JP2000041974A - Image processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To practice at high speed an image processing to a read radiation image. SOLUTION: Electric signals corresponding to dose of radiation irradiated are formed by an imaging panel 11. A region of the imaging panel 11 is divided into a plurality of blocks and image data are formed from the electric signals by image data forming parts 16 provided in corresponding to each block. Picture element data at specified positions of each block are taken out or the representative value of each block is calculated to make them image data of a contracted image. It becomes possible to rapidly set condition of image processing by using image data of this contracted image and to practice at high speed the image processing to a radiation image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an image processing apparatus. More specifically, a radiation image is divided into a plurality of blocks, image data is extracted from each block to form a reduced image, and image processing conditions are set using the reduced image.

[0002]

2. Description of the Related Art Conventionally, there has been known a radiation image reading apparatus capable of obtaining a radiation image for diagnosing a disease or the like. In this radiation image reading device, for example, a part of radiation energy is stored, and then a stimulable phosphor that emits stimulable light in accordance with the stored energy when irradiated with excitation light such as visible light is formed into a sheet. A stimulable phosphor sheet is used. In an apparatus using the stimulable phosphor sheet, radiation image information of the subject is recorded by irradiating radiation transmitted through the subject to the stimulable phosphor sheet, and the stimulable phosphor sheet on which this information is recorded. By stimulating stimulated emission obtained by irradiating a laser beam or the like with the laser beam and converting it into an electric signal by a photoelectric element, image data of a radiation image is generated based on the electric signal. In addition, Flat Panel
An apparatus called an Detector (FPD) that generates an electric signal corresponding to the dose of radiation irradiated by a plurality of two-dimensionally arranged detection elements and generates image data based on the electric signal is also used. You.

Further, in order to obtain a radiation image suitable for diagnosis or the like, image processing of the radiation image is performed. In this image processing, processing conditions are determined from the statistical properties of the image data (for example, the maximum value, minimum value, average value, histogram, etc. of the image data). Based on the determined conditions, the density and the density suitable for diagnosis and the like are determined. The gradation processing is performed so that a radiographic image with contrast can be obtained. In addition, frequency enhancement processing for controlling sharpness, and dynamic range compression processing for keeping the entire radiographic image having a wide dynamic range within a density range that is easy to view without reducing the contrast of the fine structure of the subject are also performed.

[0004]

In recent years, devices capable of obtaining radiation images as moving images have been studied. In such an apparatus, it is required that the degree of diffusion of a contrast agent injected into a blood vessel, a digestive organ, or the like for diagnosis be displayed in real time. In addition, in order to obtain a radiation image as a moving image and to display a moving image suitable for diagnosis or the like, image data of the entire radiation image must be acquired at high speed, and the above-described image processing is executed at high speed. There is a need to.

Here, in the case of using a stimulable phosphor,
Since the radiation image information is recorded on the stimulable phosphor sheet and then image data is obtained by sequential scanning with laser light or the like, image data of the entire radiation image cannot be acquired at high speed.

Further, as disclosed in Japanese Patent Application Laid-Open No. 7-72562, a radiation image is divided into a plurality of sections, a specific pixel signal value in each section is read out, and the signal value is used. It has also been proposed to read and process image data for a section in which a pixel having a signal value equal to or greater than a predetermined threshold value exists. However, in such a method, for example, when the irradiation field is not narrowed down and the specific pixel signal value in each section is equal to or more than a predetermined threshold value, the image data of all sections is read out, and the image processing conditions Since a large amount of image data is used for the determination, high-speed image processing cannot be performed.

Accordingly, the present invention provides an image processing apparatus capable of executing image processing on a read radiation image at high speed.

[0008]

According to the present invention, there is provided an image processing apparatus, comprising: a radiation image detecting unit that detects an irradiated radiation amount, generates an electric signal corresponding to the detected amount, and detects a radiation image; From the radiation image detection unit, the radiation image is divided into a plurality of blocks, an image data acquisition unit that reads out an electric signal in parallel for each block to generate image data, and when reading image data from the image data acquisition unit, A reduced image forming means for extracting pixel data at a predetermined position of the read image data and forming a reduced image.

