JP2002169237A - Method and apparatus for reading radiographic image information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the influence of the irregular moving speed in the sub- scanning direction on reading in the radiograph information reader. SOLUTION: Read is performed in a fixed read time for each read line of a stimulable phosphor sheet 50, the width Hi of the reading line is measured with a magnetic scale 60a and a magnetic detector 60b, and correction by using a correction means 31 is performed for the data which are obtained by reading the reading line according to the width Hi. Alternatively, the moving distance of the sheet 50 is measured with the magnetic scale 60a and the magnetic detector 60b, and the read time Ti of each reading line is controlled by a control means 32a so that the width of each read line of the sheet 50 becomes constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation information reading method and apparatus, and more particularly to a radiation image information reading method and apparatus for reading radiation image information stored in a stimulable phosphor sheet by a line sensor. .

[0002]

2. Description of the Related Art When radiation is irradiated, a part of the radiation energy is accumulated. Then, when irradiation with excitation light such as visible light or laser light is performed, an accumulated light exhibiting stimulated emission according to the accumulated radiation energy is emitted. Phosphor (stimulable phosphor)
The excitation light, such as laser light, is used to temporarily accumulate and record radiation image information of a subject such as a human body on a sheet-like stimulable phosphor sheet in which a stimulable phosphor is laminated on a support. Deflection scanning is performed for each pixel to generate stimulating light sequentially from each pixel, and the stimulating light is photoelectrically sequentially read by a photoelectric reading unit to obtain an image signal, and stored after reading the image signal. Image recording / reproducing system (Computed Radiodra) that irradiates erasing light to the luminescent phosphor sheet and releases radiation energy remaining on this sheet
phy = CR) is widely used in practice.

Further, in order to increase the detection quantum efficiency of radiation image formation, that is, the radiation absorptivity, the photostimulated luminous efficiency, and the extraction efficiency of the photostimulated luminescent light, the conventional photostimulable phosphor has a radiation absorbing function and an energy storage function. To separate
A phosphor with excellent radiation absorption and a phosphor with excellent response of stimulated emission are used for radiation absorption and radiation image information storage, respectively, and the phosphor with excellent radiation absorption (radiation absorbing phosphor) is used. It absorbs radiation and emits light in the ultraviolet or visible region, absorbs this emitted light using the above-mentioned phosphor having excellent responsiveness to stimulated emission (storage-dedicated phosphor), and accumulates its energy to produce a visible light. There has also been proposed a system in which light is excited by light in the infrared region to emit the energy as stimulated emission light, and the stimulated emission light is photoelectrically sequentially read by a photoelectric reading unit to obtain an image signal (Japanese Patent Application No. 2002-110,086). Flat 11-372978
issue).

The image signals obtained by these systems are subjected to image processing such as gradation processing and frequency processing suitable for observation and interpretation, and the image signals after these processings are applied to a diagnostic visible image. (Final image) recorded on film,
Alternatively, it is displayed on a high-definition CRT and used for diagnosis by a doctor or the like. On the other hand, when the stimulable phosphor sheet is irradiated with erasing light to release residual energy, the sheet can again store and record radiation image information, and can be used repeatedly.

Here, in the radiation image information reading apparatus used in the above-mentioned radiation image recording and reproducing system,
As the excitation light source, a line light source that linearly irradiates the sheet with excitation light is used, and as the photoelectric reading unit, the length direction of the linear portion of the sheet irradiated with the excitation light by the line light source (hereinafter, referred to as A line sensor in which a large number of photoelectric conversion elements are arranged along the main scanning direction), and one of the line light source and the line sensor and the phosphor sheet is positioned relative to the other. Japanese Patent Application Laid-Open No. 60-111568 and Japanese Patent Application Laid-Open No. 60-236354 disclose a configuration having a scanning unit that moves in a direction substantially perpendicular to the length direction of the shape of the portion (hereinafter referred to as a sub-scanning direction). , JP-A 1-1015
No. 40).

