configured as shown in FIG. 1 is used to amplify a portion other than the edge by amplifying a portion other than the edge while preserving an edge having a sharp change in pixel value. There is a method for emphasizing other parts (for example, Patent Document 1).

In the image signal processing apparatus shown in FIG. 1, the input image signal (pixel value) is input to the ε filter 1 and the subtraction unit 2. The ε filter 1 has an edge larger than a predetermined threshold ε ₁ , for example, an edge as shown in FIG. 2B when an image signal slightly fluctuating across a steep edge as shown in FIG. 2A is input. Is converted into an extracted image signal and output to the subtracting unit 2 and the adding unit 4.

Specific processing of the ε filter 1 will be described with reference to FIGS. 3 and 4. The ε filter 1 sequentially determines each pixel of the input image as the target pixel C, and, as shown in FIG. 3, a plurality of neighboring pixels (in this case, four pixels L2) that are continuous in the horizontal direction with the target pixel C as the center. , L1, R1, R2), and the pixel values of the target pixel C and the plurality of neighboring pixels are set to tap coefficients (eg, {1, 2, 3, 2, 1}) to obtain a conversion result C ′ corresponding to the target pixel C.
C ′ = (1 · L2 + 2 · L1 + 3 · C + 2 · R1 + 1 · R2) / 9
... (1)

However, as shown in FIG. 4, for a neighboring pixel (a neighboring pixel R2 in the case of FIG. 4) whose difference from the pixel value of the target pixel C is larger than a predetermined threshold ε ₁ , the pixel value of the target pixel C is changed. Replace it with something to calculate. That is, in the case of FIG. 4, the following equation (2) is calculated.
C ′ = (1 · L2 + 2 · L1 + 3 · C + 2 · R1 + 1 · C) / 9
... (2)

  The image signal smoothed by the ε filter 1 is also referred to as a structural component of the image signal.

  Returning to FIG. The subtracting unit 2 subtracts the image signal input from the ε filter 1 from the image signal input from the previous stage (the same as the input to the ε filter 1), thereby slightly changing the components other than the structural components of the image signal. The extracted image signal is extracted and output to the amplifying unit 3. The amplification unit 3 amplifies the output of the subtraction unit 2 and outputs the amplified output to the addition unit 4. Note that the component of the image signal that slightly varies other than the structural component is also referred to as an amplitude component of the image signal. The adder 4 adds the image signal in which a part other than the structural component output from the amplifier 3 is amplified and the structural component of the image signal input from the ε filter 1. This addition result is an image signal in which a portion other than the edge is amplified while a steep edge is held.

By the way, in the ε filter 1 of the image signal processing device shown in FIG. 1, for example, as shown in FIG. 5, even if there is a steep edge in the change of the pixel value, the size is a predetermined threshold value ε _1. Is smaller than that, the converted image signal output from the ε filter 1 is smoothed as shown in FIG. 6 and the sharp edge disappears. There has been a problem that image quality deteriorates remarkably in pattern images and the like.

  Therefore, a signal that is continuously arranged is sequentially designated as a signal of interest, and a plurality of signals that are continuously arranged in the horizontal direction or the vertical direction with respect to the designated signal of interest as a reference. Determining a neighborhood signal, computing a difference between the signal of interest and each neighborhood signal, computing a smoothed signal by weighted averaging the neighborhood signal having the difference smaller than the first threshold, and the signal of interest; A difference from the neighboring signal is calculated, and a small edge is found in the vicinity of the signal of interest depending on whether or not there is a value larger than the second threshold value compared to the difference and the second threshold value smaller than the first threshold value. It has been proposed to determine whether or not it exists and to select one of a smoothed signal or a signal of interest based on the determination result.

JP 2001-298621 A

  However, in the above method, although the amplification unit 3 can emphasize the contrast and sharpness with respect to the amplitude component, for example, when controlling to amplify the amplitude component, the noise component included in the amplitude component As a result, there is a problem that enhancement processing such as enhancing contrast and sharpness cannot be effectively performed.

  The present invention has been made in view of such a situation, and in particular, the amplitude component is separated for each band, and necessary processing is performed on each to enhance the contrast and sharpness of the input image signal. The enhancement processing such as performing can be effectively performed.

The signal processing apparatus according to the present invention includes a processing signal extraction unit that extracts a plurality of neighborhood signals as processing signals from an image signal with reference to the attention signal of interest in continuously arranged image signals; The processing difference that is the difference between each processing signal and the first threshold value are compared, and the processing signal whose processing difference is larger than the first threshold value is replaced with the attention signal, and the attention signal and the plurality of processing signals are weighted It is determined whether or not a minute edge exists in the vicinity of the signal of interest based on a comparison result between the arithmetic means for calculating the smoothed signal on the average and the processing difference and the second threshold value smaller than the first threshold value. If there is a minute edge, the difference between the maximum value and the minimum value of the image signal is the mixing ratio between the smoothed signal and the signal of interest, and if there is no minute edge, the maximum value of the processing differences is Smooth signal and signal of interest A mixing ratio calculation means for calculating a mixing ratio, based on the calculated mixing ratio by the mixing ratio calculation means, the smoothed signal, and a mixing means for the signal of interest are mixed to produce structural components of the signal of interest, attention A difference calculating means for calculating the amplitude component of the signal of interest comprising the difference between the signal and the structural component of the signal of interest; a band separating means for separating the amplitude component of the signal of interest calculated by the difference calculating means into a plurality of bands ; the amplitude component of the signal of interest which is divided into plural bands by separating means and a processing means for performing predetermined processing.

  The signal may be a pixel value of a pixel constituting the image.

  The processing means can perform a process for controlling the gain on the amplitude component of the signal of interest separated for each of the plurality of bands by the band separation means.

  The amplitude component of the signal of interest, which is separated into a plurality of bands by the band separation device and subjected to the process of controlling the gain by the processing device, is superimposed on either the signal of interest or the structural component of the signal of interest. Superimposing means can be further provided.

The signal processing method of the present invention includes a processing signal extraction step of extracting a plurality of neighboring signals as processing signals from an image signal with reference to the attention signal of interest in continuously arranged image signals, The processing difference that is the difference between each processing signal and the first threshold value are compared, and the processing signal whose processing difference is larger than the first threshold value is replaced with the attention signal, and the attention signal and the plurality of processing signals are weighted Whether or not a minute edge exists in the vicinity of the signal of interest is determined based on a comparison step between an arithmetic step for calculating a smoothed signal on average and a processing difference and a second threshold value smaller than the first threshold value. If there is a minute edge, the difference between the maximum value and the minimum value of the image signal is the mixing ratio between the smoothed signal and the signal of interest, and if there is no minute edge, the maximum value of the processing differences is Smoothed signal and note A mixing ratio calculation step of calculating a mixing ratio of the signal, based on the calculated mixing ratio in the process of mixing ratio calculating step, smoothing signals, and mixes the signal of interest, to produce a structural component of the signal of interest The difference step that calculates the amplitude component of the signal of interest consisting of the difference between the mixing step, the signal of interest and the structural component of the signal of interest, and the amplitude component of the signal of interest calculated in the processing of the difference calculation step are separated into multiple bands including to the band separation step, and a processing step of the amplitude component of the signal of interest which is divided into plural bands in the processing of band separation step performs a predetermined process.