Further, a radiation image detecting means for detecting an irradiated radiation amount, generating an electric signal corresponding to the detected amount and detecting a radiation image, and a radiation image detecting means for dividing the radiation image into a plurality of blocks. Image data obtaining means for generating image data by reading out electrical signals in parallel for each block and a block for calculating a representative value of image data for each block when reading out image data from the image data obtaining means It has a representative value calculating means and a reduced image forming means for forming a reduced image using the representative value of each block obtained by the block representative value calculating means as a signal value of one pixel.

[0010]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. Radiation output from the radiation generator to obtain a radiation image of the subject passes through the subject to the Flat Panel De of the image processing apparatus.
irrespective to the TEC (FPD). The area A of the FPD (hereinafter, referred to as “imaging panel”) 11 is divided into a plurality of blocks AR- (0,0) to AR- (m, n) as shown in FIG. In one block, for example, block AR- (0,0), as shown in FIG. 2, detection elements DT (0,0) to DT (j, k) which output electric signals in accordance with the dose of irradiated radiation. ) Are two-dimensionally arranged and scanning lines 114-0 to 114
-k and the signal lines 116-0 to 116-j are arranged to be orthogonal, for example.

The scanning lines 114-0 to 114-k correspond to the scanning drive unit 1.
4, the scanning drive unit 14 generates a readout signal RS based on a control signal CTA supplied from a control unit 40 described later, and outputs one of the scanning lines 114-0 to 114-k.
Is output to one scanning line 114-p (p is any value from 0 to k). In response to the read signal RS, the electric signals SV-0 to SV-j corresponding to the dose of the irradiated radiation are output from the detection elements DT (0, p) to DT (j, p) connected to the scanning line 114-p. Is output and supplied to the image data generator 16- (0,0) via the signal lines 116-0 to 116-j.

The other blocks AR- (0,1) to AR- (0, n), A
R- (1,0) to AR- (1, n),..., AR- (m, n) similarly to the block AR- (0,0) by the read signal RS from the scan driving circuit 14. From (j × k) detection elements in each block, an electric signal SV corresponding to the irradiated radiation dose is output, and the image data generation unit 16 corresponding to each block is output.
-(0,1) to 16- (0, n), 16- (1,0) to 16- (1, n), ...
, 16- (m, n).

Note that the scanning lines 114-0 to 114-k used in the block AR- (0,0) are also used in the other blocks as well.
If used in the same way as-(0,0), the electric signal SV can be easily output at the same timing from, for example, the detection elements of the same column number in each block.

Here, the detecting element DT should just output an electric signal corresponding to the dose of the irradiated radiation. For example, when a detection element is formed using a photoconductive layer in which an electron-hole pair is generated when radiation is irradiated and the resistance value changes, the amount of radiation generated in the photoconductive layer depends on the amount of radiation generated in the photoconductive layer. An amount of charge is stored in the charge storage capacitor, and the charge stored in the charge storage capacitor is supplied to the image data generator 16 as an electric signal. It is preferable that the photoconductive layer has a high dark resistance value, such as amorphous selenium, lead oxide, cadmium sulfide, mercuric iodide, or a photoconductive organic material (a photoconductive layer to which an X-ray absorbing compound is added). And the like, and amorphous selenium is particularly desirable.

When the detecting element DT is formed using, for example, a scintillator or the like that generates fluorescence when irradiated with radiation, a photodiode generates an electric signal based on the intensity of the fluorescence generated by the scintillator. The information may be supplied to the image data generator 16. An imaging panel 11 using such a configuration is disclosed in
As disclosed in JP-90048, X-rays are absorbed by a phosphor layer such as an intensifying screen to generate fluorescence, and the intensity of the fluorescence is detected by a photodetector such as a photodiode provided for each pixel. There is something. As other means for detecting fluorescence, CC
There is also a method using a D or C-MOS sensor. In particular, an imaging panel (FP) of the type disclosed in JP-A-6-342098
In D), since the X-ray dose is directly converted into the electric charge amount for each pixel, the sharpness in the FPD is hardly deteriorated and an image with excellent sharpness can be obtained. The effect of the image recording method is great and suitable.

