JPH0916762A - Image processor - Google Patents

Abstract

PURPOSE: To provide an image processor with which the gradation converting characteristics of a look-up table(LUT) can be rotated with a designated picture element density value as a center. CONSTITUTION: This device is provided with a converting means 100 for converting image data while using the LUT, output means 200 for outputting an image based on the output image data of the converting means, moving means 300 for rotationally moving the converting characteristics of the LUT of the converting means 100 within a function plane where those characteristics are defined, and setting means 400 for setting the center of rotational move for the converting characteristics of the LUT due to the moving means 300.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing device. More specifically, the present invention relates to an image processing device that performs gradation processing of image data using a look-up table.

[0002]

2. Description of the Related Art FIG. 16 is a block diagram showing the construction of a radiation image information reading apparatus, which is one of conventional image processing apparatuses, and is disclosed in, for example, Japanese Patent Laid-Open No. 55-12144. In FIG. 16, 71 is a radiation source such as X-rays,
Reference numeral 72 is a subject, and 73 is a radiation conversion panel.

This conversion panel 73 has a stimulable phosphor layer, and when this stimulable phosphor is irradiated with X-rays, electron beams, ultraviolet rays, etc., a part of the energy is changed to the irradiation amount. Accordingly, the stimulable phosphor is once accumulated in a metastable state in the crystal. Here, a kind of latent image is formed by the radiation energy transmitted through the subject 72.

When the conversion panel 73 is stimulated by irradiating it with stimulating excitation light such as visible light or infrared light, stimulable fluorescent light emission occurs in proportion to the accumulated energy. 74 is a stimulated excitation light source for scanning the conversion panel 73, 75 is a filter, 76 is a photoelectric converter for detecting the stimulated emission intensity of the fluorescent substance emitted by irradiation of excitation light, and 77 is an electricity from the photoelectric converter 76. An image reproducing device for forming a perspective image of the subject 72 based on the signal, 7
Reference numeral 8 is an image display device.

The radiation image information reading apparatus having such a structure has an extremely wide radiation exposure area which can be recorded, can freely process image information obtained as an electric signal, and obtains an image most suitable for the purpose. It has features such as being able to. In particular, there are various advantages such that a clear image having a wide visible range can be constantly obtained, and low dose imaging can be performed according to the purpose.

In order to be able to observe a region of interest with an appropriate density gradation when displaying a perspective image of the subject 72 on the image display device 78, the image reproducing device 77 performs gradation processing of pixel density values for image data. Is done. This gradation processing is also called window level processing. A look-up table is used for gradation processing.

FIG. 17 shows an example of conversion characteristics of the lookup table. Here, the curve a is a curve representing the conversion characteristic of the function y = f (x). The input pixel density value x is the function y
= F (x) is converted into the output pixel density value y.
The conversion characteristic can be changed by changing the shape of the curve a.

As a method of changing the shape of the curve a, there is known a method of rotating the curve a in the xy plane to change it into a conversion characteristic like the curve b or c. Various conversion characteristics can be obtained by changing the amount of rotation. Hereinafter, this is referred to as rotation of the lookup table for convenience.

There is also a method of obtaining a conversion characteristic like a curve d by translating the curve a in the x direction. Hereinafter, this is referred to as a shift of the lookup table for convenience. Conventionally, the center of rotation of the lookup table was fixed. A pixel density value corresponding to y = 0, a pixel density value corresponding to the center of the window, a pixel density value calculated from the window width and the window center, etc. have been used as the fixed center of rotation. Further, as described in Japanese Patent Laid-Open No. 3-249693, some of them are eventually determined from the window width and the window center.

[0010]

When the look-up table is rotated, the pixel density at the center of rotation does not change, but the pixel density values on the high density side and the low density side change. Therefore, when the pixel density value of the region of interest does not coincide with the center of rotation, the pixel density value of the region of interest changes as the lookup table is rotated.

When the center of rotation is fixed or mechanically determined, the pixel density value of the region of interest usually does not coincide with the center of rotation. Therefore, when the look-up table is rotated, the pixel of the region of interest is rotated. The density value changes, which causes inconvenience in image diagnosis.

