JP2534552B2 - Image processing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an image processing apparatus, and more specifically, X
The present invention relates to an image processing device that performs image calculation processing such as contrast enhancement, sharpening, smoothing, and restoration of an image obtained from a line imaging device.

[Prior Art] An example of a conventional image processing apparatus will be described with reference to FIGS. 7 to 9.

In the image processing device 11 shown in FIG. 7, the image memory unit
Reference numeral 12 stores an image from an X-ray imaging device X such as an X-ray CT device.

The image from the X-ray imaging apparatus X is displayed on the image display unit 3 after being subjected to appropriate image calculation processing by the calculation processing unit 15 for convenience of handling.

For example, the image from the X-ray imaging apparatus X may include noise n like the image OI (hereinafter referred to as the original image) shown in FIG. 9, and in order to remove this noise n,
Smoothing processing as shown in the figure is performed. This smoothing process is generally an operation of obtaining an average value of the densities of a pixel and its surrounding pixels and setting it as a new density of the pixel.

By the smoothing process, an image in which noise n is not noticeable, such as the image SI shown in FIG. 9 (hereinafter referred to as smoothed pixel), is obtained.

The images OI and SI shown in FIG. 9 are schematic representations of tomographic images of the head, where BO is the skull and BR is the brain.

[Problems to be Solved by the Invention] In the conventional image processing apparatus 11, as shown in FIG. 9, the smoothed image SI is obtained by removing the noise n of the original image OI by the smoothing process. At this time, there is a problem that the density of the pixel in the portion A near the skull BO becomes a value that is far from the actual value. This is because it is greatly affected by the concentrations of the parts of the skull BO having different qualities.

As described above, in the conventional image processing apparatus, there is a problem that the image near the boundary of the parts of different qualities is deteriorated by the image processing, and the reliability of the processed image is lowered.

Therefore, in Japanese Utility Model Laid-Open No. 58-174753, there is proposed an image processing apparatus that performs image calculation processing only within the target area when the operator sets the target area in the image.

However, when setting a target area for a plurality of related images, it is necessary to set a target area for each image, which is a problem in that the operation is complicated. Further, since the operator inputs the coordinates of the target area, there is a problem that the operation is troublesome.

On the other hand, in JP-A-62-35979, when the operator sets a target area including a target portion on the first image,
An image recording apparatus has been proposed in which the target area is also applied to the second and subsequent images to record only that portion.

However, when the position or size of the target portion changes in a plurality of images, the operator first selects the target area that can be commonly used.
There is a problem that it is not always possible to set by viewing only the image. Further, since the operator inputs the target area on the displayed image, there is a problem that the operation is troublesome.

Further, in Japanese Patent Laid-Open No. 61-7980, when an addition image obtained by sequentially adding images obtained from a scintillation camera is displayed and an operator sets a target area on the addition image,
A data processing device has been proposed in which the target area is applied to each original image to count the detection data of the portion.

However, this is a technology limited to the field of performing arithmetic processing of counting detection data in a scintillation camera, and performs image processing such as contrast enhancement, sharpening, and smoothing of an image obtained from an X-ray imaging device. Application to the field is not considered at all. Further, since the operator inputs the target area on the displayed image, there is a problem that the operation is troublesome.

Therefore, an object of the present invention is to provide a plurality of related images obtained from an X-ray imaging device in the field of performing image processing such as contrast enhancement, sharpening, and smoothing of an image obtained from the X-ray imaging device. It is an object of the present invention to provide an image processing apparatus capable of setting a target area that can be commonly used by a single operation.

[Means for Solving the Problems] In a first aspect, the present invention provides an operator with a plurality of related images obtained from an X-ray imaging apparatus or an arithmetic mean image of a plurality of images selected from the images. Area designation image display means for displaying, an area designation input means for the operator to designate a target area in the arithmetic mean image, and an original when the target area is designated in the arithmetic mean image. Calculation for generating a mask pattern for masking values outside the target area of the image and multiplying or adding this mask pattern with the image to generate a calculation area determination image in which only the values within the target area of the image are valid There is provided an image processing device comprising: a region determination image generation means; and a selective calculation processing means for performing a target image calculation process only within a target region in the calculation region determination image.