In these systems, simultaneously with the excitation by the excitation light, the phosphor sheet emits stimulable luminescent light by the excitation of the stimulating light. Charge accumulation starts in the device. The accumulated charges are transferred by the transfer circuit and read out as an image signal of the excited portion. The excited portion is called a reading line, and has a linear shape having a width larger than the beam diameter of the excitation light due to movement in the sub-scanning direction. The time from the start of charge accumulation (excitation start) to the time of reading is the reading time for the read line, and is the same value as the charge accumulation time and excitation time for the read line.

In the above system, since linear excitation and linear reading are realized using a line light source and a line sensor, the reading time of stimulated emission light can be shortened, and the apparatus can be reduced in size and cost. And so on.

[0008]

SUMMARY OF THE INVENTION
In the system, the moving speed in the sub-scanning direction is not necessarily
Because it is not constant, the excitation energy
Energy, charge storage time, etc.
There is a problem that cannot be read. For example, as shown in FIG.
The reading time for each reading line
Also, due to the unevenness of the moving speed in the sub-scanning direction,
Line width is different. In other words, in this case,
The variation in the moving speed in the direction
Reflected by key. Here, the reading line a shown in FIG.
And b, the variation in the width of each read line is
Explain the effect on the issue. In each reading line,
The excitation energy E of the unit area is calculated by the following equation (1).
Done: E_i= P_i× t_i (1) P: Excitation light intensity t: Excitation time per unit area i: Each read line Excitation time t per unit area is read per unit area
It is time and can be calculated by the following formula (2)
Can: t_i= T_i/ S_i= T_i/ (Z_i× H_i(2) T: reading time for each reading line Z: length of the reading line in the main scanning direction H: width of the reading line S: area of the reading line i: each reading line, that is, per unit area for each reading line excitation
Energy E_iIs calculated by the following equation (3).
Becomes: E_i= (P_i× T_i/ Z_i) / H_i (3) Here, the intensity P of the excitation light_i, Reading time T_i, Reading line
Length Z in the main scanning direction _iBut the same for each reading line
Therefore, the excitation per unit area for each read line
Electromotive energy E_iIs the width H of the read line_iAnd inversely proportional
Become a relationship. As the reading lines a and b, the width of the line a
H_aIs the width H of the b line_bLarger than the a line
Energy E per unit area_aBut the b line
Energy E per unit area for_bSmaller
It will be.

If the luminescence amount W of stimulated emission light per unit area of the phosphor sheet is linearly proportional to the excitation energy E per unit area, the emission amount of stimulated emission light of each line is Since it is calculated by the following equation (4), E
a is smaller than Eb, the area Sa, S
b, that is, the width Ha of the read line is offset by an amount larger than Hb. Therefore, even if the width of the reading line a and the width of the reading line b are different, the same amount of light emission Wa and Wb is output.
An accurate reading should be possible.

Wi = α × Ei × Si = α × Zi × (Ei × Hi) (4) α: proportionality coefficient However, the light emission amount W of the photostimulable light emission per unit area of the phosphor sheet is the same unit area. The read line a having a larger width emits more stimulating light than the read line b having a smaller width because the relationship is not shown in FIG. The density of the data obtained by reading the reading line a is greater than the density of the data obtained by reading the reading line b;
Since uneven density occurs in the data of each reading line, accurate data cannot be obtained.

The present invention has been made in view of the above circumstances, and when reading radiation image information using a line light source and a line sensor, each reading line is caused by non-uniformity in the moving speed in the sub-scanning direction. It is an object of the present invention to provide a radiation image information reading method and apparatus for reading out accurate image information by reducing the variation in width and the influence of the variation on reading.