A look-up table having a basic conversion characteristic is prepared, and a rotation operation is performed on the look-up table. Although the conversion characteristic is generally linear in CT and MRI, the radiation image information reader using the stimulable phosphor gives a more suitable image for diagnosis by providing the nonlinear conversion characteristic. Can be output. But,
It is not easy to rotate such a non-linear conversion characteristic with high accuracy.

Depending on the contents of the image, it may be desired to change the gradation on only one of the high density value side or the low density value side and keep the other fixed, but this is not sufficient as long as the look-up table is rotated. It is possible.

In recent years, the image data of the radiation image information reading apparatus is transferred to a medical image workstation, and image diagnosis and various advanced image processing are often performed in the medical image workstation.

At this time, it is desirable that the image can be observed with exactly the same gradation as that adjusted by the radiation image information reading apparatus. However, conventionally, since the data regarding the rotation of the look-up table is not transferred, it is necessary to perform the gradation process again, and it is difficult to observe the image with exactly the same gradation. .

The present invention has been made to solve the above problems, and an object of the present invention is to realize an image processing apparatus capable of rotating a lookup table around a designated pixel density value. That is.

Another object of the present invention is to realize an image processing apparatus which can obtain the equivalent result without rotating a look-up table having a non-linear conversion characteristic.

Another object of the present invention is to realize an image processing apparatus capable of changing the tone of only one of the high density value side and the low density value side even when the look-up table is rotated. Is.

Another object of the present invention is to realize an image processing apparatus capable of displaying an image with the same gradation even in another image processing apparatus to which image data has been transferred.

[0020]

A first invention for solving the above-mentioned problems is to provide a lookup / display system as shown in FIG.
Conversion means 100 for converting image data using a table
An output means 200 for outputting an image based on the output image data of the converting means, and a moving means 300 for rotationally moving the conversion characteristics of the lookup table of the converting means within a function plane in which the conversion characteristics are defined. And the setting means 400 for setting the center of rotational movement of the conversion characteristic of the lookup table by the moving means.

In the first invention, the setting means has a pixel density value calculated from pixels of a region of interest in the image output to the output means, a pixel density value at a specified position in the image output to the output means, and It is preferable to set any one of the designated pixel density values as the center of rotation in that the pixel density value of the region of interest does not change even if the conversion characteristics of the lookup table are rotated.

A second invention for solving the above problem is, as shown in FIG. 2, first conversion means 110 for converting image data using a lookup table having a linear conversion characteristic, The moving means 300 for moving the conversion characteristic of the lookup table of the first conversion means in the function plane in which it is defined, and the first conversion table using the lookup table having a non-linear conversion characteristic. Secondly further converting the image data converted by the converting means
And an output unit 200 that outputs an image based on the output image data of the second conversion unit.

A third invention for solving the above-mentioned problem is, as shown in FIG. 2, a first conversion means 110 for converting image data using a lookup table having a linear conversion characteristic, A moving means 300 for moving the conversion characteristic of the lookup table of the first conversion means in the function plane in which it is defined, and a plurality of lookup tables having non-linear conversion characteristics selectively. Second conversion means 120 for further converting the image data converted by the first conversion means, and output means 200 for outputting an image based on the output image data of the second conversion means are provided. An image processing device characterized by the above.

A fourth invention for solving the above-mentioned problems is, as shown in FIG. 3, conversion means 100 for converting image data using a look-up table, and the look-up table of the conversion means. Means 30 for rotatively moving the conversion characteristics of the object in the function plane in which it is defined.
0, and a transfer unit 500 that transfers the image data and the data indicating the center of the rotational movement of the conversion characteristic of the lookup table to another image processing apparatus. .

[0025]

According to the first aspect of the invention, the pixel density set by the setting means is set as the center of the rotational movement of the conversion characteristic of the look-up table. Therefore, pay attention even if the look-up table is rotated. There is an effect that the pixel density value of the existing portion does not change.

