JPH0831128B2 - Image processing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, and more specifically to an image processing apparatus that performs a process of connecting a plurality of images.

[Prior Art] In the case of a conventional imaging apparatus, for example, an imaging apparatus in a real-time display ultrasonic diagnostic apparatus, the size of a tomographic image obtained is limited depending on the apparatus. Therefore, when trying to observe a site that exceeds the size of the obtained tomographic image, a plurality of tomographic images are arranged side by side and the regions are visually judged and then input to the image device, or the tomographic image is input to an image processing device or the like. Then, a plurality of images are combined into one image and displayed by manual operation.

An apparatus for automatically performing the series of manual operations is disclosed in Japanese Patent Laid-Open No. 63-49885, but even in this case, the rough positioning between images requires the intervention of an operator.

[Problems to be Solved by the Invention] Synthesis or connection of a plurality of images by the above-described image processing device is based on the sense of the operator. Therefore, a series of operations for connection is complicated and requires skill. In addition, the processing method for performing accurate positioning is such that the correlation between the overlapping portions of the two images is calculated and the two images are displayed in a superimposed manner when the correlation is most prominent. There is. Therefore, in order to make a connection, there must be a portion where the two images overlap. Conversely, even if there is no overlapping portion between the two images, the apparatus automatically correlates the two images and forcibly superimposes the two images. Therefore, there is a big problem that the rough positioning of the operator greatly affects the subsequent operations.

In order to solve such a problem, it is an object of the present invention to provide an image processing device that automatically and accurately connects a plurality of images with almost no operator intervention.

[Means for Solving the Problem] An image processing apparatus according to the present invention includes a storage unit that stores image information of two images, and a region of interest that sets a predetermined region of interest in the image information stored in the storage unit. Setting means,
Comparing means for comparing the regions of interest with respect to two images of image information and outputting the degree of correlation between them, connection determining means for outputting a detection output when the output of the comparing means satisfies a predetermined condition, and detection Based on the output, the image information of the two images are connected in a positional relationship in which the regions of interest overlap, and a connecting unit that generates an image of the connected result, a display unit that displays the resulting image, a storage unit, and a region of interest. The control means controls the setting means, the comparing means, the connection determining means, the connecting means and the display means, and outputs the resulting image to the display means.

The image processing apparatus according to the present invention also includes a storage unit that stores image information of a plurality of images, a region-of-interest setting unit that sets a predetermined region of interest in the image information stored in the storage unit, and among the image information. On the basis of the detected output, the comparing means for comparing the regions of interest on the two images and outputting the degree of correlation between them, the connection judging means for outputting the detected output when the output of the comparing means satisfies a predetermined condition. Connecting the image information of the two images in a positional relationship in which the regions of interest overlap and generating an image of the connected result, a display unit for displaying the resulting image, a storage unit, a region of interest setting unit, Controlling the comparing means, the connection judging means, the connecting means and the displaying means to obtain a resulting image of the image information of the two images, and connect the resulting image and the image information of the other images stored in the storing means. To No, and a control means for outputting to the display means an image of the results obtained by repeating the image information stored in the storage means so.

[Operation] According to the present invention, a plurality of pieces of image information are stored in the storage means, and the ROI is set in the image information by the ROI setting means. The comparing means compares the regions of interest of the two pieces of image information,
The degree of correlation between the two is output. When the output satisfies the predetermined condition, the connection determination means generates a detection output, and based on this, the connection means connects the two at the positions where the regions of interest of the image information overlap. By repeating this connection, a plurality of images can be connected.

Embodiments Embodiments of the present invention will be specifically described with reference to the drawings.

A conventional image processing apparatus requires an operator's operation to connect a plurality of images and combine them into one image. In this embodiment, image processing is automated by adding a connection determination unit and an image connection unit to the conventional image processing apparatus. In the present embodiment, the algorithm for determining the adequacy of image connection is to take the difference between the absolute values of the gradation values of the corresponding pixels between the two images and compare this difference with a preset threshold value. Determine the connection.

First, the basic principle of the present invention will be described with reference to FIG. To process a plurality of images as one continuous image, image connection processing is performed on two of the images, and this is repeated for the entire image. Therefore, here, a method for basically connecting two images will be described. The relative positional relationship between the two images to be subjected to the connection process generally includes factors such as rotation in addition to parallel movement in the vertical and horizontal directions. The positional relationship between the images will be described as being solved only by parallel translation in the left-right direction.

