JP4671417B2 - Image processing apparatus and image processing method - Google Patents

Description

  The present invention relates to an image processing apparatus that targets a moving image sequence composed of a plurality of frames and performs image quality enhancement processing on a target image.

  Conventionally, various devices have been devised as image processing apparatuses for improving the S / N ratio of a moving image sequence composed of a plurality of frames. As an example of improving the S / N ratio, when noise removal processing is a target, there is one provided with a recursive filter as disclosed in Patent Document 1, for example. In this document, by changing the filter coefficient of the recursive filter according to the magnitude of the image signal, it is possible to perform noise removal processing based on the relationship between the image density and the noise amount, which is the characteristic of the X-ray image. it can.

Further, as a process for sharpening an image to make it easier to see, for example, as disclosed in Patent Document 2, the enhancement coefficient in the blur mask process is changed according to the subject depicted in the image. Thereby, it is possible to enhance the image signal while suppressing unnecessary noise enhancement.
JP 05-087394 A JP 7-21364 A

  In the above-described conventional recursive filter, noise can be reduced by time-direction addition of image signals over a plurality of frames, but information in the same frame is not effectively used. In the blur mask process, it is known that artifacts such as overshoot occur near the edge of the image.

  The present invention has been made in view of the above problems, and provides an image processing technique capable of improving image quality with higher effect while utilizing an image signal in the same frame and a change in the time axis direction. With the goal.

  In order to achieve the object of the present invention, for example, an image processing apparatus of the present invention comprises the following arrangement.

That is, an input means for inputting an image of each frame constituting a moving image;
Decomposition means for decomposing the image of the first frame into a plurality of frequency bands;
Wherein the coefficients belonging to a predetermined frequency band among the plurality of frequency bands in which the decomposing means is decomposed for the first frame image, the second frame of the image than the image of the first frame is an image of the previous frame Changing means for changing using a coefficient belonging to a frequency band corresponding to the predetermined frequency band among the plurality of frequency bands decomposed by the decomposition means,
By performing the processing and reverse processing of said decomposing means went based on coefficients of all the frequency band including a frequency band changed by the changing means, and reconstructing means for reconstructing an image,
Output means for outputting the image reconstructed by the reconstructing means as the image of the first frame.

  In order to achieve the object of the present invention, for example, an image processing method of the present invention comprises the following arrangement.

That is, an input process for inputting an image of each frame constituting a moving image;
A decomposing step of decomposing the image of the first frame into a plurality of frequency bands;
Wherein the coefficients belonging to a predetermined frequency band among the plurality of frequency bands decomposed by the decomposition step for a first frame image, the second frame of the image than the image of the first frame is an image of the previous frame A changing step of changing using a coefficient belonging to a frequency band corresponding to the predetermined frequency band among the plurality of frequency bands decomposed in the decomposition step;
A reconstruction process for reconstructing an image by performing a process opposite to the process performed in the decomposition process based on the coefficients of all frequency bands including the frequency band changed in the change process;
And an output step of outputting the image reconstructed in the reconstruction step as the image of the first frame.

  According to the configuration of the present invention, it is possible to improve the image quality with higher effect while using the image signal in the same frame and the change in the time axis direction.

  Hereinafter, the present invention will be described in detail according to preferred embodiments with reference to the accompanying drawings.

[First Embodiment]
FIG. 1 is a block diagram illustrating a functional configuration of the image processing apparatus 100 according to the present embodiment. As shown in FIG. 1, the image processing apparatus 100 includes an image input unit 1, a frequency resolution unit 2, a coefficient change unit 3, an image reconstruction unit 4, a coefficient storage unit 5, and an image output unit 6.

  The image input unit 1 inputs an image (image signal) of each frame constituting a moving image. As an image supply source, for example, there is a digital camera. For example, when the digital camera is a CCD camera and outputs a captured image as an analog image signal, the image input unit 1 performs A / D conversion on the analog image signal, As an image signal, it is sent to the frequency resolution unit 2 in the subsequent stage. In addition to converting the format of the input image signal, the image input unit 1 may perform a correction process specific to the digital camera, for example, on the image signal. Such correction processing includes, for example, dark correction processing when the digital camera is a CCD camera.