The image data generator 16- (0,0) converts the supplied electric signals SV-0 to SV-j into digital pixel data based on the control signal CTB supplied from the controller 40. Are stored as image data SD- (0,0) in a memory (not shown) of the image data generation unit 16- (0,0). Also, the image data generation units 16- (0,1) to 16- (0, n), 16- (1,
0) to 16- (1, n),..., 16- (m, n)
The image data SD- (0,
1) to SD- (0, n), SD- (1,0) to SD- (1, n), ..., S
D- (m, n) is held. Further, the image data generation unit 16
Are read out based on the control signal CTB and supplied to the reduced image output unit 25 and the image output unit 35 shown in FIG.

FIG. 3 shows the configuration of the reduced image output unit 25. The image data SD- (0,0) supplied from the image data generator 16- (0,0) is supplied to the data extraction circuit 251- (0,0). Similarly, image data SD- (0,1),.
-(m, n) is the data extraction circuit 251- (0,1), ..., 25
1- (m, n).

In the extraction timing signal generation circuit 252,
The number of pixels (the number of pixels) of the image data supplied from the image data generator 16 is determined based on the control signal CTC from the controller 40, and when the number of data reaches a predetermined number, the extraction timing signal TS is generated. Data extraction circuit 251- (0,
0),..., 251- (m, n).

The data extraction circuit 251- (0,0) extracts one pixel of image data from the supplied image data SD- (0,0) based on the extraction timing signal TS, and performs data writing control. The signal is supplied to a circuit 256. Similarly, the other data extraction circuit 251 also extracts one pixel of image data and supplies it to the data writing control circuit 256.

For example, as shown in FIG. 4, the image data generator 16 reads out image data at a predetermined clock frequency CK based on the control signal CTB. The extraction timing signal generation circuit 252 starts counting from the start of reading of image data by the image data generation unit 16 at a predetermined clock frequency CK based on the control signal CTC. Here, when the count value reaches a predetermined value, that is, when the number of read image data reaches the predetermined number of data, the switch is closed and the image data for one pixel is subjected to data write control. The signal is supplied to a circuit 256.

In the data write control circuit 256, the image data extracted by the data extraction circuits 251- (0,0),. It is determined whether the data is data or not, and the writing position of the reduced image memory 258 is set based on the determined position of the block AR. That is, image data of a reduced image obtained by thinning out image data (hereinafter, referred to as “reduced image data”) is written in the reduced image memory 258. The operation of the data write control circuit 256 and the reading of the reduced image data written in the reduced image memory 258 are controlled by the control signal CTC.

The extraction timing signal generation circuit 252
Then, assuming that the extraction timing signal TS is generated when the number of data reaches the first level and the second level,
Each data extraction circuit 251 may extract image data for a plurality of pixels.

The reduced image output section 25 extracts one pixel or a plurality of pixels of image data from each block. However, a representative value of each block is calculated, and this representative value is stored in the reduced image memory 258. Can also be written to.

FIG. 5 shows a configuration of the reduced image output unit 25 which calculates a representative value of each block and writes the representative value to the reduced image memory 258. In FIG. 5, the image data SD output from the image data generation unit 16- (0,0)
-(0,0) is supplied to the representative value calculation circuit 254- (0,0). Similarly, the image data SD- (0,1),..., SD- (m, n) are supplied to the representative value calculation circuit 254- (0,1),. Is done.

The representative value calculation circuit 254- (0,0) calculates representative value data of one block of image data SD- (0,0) and supplies it to the data write control circuit 256. As the representative value data, for example, an average value, a median value, a maximum value, a minimum value, a variance value, and the like are used. Similarly, the representative value calculation circuit 254 also calculates the representative value data and supplies it to the data write control circuit 256.

