JP2009278541A - Signal processing apparatus and signal processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an S/N from being deteriorated in the frequency band to be used for contour emphasis at a place where a gain is increased for correcting shading. <P>SOLUTION: Input video signals are combined after performing shading correction processing and contour emphasis processing thereon through different processing systems and an output video signal is produced, whereby an S/N is prevented from being deteriorated in the frequency band to be used for contour emphasis at a place where a gain is increased for correcting shading. Thus, a signal processing apparatus can be provided which can apply contour emphasis similarly to the normal time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a signal processing apparatus and a signal processing method, and in particular, a shading correction process for correcting shading caused by a lens and an image sensor and a process for enhancing the contour of a video signal are compatible so as not to affect each other. The present invention relates to a technique suitable for use.

As a device for performing shading correction, a shading correction device having a configuration as shown in the block diagram of FIG. 6 is the most well-known configuration.
In FIG. 6, an optical image incident on the lens 101 is formed on the image sensor 102 and converted into an electrical signal. At this time, in the performance of the lens 101 and a video signal output by the combination of the lens 101 and the image sensor 102, a phenomenon occurs in which the amount of light falls substantially concentrically from the optical center of the lens 101 toward the periphery. This is called shading in this specification.

A mechanism for correcting this shading will be described below.
The output of the image sensor 102 is input to the multiplication unit 111 and multiplied by the correction coefficient output from the shading correction coefficient generation circuit 112. As described above, assuming that the light amount decreases concentrically from the center of the lens 101 toward the periphery as described above, the correction coefficient takes a value that is 1 near the center of the lens 101 and a value that is larger than 1 in the periphery to match the correction. The coefficient is calculated based on how far each pixel is from the center.

  Further, since shading varies greatly depending on the state of the lens 101 such as the zoom position, the current state of the lens 101 is received as information from the microcomputer 114, and a correction coefficient is calculated thereon. The larger the correction coefficient, the higher the amplification factor with respect to the output signal of the image sensor, and the output of the multiplication unit 111 becomes the same level as the center of the screen, so that the shading is corrected and a flat signal can be obtained.

  The corrected signal passes only the frequency required for contour enhancement by the contour extraction filter (BPF) 107 and passes through the coring circuit 108 that sets the coring level so as not to enhance the output of the minute amplitude for the signal. Let Thereafter, amplification is performed according to the degree of contour enhancement by the contour enhancement degree setting amplifier 109.

  The signal amplified by the contour emphasis degree setting amplifier 109 is a contour emphasis component, and the emphasis component and the shading-corrected video signal output from the multiplier 111 are added by the adder 106. As described above, an output obtained by performing contour enhancement on the shading-corrected signal is obtained, and this output is output to the image output unit 113 for output as an image.

  When the correction is performed with the amplification factor using the shading correction means, the S / N is deteriorated around the amplified screen. Furthermore, since the S / N deteriorates even at the frequency required for contour enhancement, it is known that the noise component is enhanced by contour enhancement. There is something.

  For example, there is a configuration in which the coring level for contour emphasis is changed in accordance with a correction coefficient in shading correction so that the increased noise is not emphasized by the contour emphasizing means (see, for example, Patent Document 1). .

  As another approach, there is a configuration in which the amplification factor of the additional signal for contour enhancement is changed in accordance with how to apply the shading correction (see, for example, Patent Document 2). In this configuration, noise is not emphasized by reducing edge enhancement at a portion where noise has increased. In either configuration, the shading correction itself is performed in the configuration described above.

JP 2003-338949 A Japanese Patent Application Laid-Open No. 2001-39736

  However, in the above-described conventional example, contour enhancement is performed based on a signal whose S / N is deteriorated by shading correction. Therefore, even when the coring level is changed as in Patent Document 1 or when the amplification factor of the signal for edge enhancement is changed as in Patent Document 2, the S / N of the signal itself used for edge enhancement is also deteriorated. is doing. For this reason, there has been a problem that the sense of resolution changes as the shading correction changes.

  An object of the present invention is to prevent the S / N of a frequency band used for contour enhancement at a place where a gain is increased in order to correct shading, in view of the above-described problems.