[0012]

According to a first radiographic image information reading method of the present invention, a part of the surface of a stimulable phosphor sheet on which radiographic image information is stored is irradiated with excitation light in a linear manner. The stimulated emission light emitted from the linearly irradiated portion of the stimulable phosphor sheet or the back surface side portion of the stimulable phosphor sheet corresponding to the irradiated portion, the length direction of the irradiated portion A line light source and the line sensor that receive light using a line sensor divided into a plurality of pixel regions to perform photoelectric conversion, and irradiate the excitation light, and one of the phosphor sheets relative to the other. Moving in the direction different from the length direction, sequentially reading the output of the line sensor for each reading line in accordance with the movement, and obtaining the output of each pixel area for each of the moved reading lines. In the line image information reading method, the reading is performed while the reading time for each of the reading lines is kept constant, the width of each of the reading lines is measured, and the larger the width, the smaller the output of the line sensor is corrected. It is characterized by doing.

Here, as the line light source, a fluorescent lamp, a cold cathode fluorescent lamp, an LED array or the like can be applied.
In addition, the line light source is not limited to a light source itself having a linear shape like the above-described fluorescent lamp or the like, and may be a light source in which emitted excitation light is linear, and includes a broad area laser and the like. . The excitation light emitted from the line light source may be one that is continuously emitted, or may be pulsed light that is emitted in a pulse shape that repeats emission and stop, but from the viewpoint of noise reduction, It is desirable to use high-power pulsed light.

Further, the direction in which the line light source and the line sensor are moved relative to the stimulable phosphor sheet (a direction different from the length direction thereof), that is, the sub-scanning direction is defined as the length direction. It is desirable that the direction is substantially orthogonal, that is, the short axis direction.However, the direction is not limited to this direction.For example, a line light source and a line light source can be uniformly irradiated over substantially the entire surface of the sheet. The line sensor may be moved in an oblique direction deviating from a direction substantially perpendicular to the length direction of the line sensor, or may be moved in a zigzag manner with the moving direction changed.

The line light source and the line sensor may be arranged on the same side of the sheet, or may be arranged separately on opposite sides of the sheet. However, if you ’re using a separate configuration,
It is necessary to make the support of the sheet transparent to the stimulating light so that the stimulating light is transmitted to the surface of the sheet opposite to the surface on which the excitation light is incident.

In the first radiographic image information reading method of the present invention, reading is performed for each read line in a fixed reading time. However, as described above, the reading time for each reading line becomes constant. Even with such control, the width of each read line is different as shown in FIG. Further, as shown in FIG. 8, the emission amount W of the stimulable emission light per unit area of the phosphor sheet is the same as the excitation energy E per unit area.
Is not linear and linearly proportional, the reading line having a large width emits more stimulating light than the reading line having a small width, and the density of data obtained by reading the reading line having a large width is equal to the width. Therefore, according to the present invention, the reading of each reading line is performed at a constant reading time, and the width of each reading line is measured. , The correction is made so that the output of the line sensor obtained by reading the read line becomes smaller as the read line becomes larger.

For measuring the width of each read line, it is preferable to use the following method. That is, a scale is provided on any side edge of the phosphor sheet or on a member integrated with the phosphor sheet along a direction in which the edge side extends, and a positional relationship with the line sensor or the line sensor is provided. A pulse signal generator that generates a pulse signal corresponding to the movement distance is provided at a position where the distance is known, and the distance of the movement is measured from the pulse signal generated from the pulse signal generator. Preferably, the width of each of the read lines is obtained.

Here, "edge" means both ends of the phosphor sheet along the sub-scanning direction, and "a member integrated with the phosphor sheet" means a support member of the phosphor sheet. Such as a substrate that does not change its positional relationship with the phosphor sheet.

The "scale" and the "pulse signal generator" operate in pairs to measure the distance of relative movement (sub-scanning) between the phosphor sheet and the line sensor and the line light source. The most commonly used one is a so-called linear scale. When roughly classified according to the measurement method, there are a photoelectric method and a magnetic method.