According to the second aspect of the present invention, the conversion characteristic is rotated about a lookup table having a linear conversion characteristic, and the data converted by this lookup table is looked up having a non-linear conversion characteristic. Since the conversion is further performed using the table, the non-linear conversion characteristic has the effect of not requiring rotation.

According to the third aspect of the present invention, the conversion characteristic is rotated about a lookup table having a linear conversion characteristic, and the data converted by the lookup table is converted into a plurality of nonlinear conversion characteristics. Since the look-up table is selectively used for further conversion, it is possible to change the gradation of only one of the high-density value side and the low-density value side by selecting a plurality of look-up tables. There is an effect.

According to the fourth invention, the image data and the data indicating the center of the rotational movement of the look-up table are transferred to another image processing apparatus, so that the same gradation is obtained in the other image processing apparatus. This has the effect of displaying a sex image.

[0029]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 4 is a block diagram showing the configuration of an embodiment of the present invention, which is an example applied to chest radiography.

In the radiation image information recording / reading unit 4, 4
1 is an optical beam such as a gas laser, a solid-state laser, and a semiconductor laser.
An optical scanner 42 irradiates the conversion panel 3 with the optical beam from the optical beam generator 41 and scans it.
Reference numeral 43 is a photoelectric converter for detecting the stimulated emission light emitted from the conversion panel 3, and here, a condenser 43a composed of an optical fiber,
Filter 43b that passes only light in the stimulated emission wavelength range
, A photomultiplier 43c for converting the light passing through the filter 43b into an electric signal is shown.

Reference numeral 44 is a current / voltage converter for converting the output current from the photoelectric converter 43 into a voltage signal, 45 is an amplifier, 4
An A / D converter 6 converts the signal from the current / voltage converter 44 amplified by the amplifier 45 into digital data.

Reference numeral 47 is a control circuit for inputting digital data from the A / D converter 46, which controls the light beam intensity of the light beam generator 41 and the power supply voltage of the high voltage power supply 48 for the photomultiplier. The gain adjustment of the photomultiplier, the gain adjustment of the current / voltage converter 44 and the amplifier 46 and the input dynamic range adjustment of the A / D converter 46 are performed, and the read gain of the radiation image information is adjusted comprehensively.

In the control unit 5, 50 is an arithmetic control unit (hereinafter abbreviated as CPU), SB is a system bus, VB.
Is an image bus, both of which are connected to the CPU 50.
The image display means (image monitor) 51 includes a display controller 51a.
, Coupled to the CPU 50 via the image bus VB,
The frame memory 52 as a storage means is connected to the CPU 50 via the frame memory control section 52a and the image bus VB.

The image display means 51 is an embodiment of the output means 200 shown in FIGS. Image display means 51
An image display device using a CRT, a liquid crystal or the like is used as the device.

Another example of the output means 200 is a hard copy device such as an imager for reproducing an image on a medical film or a thermal printer for reproducing an image on a thermal paper. The information input means 53 comprises a keyboard 53a and an operation screen display means 53b, and an interface 53c.
Is connected to the CPU 50 via.

The synchronizing means 54 is a timing control section 54a connected to the image bus VB and the system bus SB, and an X-ray adapter 54b connected to this timing control section 54a.
The radiation source 1 includes a drive circuit 10 and a control circuit 47.
And is bound to.

Reference numeral 56 is an I / O interface for the medical workstation 6, and 57 is the magnetic disk device 5.
8 (or an external optical disk device or magnetic tape device). The CPU 50 can also be connected to an external terminal.

The operation of the apparatus thus configured will be described below. The identification information of the subject 2 to be radiographed is input from the keyboard 53a of the control unit 5. This identification information includes an ID number, name, date of birth, sex, imaged part, imaged date and time, and the like.

However, the photographing date and time may be automatically inserted by the calendar clock built in the CPU 50, or if the medical workstation 6 manages the ID information, then the photographing date and time may be automatically inserted. You may make it collate only if sent.

Alternatively, only the collation may be performed by receiving the input from the external terminal. Further, the identification information input here may be only information relating to the patient to be imaged at that time, or a series of information may be input in advance and imaging may be performed in sequence later. The identification information is input, the patient is set at the imaging position, and imaging is performed.