The signal processing apparatus of the present invention includes a band dividing unit that divides a frequency band of an input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal, and the band Shading correction means for shading correction of a low-frequency video signal divided by the dividing means, and band video in a predetermined band range from a high-frequency video signal other than the low-frequency video signal divided by the band dividing means A contour enhancement signal generating unit configured to perform contour enhancement processing on the signal to generate a contour enhancement signal, and the shading correction processing performed on the input video signal and the contour enhancement processing are separated from each other. The output video signal is generated by synthesizing after performing the above.
Another feature of the signal processing apparatus of the present invention is that the frequency band of the input video signal is divided into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal. Band dividing means for dividing, correction signal generating means for generating a shading correction coefficient for shading correction of the low-frequency video signal divided by the band dividing means, and shading correction coefficient generated by the correction signal generating means And a shading correction means for generating a shading-corrected video signal by multiplying the low-frequency video signal, a band dividing means for extracting a band video signal in a predetermined band range from the high-frequency video signal, An edge emphasis signal generating means for generating an edge emphasis signal from the band video signal extracted from the band dividing means, and output from the band dividing means A signal adding means for adding the shading-corrected video signal output from the shading correction means and the edge enhancement signal output from the edge enhancement signal generating means; The output video signal is generated by combining the shading correction process and the contour enhancement process performed on the video signal, which are performed in separate processing sequences.
Another feature of the signal processing apparatus of the present invention is that the frequency band of the input video signal is divided into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal. Band dividing means for dividing, correction signal generating means for generating a shading correction coefficient for shading correction of the low-frequency video signal divided by the band dividing means, and shading correction coefficient generated by the correction signal generating means And a shading correction unit that multiplies the low-frequency video signal to generate a shading-corrected video signal, and a lower-limit value of a band that can be divided and can be extracted from a predetermined range of the input signal. Generates an edge enhancement signal from the band dividing means set to be equal to or higher than the frequency domain to be divided by the dividing means and the output extracted from the band dividing means. A contour enhancement signal generating means; a low-frequency video signal output from the band dividing means; the shading-corrected video signal output from the shading correction means; and a contour output from the contour enhancement signal generating means. A signal adding means for adding the enhancement signal, and generating an output video signal by combining the shading correction processing and the contour enhancement processing performed on the input video signal in separate processing series It was made to do.

  An imaging apparatus according to the present invention includes any one of the signal processing apparatuses described above.

The signal processing method of the present invention includes a band dividing step of dividing a frequency band of an input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal; A shading correction step for performing shading correction on the low-frequency video signal divided in the division step, and a band image in a predetermined band range from a high-frequency video signal other than the low-frequency video signal divided in the band division step An edge emphasis signal generation step for generating an edge emphasis signal by performing an edge emphasis process on the signal, and a shading correction process performed on the input video signal and an edge emphasis process are performed separately. The output video signal is generated by synthesizing after performing the above.
Another feature of the signal processing method of the present invention is that the frequency band of the input video signal is divided into a predetermined low frequency video signal and a high frequency video signal other than the low frequency video signal. A band dividing step for dividing, a correction signal generating step for generating a shading correction coefficient for correcting shading of the low-frequency video signal divided in the band dividing step, and a shading correction coefficient generated in the correction signal generating step And a shading correction process for generating a video signal corrected by shading by multiplying the low-frequency video signal, and a band dividing process for extracting a band video signal in a predetermined band range from the high-frequency video signal; An edge emphasis signal generation step for generating an edge emphasis signal from the band video signal extracted from the band division step, and an output from the band division step. A signal addition step of adding the low-frequency video signal, the shading-corrected video signal output from the shading correction step, and the contour enhancement signal output from the contour enhancement signal generation step, The output video signal is generated by combining the shading correction processing and the contour enhancement processing performed on the input video signal in separate processing sequences.
Another feature of the signal processing method of the present invention is that the frequency band of the input video signal is divided into a predetermined low frequency video signal and a high frequency video signal other than the low frequency video signal. A band dividing step for dividing, a correction signal generating step for generating a shading correction coefficient for correcting shading of the low-frequency video signal divided in the band dividing step, and a shading correction coefficient generated in the correction signal generating step A shading correction step of multiplying the low-frequency video signal by multiplying the low-frequency video signal to generate a shading-corrected video signal; The edge enhancement signal is generated from the band division process set to be equal to or higher than the frequency domain to be divided in the division process and the output extracted from the band division process. A contour enhancement signal generating step, a low-frequency video signal output from the band dividing step, a shading corrected video signal output from the shading correction step, and a contour enhancement signal generating step. A signal addition step of adding an edge emphasis signal, and performing a shading correction process and an edge emphasis process performed on the input video signal in separate processing sequences, and then combining the output video signal It is characterized in that it is generated.