  The image signal is input to the image input unit 1 in units of frames and in the order of scan lines. That is, it is premised on the progressive scan. However, depending on the supply source of the image signal, the image signal may not be input in this order. In such a case, the image input unit 1 may change the output order of the input image signals. For example, when the image signal output from the digital camera is an interlace scan, the image input unit 1 receives this image signal, converts it into a progressive scan, and outputs it.

  In the present embodiment, the moving image input to the image input unit 1 has a predetermined frame rate (for example, 30 frames per second), and the image resolution of each frame has a predetermined resolution (for example, vertical and horizontal 1024 pixels). And

  In this embodiment, the image of each frame is an image having one color component, that is, a monochrome image. However, the present invention is not limited to this, and the image of each frame has a plurality of color components. Also good. In this case, each process described later is performed on each color component.

  Furthermore, when the image of each frame has a plurality of color components, the image input unit 1 may perform color space conversion. For example, when the image of each frame input to the image input unit 1 has three color components of RGB, the image input unit 1 converts the color space from RGB to YUV, and for the subsequent processing, the converted colors What is necessary is just to make it with respect to a component.

  Since an image is input to the frequency resolution unit 2 from the image input unit 1 in units of frames, the frequency resolution unit 2 decomposes the image into a plurality of frequency bands for each frame. Then, the frequency band coefficients decomposed for each frame are sent to the coefficient changing unit 3 for each frame.

  As a method for decomposing an image into a plurality of frequency bands, any method shown in FIG. 2 may be used. FIG. 2A is a diagram for explaining how to obtain 10 frequency bands (LL to HH1) by performing a two-dimensional discrete wavelet transform process on an image Fn of a certain frame. In the figure, three levels of decomposition are performed. Regarding discrete wavelet transform, for example, S. Mallat, “A Theory of Multiresolution Signal Decomposition: the Wavelet Representation”, IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol 11, No. 7, July 1989, 674-693, etc. The description is omitted here.

  FIG. 2B is a diagram for explaining how the three frequency bands H1, H2, and L are obtained by performing Laplacian pyramid decomposition on the image Fn of a certain frame. Here, H1 and H2 are high frequency components relating to different frequency bands, and L is a coefficient group representing components relating to the remaining low frequency bands. H2 and L have resolutions of 1/2 and 1/4 with respect to the image Fn in the horizontal and vertical directions, respectively. For Laplacian pyramid decomposition, for example, P. Burt and H. Adelson, “The Laplacian Pyramid as a Compact Image Code”, IEEE Transactions on Communications, Vol.Com-31, No.4, April 1983, 532-540, etc. Will not be described here.

The coefficient changing unit 3 uses the coefficient C _ij ^t (k) related to the frequency band k of the image of the frame t (hereinafter referred to as the t-th frame image) output from the frequency resolving unit 2 as the coefficient C ′ _ij ^t ( The process of changing to k) is performed. Here, k is a variable indicating a frequency band. When the frequency decomposition unit 2 decomposes an image into 10 frequency bands as shown in FIG. 2A, k = LL to HH1. Further, i and j are coefficients specific to each frequency band. Therefore, C _ij ^t (k) indicates a coefficient located at the position (i, j) when the coefficient group related to the frequency band k of the image in the frame t is two-dimensionally arranged.

  Here, the coefficient changing process performed by the coefficient changing unit 3 will be described.

As described above, the coefficient changing unit 3 changes the coefficient group related to each frequency band of the image of the frame output from the frequency resolving unit 2, but outputs the changed coefficient group to the image reconstruction unit 4. At the same time, it is stored in the coefficient storage unit 5. Therefore, when the coefficient changing unit 3 performs the changing process for the coefficient C _ij ^t (k) related to the frequency band k of the t-th frame image, the coefficient storage unit 5 already has the frequency of the (t−1) -th frame image. Coefficients related to the band k (changed by the coefficient changing unit 3) C ′ _ij ^(t−1) (k) are stored.

Therefore, the coefficient changing unit 3 changes C _ij ^t (k) as follows using C _ij ^t (k) and C ′ _ij ^(t−1) (k).

C ′ _ij ^t (k) = Ek {αC _ij ^t (k) + (1−α) C ′ _ij ^(t−1) (k)} d <T
C ′ _ij ^t (k) = EkC _ij ^t (k) d ≧ T
(Formula 1)
However, α and T are parameters related to noise removal, and optimum values are determined in advance according to the amount of noise included in the image signal, and are stored in the coefficient changing unit 3 in advance.