In Fig. 1, two images a21 and images to be connected
The image of b23 is composed of many pixels. Generally, pixels have various levels of luminance, but here, for simplicity, it is assumed that they are represented by binary luminance signals (0.1). Regions of the same shape and size, that is, regions of interest are provided in the two images, and the connection positions of the images a and b are determined by comparing the two regions of interest. ROI a23 is the region of interest in image a and R is the image b side.
OIb24.

The region ROIa is fixed at a preset position in the image a, but the ROIb can be set at an arbitrary position in the image b. In this embodiment, in this case, the two images are compared by parallel movement to the left and right, so the set position of the region ROIb moves the same height as the region ROIa.

While shifting the set position of the region of interest ROIb by a unit pixel in the image b, the correlation value between the regions ROIa and ROIb at the shifted position is obtained. The correlation value may be obtained by a method of accumulating the brightness of the corresponding pixels in the regions of interest ROIa and ROIb, that is, the absolute value of the difference between the gradation values.

By obtaining this correlation value while shifting it within the range in which the region of interest ROIb can be set within the image b, the correlation value distribution as shown in FIG. 2 is obtained. In the figure, a position 31 is a point where there is no relative displacement between the two images, and a position 32 is a peak value point of the correlation value distribution. This peak value point 32 is a parameter that determines the actual image connection.

In order to perform the connection procedure on the two images, the relative deviation between the two images is determined from the correlation value distribution thus obtained, and the relative deviation is displayed by the distance or written in the memory. You will have to perform a tricking operation.

The method of connecting two images will be described with reference to FIG. 3. In FIG. 3A, the images a41 and b42 have a width of s pixels, and the image a has a width of n pixels from the left end. A region of interest ROIa43 of t pixels is set. The region ROIb is displaced in the image b from the left end to the right end by one pixel at a time, and the correlation value is calculated each time. FIG. 11B shows the distribution of correlation values with respect to the shift between the regions of interest ROIa and ROIb. The point m at which the correlation value is "0" is an appropriate connection position. The figure (c) shows
An image resulting from connecting the image b to the left side of the image a at this connection position is shown.

In connection display, two images overlap each other in the range of (s-m + n) pixels. Regarding this overlapping portion, a method of displaying either one of the images a and b, a method of displaying the average value of the gradation values of both images, and the like can be considered.

In order to determine the location of the peak of the correlation value, generally, the location where the correlation value is closest to "0" is selected. However, if such a method is adopted, connection display may be performed even when two images have no connectivity. Fourth example
Shown in Figures and 5.

Image a51 in FIG. 4 (a) has circular data, and image b
Although 52 has linear data, when the correlation distribution is obtained, the distribution shown in FIG. As a result, the connection display is output and the connection image 56 as shown in FIG. In addition, regions of interest ROI a63 and RO in images a61 and b62 having layered portions as shown in FIG. 5 (a), respectively.
When Ib64 is set and the correlation distribution of FIG. 6B is obtained, for example, when noise 65 occurs, the peak of the correlation distribution due to this is detected, and both are displayed in a connected manner. Fourth
In the cases shown in FIGS. 5 and 5, the reliability of the automated system is improved if the relative positional deviation between the two images is not determined.

Therefore, as shown in FIG. 6, in order to detect the peak of the correlation distribution from the correlation value distribution for the purpose of efficiently and accurately determining the relative positional deviation,
Three thresholds TH1 to TH3 for the difference are provided. For this reason, the distribution data in the same figure is sequentially scanned with a shift of the width W, and a trigger is applied when the difference between the correlation values corresponding to the width W, that is, the amount of change in the correlation value is equal to these threshold values.

More specifically, in this example, the difference between the correlation values is initially a threshold value.
Less than TH1. The first trigger is applied at a position 71 where the scanning advances and the distribution value (SA2-SA1) becomes larger than the threshold value TH1.
Next, a second trigger is applied at a position 72 where (SB2-SB1) is approximately "0" near the peak. Then the difference is "0"
The third trigger is applied at the position 73 where SC2−SC1> TH3 is increased from. If these three triggers are applied in that order, the relative positional deviation between the two input images can be detected only when the connection processing is possible from the correlation value distribution. The relative position shift is the midpoint between the difference points of the positions where the trigger 2 is applied. In FIG. 6, (B2 +
Point B1) / 2 is the relative position shift.