The computer program of the present invention includes a band dividing step of dividing a frequency band of an input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal; A shading correction step for shading correction of the low-frequency video signal divided in the step, and a band video signal in a predetermined band range from a high-frequency video signal other than the low-frequency video signal divided in the band division step The contour emphasis signal generation step for generating the contour emphasis signal by performing the contour emphasis processing on the computer is executed, and the shading correction processing and the contour emphasis processing performed on the input video signal are performed separately. The output video signal is generated by combining after performing in series.
Another feature of the computer program of the present invention is that the frequency band of the input video signal is divided into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal. A band dividing step, a correction signal generating step for generating a shading correction coefficient for correcting shading of the low-frequency video signal divided in the band dividing step, and a shading correction coefficient generated in the correction signal generating step. A shading correction step of generating a shading-corrected video signal by multiplying the low-frequency video signal, a band dividing step for extracting a band video signal of a predetermined band range from the high-frequency video signal, and An edge emphasis signal generating step for generating an edge emphasis signal from the band video signal extracted from the band dividing step, and the band dividing step A signal adding step of adding the low-frequency video signal output from the shading correction step, the shading-corrected video signal output from the shading correction step, and the contour enhancement signal output from the contour enhancement signal generation step. The output video signal is generated by combining the shading correction process and the contour emphasizing process performed on the input video signal, which are executed by a computer, in separate processing sequences. .
Another feature of the computer program of the present invention is that the frequency band of the input video signal is divided into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal. A band dividing step, and a correction signal generating step for generating a shading correction coefficient for shading correction of the low-frequency video signal divided in the band dividing step;
A shading correction step for generating a shading-corrected video signal by multiplying the shading correction coefficient generated in the correction signal generation step and the low-frequency video signal; and extracting a predetermined range of bands from the input signal. A band dividing step in which a lower limit value of a band to be divided is set to be equal to or higher than a frequency region to be divided in the band dividing step, and a contour emphasizing signal generating step of generating an edge emphasizing signal from an output extracted from the band dividing step Adding the low-frequency video signal output from the band dividing step, the shading-corrected video signal output from the shading correction step, and the contour enhancement signal output from the contour enhancement signal generation step Shading performed on the input video signal by causing the computer to execute a signal adding step And a positive process, characterized in that as synthesized and after performing the edge enhancement processing at a separate processing sequence to produce an output video signal.

According to the present invention, an output video signal is generated by performing a shading correction process and an edge emphasis process performed on an input video signal in separate processing sequences and then combining them. As a result, it is possible to prevent the S / N of the frequency band used for contour emphasis from being deteriorated at a location where the gain is increased in order to correct shading, and contour emphasis can be applied as usual.
According to another feature of the present invention, the process of dividing the frequency band in the luminance signal and the process of dividing the color signal are made common, so that color separation, shading correction, and edge enhancement can be performed. Possible circuit configurations can be simplified.

(First embodiment)
FIG. 1 is a block diagram illustrating a first exemplary embodiment of the present invention and a configuration example of a moving image capturing apparatus. FIG. 2 shows an example of the video signal at that time. Hereinafter, a description will be given with reference to FIGS.

  The optical image incident from the lens 101 is photoelectrically converted by the image sensor 102 and converted into a video signal (electrical signal). This video signal is converted into a digital signal by an analog front end 103 including an A / D conversion circuit and input to the image processing unit 104.

  At this time, shading occurs in the input video signal S <b> 1 of the image processing unit 104 due to the performance of the lens 101 itself and the combination of the lens 101 and the image sensor 102. This video signal is schematically represented by S1 in FIG. As is clear from S1 of FIG. 2, when shading occurs, the center of the image is bright and becomes darker toward the periphery of the image.