In the data write control circuit 256, the representative value data calculated by the representative value calculation circuits 254- (0,0),. The write position of the reduced image memory 258 is set based on the determined block position. That is, the reduced image data is written in the reduced image memory 258 as in the case described above.

The reduced image data written in the reduced image memory 258 in this manner is sequentially read out based on the control signal CTC and supplied to the condition setting section 30 shown in FIG.

The condition setting section 30 uses the reduced image data from the reduced image output section 25 based on the control signal CTD from the control section 40 to perform image processing of the radiation image for obtaining a radiation image suitable for diagnosis or the like. The condition is set, and a condition setting signal JC indicating the image processing condition is supplied to the image output unit 35.

The image output unit 35 performs image processing of a radiation image based on the image data supplied from the image data generation unit 16 under the image processing conditions based on the condition setting signal JC, for example, radiation of density and contrast suitable for diagnosis or the like. Gradation processing to obtain an image, frequency emphasis processing to control sharpness, and radiographic image with a wide dynamic range to keep the whole of the radiographic image within the easy-to-view density range without reducing the contrast of the fine structure of the subject A dynamic range compression process or the like is performed.

The operations of the condition setting unit 30 and the image output unit 35 are controlled based on control signals CTD and CTE from the control unit 40.

The control unit 40 controls the control signals CTA to CTA so that a good radiation image suitable for diagnosis or the like can be obtained.
A CTE is generated and supplied to each unit as described above.

Next, the operation will be described with reference to FIG.
The area AR of the imaging panel 11 is divided into, for example, blocks of “j” × “k” pixels as shown in FIG. 6A. Here, when the irradiation of the radiation is completed, the readout control signal RC from the control unit 40 outputs an electric signal from the detection element of each block, and the memory of each image data generation unit 16 stores the electric signal of each block. Image data is held. For example, as shown in FIG. 6B, the image data of the block AR- (0,0) is stored in the memory of the image data generation unit 16- (0,0), and the image data of the block AR- (0,1) is the image data. It is stored in the memory of the data generator 16- (0,1).

Next, the image data stored in the memory of each image data generating unit 16 is read out and output to the reduced image output unit 2.
5 and the image output unit 35.

The reduced image output unit 25 counts the number of image data, and when the number of image data reaches a predetermined number, for example, when the image data at the pixel position (p, q) in the block is read out, When the number reaches a predetermined data number, image data at this pixel position (p, q) is extracted. Here, when the extracted image data is the image data supplied from the image data generation unit 16- (0,0), the image data supplied from the image data generation unit 16- (0,0) is As shown in FIG. 6A, it is the image data of the upper left block AR (0,0). Therefore, the extracted image data is
The data is written to the upper left position MP (0,0) of the reduced image memory 258. When the extracted image data is the image data supplied from the image data generation unit 16- (0,1), the image data supplied from the image data generation unit 16- (0,1) Block AR adjacent to the right of (0,0)
Since the image data is (0, 1), the reduced image memory 2
Position MP adjacent to the right of position MP (0,0) at 58
Written to (0,1). Hereinafter, similarly extracted image data is written to the reduced image memory 258 according to the position of each block. Therefore, the reduced image memory 258 stores image data of a reduced image obtained by reducing “j” × “k” pixels to one pixel. In addition,
As described above, the image data read from the image data generation unit 16 may be extracted for one block by a plurality of pixels, and the pixel data of the block, that is, “j” × “k” pixels Alternatively, a representative value may be obtained from the image data and written to the reduced image memory.