The scanning flow in the example of FIG. 6 is shown in FIG. In the flow of the figure, first, the data of images a and b are input (100), and ROIa is set in image a (102). Then, it is checked whether or not the entire set region of the image b is set as the region of interest ROI2 (104), and if set, the process ends.
If not set, set value of area ROIb from setting end to 1
It moves pixel by pixel (106). The region of interest ROIa and ROIb are correlated (108) and the difference value is determined (110). It is checked whether or not the trigger 1 is applied to the difference value (112), and if not, the process returns to 104, and if so, it is checked whether or not the trigger 2 is applied (114). If the trigger 2 is not applied, the process returns to step 104, and if it is applied, the connection point is determined (116). Then, it is checked whether the trigger 3 is applied (118). If the trigger 3 is not applied, the process returns to step 104. If the trigger 3 is applied, the images a and b are connected and displayed (120), and the process ends.

FIG. 8 shows a block diagram of an embodiment in which the present invention is applied to an image processing apparatus. In the figure, the image processing apparatus of the embodiment
Reference numeral 30 denotes the connection determination unit 154 and the image connection unit 156 connected to the conventional device, and each of 151 to 156 is connected via the data bus 150. The control unit 151 is a control function unit that controls input / output of image data of each unit. The image input unit 152 is an input device that reads image data composed of a luminance signal of each pixel for each of a plurality of images, and the image storage unit 153 stores the read image data.

The determination unit 154 determines whether the two images can be connected,
When possible, it is a functional unit that outputs a connectable signal indicating that effect. The image connection unit 155 is a processing unit that performs a connection process for connecting two image data when a connectable signal is output, and the image display unit 156 displays an image for displaying a connection image with the resulting image data. It is a device.

A specific configuration example of the connection determination unit 154 is shown in FIG. 9, which has the respective function units 200 to 204 connected as shown.
The ROIa setting unit 200 is a storage unit that inputs and stores image data of the region of interest ROIa set in the image a to be connected from the image input unit 152. The ROIb setting unit 201 stores image data of regions ROIb that are sequentially input each time the region of interest ROIb of the other image b to be connected moves.

The correlation value calculation unit 202 is a calculation unit that inputs the image data of the region of interest ROIa from the setting unit 200 and the image data of the same ROIb from the setting unit 201, and calculates and outputs the correlation value of both. The difference value calculation unit 203 is a calculation unit that receives the output, calculates the difference between the correlation values, and outputs the difference. Trigger detector 20
4 has a detection function of inputting a difference and comparing it with a threshold value to detect the presence or absence of a trigger. When the trigger is not applied, feedback is given to the ROIb setting unit 201, and the region of interest R
The same processing is performed by shifting the position of OIb. When a trigger is applied, a trigger signal is output and this signal is sent to the control unit.
It is sent to the connection determination unit 154 via 151.

Further, the image subjected to the connection processing is stored in the image storage unit 153, and the image and the new image are stored in the ROI setting units 200 and 20.
By transferring to 1 and performing the above processing, it is possible to process a larger image. By repeating this operation, it is possible to connect a plurality of images and generate one large image.

The description so far has been about the case where the gradation value data of the image takes two values of “0” and “1”, but even when the gradation value data takes a level of 2 or more, the level between the pixels is In the same manner, the connection processing can be performed by accumulating the absolute values of the difference between the key values and sending the correlation value to the determination means for triggering.

Also, if there is only one point in the image that differs from the background, as in images a300 and b301 shown in FIG. 10 (circular portion in the figure), the region of interest ROIa Two images for which is set can be connected.
However, when this is set in the position 303, it is impossible to distinguish the image from other backgrounds in the image, and thus it becomes impossible to connect the image. To deal with such cases,
The position of the region of interest ROIa is set in the manual operation mode of the operator so that the position can be changed from the position 303 to the position 302. A case where the set value of the region ROIa is fixed in advance is called a “fixed setting method”, and a case where it is manually set is called an “arbitrary setting method”.