  The input video signal S1 of the image processing unit 104 is divided into a plurality of bands by using a band division filter (HPF) 105 and a band division filter (LPF) 110. Since shading has the characteristic that the center of the screen is bright and the edges are dark, the image frequency component is about 10 kHz to 50 kHz in the case of 60 Hz interlace adopted by many of today's moving image pickup apparatuses. In the present embodiment, the band division filter 110 divides the frequency band of the input video signal into a predetermined low frequency video signal and a high frequency video signal other than the low frequency video signal. Yes.

  Therefore, the band is divided using a low-pass filter (hereinafter referred to as LPF) that passes this frequency and a high-pass filter (hereinafter referred to as HPF) that blocks the frequency. In the band division filter 105, the band-divided main line video signal S2 whose lower limit value is set to be equal to or higher than the frequency domain divided by the band division filter 110 is a video signal excluding shading and a low band of the video signal. An edge emphasis signal is generated from the main line video signal S2. The contour emphasis signal is generated by being divided by a contour extraction filter (BPF) 107.

  The frequency used for contour enhancement is generally said to be 0.5 MHz to 6 MHz, and can be divided without any problem because the band is different from the LPF. The component extracted by the BPF 107 is amplified by the edge enhancement degree setting amplifier 109 after removing a signal whose amplitude is smaller than a predetermined value in the coring circuit 108, and becomes the edge enhancement component video signal S6.

  On the other hand, the video signal S4 that has passed through the band division filter (LPF) 110 is a video signal that is a combination of shading and a low-frequency signal of the video signal. In general, since shading varies greatly depending on the state of the lens 101, it is necessary to examine the state of the lens 101 in order to correct with high accuracy. Therefore, in the present embodiment, the state of the lens 101 is sent from the microcomputer 114 to the shading correction coefficient generation circuit 112. Based on the result, the shading correction coefficient generation circuit 112 generates a correction signal for performing shading correction, and sends it to the multiplier 111.

  The multiplication unit 111 corrects shading by multiplying the video signal S4 and the shading correction coefficient for each pixel. The corrected result is the shading-corrected low-frequency video signal S5.

  Three video signals in each band, that is, main line video signal S2, contour emphasis component video signal S6, and shading-corrected low-frequency video signal S5 are added by addition unit 106, and output video signal S3 of image processing unit 104 is output. It becomes. The output video signal S3 is output to the image output unit 113 that performs processing for outputting video. FIG. 3 summarizes the bands of the respective video signals.

  In FIG. 3, since the input video signal S1 of the image processing unit 104 is an input signal, it has the same possible bandwidth. Since the main line video signal S2 has passed through the band division filter (HPF) 105 of 150 kHz or higher, the band is 150 kHz.

  Since the video signal S4 input to the multiplication unit has passed through the band division filter (LPF) 110 of 150 kHz or less, the band is ˜150 kHz. Since the contour emphasis component video signal S6 has passed through the contour extraction filter (BPF) 107 of 300 kHz to 6 MHz, the band is 300 kHz to 6 MHz. Since the video signal S5 is contour-corrected by changing the amplification factor, it has the same signal intensity as the band of the video signal S4 input to the multiplier. Since the output video signal S3 is obtained by adding the main line video signal S2, the contour emphasis component video signal S6, and the video signal S5, the output video signal S3 has a band obtained by adding them.

  In the output video signal S3 obtained in this way, even if the amplification factor around the screen is changed by shading correction, the outline emphasis band is not affected, and therefore the influence of the shading correction does not appear. For this reason, it is possible to prevent a problem that noise is emphasized by contour enhancement in the vicinity without adding a separate noise filter or changing the coring or amplification degree of contour enhancement.

Next, an outline of the operation of the moving image capturing apparatus of the present embodiment will be described with reference to the flowchart of FIG.
When the process is started, in step S501, the optical image incident from the lens 101 is photoelectrically converted by the image sensor 102 to generate a video signal.
In step S502, the photoelectrically converted video signal is converted into a digital signal.
In step S503, the frequency band of the digitized video signal is divided into a low-frequency video signal S4 and other high-frequency video signals.