As described above, the image processing conditions are set by the condition setting section 30 using the image data written in the reduced image memory 258. Here, in order to perform image processing properly, it is necessary to reduce the pixel size and increase the number of pixels so that the reduced image has the features of the original image.
Further, in order to obtain processing conditions at high speed, it is desirable to increase the pixel size and reduce the number of pixels. For this reason, the size of one pixel of the reduced image is desirably about 1 mm to about 5 mm.
When the size of one pixel of the reduced image is 1 mm × 1 mm when the size is about 0 μm to 200 μm, 5 × 5 pixels to 1
0 × 10 pixels constitute one block. In addition, 1 of the reduced image
If the size of the pixel is 5 mm × 5 mm, 25 × 25 pixels to 50 × 50 pixels constitute one block. Image data of one pixel of the reduced image is generated from the image data in this block.

In the condition setting section 30, since the reduced image has the features of the original image and the number of pixels is reduced, the use of the reduced image data is faster than the case of using the image data before the reduction. The image output unit 35 can perform image processing on the radiation image at high speed to obtain a radiation image suitable for diagnosis or the like.

When the image processing is performed again by storing the image data of the reduced image and the image data of the original image in a recording medium, for example, different processing is performed, or the image processing conditions once obtained are not optimal. In this case, by using the stored reduced image data, it is not necessary to obtain the reduced image again, and it is possible to quickly perform different processing, and to obtain the image processing condition again or to calculate the image processing condition again. By changing the above parameters, new image processing conditions can be quickly obtained, and a radiation image that has been subjected to image processing under various image processing conditions can be obtained quickly. If the image processing conditions obtained once are also stored, by using these image processing conditions, an image output after the image processing can be promptly obtained for a radiation image that has undergone image processing.

In the above-described embodiment, the block A
The image data generator 16 is provided for each of R- (0,0) to AR- (m, n).
0), AR- (0,1) to AR- (0, n), if the readout signal RS is sequentially output to any one of the scanning lines, the block AR- (0 , 0), AR- (0,1) to AR-
One image data generator may be provided for (0, n). For this reason, if the other blocks have the same configuration, the image data for one screen can be generated by the m image data generation units, and the configuration can be simplified.

[0039]

According to the present invention, it is possible to perform high-speed image processing on a radiation image.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an image processing apparatus.

FIG. 2 is a diagram showing a block AR- (0,0).

FIG. 3 is a diagram illustrating a configuration of a reduced image output unit.

FIG. 4 is a diagram for explaining operations of an extraction timing signal generation circuit and a data extraction circuit.

FIG. 5 is a diagram illustrating another configuration of the reduced image output unit.

FIG. 6 is a diagram illustrating the operation of the image processing apparatus.

[Explanation of symbols]

 Reference Signs List 11 imaging panel 14 scan driver 16 image data generator 25 reduced image output unit 30 condition setting unit 35 image output unit 40 control unit

Claims (4)

[Claims] 1. A radiation image detecting means for detecting an irradiated radiation amount, generating an electric signal according to the detected amount and detecting a radiation image, and detecting a plurality of the radiation images from the radiation image detecting means. Image data obtaining means for generating image data by reading out electric signals in parallel for each block, and reading image data from the image data obtaining means; An image processing apparatus comprising: a reduced image forming unit that extracts pixel data to form a reduced image. 2. A radiation image detecting means for detecting an irradiated radiation amount, generating an electric signal according to the detected amount and detecting a radiation image, and detecting a plurality of the radiation images from the radiation image detecting means. An image data acquisition unit that divides the image data into blocks and reads out electric signals in parallel for each block to generate image data; and when image data is read from the image data acquisition unit, a representative value of the image data for each block is obtained. Image processing comprising: a block representative value calculating means for calculating; and a reduced image forming means for forming a reduced image using the representative value of each block obtained by the block representative value calculating means as a signal value of one pixel. apparatus. 3. A conversion processing condition calculation unit for calculating a conversion processing condition for converting the radiation image into an image optimal for image interpretation, wherein the conversion processing condition calculation unit performs conversion based on the reduced image. The image processing apparatus according to claim 1, wherein a processing condition is calculated. 4. The image processing apparatus according to claim 1, further comprising a reduced image storage unit that stores the reduced image in association with a corresponding original image.