In the case of the fixed setting method, the region of interest ROIa is set in the center of the input image because it is premised that there is no information as to which direction the image b is displaced with respect to the image a. is there. When the information is known, in order to detect a larger relative position shift, if the image b is shifted to the right of the image a, the set position of the region ROIa is set to the image a.
Is set to the right side of the image b, and if it is shifted to the left side, the setting position of the region ROIa may be set to the left side of the image b. The case where the set value is corrected when it is deviated to the right side is called the "right direction limited setting method", and the correction when it is deviated to the left side is called the "left direction limited setting method".

In this embodiment, the operator can select one of these four methods for setting the position of the region of interest ROIa. ROIa
The setting unit 90 has a structure as shown in FIG.

The operator inputs an operation selection command to the image processing device 80, and this command is sent from the image input unit 152 or the image storage unit 153 to the setting control unit 320. The same unit 320 uses the fixed setting unit 321 when the command is fixedly set, the arbitrary setting unit 322 when the command is arbitrarily selected, the left-direction limited setting unit 323 when the command is set only in the left direction, and the right direction. At the time of setting, the right-direction limited setting unit 324 is connected to execute the command.

The regions of interest ROIa and ROIb must have substantially the same shape and the same number of pixels. However, they do not have to be rectangular as in the examples shown so far. Further, when the region of interest ROI is composed of a plurality of parts, there is an advantage that a wide image region can be set as the region of interest ROI with a small number of pixels.

If the positional relationship between the images is not solved only by the horizontal translation, but the vertical translation component is also included, the series of operations described in FIG. 3 is performed by changing the set height of the region of interest ROIb. The processing can be performed by changing the ROIb until it is set in the entire area of the image b. When a rotation element is included, it can be processed by rotating the region of interest ROIb little by little for each horizontal scanning and then performing parallel movement to detect the peak value.

An image processing device 82 according to another embodiment of the present invention is shown in FIG. The device 82 has an image data memory 402 and an image display memory 405, and the CPU 401 is a program memory 409.
The respective routines of the program stored in can operate the apparatus as image information storage means, ROI setting means, correlation degree comparing means, image connecting means or display means.

In the image information storage routine, a plurality of image data is input to the image data memory 402 via the data bus 408 from an image input unit (not shown). In the ROI setting routine, the address corresponding to the ROI in the image data memory 402 is stored in the program memory 409. In the comparison routine, the data included in the region of interest set for each of the two images stored in the image data memory 402 is compared by the same method as the correlation degree comparison method described above.

In the image connection routine, the image data memory 402
The image inside is transferred to the image display memory 405 via the data bus 4048 and the gate circuit 403. Here, the two images are recorded in such a positional relationship that the connection point obtained by the comparison routine takes the same address in the image display memory 405. That is, the image display memory 405 stores the data of one image in which two images are connected.

In the display routine, the image data in the image display memory 405 is sequentially read in synchronization with the scanning line (raster) of the display 407 such as a CRT, and the gate circuits 404 and D
Each pixel data is brightness-modulated via the A converter 406 and displayed on the display 407 as a connected image.

The details of the operation of the image connection routine will be described below. In the image data memory 402, the data of the image a of mxn pixels is diagonally located at the storage positions (Xa1, Y1) to (Xam, Yn), and the data of the image b of mxn pixels is also recorded at the recording position ( Xb1, Y
1) to (Xbm, Yn) are assumed to be recorded in the diagonally opposite areas. Considering the case of movement only in the X direction as in the above example, it is assumed that the connection points detected by the comparison routine stored in the program memory 409 are Xaj in the image a and Xbj in the image b. Image b
Is connected to the right side of image a.

Now, in the write cycle of the image display memory 405, C
The PU 401 transfers the data D (Xa1, Y1) to D (Xaj, Yn) of the image a from the data bus 408 and the gate circuit 403 to the addresses (U1, V1) to ((1) to (1) of the image display memory 405 of FIG. 14 (b). Uk−1, Vn)
Data of image b, and then data D (Xb1, Y1) to D (Xbm,
Yn) is the address of the image display memory 405 (Uk, V1)
Transfer to ~ (U1, Vn). As a result, as shown in FIG. 14B, the image display memory 405 reconstructs image data in which the image a and the image b are connected. The data Q transferred to the image display memory 405 is displayed on the display unit 407.
The first raster: Q (U1, V1), Q (U2, V1), Q (U3, V1), ..., Q (Ue, V1), second raster: Q (U1, V2), Q (U2, V2), Q (U3, V2), ..., Q (Ue, V2), Third raster: Q (U1, V3), Q (U2, V3), Q (U3, V3), ..., Q (Ue, V3), are read in this order up to the nth raster, and the gate circuit 404 outputs D
It is input to the A converter 406 and, after digital / analog conversion, is displayed as a single connected image on the display 407. However, (Ux, Vy) = (x, y); x = 1 to e, y = 1 to n (Uk−1, Vn) = (Xaj−Xa1, Yn) (Uk, V1) = (Xaj−Xa1 + 1) , 1) (UL <Vn) = (Uk + Xbm−Xbj, Yn), and e ≧ L. Ue is the X-direction final address of the image display memory.