When the photographing button provided on the information input means 53 is pressed, the timing control section 54a controls the drive circuit 10 via the X-ray adapter 54b, and the radiation source 1
, The X-ray tube voltage, tube current, and irradiation time are given according to the imaged region.

With this, the radiation source 1 irradiates the subject (human chest or the like) 2 with radiation (X-rays). This radiation passes through the subject 2, energy is accumulated in the photostimulable phosphor layer of the conversion panel 3 according to the radiation transmittance distribution of the subject 2, and a latent image of the subject 2 is formed there. Thus, the X-ray photography is completed.

When the X-ray photography is completed, the light beam generator 4
Reference numeral 1 denotes an optical beam whose emission intensity is controlled. The optical beam is deflected by the optical scanner 42, its optical path is changed by a reflecting mirror, and is guided to the conversion panel 3 as excitation scanning light. The conversion panel 3 outputs stimulated emission light, which is substantially proportional to the latent image energy, by the excitation scanning light.

The photoelectric converter 43 detects this stimulated emission light and outputs a current signal corresponding to the incident light. This output current becomes digital image data through the current / voltage converter 44, the amplifier 45, and the A / D converter 46, and is applied to the control circuit 47, where the reading gain of the radiation image information is comprehensively obtained. It is adjusted and transferred to the control unit 5.

FIG. 5 is a block diagram showing a part of the timing control section 54a in the control section 5. The timing control section 54a is composed of an input switch SW1 and an output switch SW2 that are switched in synchronization with each other, line buffers A and B composed of a RAM having a storage capacity of 2048 pixels, for example, and a control circuit C.

Here, the line buffers A and B correspond to one line of the image data in the main scanning direction. Record reading unit 4
When the image data of the first line is stored in the line buffer A, the switch SW1 and the output switch SW2 are switched, and the image data of the second line is stored in the line buffer B.
Is stored.

At the same time, the image data of the first line of the line buffer A is output and sequentially stored in the frame memory 52 through the image bus VB. The input / output switches SW1 and SW2 are switched for each line, and the line buffers A / B change their roles.

FIG. 6 is a schematic diagram of the configuration of the frame memory 52. This frame memory 52 is 2048 × 2560
It is composed of a RAM having a storage capacity for pixels. The image data converted by the recording / reading unit 4 and temporarily stored in the line buffers A / B are stored in the frame memory 52 line by line.

At the same time, the stored image data is transferred to the display controller 51a or the magnetic disk controller 57 via the image bus VB. FIG. 7 is a block diagram showing the configuration of another part of the timing controller 54a.
Data transfer control circuit CNT and data conversion circuit CNV
Are provided inside the timing control section 54a.

An image bus V for transferring image data
B is composed of an input bus, an output bus, and a control bus. The data conversion circuit has three systems, a non-conversion circuit CKT, a shift register circuit SFT, and a conversion circuit GRY.

Here, the conversion circuit GRY is for converting the gradation of the density value of the image data, and the lookup circuit
Have a table. The conversion circuit GRY will be described later again.

The image data transfer according to the configuration of FIGS. 5 to 7 is performed as follows. (Transfer Example 1) Transfer from line buffer A / B to frame memory 52 The data transfer control circuit CNT causes the line buffer A / B to output one pixel data to the input bus at a time. The data on the input bus is latched by the non-conversion circuit CKT and output as it is to the output bus. The data transfer control circuit CNT transfers the data on the output bus to the frame memory controller 52a.

When one pixel is transferred, the line buffer A / B
Then, the address of the frame memory 52 is incremented by 1. This is performed simultaneously and in parallel, and data for one line is transferred at high speed.

(Transfer example 2) Transfer data from frame memory 52 to display control unit 51a The transfer data transfer control circuit CNT causes the frame memory 52 to output one pixel data to the input bus. Input bus data
Data is input to the conversion circuit GRY, subjected to gradation conversion by the look-up table, latched, and output to the output bus.