  Here, α represents the mixing ratio of the coefficients related to the current and past frames in generating the changed coefficient. In the case of this embodiment, the coefficient in the frame t and the coefficient in the frame (t−1) are combined with a combining ratio determined by α.

  T is a parameter for eliminating the influence of the coefficient of the past frame and eliminating the unnecessary afterimage effect by excluding the part having a large coefficient difference as a part having motion. Therefore, d is expressed by the following equation.

d = | C _ij ^t (k) −C ′ _ij ^(t−1) (k) |
This d is calculated by the coefficient changing unit 3. Ek is an enhancement coefficient for the frequency band k, which is set in advance according to the required enhancement strength, and is also held in the coefficient changing unit 3 in advance.

  The coefficient changing unit 3 performs the coefficient changing process described above for all frequency bands. For example, when the frequency decomposition unit 2 decomposes the image into 10 frequency bands as shown in FIG. 2A, the coefficient changing process described above for k = LL to HH1 is performed.

  As described above, the coefficient changing unit 3 performs a process of changing the coefficient group belonging to each frequency band in the current frame with the changed coefficient group in the previous frame. As described above, in the present embodiment, when the coefficient group in the current frame is changed, the changed coefficient group in the previous frame is used, but the changed coefficient in two or more previous frames is used. A group may be used.

  The coefficient changing unit 3 outputs the changed coefficient group to the image reconstruction unit 4 and stores it in the coefficient storage unit 5 for use when changing the coefficient group in the next frame.

In addition, before performing the calculation process according to the above (formula 1), the degeneration process of the coefficient C _ij ^t (k) may be performed according to the following formula.

C _ij ^t (k) = C _ij ^t (k) C _ij ^t (k) ≧ Ts
C _ij ^t (k) = 0 C _ij ^t (k) <Ts
(Formula 3)
_Further, the value of _C ^ij t (k), rather than suddenly than to zero just because less than the threshold value _Ts, if the value of _C ^ij t (k) is smaller than the threshold Ts, according to the value Alternatively, it may be reduced by the attenuation rate.

  When the image reconstructing unit 4 receives from the coefficient changing unit 3 the changed coefficient group belonging to each frequency band of the image for one frame, a process opposite to the process performed by the frequency resolving unit 2 To reconstruct the image. For example, if the frequency resolving unit 2 performs a two-dimensional discrete wavelet transform process, the image reconstruction unit 4 performs a two-dimensional discrete inverse wavelet transform process.

  The image output unit 6 outputs the reconstructed image obtained by the image reconstruction unit 4.

  By each unit described above, the coefficient group in each frequency band in the image of each frame input to the image input unit 1 can be corrected using the coefficient group in the corresponding frequency band in the image of the previous frame. . Images reconstructed based on the corrected coefficient group can be sequentially output by the image output unit 6.

  The output destination by the image output unit 6 is not particularly limited, but the format of the output image needs to be changed depending on the output destination device. Therefore, in such a case, the image output unit 6 changes the format of the image to a format according to the output destination apparatus and outputs the image.

  Here, each unit shown in FIG. 1 may be configured with dedicated hardware, and as a result, the image processing apparatus 100 may be configured as one chip. In the present embodiment, the components other than the coefficient storage unit 5 are configured by software, and the coefficient storage unit 5 is configured by a memory such as a RAM. In this case, the image processing apparatus shown in FIG. 1 can be configured by a computer such as a general PC (personal computer) or WS (workstation).

  FIG. 3 is a block diagram illustrating a hardware configuration of a computer applied as an image processing apparatus and its peripheral devices.

  As shown in the figure, a computer 300 is connected to an imaging device 360 and a file server 370 via a network 350, and is configured to be able to perform data communication with each other.

  First, the computer 300 will be described.

  A CPU 301 controls the entire computer 300 using programs and data stored in the RAM 302 and the ROM 303 and executes each process performed by the image processing apparatus 100 to which the computer 300 is applied.