The recording medium program of the present invention is a processing signal extraction control step for controlling extraction of a plurality of neighboring signals as processing signals from an image signal with reference to a target signal of interest in continuously arranged image signals. And a processing difference that is a difference between the attention signal and each processing signal and the first threshold value, and a processing signal having a processing difference larger than the first threshold value is replaced with the attention signal, so that the attention signal Based on the result of comparison between the calculation control step for controlling the calculation of the smoothed signal by the weighted average of the processed signals and the second threshold value smaller than the first threshold value , there is a minute edge in the vicinity of the signal of interest. If there is a minute edge, the difference between the maximum value and the minimum value of the image signal is taken as the mixing ratio between the smoothed signal and the signal of interest. If there is no minute edge, the processing difference The maximum value of among a mixing ratio calculation control step of controlling the calculation of the mixing ratio of the smoothed signal and the signal of interest, based on the calculated mixing ratio in the processing of the mixture ratio calculation control step, the smoothed signal, And a mixing control step for controlling the generation of the structural component of the signal of interest by mixing the signal of interest and a difference calculation control step for controlling the calculation of the amplitude component of the signal of interest comprising the difference between the signal of interest and the structural component of the signal of interest. And a band separation control step for controlling separation of a plurality of bands of the amplitude component of the signal of interest calculated in the difference calculation control step processing, and an amplitude of the signal of interest separated into the plurality of bands in the processing of the band separation control step And causing the computer to execute a process including a process control step for performing control so as to perform a predetermined process for the component.

The program according to the present invention includes a processing signal extraction control step for controlling extraction of a plurality of neighboring signals as processing signals from an image signal with reference to the attention signal of interest in continuously arranged image signals ; The processing difference that is the difference between the signal and each processing signal is compared with the first threshold value, and the processing signal with the processing difference larger than the first threshold value is replaced with the attention signal, and the attention signal and the plurality of processing signals Whether there is a minute edge in the vicinity of the signal of interest based on the comparison result between the calculation control step for controlling the calculation of the smoothed signal by the weighted average of and the processing difference and the second threshold value smaller than the first threshold value . If there is a minute edge, the difference between the maximum value and the minimum value of the image signal is taken as the mixing ratio between the smoothed signal and the signal of interest. Most Values, and the mixing ratio calculation control step of controlling the calculation of the mixing ratio of the smoothed signal and the signal of interest, based on the calculated mixing ratio in the processing of the mixture ratio calculation control step, the smoothed signal, and interest A mixing control step for controlling the generation of the structural component of the signal of interest by mixing the signals, and a difference calculation control step for controlling the calculation of the amplitude component of the signal of interest consisting of the difference between the signal of interest and the structural component of the signal of interest;
The band separation control step for controlling the separation of the plurality of bands of the amplitude component of the signal of interest calculated in the difference calculation control step processing, and the amplitude component of the signal of interest separated into the plurality of bands in the processing of the band separation control step And causing a computer to execute a process including a process control step for controlling to perform a predetermined process.

In the signal processing apparatus and method, and the program of the present invention, a plurality of neighboring signals are extracted as processing signals from the image signal with reference to the attention signal of interest in the continuously arranged image signals, and the attention signal Is compared with the first threshold value, and the processing signal with the processing difference larger than the first threshold value is replaced with the attention signal, so that the attention signal and the plurality of processing signals are changed. A smoothed signal is calculated by weighted averaging, and based on a comparison result between the processing difference and a second threshold value smaller than the first threshold value, it is determined whether or not a minute edge exists in the vicinity of the signal of interest, If there is a minute edge, the difference between the maximum value and the minimum value of the image signal is the mixing ratio of the smoothed signal and the signal of interest. If there is no minute edge, the maximum value among the processing differences is smoothed. Conversion No. and which is calculated with the mixing ratio of the signal of interest, based on the calculated mixing ratio, smoothed signal, and, the signal of interest are mixed, produced structural component of the signal of interest is, the signal of interest and the signal of interest amplitude component of the signal of interest consisting of the difference between the structural components are calculated and are separated amplitude component of the calculated signal of interest into a plurality of bands, a predetermined process on the amplitude component of the signal of interest which is divided into plural bands facilities Is done.

  The signal processing apparatus of the present invention may be an independent apparatus or a block that performs signal processing.

  According to the present invention, it is possible to effectively perform enhancement processing on an input signal.

  Embodiments of the present invention will be described below. The correspondence relationship between the invention described in this specification and the embodiments of the invention is exemplified as follows. This description is intended to confirm that the embodiments supporting the invention described in this specification are described in this specification. Therefore, although there is an embodiment which is described in the embodiment of the invention but is not described here as corresponding to the invention, it means that the embodiment is not It does not mean that it does not correspond to the invention. Conversely, even if an embodiment is described herein as corresponding to an invention, that means that the embodiment does not correspond to an invention other than the invention. Absent.

  Further, this description does not mean all the inventions described in this specification. In other words, this description is for the invention described in the present specification, which is not claimed in this application, that is, for the invention that will be applied for in the future or that will appear and be added by amendment. It does not deny existence.

That is, the signal processing apparatus according to the present invention is a processing signal extraction unit (for example, a plurality of neighboring signals extracted as processing signals from image signals with reference to a target signal of interest in continuously arranged image signals. The control signal generating unit 52) in FIG. 9 compares the processing difference that is the difference between the attention signal and each processing signal with the first threshold value, and the processing signal with the processing difference larger than the first threshold value is the attention signal. , A calculation means (for example, LPF 42 in FIG. 9) for calculating a smoothed signal by weighted averaging of the signal of interest and a plurality of processing signals, a processing difference, and a second threshold smaller than the first threshold Based on the comparison result, it is determined whether or not there is a minute edge in the vicinity of the signal of interest, and if there is a minute edge, the difference between the maximum value and the minimum value of the image signal is determined as the smoothed signal and the signal of interest. With a mixing ratio and a minute edge If not, the maximum value of the processing differences, and the mixing ratio calculating means for calculating a mixing ratio of the smoothed signal and the signal of interest (e.g., the mix rate detector 43 of FIG. 9), calculated by the mixing ratio calculation means Based on the mixed ratio, the smoothing signal and the attention signal are mixed to generate a structural component of the attention signal (for example, the mixing unit 42 in FIG. 9), and the structural component of the attention signal and the attention signal Difference calculating means (for example, the adder 22 in FIG. 7) for calculating the amplitude component of the signal of interest consisting of the difference between the two and the band separating means for separating the amplitude component of the signal of interest calculated by the difference calculating means into a plurality of bands (For example, the band separation unit 23 in FIG. 7) and processing means for performing predetermined processing on the amplitude components of the signal of interest separated into a plurality of bands by the band separation unit (for example, the gain control unit 24-1 in FIG. 24-2) And wherein the door.