Data transfer control circuit The data on the CNT output bus is transferred to the display control section 51a. Display control unit 51a
The display memory (not shown) is built in, and the pixels are sequentially stored in the display memory.

The display memory is composed of 512 × 640 pixels × 8 bits. The address of the frame memory 52 is +4 and the address of the display memory is +1 for each pixel transfer.

This is 1 for both main scanning and sub scanning during reading.
This is because the whole display is performed by thinning out to / 4, and the address of the frame memory 52 is +2 (2 times enlargement) during enlarged display.
Or +1 (4 times enlargement). The transfer of 512 pixels at the maximum completes the transfer of one line. At the time of reading, this transfer is performed once every four lines are read.

(Transfer Example 3) Transfer from Frame Memory 52 to Magnetic Disk Control Section 57 The transfer data transfer control circuit CNT causes the frame memory 52 to output pixel data to the input bus one pixel at a time. Input bus data
Data is latched in the shift register circuit SFT.

In the shift register circuit SFT, the image data has a 10-bit / pixel configuration, and the magnetic disk controller 57 has 16 bits.
Since the data width is different, such as the bit structure,
Is a circuit for rearranging the data bits as shown in.

That is, 80-bit image data for 8 pixels is rearranged into 16-bit × 5-word data. Each time the shift register circuit SFT outputs one word, it is latched in the output bus.

The data transfer control circuit CNT causes the magnetic disk controller 57 to transfer one word at a time. Therefore, one line of 2048 pixel data is converted into 1280 words and sent to the magnetic disk controller 57.

In the magnetic disk controller 57, 1 word 16
Bit is divided into 2 bytes and magnetic disk device 58
Since it is stored in, one line becomes 2560 bytes. The magnetic disk device 58 transfers data to 512 bytes / block.
Since it is matted, it is temporarily stored as 5 blocks / 1 line.

These transfers are extremely fast, and when they are read line by line by the recording / reading unit 4, they are apparently transferred in parallel while switching the image bus VB in time division.

Accordingly, an image is displayed on the image monitor 51 at the same time as it is read by the recording / reading unit 4, and is also stored in the magnetic disk device 58. When the reading is finished and the afterimage erasing of the conversion panel 3 is started, the display and the storage in the magnetic disk device 58 are finished almost at the same time.

The magnetic disk device 58 uses a 150-megabyte magnetic disk device and can temporarily store 20 sheets, so continuous shooting is also possible. here,
The magnetic disk device 58 is used as a memory for temporary storage because it is assumed that precise diagnosis and long-term image data storage will be performed by the higher-level medical workstation 6. This is because the image data is temporarily stored until it is transferred to the workstation 6. Further, if the semiconductor memory has a large capacity, it is naturally possible to configure the semiconductor memory.

When online data transfer with the medical workstation 6 is impossible, an optical disk device or a magnetic tape device is arranged in parallel with the magnetic disk device as shown by a broken line.
It is also possible to connect a device to transfer data offline.

However, since the recording speed is slow in this case, the speed of the entire device may be sacrificed unless it is combined with an appropriate data compression device. The image data temporarily stored in the magnetic disk device 58 can be selectively redisplayed.

In this case, in order to select an image to be displayed, a list of temporarily stored images of the magnetic disk device 58 is displayed on the operation screen display means 53b in the information input means 53, and the keyboard 53a is displayed. From the ID information may be used.

Further, the image data temporarily stored in the magnetic disk device 58 can be transferred to the medical work station 6 through the I / O interface 56.
In this case, it is desirable to be activated by a transfer request from the medical workstation 6. By this transfer request,
There are the following two types of transfer modes for transferring image data.

(1) A mode in which images are transferred in the order of earliest shooting time from the temporarily stored images. Usually, this mode is used. (2) The search list is first transferred to the medical workstation 6, and the image data to be transferred based on the list.
The mode that determines the data.

In each of these transfer modes, the identification information is transferred at the same time as the image data. As a result, the medical workstation 6 can easily create the image management information (database).