In the above example, the image display memory 405 is provided separately from the image data memory 402, but the memory may be configured to also serve as these memories. An image processing apparatus 84 according to the embodiment in that case is shown in FIG. Similar to the embodiment shown in FIG. 12, the CPU 501 can operate this apparatus as each means such as image information storage means by each routine stored in the program memory 510.

It is assumed that the image a and the image b are stored in the image memory 505 similarly to the image data memory 402 described above. Now, the connection points Xaj (image a) and Xbj (image b) detected by the comparison routine stored in the program memory 510.
Are stored in the connection address register 502. In the display cycle of the image memory 505, the gate circuit 503 is turned off, the gate circuit 504 is turned on, and the image data is transferred to the DA converter 506
Sent to the display 507 via. The contents of the image memory 505 are sequentially read out in synchronization with the raster of the display 507.
At this time, the X address is selected by the connection address register
The contents of 502 are referenced, and Xa1, Xa2, Xa3, ..., Xaj−2, Xaj−
The sequence is 1, Xbj, Xbj + 1, Xbj + 2, ..., Xbn. As a result, the output data is the first raster: D (Xa1, Y1), D (Xa2, Y1), D (Xa3, Y1), ..., D (Xaj-
1, Y1), D (Xbj, Y1), D (Xbj + 1, Y1) D (Xbj + 2, Y1), ..., D (Xbn, Y1) Second raster: D (Xa1, Y2), D (Xa2, Y2), D (Xa3, Y2), ..., D (Xaj−
1, Y2), D (Xbj, Y2), D (Xbj + 1, Y2) D (Xbj + 2, Y2), ..., D (Xbn, Y2) are output in this order, and after DA conversion, they are output as shown in FIG. The image is displayed on the display unit 507 as a single image connected as shown in FIG.

FIG. 15 shows how the contents of the image memory 505 in the embodiment shown in FIG. 13 are changed by this repeated operation. Before the processing is performed, the image memory 505 stores data of a plurality of images, that is, four images in this example, as shown in FIG.

First, a connection is determined for the data of image a and image b, and when the regions of interest ROIa and ROIb are set in the hatched portions of images a and b, respectively, a connectable signal is output. Shall be done.
The contents of the image memory 505 are rearranged based on the data of this connection position, and the result becomes the contents shown in FIG.

Next, when the data of the image ab and the data of the image c resulting from the connection of the images a and b are similarly determined to be connectable and the connection becomes possible, the content of the image memory 505 is the state shown in (c). Relocated to. This constitutes the image abc.

Similarly, when the image abc and the image d are connectable, the image memory 505 is rearranged as shown in (d), and this ends the repetitive operation. The image represented by the completed image data in the image memory 505 is displayed on the display 507.

FIG. 16 shows an example of the processing flow for connecting such three or more images. The processing flow of the figure is different from the latter in that steps 123 and 125 are inserted therein as shown in FIG. In step 125, the data obtained by connecting the two images a and b is stored in the image memory 505, and the process returns to step 123 in the loop of the interlace symbol 13. Step 123
Then, the presence / absence of image data to be connected is determined, and if there is no image data, step 120 is executed and the processing ends, but if there is, the same connection processing is repeated. Other processes may be almost the same as the processes with the same reference numerals in the flow of FIG.