  The amplitude component of the signal of interest, which is separated into a plurality of bands by the band separation device and subjected to the process of controlling the gain by the processing device, is superimposed on either the signal of interest or the structural component of the signal of interest. Superposition means (for example, the adder 26 in FIG. 7 or the adder 111 in FIG. 23) may be further provided.

The signal processing method of the present invention is a processing signal extraction step (for example, FIG. 10) that extracts a plurality of neighboring signals as processing signals from an image signal with reference to a target signal of interest in consecutively arranged image signals . In step S1 in the flowchart), a processing difference that is a difference between the attention signal and each processing signal, and the first threshold value, and a processing signal having a processing difference larger than the first threshold value is set as the attention signal. substituted, the arithmetic step of calculating a smoothed signal of interest signal and a plurality of processed signals to a weighted average (e.g., the processing in step S22 in the flowchart of FIG. 11) and, second smaller than the processing difference and the first threshold value based on the comparison result between the second threshold, it is determined whether fine edge in the vicinity of the target signal is present, the difference in the case where fine edge exists, the maximum value and the minimum value of the image signal And the mixing ratio of the smoothed signal and the signal of interest, if there is no minute edge, the maximum value of the processing difference, mixing ratio calculating step of calculating a mixing ratio of the smoothed signal and the signal of interest (e.g., The smoothed signal and the signal of interest are mixed based on the mixing ratio calculated in the processing of the steps S25 and S27 in the flowchart of FIG. 11 and the processing of the mixture ratio calculation step to generate the structural component of the signal of interest. A difference calculation step (for example, the step of the flowchart of FIG. 10) that calculates the amplitude component of the signal of interest that is the difference between the signal of interest and the structural component of the signal of interest and the mixing step (for example, the process of step S26 in the flowchart of FIG. 11). and processing S2), the band separating step of separating the amplitude components of the calculated signal of interest in the processing of the difference calculation step into a plurality of bands (e.g., Fig. 0 step S3 of the flowchart of), the process performs a predetermined process on the amplitude component of the signal of interest which is divided into plural bands in the processing of band separation step step (e.g., process of step S4 in the flowchart of FIG. 10) It is characterized by including.

  FIG. 7 is a diagram showing a configuration of an embodiment of an enhancement processing apparatus 11 that performs enhancement processing on an image signal to which the present invention is applied.

  The non-linear smoothing processing unit 21 performs non-linear smoothing processing on the target pixel with respect to the input image signal using the target pixel and the neighboring pixels, respectively, and adds the adder 22, as the structural component of the input image signal. 26. The detailed configuration of the nonlinear smoothing processing unit 21 will be described later with reference to FIG.

  The adder 22 subtracts the structural component of the input image signal supplied from the nonlinear smoothing processing unit 21 from the input image signal, and band-separates the result of the subtraction as the amplitude component of the input image signal. To the unit 23. That is, the image signal input by the nonlinear smoothing processing unit 21 and the adder 22 is separated into a structural component and an amplitude component. Therefore, the sum of the structural component and the amplitude component separated by the nonlinear smoothing processing unit 21 and the adder 22 is an input image signal.

  The band separation unit 23 separates the input amplitude component supplied from the adder 22 into two signals for each band, and outputs the separated signals to the gain control units 24-1 and 24-2. More specifically, the band separation unit 23 includes an LPF 31 and an adder 32 as shown in FIG. That is, the LPF 31 extracts a low frequency component smaller than a predetermined frequency from the input amplitude components, and outputs the low frequency component to the gain control unit 24-1 and the adder 32. The adder 32 subtracts the low frequency component supplied from the LPF 31 from the input amplitude component, extracts only the high frequency component, and outputs it to the gain control unit 24-2. FIG. 7 shows a configuration of an example in which the amplitude component is separated into two bands of a low frequency component lower than a threshold for specifying a predetermined frequency of LPF 31 in FIG. 8 and other high frequency components. May be separated into a larger number of bands. In this case, for example, the LPF 31 and the adder 32 shown in FIG. You may do it.

  The gain control units 24-1 and 24-2 respectively amplify the low frequency component and the high frequency component supplied from the band separation unit 23 to the magnification set by the operation unit 27 (determining the amplification amount and further receiving the input). Are added to the low frequency component and the high frequency component of the received signal) and output to the adder 25. The adder 25 adds the low frequency component and the high frequency component of the amplitude component amplified by a predetermined magnification supplied from the gain control units 24-1 and 24-2, and outputs the result to the adder 26. That is, the adder 26 adds the signals that have been amplified for each band (enhanced signals) to generate an amplitude component.

  The adder 26 adds the structural component supplied from the nonlinear smoothing processing unit 21 and the amplitude component supplied from the adder 25 and amplified for each band, and outputs the result as an enhanced image signal. To do.

  The operation unit 27 includes a keyboard and operation buttons. The operation unit 27 is operated when setting gains of the gain control units 24-1 and 24-2, and generates a signal corresponding to the operation content. Set the amplification factor of -1,24-2.

  Next, the detailed configuration of the nonlinear smoothing processing unit 21 will be described with reference to FIG.

The non-linear filter 41 of the non-linear smoothing processing unit 21 holds a steep edge whose size is larger than the threshold value ε ₁ among the fluctuations of the pixels constituting the input image signal S _I, and a portion other than the edge , And the smoothed image signal S _LPF-H is output to the mixing unit 42.

The mixing ratio detection unit 43 calculates the mixing ratio based on a minute change among the fluctuations of the pixels constituting the input image signal S _I and supplies it to the mixing unit 42.

Mixing unit 42, an image signal S _I that is input that is not the image signal S _LPF-H and smoothing is smoothed, based on the mixture ratio supplied from the mix rate detector 43, were mixed, nonlinear A smoothed image signal S _FH is output.

An LPF (Low Pass Filter) 41 of the non-linear filter 41 smoothes the pixel of interest using the pixel value of the pixel of interest and two adjacent pixels based on the control signal supplied from the control signal generator 52. The smoothed image signal S _LPF-H is output to the mixing unit 42. The control signal generation unit 52 calculates a difference absolute value between pixel values of the target pixel and adjacent pixels, generates a control signal for controlling the LPF 51 based on the calculation result, and supplies the control signal to the LPF 51. As the nonlinear filter 41, for example, the conventional ε filter 1 described above may be used.

  Next, with reference to the flowchart of FIG. 10, the enhancement process by the enhancement processing apparatus 11 of FIG. 7 will be described.