  In step S504, it is determined whether the digital video signal is a low-frequency video signal. If the result of this determination is not a low-frequency video signal, the process proceeds to step S505. In step S505, the band division filter (HPF) 105 performs band division to generate a main line video signal S2 and a signal component of a predetermined band used for contour enhancement. Thereafter, the process proceeds to step S506. In step S506, it is determined whether or not the main-line video signal S2 is subjected to band division. If the result of this determination is that the video signal has been divided into bands, the process proceeds to step S507.

  In step S507, the signal subjected to the band division process in step S505 is amplified after setting the coring level so as not to emphasize the output of the minute amplitude. As a result, a contour emphasis signal is generated by performing contour emphasis processing on a band video signal in a predetermined band range to generate a contour emphasis component video signal S6.

On the other hand, if the result of determination in step S504 is a low-frequency video signal S4, the process proceeds to step S508, where shading correction is performed on the low-frequency video signal S4 to generate a shading-corrected low-frequency video signal S5.
In step S509, the main video signal S2, the contour enhancement component video signal S6, and the shading-corrected low-frequency video signal S5 are added to generate an output video signal S3.

(Second Embodiment)
FIG. 4 is a block diagram showing a configuration according to the second embodiment of the present invention.
This embodiment is different from the first embodiment in a portion for performing color signal division and extracting and dividing low-frequency components used for shading correction in a filter for color division in the image processing unit 104. . Note that the operation until the output of the analog front end 103 is obtained is the same as that in the first embodiment, and is therefore omitted.

  The output of the analog front end 103 is input to the contour extraction filter 107 and the color signal dividing circuit 401. As for the system input to the contour extraction filter 107, the contour enhancement component video signal S6 is obtained as in the first embodiment.

  The color signal division circuit 401 divides the color signal division and luminance signal main-line video signal S2 and the video signal S4 input to the multiplication unit and outputs the divided signal. The color signal is processed by the color processing circuit 402 and output as a color signal output S7.

  The video signal S4 input to the multiplication unit 111 is a video signal in which luminance shading and a low frequency signal of the video signal are combined. In general, since shading varies greatly depending on the state of the lens 101, it is necessary to examine the state of the lens 101 in order to correct with high accuracy.

  Thus, the state of the lens 101 is sent from the microcomputer 114 to the shading correction coefficient generation circuit 112, and the shading correction coefficient generation circuit 112 generates a shading correction coefficient based on the result, and the generated shading correction coefficient is sent to the multiplication unit 111. send.

  The multiplication unit 111 corrects shading by multiplying the video signal S4 and the shading correction coefficient for each pixel. The result of correction in this manner is the shading corrected low-frequency video signal S5.

  The main line video signal S2, the contour enhancement component video signal S6, and the shading-corrected low-frequency video signal S5 obtained above are added by the adder 106 and output as a luminance output video signal S3.

(Another embodiment according to the present invention)
Each means constituting the signal processing apparatus and the imaging apparatus according to the above-described embodiment of the present invention can be realized by operating a program stored in a RAM or ROM of a computer. This program and a computer-readable recording medium recording the program are included in the present invention.

  In addition, the present invention can be implemented as a system, apparatus, method, program, storage medium, or the like, and can be applied to a system composed of a plurality of devices. Moreover, you may apply to the apparatus which consists of one apparatus.

  In the present invention, a software program (in the embodiment, a program corresponding to the flowchart shown in FIG. 5) for executing each step in the signal processing method described above is supplied directly or remotely to a system or apparatus. In addition, this includes a case where the system or the computer of the apparatus is also achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, or the like.

  Various recording media can be used as a recording medium for supplying the program. For example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD- R).

  As another program supply method, a browser on a client computer is used to connect to an Internet home page. The computer program itself of the present invention or a compressed file including an automatic installation function can be downloaded from the homepage by downloading it to a recording medium such as a hard disk.

  It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. Let It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  In addition to the functions of the above-described embodiments being realized by the computer executing the read program, the OS running on the computer performs part or all of the actual processing. Also, the functions of the above-described embodiments can be realized.

  Further, the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, the CPU of the function expansion board or function expansion unit performs part or all of the actual processing based on the instructions of the program, and the functions of the above-described embodiments are realized by the processing.