When the recording / reading unit 4 starts the operation during the transfer operation of the image data as described above, the recording / reading operation is prioritized, and the transfer of the image data is temporarily interrupted to perform the recording / reading operation. After the operation is completed, the transfer of the image data is continued again.

This is because if the magnetic disk device 58 makes a random access, the access time becomes extremely long and there is a possibility that the read image data will not be stored in time.

By providing the image data transfer function as described above, the magnetic tape is provided inside the control unit 5.
It is not necessary to have a long-term image data storage means such as a tape device or an optical disk device, and the device can be constructed inexpensively and compactly.

Further, the user of the apparatus can perform the photographing work without being aware of the fact that communication is in progress. When transferring the image data to the medical workstation 6, it is necessary to select whether to save the temporarily stored image data or to delete the temporarily stored image data. In this case, the transfer request content from the medical workstation 6 may include erasure / save selection information.

When the medical workstation 6 stops transferring image data for some reason, the magnetic disk device 58 may become full of image data. At this time, a warning is displayed and the next shooting is not accepted.

For the image displayed on the image monitor 51, it is necessary to perform various kinds of image processing and image measurement in order to facilitate observation of the image. Here, image processing includes gradation processing, frequency processing, and the like, and image measurement includes distance / angle measurement, density value measurement, profile, histogram, and the like.

These image processing and image measurement functions can be provided in the control section 5, but in order to avoid the increase in size and cost of the apparatus, the medical workstation 6 is used for advanced image processing. It may be performed.

The control section 5 has a main purpose of observing an image, and has a relatively simple image processing function such as gradation processing, negative / positive inversion processing, enlargement and movement processing in the timing control section 54a. This can be performed by the data transfer control circuit CNT and the data conversion circuit CNV.

Next, the gradation processing of image data according to the embodiment of the present invention will be described. The gradation processing involves the CPU 50, the memory 59, the image monitor 51, the display control unit 51a, the frame memory 52, the frame memory control unit 52a, the information input means 53, the interface 53c, and the timing control unit 54a. Various programs necessary for the operation of the CPU 50 are stored in the memory 59.

In the timing controller 54a, the data transfer control circuit CNT and the data conversion circuit CNV are involved. Among the data conversion circuits CNV, especially the conversion circuit GRY
Is involved. The conversion circuit GRY has a look-up table for gradation conversion.

From the operator through the information input means 53, the CP
Various commands are given to U50. The CPU 50 carries out the following gradation processing by performing predetermined data processing based on these commands and controlling each part.

FIG. 9 shows a conceptual diagram of gradation processing according to the embodiment of the present invention. The operator designates the center of rotation of the look-up table through the information input means 53. The center of rotation is designated by either a desired pixel density value, a desired position on the image displayed on the image monitor 51, or a region of interest (ROI) that includes a region of interest.

When the pixel density value itself is designated, it is selected as the center of rotation. When a desired position on the image is designated, the pixel density value at that position is selected as the center of rotation. When the ROI is designated, the pixel density value calculated from the pixels in the region of interest is selected as the center of rotation.

As a method of designating the ROI, a method of using a fixed figure such as a quadrangle or a circle, a method of tracing the contour of the region of interest or a name of the region of interest, for example, a lung field,
It is possible to use a method of inputting the abdomen, ribs, heart, etc. and specifying them by automatic recognition.

That is, if a perspective image of the chest as shown in FIG. 10 is obtained, for example, the lung field is designated by the square RC, the abdomen is designated by the circle CL, or "heart" is input. R for heart HT by automatic recognition
Set as OI.

The pixel density value calculated from the pixels in the region of interest is, for example, an average value, an intermediate value, a most frequent value, a designated value (percentage) of the cumulative frequency, etc., which is appropriate for the purpose of image diagnosis. Things are used.

The memory 59 stores a lookup table (basic LUT) having basic conversion characteristics. The basic LUT has a non-linear conversion characteristic like the function curve i shown in FIG. 11, for example. Although linear conversion characteristics are generally used in CT, MRI, etc., in the present reader using a stimulable phosphor, in particular, diagnosis is performed by using a basic LUT having such non-linear conversion characteristics. An image suitable for can be reproduced.