  In step S1, the nonlinear smoothing processing unit 21 performs nonlinear smoothing processing on the input image signal.

  Here, the non-linear smoothing process by the non-linear smoothing process part 21 is demonstrated with reference to the flowchart of FIG.

  In step S <b> 21, the control signal generation unit 52 of the nonlinear filter 41 calculates a difference absolute value between pixel values of the target pixel and neighboring pixels. That is, for example, in the case of FIG. 3, the control signal generation unit 52 determines the absolute difference values | C−L2 |, | C -L1 |, | C-R1 |, | C-R2 | are calculated.

In step S22, LPF 51 compares the difference absolute values calculated by the control signal generator 52 and a predetermined threshold epsilon _2, in response to this comparison result, non-linear filtering process on the image signal S _I to be input Apply. More specifically, the LPF 51 performs a weighted average of the pixel values of the target pixel C and the neighboring pixels using a tap coefficient, for example, as in Expression (1), and converts the result C ′ corresponding to the target pixel C. _Is output to the mixing unit 42 as a smoothed image signal S _LPF-H . However, for neighboring pixels in which the absolute difference from the pixel value of the target pixel C is greater than a predetermined threshold ε ₂ , the pixel value is replaced with the pixel value of the target pixel C (for example, (Calculate as shown in equation (2)).

  In step S23, the mixture ratio detection unit 43 performs a minute edge determination process to determine whether or not a minute edge exists.

  Here, the minute edge determination process will be described with reference to the flowchart of FIG.

In step S41, the mixture ratio detection unit 43 calculates a difference absolute value of the pixel value between the target pixel and each neighboring pixel, and whether or not all the difference absolute values are smaller than the threshold value ε ₃ (<< ε ₂ ). It is determined whether or not a minute edge exists based on the determination result.

That is, for example, as illustrated in FIG. 3, the mixture ratio detection unit 43 calculates a difference absolute value of pixel values between the target pixel C and each of the neighboring pixels L2, L1, R1, and R2, and each difference absolute value There all, determines whether less or not than the threshold epsilon _3, when it is determined that the difference absolute value is smaller than all the threshold epsilon _3, assume there is no change in pixel value between the target pixel and neighboring pixels, Proceeding to step S44, it is determined that no minute edge exists in the vicinity of the target pixel.

On the other hand, in step S41, among the calculated absolute difference value, if it is determined that even one has a threshold epsilon ₃ or more of, the process proceeds to step S42, the mix rate detector 43, one of the left and right of the pixel of interest The absolute difference values between the neighboring pixels on the side and the target pixel are all smaller than the threshold ε ₃ , and the absolute differences between the neighboring pixels on the left and right sides of the target pixel and the target pixel are all greater than or equal to the threshold ε _3. In addition, it is determined whether the positive and negative of each difference between the pixel on the other side on the left and right sides of the pixel of interest and the pixel of interest match.

That is, the left and right neighboring pixels of the target pixel C are, for example, the pixels L2 and L1 in FIG. 3, and the left and right neighboring pixels of the target pixel C are the pixels R2 and R1 in FIG. The mixture ratio detection unit 43 has the difference absolute values between the neighboring pixels on the left and right sides of the target pixel C and the target pixel C all smaller than the threshold value ε ₃ , and the neighboring pixels on the left and right sides of the target pixel C. R1, R2 absolute difference value between the target pixel C is not more all threshold epsilon ₃ or more and, and, positive and negative of each difference between the neighboring pixels R1, R2 and the target pixel C of the left and right on the other side of the target pixel C is one Determine whether you are doing it.

  For example, when it is determined that the above condition is satisfied, in step S43, the mixture ratio detection unit 43 determines that a minute edge exists in the vicinity of the target pixel.

  On the other hand, when it is determined in step S42 that the above condition is not satisfied, in step S44, the mixture ratio detection unit 43 determines that there is no minute edge in the vicinity of the target pixel.

For example, when the relationship between the target pixel C and the neighboring pixels L2, L1, R1, and R2 is as shown in FIG. 13, the absolute difference values | L2-C |, | L1- of the target pixel C and the left neighboring pixels L2, L1. C | is smaller than the threshold ε ₃ , the difference absolute values | R1-C |, | R2-C | of the pixel of interest C and the right neighboring pixels R1, R2 are greater than or equal to the threshold ε ₃ , and the pixel of interest Since the signs of differences (R1-C) and (R2-C) between C and the right neighboring pixels R1, R2 match (both are positive in this case), it is determined that a minute edge exists in the vicinity of the target pixel C. Is done.

Further, for example, when the relationship between the target pixel C and the neighboring pixels L2, L1, R1, and R2 is as shown in FIG. 14, the difference absolute value | L2-C |, | between the target pixel C and the left neighboring pixels L2 and L1. Although L1-C | is smaller than the threshold ε ₃ and the difference absolute values | R1-C |, | R2-C | of the pixel of interest C and the right neighboring pixels R1, R2 are equal to or larger than the threshold ε ₃ , Since the signs of the differences (R1−C) and (R2−C) of the difference between the pixel C and the right neighboring pixels R1 and R2 do not match (in this case, positive and negative respectively), there is a minute edge in the vicinity of the target pixel C. It is determined that it does not exist.

Further, for example, when the relationship between the target pixel C and the neighboring pixels L2, L1, R1, and R2 is as shown in FIG. 15, all the absolute differences between the target pixel C and the neighboring pixels are all on the left and right sides of the target pixel C. Since it is not smaller than the threshold value ε _3, it is determined that there is no minute edge in the vicinity of the target pixel C.

  Thus, after determining whether or not a minute edge exists in the vicinity of the target pixel, the process returns to step S24 in FIG.

When the process of step S23 ends, in step S24, the mixture ratio detection unit 43 determines whether or not the determination result by the minute edge determination process in step S23 is “a minute edge exists in the vicinity of the target pixel C”. Determine. For example, when the determination result by the minute edge determination process is “a minute edge is present in the vicinity of the target pixel C”, in step S25, the mixture ratio detection unit 43 performs the image signal subjected to the non-linear filtering process in the horizontal direction. the mix rate Mr _-H mixture ratios of S _LPF-H and the input image signal S _I output to the mixing unit 42 as the maximum mix rate Mr _{-H max.} The maximum Mix rate Mr _{-H max} is the maximum value of the Mix rate Mr _-H, i.e., the difference absolute value between the maximum value and the minimum value of the dynamic range of pixel values.

In step S26, the mixing unit 42, based on the Mix rate Mr _-H supplied from the mix rate detector 43, the image signal is non-linearly smoothed by the image signal S _I and the non-linear filter 41 to be input S _{LPF- H} is mixed and output to the buffer 23 as a non-linearly smoothed image signal _SFH . More specifically, the mixing unit 42 calculates the following equation (3), mixing the image signal S _LPF-H which is nonlinear smoothing the image signal S _I and the non-linear filter input, structural components Are output to the adders 22 and 26, respectively.