  A RAM 302 has an area for temporarily storing programs and data loaded from the magneto-optical disk 305 and the hard disk 304. Further, the RAM 302 includes an area for temporarily storing image data downloaded from the imaging device 360 or the file server 370 via the network 350. The RAM 302 also includes a work area that is used when the CPU 301 executes various processes.

  A ROM 303 stores setting data of the computer 300, a boot program, and the like.

  A hard disk 304 performs the above-described processes performed by the OS (operating system), the image input unit 1, the frequency decomposition unit 2, the coefficient changing unit 3, the image reconstruction unit 4, and the image output unit 6 shown in FIG. A program and data to be executed by the CPU 301 are held. These are appropriately loaded into the RAM 302 according to the control by the CPU 301 and are processed by the CPU 301. The moving image data may be stored in the hard disk 304.

  A magneto-optical disk 305 is an example of an information storage medium, and a part or all of programs and data stored in the hard disk 304 may be stored in the magneto-optical disk 305.

  Reference numerals 306 and 307 are a mouse and a keyboard, respectively, and various instructions can be input to the CPU 301 by an operator of the computer 300.

  A printer 308 is an example of an output destination by the image output unit 6.

  Reference numeral 309 denotes a display device, which includes a CRT, a liquid crystal screen, and the like, and displays the processing result by the CPU 301 using images, characters, and the like. For example, the image of each frame processed by each unit shown in FIG. 1 and finally output from the image output unit 6 is displayed.

  A bus 310 connects the above-described units.

  Next, the imaging device 360 will be described. The imaging device 360 is a device that captures a moving image, such as a digital camera, and the data of the captured moving image is supplied to the computer 300 via the network 350. Note that the moving image data may be supplied to the computer 300 for a plurality of frames, or may be supplied for each captured frame.

  Next, the file server 370 will be described. Various information including image data can be stored in the file server 370. In the case of the present embodiment, an image of each frame obtained by each of the processes performed by each unit shown in FIG. 1 can be stored. it can. Therefore, when the computer 300 performs the processing by each unit shown in FIG. 1 on the image of each frame, the computer 300 transfers the processed image of each frame to the file server 370 via the network 350. Thereby, the moving image data processed by the computer 300 can be registered in the file server 370.

  Next, the network 350 will be described. The network 350 is configured by a network such as a LAN or the Internet. Note that the network 350 may be either wireless or wired, or a combination of both.

  FIG. 8 is a flowchart of processing performed by each unit shown in FIG. Note that programs and data for causing the CPU 301 of the computer 300 to execute the processing according to the flowchart of FIG. 3 are stored in the hard disk 304 and the magneto-optical disk 305 and are appropriately loaded into the RAM 302 by the CPU 301. And when CPU301 performs a process using this, the computer 300 performs each process demonstrated below.

  Note that the flowchart of FIG. 5 is for an image of one frame (t-th frame). Therefore, when the same processing is performed for each of a plurality of frames, the processing according to the flowchart of FIG. You can do it.

  First, the CPU 301 functions as the frequency decomposing unit 2 and performs a process of decomposing the t-th frame image held in the RAM 302 into a plurality of frequency bands (step S802). Next, the processing from step S803 to step S806 is performed for each decomposed frequency band.

First, the coefficient C ′ _ij ^(t−1) (k) related to the frequency band k of the (t−1) th frame image held in the hard disk 304 or RAM 302 is read (step S803). Then, the CPU 301 functions as the coefficient changing unit 3 and uses this read coefficient to perform processing for changing the coefficient C _ij ^t (k) related to the frequency band k of the t-th frame image according to the above (Equation 1) ( Step S804). As described above, the coefficient degeneration processing may be performed by the processing according to the above (Equation 3) or the like before the present step.

Next, the CPU 301 determines whether or not change processing has been performed for all the coefficients belonging to the frequency band k of the t-th frame image (step S805), and if not, returns the processing to step S803. Then, the step S803 and subsequent steps for the coefficients C _{ij t} according to the frequency band k of the t frame image not yet subjected to change ^_(k).

  On the other hand, if the changing process has been performed for all the coefficients belonging to the frequency band k of the t-th frame image, the process proceeds to step S806. Then, it is determined whether or not the change processing in step S804 has been performed for all frequency bands to be processed (variable k for all frequency bands to be processed) (step S806). If not, the process returns to step S803, and the processes after step S803 are performed on the frequency bands not yet processed among the plurality of frequency bands of the t-th frame image.