The photoelectric type is divided into a scale having a light and dark grid (corresponding to the scale of the present invention) and a light source / detection unit (corresponding to the pulse signal generator of the present invention).
The light source / detection unit irradiates the scale with light, and detects a change in the amount of light passing through the scale grid as the scale moves relative to the light source / detection unit.
A pulse signal corresponding to the distance of this relative movement is generated.

On the other hand, the magnetic type has a scale (corresponding to the scale of the present invention) on which magnetic signals having different polarities are recorded, and a magnetic head (the pulse of the present invention) for detecting the magnetic signal and converting it into an electric signal. Signal head), and the magnetic head detects a change in the polarity of the magnetic signal on the scale with the relative movement with the scale, thereby generating a pulse signal corresponding to the distance of the relative movement. appear.

The "scale" and the "pulse signal generator" in the present invention may be any as long as they can measure the relative movement (sub-scanning) distance between the line sensor and the line light source. Either the photoelectric linear scale or the magnetic linear scale may be applied.

Also, since the magnetic resolution or optical pitch on the scale is generally very fine, the scale and the pulse signal generator must be separated by a very small gap to accurately measure the distance of the movement. It is desirable to install them closely.

The description relating to the above-mentioned "scale" and "pulse signal generator" is also applied to a radiation image information reading method and apparatus described later.

Note that the distance moved while reading a read line during the fixed read time is the width of the read line.

In order to simplify the calculation, a method of correcting the output of the line sensor obtained by reading each reading line includes a method of correcting the relationship between the width of each reading line and the correction value for the output of the line sensor. It is preferable to create a conversion table shown below and use the conversion table to correct the output of the line sensor.

Further, in order to obtain the correction effect precisely, the conversion table is stored in the relationship between the amount of stimulated emission from the phosphor sheet and the excitation energy (ie, the relationship shown in FIG. 8).
It is preferable to create based on.

More specifically, using the curve data shown in FIG. 8, correction is performed so as to obtain the same amount of stimulated emission light (W _i × S _i ) regardless of the width of each read line. the value K _i may be obtained as follows.

Firstly, for each reading line with a density as shown in FIG. 7, determines the reading line Z ₀ as a reference. . Regardless of the size of the width, the amount of the stimulated emission light from each read line becomes the reference amount of the stimulated emission light (W ₀ × S ₀ ) according to the following equation. The correction value _Ki is obtained.

K _i = (W ₀ × S ₀ ) / (W _i × S _i ) = (H ₀ / H _i ) × (W ₀ / W _i ) (5) Here, the unit area of each read line is Amount of stimulated emission light W _i
Since it can be determined from the curve shown in FIG. 8, it is possible to obtain a correction value K _i for each read line.

[0031] creates a conversion table showing the relationship between the correction value K _i for the output of the thus the width H _i of each read line the line sensor, by using the conversion table, the width H _i for each reading line Accordingly, the output of each read line is corrected by multiplying the output of the line sensor by Ki.

According to a second radiation image information reading method of the present invention, a part of the surface of the stimulable phosphor sheet in which the radiation image information is stored is irradiated linearly with excitation light, and the stimulable phosphor sheet is irradiated with the excitation light. The stimulated emission light emitted from the linearly irradiated portion or the backside portion of the stimulable phosphor sheet corresponding to the irradiated portion is applied to a plurality of pixel regions in the length direction of the irradiated portion. The photoelectric conversion is performed by receiving light using the divided line sensor, and the line light source and the line sensor for irradiating the excitation light, and one of the phosphor sheets relative to the other, the length direction and A radiation image information reading method for moving in different directions, sequentially reading the output of the line sensor for each reading line according to the movement, and obtaining the output of each pixel area for each of the moved reading lines. The moving distance is measured, and the reading time for each of the reading lines is controlled according to the moving distance so that the width of each of the reading lines is constant.