S _FH = S _I × Mr _−H / Mr _{−H max} + S _LPF−H × (1−Mr _−H / Mr _{−H max} )
... (3)
Here, Mr _-H is the Mix rate, and Mr _{-H max} is the maximum value of the Mix rate Mr _-H , that is, the absolute difference between the maximum value and the minimum value of the pixel values.

As shown in Expression (3), if the mix rate Mr _−H is large, the weight of the image signal S _LPF-H processed by the nonlinear filter 41 becomes small, and the input unprocessed image signal S _I The weight increases. On the contrary, if the mix rate Mr- _H is small, that is, the difference absolute value of the pixel value between adjacent pixels is small, the weight of the image signal S _LPF-H processed by the non-linear filter increases and is input. The weight of the unprocessed image signal is reduced.

Therefore, if the minute edge is detected, the Mix rate Mr _-H is maximized Mix rate Mr _{-H max,} substantially inputted image signal S _I is to be output as it is.

On the other hand, when it is determined in step S24 that “a minute edge does not exist”, in step S27, the mixture ratio detection unit 43 calculates the difference absolute value of the pixel value between the target pixel and each neighboring pixel, The maximum value of the calculated absolute values of differences is obtained as the mixing rate, which is the mix rate Mr- _H , and is output to the mixing unit 42, and the process proceeds to step S26.

That is, in the case of FIG. 3, the mixture ratio detection unit 43 calculates the difference absolute values | C−L2 |, | C−L1 |, | of the pixel values of the target pixel C and the neighboring pixels L2, L1, R1, and R2. C−R1 | and | C−R2 | are calculated, and the maximum value among the calculated absolute differences is obtained as a mix rate Mr _−H that is a mixing ratio, and is output to the mixing unit.

That is, when there is no minute edge, the image signal S _LPF-H subjected to nonlinear filtering and the input image signal S _I according to the maximum absolute value of the difference in pixel value between the target pixel and each neighboring pixel Are mixed and non-linearly smoothed image signal S _FH is generated as a structural component. If there is a minute edge, the input image signal S _I is output as a structural component as it is.

As a result, the non-linear smoothing processing unit 21 detects a minute edge with reference to the threshold ε ₃ , so that the non-linear smoothing process is not performed on the portion where the minute edge exists, Even in the part where there is no edge, the pixel value that has been subjected to the nonlinear smoothing process according to the magnitude of the absolute value of the difference is mixed with the input image signal. It is possible to suppress a situation in which the image quality is significantly deteriorated by a simple pattern image or the like configured.

  Now, the description returns to the flowchart of FIG.

  In step S2, the adder 22 receives the input image signal by subtracting the structural component of the input image signal generated by the non-linear smoothing processing from the non-linear smoothing processing unit 21 from the input image signal. An amplitude component of the image signal is extracted and generated, and is output to the band separation unit 23.

  In step S3, the band separation unit 23 performs an amplitude component band separation process on the amplitude component of the input image signal, and outputs the separated amplitude component signals of the respective bands to the gain control units 24-1 and 24-2. Output to each.

  Here, the amplitude component band separation processing by the band separation unit 23 will be described with reference to the flowchart of FIG.

  In step S 61, the LPF 31 of the band separation unit 23 supplies a low frequency component lower than a predetermined frequency of the amplitude component supplied from the adder 22 to the gain control unit 24-1 and the adder 32.

  In step S62, the adder 32 subtracts the low frequency component of the amplitude component supplied from the band separation unit 23 from the amplitude component supplied from the adder 22, extracts the high frequency component of the amplitude component, and performs gain control. To the unit 24-2.

  Through the above processing, the low frequency component of the amplitude component is separated and extracted from the LPF 31, and the high frequency component of the amplitude component is separated and extracted by the adder 32.

  Now, the description returns to the flowchart of FIG.

  In step S4, the gain control units 24-1 and 24-2 respectively amplify the low frequency component and the high frequency component of the amplitude component supplied from the band separation unit 23 with the amplification factor set in advance by the operation unit 27. (Amplification is performed to obtain an amplification amount, which is further added to the low frequency component and high frequency component of the input amplitude component), and the gain is controlled (enhanced) and output to the adder 25.

  For example, as shown in FIG. 17, the amplification factor of the low frequency component may be increased and the amplification factor of the high frequency component may be decreased. Here, in FIG. 17, the solid line indicates the amount of amplification of the low-frequency component that is amplified by the gain control unit 24-1 among the input amplitude components. In FIG. 17, the dotted line indicates the amplification amount of the high frequency component amplified by the gain control unit 24-1 among the input amplitude components. Here, in FIG. 17, the horizontal axis indicates the level of the input signal, and the vertical axis indicates the amount of amplification of the signal to be amplified.

  As shown in FIG. 17, the amplification amount of the low frequency component is set so that a large magnification is set in the range where the absolute value of the level of the input signal is near 0, and when the absolute value of the level becomes large, it is amplified at a small magnification. It has become. On the other hand, the amount of amplification of the high frequency component also changes corresponding to the amplification factor of the low frequency component, but since it contains more noise components than the low frequency component, the amplification magnification is generally reduced compared to the low frequency component, When the absolute value of the level of the input signal is close to 0, the amplification factor is set to 0, and noise amplification is set to be suppressed.

  Note that the amplification factor shown in FIG. 17 is merely an example, and the operation unit 27 may set other amplification factors.

  In step S <b> 5, the adder 25 adds the signals whose gains are controlled (enhanced) for each band supplied from the gain control units 24-1 and 24-2 and outputs the added signals to the adder 26. . That is, the adder 25 synthesizes the signals whose gain is controlled for each band, generates a gain-controlled amplitude component, and supplies the amplitude component to the adder 26.

  In step S <b> 6, the adder 26 adds the structural component supplied from the nonlinear smoothing processing unit 21 and the amplitude component that has been gain-adjusted (enhanced) for each band supplied from the adder 25. Thus, an image signal whose amplitude component is gain-adjusted for each band is output as an output signal.

  In step S7, the non-linear smoothing processing unit 21 determines whether or not the next image signal has been input. For example, if it is determined that the next image signal has been input, the processing is performed in step S1. Return to, and the subsequent processing is repeated. On the other hand, if it is determined in step S7 that the next image signal has not been input, the processing ends.

  With the above processing, it becomes possible to set the amplification factor for each frequency band of the amplitude component, and by setting each frequency band, for example, it is possible to perform processing by adding amplification processing only to a specific frequency band Become. As a result, it is possible to suppress amplification processing of amplitude components in frequency bands that contain a lot of noise, and to emphasize and amplify amplitude components in frequency bands that do not contain other noises. It is possible to realize a typical enhancement process.