In the above configuration, the target image calculation process is an image process that uses information of another pixel to process one pixel,
For example, it refers to image processing such as contrast enhancement using a spatial filter, sharpening, smoothing, and restoration.

[Operation] In the image processing apparatus according to the first aspect described above, an arithmetic average image of a plurality of related images or a plurality of images selected from the images is displayed to the operator, and based on the arithmetic average image. The operator to specify the target area. Therefore, it is possible to set a target area that can be commonly used for a series of images by one operation.

[Examples] The present invention will be described in more detail below with reference to the examples shown in the drawings. It should be noted that the present invention is not limited by this.

FIG. 1 is a block diagram of an image processing apparatus 1 according to an embodiment of the present invention.

The image memory unit 2 is an X-ray imaging device X such as an X-ray CT device.
The original image OI shown in FIG. 3 is stored. This original image OI contains noise n.

When the image processing unit 5 performs image processing on only one image, the original image OI is displayed on the image display unit 3 (image display for region designation) and a message indicating that the target region should be designated. Display. This is represented by step S1 in FIG.

Therefore, the operator makes an input to specify the target area from the area specifying input unit 4. For example, a light pen, a trackball, a mouse, or other means is used to input a closed curve designating line SL as shown in FIG. 3 and to indicate which side of the designating line SL is the target area. This is shown in step S2 in FIG.

When the target area is designated, the arithmetic processing section 5 creates a mask pattern MP as shown in FIG. 3, and an arithmetic area determination image capable of clearly identifying the arithmetic area from the mask pattern MP and the original image OI. Create MI. This is represented by step S3 in FIG.

Specifically, for example, if all the densities of the pixels of the original image OI have values sufficiently larger than 0, the mask pattern MP is a matrix having the same array as the pixel array of the original image OI. , A matrix in which the value of the portion outside the target area (hatched portion of the mask pattern MP in FIG. 3) is 0 and the value of the portion inside the target area (blank portion of the mask pattern MP in FIG. 3) is 1 column is created To be done. Then, the mask pattern MP is multiplied by the original image by OI to obtain the calculation area determination image.
MI is created. In this calculation region determination image MI, a pixel having a pixel density of 0 is outside the target region.

In addition, as another specific example, if the density value of the pixel of the original image OI can be 0, but if it does not become a value larger than a certain value α, the mask pattern MP is
A matrix having the same array as the pixel array of the OI, and the value outside the target area (hatched portion of the mask pattern MP in FIG. 3) is α, and inside the target area (mask pattern MP in FIG. 3) A blank matrix whose value is 0 is created. Then, the calculation area determination image MI is created by adding the original image OI to the mask pattern MP. In this calculation area determination image MI, pixels having a pixel density of α or higher are outside the target area.

After creating the calculation region determination image MI, the calculation processing unit 5
Perform the target image calculation processing. Step S4 in FIG. 2 represents a case where the target image calculation process is a smoothing process.

As described above, since the target area and other areas can be clearly identified, it is easy to remove the influence outside the target area and perform the image calculation process.

For example, in the case of an example of the smoothing process, an average value of the densities of the pixels in a 3 × 3 square area centered on one pixel in the target area is obtained and the calculation of the density of the one pixel is performed. Do (so-called 3x3 median filter),
The pixel value in the 3 × 3 square area is 0 (mask pattern MP
Is a matrix of 0,1) or more than α (mask pattern MP
Is a matrix of α, 0), the average calculation may be performed without including the pixel.

As described above, the processed image SI as shown in FIG. 3 is obtained, but the image in the target area is image-processed without being influenced by the image outside the target area.