  Here, the frequency band to be processed is determined in advance, and information indicating the frequency band to be processed is held in the RAM 302 in advance. The frequency band to be processed is desirably a band containing a lot of high frequency components in order to effectively remove noise. Therefore, for example, in the case of the discrete wavelet transform shown in FIG. 2A, all frequency bands except LL may be set as frequency bands to be processed. In the case of the Laplacian pyramid shown in FIG. 2B, all frequency bands except L may be set as frequency bands to be processed.

  On the other hand, when the change process in step S804 has been performed for all target frequency bands, the process proceeds to step S807. Then, the CPU 301 functions as the image reconstruction unit 4, and reconstructs an image by performing reverse processing of the processing performed in step S802 on a plurality of changed frequency bands of the t-th frame image. S807). The CPU 301 functions as the image output unit 6 and outputs the reconstructed image to the hard disk 304, the RAM 302, the file server 370, etc. as the t-th frame image (step S808). Further, it may be output to the display device 309.

  As described above, according to the present embodiment, it is possible to effectively perform processing in the frequency space on a moving image composed of a plurality of frames, and to realize a higher noise removal effect and sharpening processing. It becomes possible.

[Second Embodiment]
In the present embodiment, information related to the image input to the image input unit 1 is further input in the processing according to the first embodiment. Thereby, it is possible to process a moving image according to the type of image to be input, shooting conditions, and the like.

  FIG. 4 is a block diagram illustrating a functional configuration of the image processing apparatus 400 according to the present embodiment. In this figure, the same parts as those in FIG. As shown in the figure, an image processing apparatus 400 according to the present embodiment has a configuration in which an imaging condition input unit 7 is added to the image processing apparatus 100 according to the first embodiment shown in FIG.

  The shooting condition input unit 7 inputs information related to a moving image such as a shooting condition of the moving image input to the image input unit 1. “Information relating to the moving image” is not particularly limited, but in the present embodiment, a case where the input image is a medical X-ray image will be described.

  When a processing target is a medical X-ray moving image, imaging conditions include an imaging region, an X-ray irradiation amount, an imaging method, and the like. These pieces of information are input to the imaging condition input unit 7.

  For example, the imaging condition input unit 7 determines the frequency resolution level in the frequency resolution unit 2 and the image reconstruction unit 4 in accordance with the imaging methods listed below.

(1) Perspective (2) DSA
(3) Still image shooting For example, when “information indicating that the shooting method is fluoroscopic” is input to the shooting condition input unit 7, the frequency resolution level in the frequency resolution unit 2 and the image reconstruction unit 4 is set to 3 And decide. When “information indicating that the imaging method is DSA” is input to the imaging condition input unit 7, the frequency resolution level in the frequency resolution unit 2 and the image reconstruction unit 4 is determined to be 5. When “information indicating that the shooting method is still image shooting” is input to the shooting condition input unit 7, the frequency resolution level in the frequency resolution unit 2 and the image reconstruction unit 4 is determined to be 7.

  By taking a large frequency resolution level, finer frequency processing becomes possible. However, in fluoroscopic imaging, it is sufficient if the use is not diagnosis but the position of a surgical device such as a catheter can be confirmed. However, in order to avoid display delay, the frame rate needs to be high. Therefore, by setting the decomposition level low for fluoroscopy, it is possible to reduce the amount of calculation and realize processing optimal for fluoroscopy.

  On the other hand, in DSA, the frame rate is, for example, about 7 frames per second, but it is desirable to perform processing at a higher decomposition level because of the need to depict even fine blood vessel structures. Furthermore, in still image shooting, it is necessary to set a high resolution level in order to achieve as high a picture quality as possible even if the amount of calculation increases in order to obtain an image quality that can withstand diagnosis.

  In this way, by changing the frequency resolution level according to the photographing method, processing according to the purpose can be realized.

  Further, not only the decomposition level but also the processing parameters in the coefficient changing unit 3 may be changed. For example, the value of α in (Expression 1) is changed so as to be small in the case of fluoroscopy and to be large in the case of DSA. In the case of fluoroscopy, the amount of X-ray irradiation is reduced in order to reduce the amount of exposure, but this increases the amount of noise in the image. For this reason, the noise removal effect can be further enhanced by increasing the weight for the coefficient of the previous frame.