[Effects of the Invention] As described in detail above, the present invention determines whether or not a plurality of images can be connected in an image processing apparatus, and performs connection processing only when connection is possible. Without this, there is an effect that an image of a wide area is accurately processed and displayed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram illustrating positions of regions of interest set in two images in an embodiment of the present invention, and FIG. 2 is a diagram showing a correlation distribution between regions of interest. 3 (a), (b) and (c) are explanatory views showing two connectable images, their correlation distributions and connected images, and FIGS. 4 (a), (b) and (c) are , Two unconnectable images, their correlation distributions and connected images, and FIGS. 5 (a) and 5 (b) are two images with noise and their correlation distributions, respectively. FIG. 6 is a diagram showing a threshold and a trigger for detecting the peak of the correlation distribution, FIG. 7 is a flow chart showing an example of an operation flow of peak detection in the example of FIG. 6, and FIG. 8 is an image according to the present invention. FIG. 9 is a functional block diagram showing an embodiment of the processing device, and FIG. 10 is a functional block diagram of the disconnection portion, FIG. 10 is a diagram showing connectable and non-connectable positions of the region of interest, FIG. 11 is a functional block diagram showing a configuration example of the region of interest setting unit, FIG. 12 and FIG. FIG. 13 is a functional block diagram showing another embodiment of the present invention, and FIGS. 14A and 14B show examples of internal layouts of the image data memory and the image display memory in these embodiments, respectively. Explanatory diagram, FIG. 15 is an explanatory diagram showing how the contents of the image memory change in the embodiment shown in FIG. 13, and FIG. 16 shows an example of a processing flow for connecting three or more images, It is a flowchart similar to a figure. Description of symbols of main parts 80, 82, 84 …… Image processing device 90 …… Region of interest setting unit 151 …… Control unit 152 …… Image input unit 153 …… Image storage unit 154 …… Connection determination unit 156 …… Image display section 401,501 …… CPU 402 …… Image data memory 405 …… Image display memory 406,506 …… D / A converter 407,507 …… Display unit 409,510 …… Program memory 505 …… Image memory

Claims (4)

[Claims] 1. A storage means for storing image information of two images, and a region-of-interest setting means for setting a predetermined region of interest in the image information stored in the storage means, wherein at least one image. A region of interest setting means for moving the position of the region of interest set for the image information, and comparing means for comparing the regions of interest with respect to the two images of the image information, and outputting the degree of correlation between them. Comparing means for outputting the degree of correlation at each position of the region of interest moved by the region of interest setting means, and comparing the amount of change in the degree of correlation according to the movement of the region of interest with a predetermined level, and comparing A connection determination unit that outputs a detection output according to the result, and the image information of the two images are connected in a positional relationship in which regions of interest overlap each other based on the detection output output from the connection determination unit, and the connection is made. A connecting means for generating an image of the result obtained, a display means for displaying the image of the result connected by the connecting means, the storage means, the region of interest setting means, the comparing means, the connection judging means, the connecting means and the displaying means. An image processing apparatus comprising: a control unit that controls and outputs the resulting image to the display unit. 2. Storage means for storing image information of a plurality of images, and interest area setting means for setting a predetermined area of interest in the image information stored in the storage means, wherein at least one image Region of interest setting means for moving the position of the region of interest set for the image information, and comparing means for comparing the regions of interest for two images of the image information and outputting the degree of correlation between them. , Comparing means for outputting the degree of correlation at each of the positions of the region of interest moved by the region of interest setting means, and comparing the amount of change in the degree of correlation according to the movement of the region of interest with a predetermined level, Connection determination means for outputting a detection output according to the comparison result, and connection of image information of the two images based on the detection output output from the connection determination means in a positional relationship where regions of interest overlap. Connection means for generating an image of the connection result, display means for displaying the image of the connection result by the connection means, the storage means, the region of interest setting means, the comparing means, the connection determining means, the connecting means, and The display means is controlled to obtain the result image with respect to the image information of the two images, and the connection operation is performed with respect to the result image and the image information of the other image stored in the storage means. An image processing apparatus comprising: a control unit that causes the display unit to output an image of a result obtained by repeating the image information stored in the storage unit. 3. The apparatus according to claim 1 or 2, wherein
The comparing means obtains an absolute value of a difference in gradation value between pixels having a corresponding positional relationship in a region of interest set in the image information of the two images, and based on a value obtained by accumulating the absolute values. An image processing apparatus, which outputs the degree of correlation. 4. An ultrasonic diagnostic apparatus comprising the image processing device according to claim 1.