In the initial state, this basic LUT is the conversion circuit G.
An image loaded in RY and subjected to gradation processing is displayed on the image monitor 51. This basic LUT is rotated around the selected center. The amount of rotation is specified by the operator. For example, if the R point is selected as the center of rotation, rotation is performed around this R point and a conversion characteristic like the curve j is formed.

As a result, the image subjected to gradation processing according to the curve j is displayed on the image monitor 51. In the display image, the pixel density value at the point R selected as the center of rotation does not change, but the pixel values on the high density value side and the low density value side than that change. In the case of the curve j, the gradation characteristics on the high density value side and the low density value side are emphasized. Gradation can be weakened by reversing the direction of rotation.

The center of rotation can be arbitrarily designated according to the region of interest. For example, if S point is specified, this S
A conversion characteristic like a curve k rotated about a point can be obtained. In this case, it is possible to change the gradation of the pixel density values on both the high and low sides without changing the pixel density value corresponding to the point S.

By designating the shift amount, the conversion characteristic after rotation can be moved in parallel like k '. It is also possible to specify a new center of rotation on the conversion characteristic moved in this way and further rotate around that.

FIG. 12 shows a conceptual diagram of gradation processing according to another embodiment of the present invention. The gradation processing here is performed using a linear LUT and a non-linear LUT. Non-linear LUT is a basic LU
Multiple sets of T are provided and one of them is selectively used.

The straight line LUT has a conversion characteristic like the straight line m shown in FIG. 13, for example. Multiple basic LUTs
Have non-linear conversion characteristics such as curves u, v, and w shown in FIG. 14, respectively. Here, as the curves u, v, and w, an example in which the conversion characteristics on the low-density side are common and the conversion characteristics on the high-density side are different is given.

The image data is first converted by the linear LUT, which is further converted by the basic LUT and output as image data which has been subjected to gradation processing. The shift or rotation of the conversion characteristic is performed on the linear LUT. That is, for example, the straight line m is shifted to form the straight line n, which is rotated about the point T to obtain the conversion characteristic n ′. Then, the image data converted by this conversion characteristic n ′ is further converted by the basic LUT and becomes output image data.

At this time, the shift and rotation of the linear LUT gives the same effect as the shift and rotation of the non-linear conversion characteristic to the output image data. that time,
The advantage is that rotating a linear LUT is much easier than rotating a non-linear LUT.

Further, when the conversion characteristic is switched from the curve u to the curve v or w by selecting the basic LUT, only the gradation characteristic on the high density side is emphasized or attenuated without changing the gradation characteristic on the low density side. Will be possible. It is also convenient that it is not necessary to shift and rotate the basic LUT every time the basic LUT is selected.

When an image having an optimum gradation is obtained by such gradation processing, the image data is stored in the magnetic disk device 58 together with the data concerning gradation processing.
The data related to gradation processing includes the center of rotation, the amount of rotation, the amount of shift, and the like. These data are used to reproduce the gradation when redisplaying the image.

The image data is the medical workstation 6
Then, the medical workstation 6 can perform image diagnosis. At that time, data related to gradation processing is also transferred.

FIG. 15 shows an example of the structure of transfer data.
The transfer data includes patient information, image processing information, LUT information, and image data. The image processing information includes data related to gradation processing such as the center of rotation, the amount of rotation, and the amount of shift. The LUT information includes information indicating the conversion characteristics of the lookup table. When both the linear LUT and the non-linear basic LUT are used, the LUT information includes both data.

By transferring such information, it is possible to reproduce an image with the same gradation even in the medical workstation 6. If a plurality of basic LUTs (for example, u, v, w, etc.) are transferred to the medical workstation 6 in advance online or offline, the gradation can be selected in the medical workstation 6 by selecting the basic LUT as in the case of this reading device. You can change your gender.

Although the above embodiment is an example realized by hardware, the same function can be realized by software. In that case, by porting the software to the medical workstation 6, what is performed by the reading device can be realized on the medical workstation 6.