  Further, the selection of the processing target frequency band may be performed only for a predetermined number of bands from the highest frequency band based on the input to the imaging condition input unit 7. In particular, in the case where there is a movement in a subject projected in an image such as fluoroscopic photography, an afterimage may occur when the above-described processing is performed on a low frequency band. Accordingly, in such shooting, a predetermined number of high frequency bands may be selected as frequency bands to be processed.

  For example, in the case of discrete wavelet transform, noise removal can be performed while suppressing the influence of afterimages by removing bands other than LL and HL3, LH3, and HH3 from the processing target.

[Third Embodiment]
In the first embodiment, the coefficient C ′ _ij ^t (k) changed by the coefficient changing unit 3 is stored in the coefficient storage unit 5, but the coefficient C _ij ^t (k) before the change is stored. May be. In that case, the coefficient changing unit 3 performs the process of changing the coefficient using the following (Expression 4) instead of the above (Expression 1).

C ′ _ij ^t (k) = Ek {αC _ij ^t (k) + (1−α) C _ij ^(t−1) (k)} d <T
C ′ _ij ^t (k) = EkC _ij ^t (k) d ≧ T
(Formula 4)
That is, instead of the coefficient C _'ij in the first embodiment ^{(t-1) (k)} , the coefficient ^{_{C ij (t-1) (}} k) may be used.

  Further, whether the coefficient changing unit 3 changes the coefficient based on (Equation 1) or whether the coefficient is changed using (Equation 4) is input to the imaging condition input unit 7 shown in FIG. It may be determined based on information.

  For example, if the subject in the image input to the image input unit 1 has a fine structure and has a certain amount of movement, the afterimage effect increases when recursive filtering based on (Equation 1) is used. It is not preferable. However, if (Equation 4) is used, the influence can be suppressed.

  Accordingly, when the image input to the image input unit 1 is a medical image and the image capturing method is angiography, the following may be performed. That is, at the same time when the imaging condition input unit 7 switches the processing parameters in the coefficient changing unit 3, when using (Equation 1), the input to the coefficient storage unit 5 is used as the output by the coefficient changing unit 3, and (Equation 4) is When used, it is output by the frequency resolving unit 2. Thereby, it becomes possible to select a process most suitable for the subject and the photographing method.

  Further, the coefficient storage unit 5 may hold the coefficients of a plurality of past frames of the frame to be processed by the current coefficient changing unit 3, and in that case, in (Expression 1) and (Expression 4) The weighting coefficient α may be changed for each past frame.

[Fourth Embodiment]
In the first embodiment, the process according to the flowchart illustrated in FIG. 8 has been described as being performed on one entire frame image. However, as shown in FIG. 5, one frame image may be divided into a plurality of rectangles (rectangular images), and processing according to the flowchart shown in FIG. 8 may be performed for each rectangle. FIG. 5 is a diagram illustrating a state in which one frame image is divided into 16 rectangular images (T1 to T16).

  In this case, the t-th frame image used in the description in the first embodiment corresponds to one rectangular image (t-th rectangular image) obtained by dividing the frame image in the t-th frame. The (t-1) th frame image corresponds to a rectangular image ((t-1) rectangular image) that corresponds to the tth rectangular image in the frame image in the (t-1) th frame. .

  With this configuration, it is possible to reduce a required memory amount when performing frequency decomposition in the frequency decomposition unit 2. Furthermore, the processing conditions may be changed for each rectangular image.

  FIG. 6 is a block diagram illustrating a functional configuration of the image processing apparatus 600 according to the present embodiment. In addition, the same number is attached | subjected about the same part as FIG.1, 4, The description is abbreviate | omitted. As shown in FIG. 6, the image processing apparatus 600 according to this embodiment has a configuration in which an image analysis unit 8 is further added to the image processing apparatus 400 shown in FIG.

  In such a configuration, the image input unit 1 divides a frame image input from the outside into a plurality of rectangular images and outputs each rectangular image. When receiving the rectangular image, the image analysis unit 8 obtains an average pixel value and a variance value of the pixel values using the pixel values of all the pixels constituting the rectangular image. Then, based on these obtained statistical values, the amount of noise included in the rectangular image is determined (for example, the amount of noise is determined in three stages of large, normal and small), and the result of the determination Is notified to the coefficient changing unit 3.