  In the above description, the amplitude component of the image signal has been described as being divided into a low frequency component lower than a predetermined frequency and a high frequency component other than that, and gain control is performed for each of them. Alternatively, the processing may be performed separately in the bands.

  FIG. 18 shows a configuration of the enhancement processing device 11 when the amplitude component of the image signal is separated into n frequency bands and gain control is performed on each of the frequency bands. In FIG. 18, configurations corresponding to the configuration of the enhancement processing device 11 in FIG. 7 are denoted with the same reference numerals, and description thereof will be omitted as appropriate.

  The enhancement processing device 11 of FIG. 18 differs from the enhancement processing device 11 of FIG. 7 in that, instead of the band separation unit 23, the gain control units 24-1 and 24-2, the adder 25, and the operation unit 27, A band separation unit 71, gain control units 73-1 to 73-n, adders 74-1 to 74- (n-1), and an operation unit 72 are provided.

  The basic function of the band separation unit 71 is the same as that of the band separation unit 23. The input amplitude component is separated into n frequency bands and supplied to the gain control units 73-1 to 73-n, respectively. . More specifically, the band separation unit 71 may be configured to separate into a plurality of bands by configuring the LPF 31 and the adder 32 of FIG. 8 in multiple stages, for example, as shown in FIG. In addition, BPFs (Band Pass Filters) 91-1 to 91-n are provided so that signals are extracted from amplitude components for each predetermined band and supplied to the gain control units 73-1 to 73-n. Also good.

  The gain control units 73-1 to 73-n basically have the same functions as the gain control units 24-1 and 24-2, and are amplified at a magnification set by the operation unit 72 for each band. (Amplification is performed to obtain an amplification amount, which is added to a signal separated for each input band), and is output to adders 74-1 to 74- (n-1), respectively.

  The adders 74-1 to 74- (n-1) sequentially add the signals, which are supplied from the gain control units 73-1 to 73-n and gain-adjusted for each band. As a result, the signal finally added from the adder 74-1 is output to the adder 26 as an amplitude component whose gain is adjusted for each band.

  The operation unit 72 has basically the same function as the operation unit 27, but the operation unit 27 has two gain control units 24-1 and 24-2, which set the amplification factor. On the other hand, the operation unit 72 sets n amplification factors of the gain control units 73-1 to 73-n.

  Next, enhancement processing by the enhancement processing apparatus 11 in FIG. 18 will be described. The basic processing is the same as the processing in the flowchart in FIG. That is, the amplitude component band separation process of step S3 by the band separation unit 71 is a process as shown in FIG. Accordingly, in step S71, the BPFs 73-1 to 73-n extract amplitude components for each predetermined band and output the amplitude components to the gain control units 73-1 to 73-n, respectively. Thus, the amplitude components are separated into n bands by the BPFs 73-1 to 73-n.

  The other processes are basically the same, but in step S4, the gain control units 73-1 to 73-n amplify (amplify) the gains set by the operation unit 72 for each band. The amount of amplification is obtained and added to the signal separated for each input band) and output to the adders 74-1 to 74- (n-1), respectively.

  Further, in step S5, the adders 74-1 to 74- (n-1) are supplied from the gain control units 73-1 to 73-n, and are signals that are gain-adjusted for each band (enhanced). Are added in order, and finally the signal added by the adder 74-1 is output to the adder 26 as an amplitude component whose gain is adjusted for each band.

  Since other processes are the same, the description thereof is omitted.

  In the above description, the amplitude component is separated for each frequency band and gain control is performed for each. However, not only the amplitude component but also the structural component is similarly separated for each band for gain control. You may do it.

  FIG. 21 shows a configuration of the enhancement processing apparatus 11 in which structural components are also divided into k bands and gain control is performed for each band. In addition, about the structure corresponding to the enhancement processing apparatus 11 of FIG. 18, the same code | symbol is attached | subjected and the description shall be abbreviate | omitted suitably.

  The enhancement processing device 11 in FIG. 21 differs from the enhancement processing device 11 in FIG. 21 in that a structural component band separation unit 102, gain control units 103-1 to 103-k, and adders 104-1 to 104- ( k-1) is provided, and an operation unit 101 is provided instead of the operation unit 72.

  The band separation unit 102, the gain control units 103-1 to 103-k, and the adders 104-1 to 104- (k-1) are basically composed of a band separation unit 71 and gain control units 73-1 to 73-k, respectively. The adders 74-1 to 74- (n-1) are functionally similar, but the processing bands of the gain control units 103-1 to 103-k are different. The function of the operation unit 101 is basically the same as that of the operation unit 72, and in addition to the gain control units 73-1 to 73-n, the gains of the gain control units 103-1 to 103-k are also included. The only difference is that it can be set.

  Next, the enhancement processing by the enhancement processing device 11 in FIG. 21 will be described with reference to the flowchart in FIG. 22. The processing in steps S101 to S103, S105, S107, S109, and S110 in FIG. Since this is the same as steps S1 to S7 described with reference to the flowchart of FIG. 10, the description thereof is omitted.

  In step S104, the band separation unit 102 performs structural component band separation processing on the structural components of the input image signal, and outputs the separated amplitude component signals of the respective bands to the gain control units 73-1 to 73-n. Output to each. The structural component band separation process is the same process except that the processing target in the amplitude component band separation process is changed from the amplitude component to the structural component, and the description of the process is omitted.

  In step S <b> 106, the gain control units 103-1 to 103-k amplify individual frequency components separated from the structural components supplied from the band separation unit 102 with the amplification factor set in advance by the operation unit 101. (Amplification is performed to obtain an amplification amount, which is further added to the input individual frequency component signal), and the gain is controlled and output to the adders 104-1 to 104- (k-1).

  The adders 104-1 to 104- (k-1) add the signals whose gains are controlled (enhanced) for each band supplied from the gain control units 103-1 to 103-k, respectively. The result is output to the adder 26. That is, the adders 104-1 to 104- (k-1) synthesize the gain-controlled signal for each band, generate a gain-controlled structural component, and supply it to the adder 26.

  With the above processing, not only the amplitude component but also the structural component can be controlled for the gain by controlling the gain for each band, and the gain for the structural component can be effectively increased while suppressing noise. It becomes possible to control, and more effective enhancement processing can be realized.

  In the above description, an example in which a structural component and an amplitude component whose gain is adjusted for each band is added to obtain a final output signal has been described. For example, an amplitude component whose gain is adjusted for each band is used as an input signal. A final output signal may be generated by addition.

  FIG. 23 shows a configuration of the enhancement processing device 11 that generates a final output signal by adding an amplitude component whose gain is adjusted for each band to an input signal. In the configuration of the enhancement processing apparatus 11 in FIG. 23, the same reference numerals are given to the configuration corresponding to the configuration of the enhancement processing apparatus 11 in FIG. 7, and the description thereof is omitted as appropriate.