As a method for measuring the distance of the movement, a scale is provided along one of the side edges of the phosphor sheet or on a member integrated with the phosphor sheet along a direction in which the edge side extends. , At a position where the positional relationship with the line sensor or with the line sensor is known,
It is preferable that a pulse signal generator that generates a pulse signal according to the distance of the movement corresponding to the scale is provided, and the distance of the movement is measured from the pulse signal emitted from the pulse signal generator.

This second method for reading radiation image information
By controlling the reading time for the
As shown in FIG. 9, the width of each reading line is fixed.
Each reading line due to variations in the moving speed in the sub-scanning direction.
Variation in the scanning width can be eliminated, but the sub-scanning speed
The reading line having a large (for example, reading line a)
A scanning line with a relatively low scanning speed (for example, a scanning line)
Reading time T compared to_aIs also shorter, so read
Energy E per unit area in line a _aIs E
_bLess than. On the other hand, the surfaces of the read line a and the read line b
Since the product is the same, the stimulating light emitted from the reading line a
The volume is less for read line b. Therefore, more positive
In order to obtain accurate image data, in the present invention,
As mentioned, the unevenness of the reading time for each reading line
For each read line to reduce the effect of
Preferably, the output of the line sensor is corrected.
In other words, the longer the reading time for each reading line,
Correct the output so as to reduce the output of the line sensor.
Is preferred.

In order to simplify the calculation, a method for correcting the output of the line sensor obtained by reading each read line includes a relation between a read time for each read line and a correction value for the output of the line sensor. It is preferable to create a conversion table indicating the following, and correct the output of the line sensor using the conversion table.

In order to accurately obtain the correction effect, the conversion table is stored in the relationship between the amount of stimulated emission from the phosphor sheet and the excitation energy (ie, the relationship shown in FIG. 8).
It is preferable to create based on. Specifically, FIG.
Using the data of the curve shown in ( ₁ ), regardless of the length of the read time for each read line, the amount of stimulated light emitted from each read line (W ₀ × S ₀ ) is a reference.
So that, according to the following equation, we obtain the correction value G _i to the output of the read line i.

G _i = (W ₀ × S ₀ ) / (W _i × S _i ) = W ₀ / W _i = f (E ₀ ) / f (E _i ) (6) where f () is 9 is a function showing the curve of FIG. Further, since the excitation energy E _i per unit area is as shown in equation (7), from the curve shown in FIG. 8, stimulated emission amount per average area of the read line corresponding to the read time T _i W _i Can be requested.

[0038] _{E i = (P i × T} i) / S i (7) (Pi, Si is the same in each read line) In this way the reading time _{T i} for each reading line of the line sensor create a conversion table showing the relationship between the correction value G _i to the output, by using the conversion table, in response to reading time corresponding T _i to each read line, by multiplying the G _i to the output of the line sensor, The output of each reading line is corrected.

A first radiation image information reading apparatus according to the present invention comprises: a line light source for linearly irradiating a part of the surface of a stimulable phosphor sheet on which radiation image information is stored and recorded with excitation light; Receiving photostimulated light emitted from the linearly irradiated portion of the phosphor sheet or the back side portion of the stimulable phosphor sheet corresponding to the irradiated portion and performing photoelectric conversion, A line sensor divided into a plurality of pixel regions in the length direction of the portion, the line light source and the line sensor, and one of the stimulable phosphor sheets relative to the other; Scanning means for moving in a direction different from the length direction, and sequentially reading the output of the line sensor according to the movement for a certain reading time for each reading line, and A radiation image information reading device that obtains an output of each pixel area, wherein a moving distance sensor that measures the distance of the movement, and a width of each of the reading lines are obtained from the distance of the movement during the fixed reading time, and the reading is performed. A correction means is provided for correcting the output of the line sensor so as to decrease as the line width increases.

The moving distance sensor includes a scale provided along one of the side edges of the phosphor sheet or a member integrated with the phosphor sheet along a direction in which the edge side extends. Alternatively, a pulse signal generator is provided at a position where the positional relationship with the line sensor is known, and generates a pulse signal corresponding to the scale and corresponding to the movement distance.