  When the frame image is a medical X-ray image, the average pixel value is low and the amount of noise is increased for a rectangular image in which an organ with high X-ray absorption is projected. There is. Therefore, for the rectangular image determined by the image analysis unit 8 that the amount of noise is large, more effective processing is performed by changing the processing parameter in the coefficient changing unit 3 as described in the second embodiment. It becomes possible.

[Fifth Embodiment]
When the imaging device 360 as shown in FIG. 2 is configured by a plurality of units, an image processing device as described in the above embodiment may be connected to each unit. In this case, the image processing apparatus is preferably configured with a single chip. Then, the output of the image processing apparatus connected to each unit is finally combined to obtain a final output.

  FIG. 7A is a diagram illustrating a schematic configuration of the imaging apparatus when the image processing apparatus as described in the above embodiment is connected to each unit configuring the imaging apparatus. In the figure, reference numerals 701 and 702 denote units (U1 and U2, respectively) constituting a flat sensor. That is, this flat sensor has a configuration in which two units 701 and 702 are bonded together.

  Reference numerals 711 and 712 denote image processing apparatuses (IP1 and IP2, respectively), and have a configuration as shown in FIG. Each of the image processing devices 711 and 712 receives the image signal from the units 701 and 702 and performs processing on the frame image as described above. In this configuration, the image processing devices 711 and 712 perform processing in parallel and output the processing result to the image composition unit 9.

  The image synthesizing unit 9 synthesizes the outputs from the respective image processing devices 711 and 712 and finally outputs one frame image.

  When the sensor is composed of a plurality of units in this way, it is possible to obtain higher processing efficiency by connecting the image processing apparatus to each unit so that processing can be performed in parallel.

  Also, as shown in FIG. 7B, a configuration in which a plurality of units (U1 to U4) are connected to the image processing apparatus 711 and a plurality of units (U5 to U8) are connected to the image processing apparatus 712. It may be. In this case, one unit is sequentially selected for each of the image processing apparatuses 711 and 712, and an image signal from the selected unit is received. FIG. 7B is a diagram illustrating a schematic configuration of the imaging apparatus when a plurality of units are connected to the image processing apparatus as described in the above embodiment.

  Moreover, you may combine said each embodiment suitably.

  According to each of the embodiments described above, when processing a moving image, it is possible to improve image quality with a higher effect while using an image signal in the same frame and a change in the time axis direction.

[Other Embodiments]
Needless to say, the object of the present invention can be achieved as follows. That is, a recording medium (or storage medium) in which a program code of software that realizes the functions of the above-described embodiments is recorded is supplied to the system or apparatus. Then, the computer (or CPU or MPU) of the system or apparatus reads and executes the program code stored in the recording medium. In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiment, and the recording medium on which the program code is recorded constitutes the present invention.

  Also, by executing the program code read by the computer, an operating system (OS) or the like running on the computer performs part or all of the actual processing based on the instruction of the program code. Needless to say, the process includes the case where the functions of the above-described embodiments are realized.

  Furthermore, it is assumed that the program code read from the recording medium is written in a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer. After that, based on the instruction of the program code, the CPU of the function expansion card or function expansion unit performs part or all of the actual processing, and the function of the above-described embodiment is realized by the processing. Needless to say.

  When the present invention is applied to the recording medium, program code corresponding to the flowchart described above is stored in the recording medium.

It is a block diagram which shows the function structure of the image processing apparatus 100 which concerns on the 1st Embodiment of this invention. (A) is a figure explaining a mode that 10 frequency bands are obtained by performing a two-dimensional discrete wavelet transform process on the image Fn, and (b) is by performing Laplacian pyramid decomposition on the image Fn. It is a figure explaining a mode that three frequency bands are obtained. It is a block diagram which shows the hardware constitutions of the computer applied as an image processing apparatus, and its peripheral device. It is a block diagram which shows the function structure of the image processing apparatus 400 which concerns on the 2nd Embodiment of this invention. It is a figure which shows a mode that one frame image was divided | segmented into 16 rectangular images (T1-T16). It is a block diagram which shows the function structure of the image processing apparatus 600 which concerns on the 1st Embodiment of this invention. (A) is a figure which shows schematic structure of this imaging device at the time of connecting an image processing device to each unit which comprises an imaging device, (b) is a plurality with respect to an image processing device. It is a figure which shows schematic structure of an imaging device at the time of connecting a unit. It is a flowchart of the process which each part shown in FIG. 1 performs.