Now, FIGS. 4A and 4B show the case where the original images OI1 and OI2 are tomographic images of the chest, respectively. As described above, the mask patterns MP1 and MP1 are separately provided for the original images OI1 and OI2. , MP2 can be created to obtain processed images SI1 and SI2.

However, since the lungs are expanding and contracting due to breathing, for example, the point Q is outside the target area in FIG. 4A and inside the target area in FIG. 4B.

Therefore, even if an attempt is made to obtain a time-series change in the lung (for example, CBF, FI) from a series of tomographic images of the chest, the point Q cannot be obtained. Therefore, it is meaningless that the portion of the point Q is in the target area in FIG. 4B, at least when trying to obtain a time series change.

Therefore, when performing image processing on a series of images, the arithmetic processing unit 5 creates an arithmetic mean image by arithmetically averaging all or several images of the series of images as shown in FIGS. 5 and 6. , Is displayed on the image display unit 3.

Therefore, the operator can specify the target area that can be commonly used for a series of images at one time based on the arithmetic mean image. The mask pattern MT in FIG. 5 represents such a common mask pattern.

By using this mask pattern MT to determine the calculation area for each of the images OI1, OI2, ... And performing the image calculation processing within that area, it is possible to eliminate unnecessary processing time.

As another embodiment, for example, in an X-ray CT apparatus, "id
If you have "entify function",
Upper limit value of the density of pixels in a predetermined area using the "function",
Since the lower limit value can be obtained, it is possible to set the lower limit value as the target area. In this case, the accuracy is poor, but the operability is very good.

EFFECTS OF THE INVENTION According to the image processing apparatus of the present invention, since the image calculation processing is performed only within the target area, it is possible to avoid adverse effects due to information outside the target area and improve the reliability of the processed image. Become.

Moreover, since the operator can specify the target area, the target area can be set accurately without complicated processing.

Further, since the target area can be set based on the arithmetic mean image of a plurality of images, it becomes possible to set a common target area for a series of images at once.

[Brief description of drawings]

FIG. 1 is a block diagram of an image processing apparatus according to an embodiment of the present invention, FIG. 2 is a flow chart of an essential part of operation of an arithmetic processing section of the image processing apparatus shown in FIG. 1, and FIG. 3 is shown in FIG. Schematic diagram of each image for explaining the operation of the image processing device,
FIGS. 5A and 5B are schematic diagrams of respective images for explaining the operation of the image processing apparatus shown in FIG. 1, and FIG. 5 is respective images for explaining the operation of the image processing apparatus shown in FIG. FIG. 6, FIG. 6 is a main part flowchart of the operation of the arithmetic processing unit of the image processing apparatus shown in FIG. 1, FIG. 7 is a block diagram of an example of a conventional image processing apparatus, and FIG. 8 is FIG. The flow chart of the main part of the operation of the arithmetic processing section of the image processing apparatus shown in FIG.
FIG. 7 is a schematic diagram of each image for explaining the operation of the image processing apparatus shown in the figure. (Description of symbols) 1 ... Image processing device 2 ... Image memory unit, 3 ... Image display unit, 4 ... Area designation input unit 5 ... Arithmetic processing unit, X ... X-ray imaging device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page Examiner Katsuhiro Kobayashi (56) References JP 63-170788 (JP, A) JP 62-35979 (JP, A) JP 61-7980 (JP, A) Special Kai 48-24622 (JP, A) JP 60-59484 (JP, A) Actual 58-174753 (JP, U)

Claims (1)

(57) [Claims] 1. A region specifying image display means for displaying to an operator a plurality of related images obtained from an X-ray imaging apparatus or an averaged image of a plurality of images selected from the images, and an operation. Input means for designating a target area in the arithmetic mean image by a person, and a mask pattern for masking values outside the target area of the original image when the target area is designated in the arithmetic mean image Calculation area determination image generating means for generating a calculation area determination image in which only the value in the target area of the image is valid by multiplying or adding the mask pattern and the image, and An image processing apparatus comprising: a selective calculation processing unit that performs a target image calculation process only within a target area.