1 is a block diagram illustrating a configuration example of a moving image capturing apparatus according to a first embodiment of the present invention. It is the figure which showed the 1st Embodiment of this invention and showed an example of the video signal of each part of a moving image imaging device. It is a figure which shows the 1st Embodiment of this invention and demonstrates the zone | band of a video signal. It is a block diagram which shows the 2nd Embodiment of this invention and shows the structural example of a moving image imaging device. It is a flowchart explaining the outline of operation | movement of a moving image imaging device. It is a block diagram explaining the structural example of the apparatus which performs the conventional shading correction | amendment.

Explanation of symbols

101 Lens 102 Image Sensor 103 Analog Front End 104 Image Processing Unit 105 Band Division Filter (HPF)
106 adder 107 contour extraction filter (BPF)
108 Coring circuit 109 Edge enhancement setting amplifier 110 Band division filter (LPF)
111 Multiplying unit 112 Shading correction coefficient generating circuit 113 Image output unit 114 Microcomputer 401 Color signal dividing circuit 402 Color processing circuit S1 Input video signal S2 of image processing unit Main line type video signal S3 Output video signal S4 of image processing unit For shading correction Video signal S5 input to multiplication unit Video signal S6 after shading correction Outline enhancement component video signal S7 Color signal output

Claims (12)