[0103]

As described in detail above, according to the first aspect of the invention, the pixel density set by the setting means is used as the center of the rotational movement of the conversion characteristic of the look-up table. -Advantageously, the pixel density value of the part of interest does not change even if the table is rotated.

According to the second aspect of the invention, the conversion characteristic is rotated about a lookup table having a linear conversion characteristic, and the data converted by this lookup table has a non-linear conversion characteristic. Since the conversion is further performed by using the look-up table, the non-linear conversion characteristic has the effect of not requiring rotation.

Further, according to the third invention, the conversion characteristic is rotated about a lookup table having a linear conversion characteristic, and the data converted by this lookup table has a non-linear conversion characteristic. Since more than one lookup table is selectively used for further conversion, it is possible to change the gradation of only one of the high density value side and the low density value side by selecting multiple lookup tables. There is an effect that can be done.

Further, according to the fourth invention, the image data and the data indicating the center of the rotational movement of the look-up table are transferred to another image processing apparatus, so that the same can be applied to other image processing apparatuses. This has the effect of displaying a gradation image.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a principle configuration of an apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the principle configuration of the device according to the embodiment of the present invention.

FIG. 3 is a block diagram showing the principle configuration of the device according to the embodiment of the present invention.

FIG. 4 is a configuration block diagram showing an embodiment of the present invention.

FIG. 5 is a configuration block diagram of a part of a timing control unit.

FIG. 6 is a schematic diagram of the configuration of a frame memory.

FIG. 7 is a configuration block diagram of a part of a timing control unit.

FIG. 8 is an operation explanatory diagram of a shift register circuit.

FIG. 9 is a conceptual diagram of gradation processing.

FIG. 10 is a diagram showing an example of a display screen displayed on the display means in a photograph of a halftone image in the embodiment of the present invention.

FIG. 11 is a diagram showing conversion characteristics of a lookup table.

FIG. 12 is a conceptual diagram of gradation processing.

FIG. 13 is a diagram showing conversion characteristics of a lookup table.

FIG. 14 is a diagram showing conversion characteristics of a lookup table.

FIG. 15 is a configuration diagram of transfer data.

FIG. 16 is a configuration block diagram of a radiation image information reading device.

FIG. 17 is a diagram showing conversion characteristics of a lookup table.

[Explanation of symbols]

 100 converting means 110 first converting means 120 second converting means 200 output means 300 moving means 400 transfer means

Claims (5)

[Claims] 1. A conversion means for converting image data using a look-up table, an output means for outputting an image based on output image data of the conversion means, and a conversion of the look-up table of the conversion means. Moving means for rotationally moving the characteristic in the function plane in which it is defined,
An image processing apparatus, comprising: setting means for setting the center of rotational movement of the conversion characteristic of the lookup table by the moving means. 2. The setting means is a pixel density value calculated from pixels of a region of interest in the image output to the output means, a pixel density value at a specified position in the image output to the output means, and a specified pixel density. 2. Any one of the values is set as the center of rotation.
An image processing apparatus according to claim 1. 3. A lookup having a linear conversion characteristic.
First conversion means for converting image data using a table, moving means for moving the conversion characteristics of the lookup table of the first conversion means within a function plane in which it is defined, and non-linear Second conversion means for further converting the image data converted by the first conversion means using a lookup table having a dynamic conversion characteristic, and an image based on the output image data of the second conversion means. An image processing apparatus comprising: an output unit for outputting. 4. A look-up having a linear conversion characteristic.
First conversion means for converting image data using a table, moving means for moving the conversion characteristics of the lookup table of the first conversion means within a function plane in which it is defined, and non-linear Second conversion means for further converting the image data converted by the first conversion means by selectively using a plurality of lookup tables having dynamic conversion characteristics, and output image data of the second conversion means And an output unit that outputs an image based on the image processing apparatus. 5. A conversion means for converting image data using a look-up table, and a moving means for rotationally moving a conversion characteristic of the look-up table of the conversion means within a function plane in which it is defined. An image processing apparatus comprising: a transfer unit configured to transfer the image data and data indicating a center of rotational movement of the conversion characteristic of the lookup table to another image processing apparatus.