  23 differs from FIG. 7 in that the output of the structural component is abolished, and an adder 111 is provided in place of the adder 26 to add the amplitude component whose gain is controlled for each band and the input image signal. And gain control units 112-1 and 112-2 in place of the gain control units 24-1 and 24-2.

  The gain control units 112-1 and 112-2 perform amplification processing on the signals separated for each band of the input structural component, basically in the same manner as the gain control units 24-1 and 24-2. The amplification process is strictly different.

  That is, for example, it is assumed that the gain control units 24-1 and 24-2 in FIG. 7 amplify the amplitude component for each band by 1.5 times and 1.3 times, respectively. The amplitude component is amplified 1.5 times and 1.3 times for each band, but the structural component remains unchanged and is finally added to the amplitude component whose gain is adjusted for each band. . Here, the gain control units 24-1 and 24-2 amplify the amplitude component by 1.5 and 1.3 times for each band, respectively, that the input signal is 0 for each band. After obtaining the amplification amount by multiplying by .5 and 0.3, it is added to the input signal, and the amplitude component separated for each band is directly multiplied by 1.5 and 1.3. It is not calculated by double amplification. That is, the outputs of the gain control units 24-1 and 24-2 are the sum of the amplification amount (= amplification factor × input signal for each band) and the input signal for each band.

  On the other hand, in FIG. 23, the gain control units 112-1 and 112-2 simply amplify each 0.5 times and 0.3 times and output the amplification amount itself. As a result, the adder 111 adds to the components originally included in the respective bands of the amplitude components included in the input image, whereby the above-described gain control units 24-1 and 24-2 in FIG. Can be enhanced in the same manner as in the case where each is amplified by 1.5 times and 1.3 times for each band. That is, the outputs of the gain control units 112-1 and 112-2 are the amplification amount (= amplification factor × input signal for each band) itself.

  From the relationship as described above, the same enhancement processing can be realized regardless of whether the configuration is FIG. 7 or FIG. The enhancement processing apparatus 11 shown in FIGS. 18 and 21 can have the same configuration. The enhancement processing by the enhancement processing device 11 in FIG. 23 is the same as the enhancement processing by the enhancement processing device 11 in FIG. 7 except that the amplification processing in the gain control unit 112 described above is different. Shall be omitted.

  According to the above, it becomes possible to set the amplification factor for each frequency band of the amplitude component, suppress the amplification processing of the amplitude component of the frequency band including a lot of noise, and the amplitude component of the frequency band not including other noise Thus, it is possible to realize an effective enhancement process while suppressing the amplification of noise.

  The series of processes described above can be executed by hardware, but can also be executed by software. When a series of processes is executed by software, a program constituting the software may execute various functions by installing a computer incorporated in dedicated hardware or various programs. For example, it is installed from a recording medium in a general-purpose personal computer or the like.

  FIG. 24 shows the configuration of an embodiment of a personal computer when the electrical internal configuration of the enhancement processing apparatus 11 of FIGS. 7, 18, 21, and 23 is realized by software. The CPU 201 of the personal computer controls the overall operation of the personal computer. Further, when a command is input from the input unit 206 such as a keyboard or a mouse from the user via the bus 204 and the input / output interface 205, the CPU 201 is stored in a ROM (Read Only Memory) 202 correspondingly. Run the program. Alternatively, the CPU 201 reads a program read from the magnetic disk 221, the optical disk 222, the magneto-optical disk 223, or the semiconductor memory 224 connected to the drive 210 and installed in the storage unit 208 into a RAM (Random Access Memory) 203. To load and execute. Thereby, the function of the enhancement processing apparatus 11 shown in FIGS. 7, 18, 21, and 23 is realized by software. Further, the CPU 201 controls the communication unit 209 to communicate with the outside and exchange data.

  As shown in FIG. 24, the recording medium on which the program is recorded is distributed to provide the program to the user separately from the computer, and a magnetic disk 221 (including a flexible disk) on which the program is recorded, By a package medium composed of an optical disk 222 (including compact disc-read only memory (CD-ROM), DVD (digital versatile disk)), a magneto-optical disk 223 (including MD (mini-disc)), or a semiconductor memory 224 In addition to being configured, it is configured by a ROM 202 on which a program is recorded, a hard disk included in the storage unit 208, and the like provided to the user in a state of being incorporated in a computer in advance.

  In this specification, the step of describing the program recorded on the recording medium is not limited to the processing performed in time series in the order described, but of course, it is not necessarily performed in time series. Or the process performed separately is included.

It is a block diagram which shows the structural example of the image signal processing apparatus which emphasizes parts other than an edge in the state which preserve | saved the steep edge in an image. It is a figure which shows the image signal input into the epsilon filter of FIG. 1, and the output image signal. It is a figure which shows an example of the tap used with the epsilon filter of FIG. It is a figure for demonstrating operation | movement of the epsilon filter of FIG. It is a figure for demonstrating the problem of the epsilon filter of FIG. It is a figure for demonstrating the problem of the epsilon filter of FIG. It is a block diagram which shows the structure of one Embodiment of the enhancement processing apparatus to which this invention is applied. It is a block diagram which shows the structure of the band separation part of FIG. It is a block diagram which shows the structure of the nonlinear smoothing process part of FIG. It is a flowchart explaining the enhancement process by the enhancement processing apparatus of FIG. It is a flowchart explaining the nonlinear smoothing process by the enhancement processing apparatus of FIG. It is a flowchart explaining the minute edge determination process by the enhancement processing apparatus of FIG. It is a figure explaining the fine edge determination processing by the enhancement processing apparatus of FIG. It is a figure explaining the fine edge determination processing by the enhancement processing apparatus of FIG. It is a figure explaining the fine edge determination processing by the enhancement processing apparatus of FIG. It is a flowchart explaining the amplitude component band separation process by the enhancement processing apparatus of FIG. It is a figure explaining the gain control by the enhancement processing apparatus of FIG. It is a block diagram which shows the other structure of an enhancement processing apparatus. It is a block diagram which shows the structure of the band separation part of FIG. It is a flowchart explaining the amplitude component band separation process by the enhancement processing apparatus of FIG. It is a block diagram which shows the further another structure of an enhancement processing apparatus. It is a flowchart explaining the enhancement process by the enhancement processing apparatus of FIG. It is a block diagram which shows the further another structure of an enhancement processing apparatus. It is a figure explaining a medium.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 Enhancement processing apparatus, 21 Non-linear smoothing processing part, 22 Adder, 23 Band separation part, 24-1, 24-2 Gain control part, 25, 26 Adder, 27 Operation part, 31 LPF, 32 Adder, 41 Nonlinear filter, 42 mixing unit, 43 mixing ratio detection unit, 51 LPF, 52 control signal generation unit, 71 band separation unit, 72 operation unit, 73-1 to 73-n gain control unit, 74-1 to 74- (n -1) Adder, 91-1 to 91-n BPF, 101 operation unit, 102 band separation unit, 103-1 to 103-k gain control unit, 104-1 to 104- (k-1) adder, 111 Adder, 112-1, 112-2 Gain control unit