Band dividing means for dividing the frequency band of the input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal;
Shading correction means for correcting shading for a low-frequency video signal divided by the band dividing means;
Contour enhancement signal generation means for generating an edge enhancement signal by performing edge enhancement processing on a band video signal in a predetermined band range from a high frequency video signal other than the low frequency video signal divided by the band division means; Have
A signal processing apparatus characterized in that a shading correction process and an edge emphasis process performed on the input video signal are performed in separate processing sequences and then combined to generate an output video signal. Band dividing means for dividing the frequency band of the input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal;
Correction signal generating means for generating a shading correction coefficient for correcting shading of the low-frequency video signal divided by the band dividing means;
Shading correction means for generating a video signal corrected by shading by multiplying the shading correction coefficient generated by the correction signal generation means and the low-frequency video signal;
Band dividing means for extracting a band video signal of a predetermined band range from the high band video signal;
An edge emphasis signal generating means for generating an edge emphasis signal from the band video signal extracted from the band dividing means;
A signal for adding the low-frequency video signal output from the band dividing unit, the shading-corrected video signal output from the shading correction unit, and the contour enhancement signal output from the contour enhancement signal generation unit Adding means,
A signal processing apparatus characterized in that a shading correction process and an edge emphasis process performed on the input video signal are performed in separate processing sequences and then combined to generate an output video signal. Band dividing means for dividing the frequency band of the input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal;
Correction signal generating means for generating a shading correction coefficient for correcting shading of the low-frequency video signal divided by the band dividing means;
Shading correction means for generating a video signal corrected by shading by multiplying the shading correction coefficient generated by the correction signal generation means and the low-frequency video signal;
A band dividing unit that can extract a band in a predetermined range from an input signal and has a lower limit of a band to be divided is set to be equal to or higher than a frequency region divided by the band dividing unit;
An edge enhancement signal generating means for generating an edge enhancement signal from the output extracted from the band dividing means;
A signal for adding the low-frequency video signal output from the band dividing unit, the shading-corrected video signal output from the shading correction unit, and the contour enhancement signal output from the contour enhancement signal generation unit Adding means,
A signal processing apparatus characterized in that a shading correction process and an edge emphasis process performed on the input video signal are performed in separate processing sequences and then combined to generate an output video signal.   An imaging apparatus comprising the signal processing apparatus according to claim 1.   A process of dividing a frequency band of the input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal; and a color signal from the input video signal The image pickup apparatus according to claim 4, further comprising a color signal dividing unit that performs a dividing process. A band dividing step of dividing the frequency band of the input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal;
A shading correction step for correcting shading for the low-frequency video signal divided in the band division step;
A contour emphasis signal generating step of generating a contour emphasis signal by performing contour emphasis processing on a band video signal in a predetermined band range from a high frequency video signal other than the low frequency video signal divided in the band division step; Have
A signal processing method characterized in that a shading correction process and an edge emphasis process performed on the input video signal are performed in separate processing sequences and then combined to generate an output video signal. A band dividing step of dividing the frequency band of the input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal;
A correction signal generating step for generating a shading correction coefficient for correcting shading of the low-frequency video signal divided in the band dividing step;
A shading correction step for generating a shading-corrected video signal by multiplying the low-frequency video signal by the shading correction coefficient generated in the correction signal generation step;
A band dividing step for extracting a band video signal of a predetermined band range from the high frequency video signal;
An edge emphasis signal generating step for generating an edge emphasis signal from the band video signal extracted from the band dividing step;
A signal for adding the low-frequency video signal output from the band dividing step, the shading-corrected video signal output from the shading correction step, and the contour enhancement signal output from the contour enhancement signal generation step An adding step,
A signal processing method characterized in that a shading correction process and an edge emphasis process performed on the input video signal are performed in separate processing sequences and then combined to generate an output video signal. A band dividing step of dividing the frequency band of the input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal;
A correction signal generating step for generating a shading correction coefficient for correcting shading of the low-frequency video signal divided in the band dividing step;
A shading correction step for generating a shading-corrected video signal by multiplying the low-frequency video signal by the shading correction coefficient generated in the correction signal generation step;
A band dividing step in which a lower limit value of a band to be divided in which a band in a predetermined range can be extracted from the input signal is set to be equal to or higher than a frequency region to be divided in the band dividing step;
An edge emphasis signal generating step for generating an edge emphasis signal from the output extracted from the band dividing step;
A signal for adding the low-frequency video signal output from the band dividing step, the shading-corrected video signal output from the shading correction step, and the contour enhancement signal output from the contour enhancement signal generation step An adding step,
A signal processing method characterized in that a shading correction process and an edge emphasis process performed on the input video signal are performed in separate processing sequences and then combined to generate an output video signal. A band dividing step of dividing the frequency band of the input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal;
A shading correction step for correcting shading for the low-frequency video signal divided in the band division step;
A contour emphasis signal generating step of generating a contour emphasis signal by performing contour emphasis processing on a band video signal in a predetermined band range from a high frequency video signal other than the low frequency video signal divided in the band division step; To the computer,
A computer program characterized in that a shading correction process and an edge emphasis process performed on the input video signal are performed in separate processing sequences and then combined to generate an output video signal. A band dividing step of dividing the frequency band of the input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal;
A correction signal generating step for generating a shading correction coefficient for correcting shading of the low-frequency video signal divided in the band dividing step;
A shading correction step for generating a shading-corrected video signal by multiplying the low-frequency video signal by the shading correction coefficient generated in the correction signal generation step;
A band dividing step for extracting a band video signal of a predetermined band range from the high frequency video signal;
An edge emphasis signal generating step for generating an edge emphasis signal from the band video signal extracted from the band dividing step;
A signal for adding the low-frequency video signal output from the band dividing step, the shading-corrected video signal output from the shading correction step, and the contour enhancement signal output from the contour enhancement signal generation step Let the computer execute the addition process,
A computer program characterized in that a shading correction process and an edge emphasis process performed on the input video signal are performed in separate processing sequences and then combined to generate an output video signal. A band dividing step of dividing the frequency band of the input video signal into a predetermined low-frequency video signal and a high-frequency video signal other than the low-frequency video signal;
A correction signal generating step for generating a shading correction coefficient for correcting shading of the low-frequency video signal divided in the band dividing step;
A shading correction step for generating a shading-corrected video signal by multiplying the low-frequency video signal by the shading correction coefficient generated in the correction signal generation step;
A band dividing step in which a lower limit value of a band to be divided in which a band in a predetermined range can be extracted from the input signal is set to be equal to or higher than a frequency region to be divided in the band dividing step;
An edge emphasis signal generating step for generating an edge emphasis signal from the output extracted from the band dividing step;
A signal for adding the low-frequency video signal output from the band dividing step, the shading-corrected video signal output from the shading correction step, and the contour enhancement signal output from the contour enhancement signal generation step Let the computer execute the addition process,
A computer program characterized in that a shading correction process and an edge emphasis process performed on the input video signal are performed in separate processing sequences and then combined to generate an output video signal.   A computer-readable storage medium storing the computer program according to any one of claims 9 to 11.

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