Since the pulse signal generated from the pulse signal generator of the moving distance sensor is based on the distance of the relative movement between the line sensor and the phosphor sheet, the pulse signal is used to calculate the moving distance from the pulse signal. The distance can be measured. Note that the distance moved while the reading line is being read during the fixed reading time is the width of the reading line.

Further, in order to simplify the calculation, the correction means has a conversion table indicating the relationship between the width of each read line and the correction value for the output of the line sensor. Preferably, the output of the line sensor is corrected.

Further, in order to obtain more accurate read data, the conversion table may be created based on the relationship between the amount of stimulated emission from the phosphor sheet and the excitation energy shown in FIG. preferable.

According to a second radiation image information reading apparatus of the present invention, there is provided a line light source for linearly irradiating excitation light to a part of the surface of a stimulable phosphor sheet on which radiation image information is stored and recorded; Receiving photostimulated light emitted from the linearly irradiated portion of the phosphor sheet or the back side portion of the stimulable phosphor sheet corresponding to the irradiated portion and performing photoelectric conversion, A line sensor divided into a plurality of pixel regions in the length direction of the portion, the line light source and the line sensor, and one of the stimulable phosphor sheets relative to the other; Scanning means for moving in a direction different from the length direction, and sequentially reading the output of the line sensor for each reading line in accordance with the movement, and outputting the pixel area for each of the moved reading lines. A moving distance sensor for measuring the distance of the movement, and a reading time for each of the reading lines according to the distance of the movement such that the width of each of the reading lines is constant. And a reading time control means for controlling.

The same moving distance sensor as that of the first radiation image information reading apparatus described above can be applied.

In order to obtain more accurate read data, the radiation image information reading apparatus of the present invention further comprises a correcting means for correcting the output of the line sensor to be smaller as the reading time for each of the read lines is longer. Preferably, it is provided.

Further, in order to simplify the calculation, the correction means has a conversion table indicating the relationship between the read time for each of the read lines and the correction value for the output of the line sensor. Preferably, the output of the line sensor is corrected.

Further, in order to obtain a precise correction effect, the conversion table may be created based on the relationship between the amount of stimulated emission from the phosphor sheet and the excitation energy shown in FIG. More preferred.

The storage phosphor sheet used in the first radiation image information reading method and apparatus and the second radiation image information reading method and apparatus described above includes a radiation absorbing phosphor and radiation energy. That is, a normal stimulable phosphor sheet which also serves as both a phosphor for accumulating radiation image information may be used. However, it is preferable that the sheet contains a phosphor dedicated to accumulation for the following reasons. That is, as proposed in Japanese Patent Application No. 11-372978, the radiation absorbing function and the energy storage function of the conventional stimulable phosphor are separated, and the phosphor having excellent radiation absorption and the response of the stimulable luminescence are separated. Fluorescent materials with excellent properties are used for radiation absorption and radiation image information storage, respectively, and radiation is absorbed and emitted in the ultraviolet or visible region by using a fluorescent material with excellent radiation absorption (radiation absorbing phosphor). The emitted light is absorbed by using the above-described phosphor having excellent responsiveness to stimulated emission (storage-dedicated phosphor) and its energy is accumulated, and is excited by light in the visible to infrared region to excite the energy. By using a system that emits light as luminescent light and sequentially obtains an image signal by photoelectrically reading the stimulated luminescent light by photoelectric reading means, the detection quantum efficiency of radiation image formation, that is, the radiation absorption rate, the stimulated luminescent efficiency, and the luminescent Exhaustion It is possible to increase such a overall light extraction efficiency.

Here, the storage-dedicated phosphor absorbs light emitted from the radiation-absorbing phosphor in the ultraviolet or visible region and accumulates its energy to produce image information. Since the emitted light in the area is emitted by the radiation absorbing phosphor absorbing the radiation, the image information stored in the storage phosphor sheet is also referred to as radiation image information.