Claims (7)

Processing signal extraction means for extracting a plurality of neighboring signals as processing signals from the image signal with reference to the attention signal of interest in the continuously arranged image signals ;
A processing difference that is a difference between the attention signal and each processing signal is compared with a first threshold value, and a processing signal with the processing difference larger than the first threshold value is replaced with the attention signal, and the attention signal is calculated. Computing means for computing a smoothed signal by weighted averaging of the signal and the plurality of processed signals;
Based on the comparison result between the processing difference and a second threshold value that is smaller than the first threshold value, it is determined whether or not a minute edge exists in the vicinity of the signal of interest, and when the minute edge exists, When the difference between the maximum value and the minimum value of the image signal is a mixing ratio between the smoothed signal and the signal of interest, and the minute edge does not exist, the maximum value of the processing differences is determined as the smoothed signal. A mixing ratio calculating means for calculating the mixing ratio between the signal of interest and the signal of interest ;
Mixing means for mixing the smoothed signal and the signal of interest based on the mixture ratio calculated by the mixture ratio calculating means to generate a structural component of the signal of interest;
Difference calculating means for calculating an amplitude component of the signal of interest comprising a difference between the signal of interest and a structural component of the signal of interest;
Band separation means for separating the amplitude component of the signal of interest calculated by the difference calculation means into a plurality of bands ;
Processing means for performing predetermined processing on the amplitude component of the signal of interest separated into a plurality of bands by the band separation means;
A signal processing apparatus comprising: The image signal is a pixel value of a pixel constituting the image.
The signal processing apparatus according to claim 1 . The processing means performs a process for controlling a gain on the amplitude component of the signal of interest separated into a plurality of bands by the band separating means.
The signal processing apparatus according to claim 1 . The amplitude component of the signal of interest, which is separated into a plurality of bands by the band separation unit and subjected to the process of controlling the gain by the processing unit, is either the signal of interest or the structural component of the signal of interest. Superimposing means for superimposing further
The signal processing apparatus according to claim 3 . A processing signal extraction step for extracting a plurality of neighboring signals as processing signals from the image signals with reference to a target signal of interest in image signals that are continuously arranged , and
A processing difference that is a difference between the attention signal and each processing signal is compared with a first threshold value, and a processing signal with the processing difference larger than the first threshold value is replaced with the attention signal, and the attention signal is calculated. A calculation step of calculating a smoothed signal by weighted averaging of the signal and the plurality of processed signals;
Based on the comparison result between the processing difference and a second threshold value that is smaller than the first threshold value, it is determined whether or not a minute edge exists in the vicinity of the signal of interest, and when the minute edge exists, When the difference between the maximum value and the minimum value of the image signal is a mixing ratio between the smoothed signal and the signal of interest, and the minute edge does not exist, the maximum value of the processing differences is determined as the smoothed signal. And a mixing ratio calculating step for calculating as a mixing ratio between the signal of interest and the signal of interest ;
A mixing step of mixing the smoothed signal and the signal of interest based on the mixture ratio calculated in the processing of the mixture ratio calculating step to generate a structural component of the signal of interest;
A difference calculating step of calculating an amplitude component of the signal of interest comprising a difference between the signal of interest and a structural component of the signal of interest;
A band separation step of separating the amplitude component of the signal of interest calculated in the processing of the difference calculation step into a plurality of bands ;
A processing step of performing predetermined processing on the amplitude component of the signal of interest separated into a plurality of bands in the processing of the band separation step;
A signal processing method including : A processing signal extraction control step for controlling extraction as processing signals of a plurality of neighboring signals from among the image signals with reference to a target signal of interest in continuously arranged image signals ;
A processing difference that is a difference between the attention signal and each processing signal is compared with a first threshold value, and a processing signal with the processing difference larger than the first threshold value is replaced with the attention signal, and the attention signal is calculated. A calculation control step for controlling calculation of a smoothed signal by weighted averaging of the signal and the plurality of processed signals;
Based on the comparison result between the processing difference and a second threshold value that is smaller than the first threshold value, it is determined whether or not a minute edge exists in the vicinity of the signal of interest, and when the minute edge exists, When the difference between the maximum value and the minimum value of the image signal is a mixing ratio between the smoothed signal and the signal of interest, and the minute edge does not exist, the maximum value of the processing differences is determined as the smoothed signal. And a mixing ratio calculation control step for controlling calculation to be a mixing ratio between the signal of interest and the signal of interest ;
A mixing control step for controlling generation of a structural component of the signal of interest by mixing the smoothed signal and the signal of interest based on the mixing ratio calculated in the processing of the mixing ratio calculation control step;
A difference calculation control step for controlling calculation of an amplitude component of the signal of interest comprising a difference between the signal of interest and a structural component of the signal of interest;
A band separation control step for controlling separation of a plurality of bands of the amplitude component of the signal of interest calculated in the processing of the difference calculation control step;
A recording medium on which is recorded a program that causes a computer to execute a process including a process control step for performing a predetermined process on the amplitude component of the signal of interest separated into a plurality of bands in the process of the band separation control step . A processing signal extraction control step for controlling extraction as processing signals of a plurality of neighboring signals from among the image signals with reference to a target signal of interest in continuously arranged image signals ;
A processing difference that is a difference between the attention signal and each processing signal is compared with a first threshold value, and a processing signal with the processing difference larger than the first threshold value is replaced with the attention signal, and the attention signal is calculated. A calculation control step for controlling calculation of a smoothed signal by weighted averaging of the signal and the plurality of processed signals;
Based on the comparison result between the processing difference and a second threshold value that is smaller than the first threshold value, it is determined whether or not a minute edge exists in the vicinity of the signal of interest, and when the minute edge exists, When the difference between the maximum value and the minimum value of the image signal is a mixing ratio between the smoothed signal and the signal of interest, and the minute edge does not exist, the maximum value of the processing differences is determined as the smoothed signal. And a mixing ratio calculation control step for controlling calculation to be a mixing ratio between the signal of interest and the signal of interest ;
A mixing control step for controlling generation of a structural component of the signal of interest by mixing the smoothed signal and the signal of interest based on the mixing ratio calculated in the processing of the mixing ratio calculation control step;
A difference calculation control step for controlling calculation of an amplitude component of the signal of interest comprising a difference between the signal of interest and a structural component of the signal of interest;
A band separation control step for controlling separation of a plurality of bands of the amplitude component of the signal of interest calculated in the processing of the difference calculation control step;
A program for causing a computer to execute a process including a process control step for performing a predetermined process on the amplitude component of the signal of interest separated into a plurality of bands in the process of the band separation control step.

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