Claims (16)

An input means for inputting an image of each frame constituting the moving image;
Decomposition means for decomposing the image of the first frame into a plurality of frequency bands;
Wherein the coefficients belonging to a predetermined frequency band among the plurality of frequency bands in which the decomposing means is decomposed for the first frame image, the second frame of the image than the image of the first frame is an image of the previous frame Changing means for changing using a coefficient belonging to a frequency band corresponding to the predetermined frequency band among the plurality of frequency bands decomposed by the decomposition means,
By performing the processing and reverse processing of said decomposing means went based on coefficients of all the frequency band including a frequency band changed by the changing means, and reconstructing means for reconstructing an image,
An image processing apparatus comprising: output means for outputting the image reconstructed by the reconstructing means as the image of the first frame.   The image processing apparatus according to claim 1, wherein the decomposing unit decomposes the image into a plurality of frequency bands by using wavelet transform. The image processing apparatus according to claim 2, wherein the predetermined frequency band is all frequency bands except LL.   The image processing apparatus according to claim 1, wherein the decomposition unit decomposes the image into a plurality of frequency bands by performing Laplacian pyramid decomposition. The image processing apparatus according to claim 4, wherein the predetermined frequency band is all frequency bands excluding L. The changing means is
The process of changing with the coefficients of the coefficients of a predetermined frequency band in the first frame image, the second frame frequency band corresponding to the predetermined frequency band in the image of the first frame The image processing apparatus according to claim 1, wherein the image processing apparatus performs the processing for each frequency band in the image. Coefficients belonging to image each frequency band in which the decomposing means is decomposed for the second frame is already the changes when used to modify the coefficients of the predetermined frequency band in the first frame of the image The image processing apparatus according to claim 1, wherein the image processing apparatus is changed by means. Furthermore,
Based on information related to the image input to the input means,
As a coefficient belonging to image each frequency band in which the decomposing means is decomposed for the second frame, already the changes when used to modify the coefficients of the predetermined frequency band in the first frame of the image The image processing apparatus according to claim 1, further comprising: a unit that switches between using a unit that has been changed by the unit and a unit that has not been changed.   The image processing apparatus according to claim 1, further comprising means for controlling a decomposition level by the decomposition means and the reconstruction means based on information relating to an image input to the input means.   The image processing apparatus according to claim 1, further comprising a unit that controls a parameter related to a change process by the change unit based on information about the image input to the input unit. The second frame image, the image processing apparatus according to claim 1, characterized in that than the image of the first frame is a previous plurality of frame images. The first frame of the image is a rectangular image obtained by dividing the image into a plurality of rectangular in the first frame, the second frame of the image, the image more in the frame before the first frame The image processing apparatus according to claim 1, wherein the image processing apparatus is a rectangular image corresponding to the rectangular image when divided into rectangles. Furthermore,
Determining means for determining an amount of noise in the image of the first frame;
The image processing apparatus according to claim 12, further comprising: a unit that controls a parameter related to processing by the changing unit according to a determination by the determining unit. An input step of inputting an image of each frame constituting the moving image;
A decomposing step of decomposing the image of the first frame into a plurality of frequency bands;
Wherein the coefficients belonging to a predetermined frequency band among the plurality of frequency bands decomposed by the decomposition step for a first frame image, the second frame of the image than the image of the first frame is an image of the previous frame A changing step of changing using a coefficient belonging to a frequency band corresponding to the predetermined frequency band among the plurality of frequency bands decomposed in the decomposition step;
A reconstruction process for reconstructing an image by performing a process opposite to the process performed in the decomposition process based on the coefficients of all frequency bands including the frequency band changed in the change process;
An image processing method comprising: an output step of outputting the image reconstructed in the reconstruction step as the image of the first frame. A program for a computer to function as each unit included in the image processing apparatus according to any one of claims 1 to 13.   A computer-readable storage medium storing the program according to claim 15.

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