[0051]

According to the first radiographic image information reading method and apparatus of the present invention, each reading line is read at a fixed reading time while the moving distance in the sub-scanning direction is measured, whereby each line is read. The width of the read line is obtained, and the output of the line sensor with respect to the read line is corrected to be smaller as the width of the read line is larger in accordance with the width of the read line. It is possible to reduce the influence of gender on reading. If a table showing the relationship between the width of the read line and the correction value is prepared in advance at the time of correction, the calculation for correction is simplified, and the efficiency of the entire reading is improved. Further, if the conversion table for correction is created based on the relationship between the amount of stimulated emission from the phosphor sheet and the excitation energy shown in FIG. 8, a more precise correction effect can be obtained, and as a result, Can obtain a high-quality image.

The second radiographic image information reading method and apparatus of the present invention measures the moving distance in the sub-scanning direction and controls the reading time for each reading line according to the moving distance. Variations in the width of each read line due to variations in the moving speed in the direction can be eliminated, that is, the width of each read line can be made constant. In addition, in order to obtain accurate read data, it is possible to perform correction in accordance with the read time for each read line so that the longer the read time of the read line, the smaller the output of the line sensor for the read line. Therefore, the influence on the reading due to the non-uniformity of the moving speed in the sub-scanning direction can be reduced. If a table indicating the relationship between the reading time for the reading line and the correction value is prepared in advance when performing the correction, the calculation for the correction is simplified, and the efficiency of the entire reading is improved. Further, the conversion table for correction,
If it is created based on the relationship between the amount of stimulated emission from the phosphor sheet and the excitation energy shown in FIG. 8, a more precise correction effect can be obtained, and as a result, a high-quality image can be obtained. Becomes

Furthermore, if the above-mentioned phosphor sheet dedicated to storage is used as the stimulable phosphor sheet to be read by the radiation image information reading method and apparatus of the present invention, the detection quantum efficiency of radiation image formation can be increased. Therefore, the quality of the image can be further improved.

[0054]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a radiation image information reading method and apparatus according to the present invention.

FIG. 1 is a perspective view showing a radiation image information reading apparatus according to a first embodiment of the present invention, and FIG. 2 is a sectional view showing a cross section taken along line II of the radiation image information reading apparatus shown in FIG. .

The illustrated radiation image information reading apparatus has a stimulable phosphor sheet (hereinafter, referred to as a phosphor sheet) on which radiation image information is stored and recorded.
A scanning belt 40 on which a sheet 50 is placed and conveyed in the direction of the arrow Y, a broad area laser (hereinafter, simply referred to as excitation light) L that emits linear secondary excitation light (hereinafter, simply referred to as excitation light) L substantially parallel to the surface of the sheet 50. An optical system 12 comprising a combination of a collimator lens for condensing the linear excitation light L emitted from the BLD 11 and a toric lens for expanding the beam only in one direction, an angle of 45 degrees with respect to the surface of the sheet 50 The stimulated emission light M, which reflects the excitation light L and is
Dichroic mirror 14, which is set to transmit light
The linear excitation light L reflected by the dichroic mirror 14 is condensed on the sheet 50 in a linear shape extending along the arrow X direction, and the linear excitation light L is condensed on the sheet 50.
A gradient index lens array (a lens in which a large number of gradient index lenses are arranged, and a plurality of gradient index lenses are arranged in the form of a parallel luminous flux of stimulating luminescence light M according to accumulated and recorded radiation image information emitted from A first selfoc lens array 15) and the first selfoc lens array 15
A second selfoc lens array 16 for condensing the photostimulated light M transmitted through the dichroic mirror 14 on a line sensor 20 described later, and a photostimulator transmitted through the second selfoc lens array 16 The excitation light L, which is slightly mixed with the emission light M, is cut off the excitation light L reflected on the surface of the sheet 50, and the excitation light cut filter 17, which transmits the excitation light M, and the stimulated emission light M transmitted through the excitation light cut filter 17, A line sensor 20 for receiving and photoelectrically converting light, and a correction unit for performing correction processing on data obtained by reading each reading line
And an image information reading means 30 for outputting the data corrected by the correcting means 31 to the image processing apparatus in a manner corresponding to the portion of the sheet 50.

At one edge of the sheet 50, a magnetic scale 60
a is provided, and a magnetic detector 60b installed near the line sensor 20 with a small gap between the magnetic scale 60a detects a change in the magnetic signal of the scale 60a.

The first selfoc lens array 15 has an effect on the dichroic mirror 14 of setting an emission area of the stimulating emission light M on the sheet 50 as an image plane for forming an image with a one-to-one size. The second selfoc lens array 16 has a dichroic mirror 14 on the light receiving surface of the line sensor.
The image of the photostimulated luminescence light M above is formed into an image plane on which the image is formed in a one-to-one size.

The optical system 12 composed of a collimator lens and a toric lens expands the excitation light L from the BLD 11 onto a dichroic quick mirror 14 to a desired irradiation area.

Next, the operation of the radiation image information reading apparatus of this embodiment will be described.

First, as the scanning belt 40 moves in the direction of the arrow Y, the sheet 50 on which the radiation image information is accumulated and recorded is conveyed in the direction of the arrow Y. At the same time as the sheet 50 moves in the arrow Y direction, the scale 60a also moves. The magnetic detector 60b detects a change in the polarity of the magnetic signal on the scale 60a, and outputs a pulse signal according to the movement of the sheet 50 and the scale 60a,
The moving distance of the sheet in the Y direction is obtained from the pulse signal, and this distance is output to the image information reading means 30 and the correcting means 31.

On the other hand, the BLD 11 emits the linear excitation light L substantially parallel to the surface of the sheet 50, and the excitation light L is transmitted through an optical system including a collimator lens and a toric lens provided on the optical path. 12, a parallel beam is reflected by the dichroic mirror 14, travels in a direction perpendicular to the surface of the sheet 50, and is extended by the first selfoc lens 15 onto the sheet 50 along the arrow X direction. It is condensed in a shape. In addition, the control is performed so that the excitation time by the excitation light L is equal for each reading line.

The excitation of the linear excitation light L incident on the sheet 50 causes the stimulated emission light M having an intensity according to the accumulated and recorded radiation image information to be emitted from the condensing area of the sheet 50 and its vicinity. You. The stimulated emission light M is converted into a parallel light beam by the first selfoc lens 15, passes through the dichroic mirror 14, and is condensed on each pixel area of the line sensor 20 by the second selfoc lens array 16. . At this time, the excitation light L slightly reflected on the stimulated emission light M transmitted through the second selfoc lens array 16 and reflected on the surface of the sheet 50 is cut by the excitation light cut filter 17.

In the present embodiment, the optical system between the sheet 50 and the line sensor 20 is set to a 1: 1 imaging system for the sake of simplicity, but it is a matter of course that an enlargement / reduction optical system may be used. . However, from the viewpoint of increasing the light-collecting efficiency, it is preferable to use the same-size or magnifying optical system.

The line sensor 20 receives the stimulated emission light from the sheet 50, performs photoelectric conversion, and outputs read data for each read line to the correction means 31. Since the line sensor 20 performs reading in synchronization with the excitation by the excitation light L, the reading time for each reading line is the same.

[0066] correction means 31, because it is informed the moving distance of the sheet 50 from the magnetic detector 60b, the moving distance in time doing the reading for each read line, the width H _i of the corresponding read line Ask. Further, the correction means 31
When the reading time is fixed for each reading line,
Pre created based on the curve shown in FIG. 8, be one having a conversion table in correspondence with the width H _i of each read line and a correction value K _i, when receiving the read data from the line sensor 20, A correction value K _i is determined from the conversion table based on the width H _i of the corresponding read line, and corrected data obtained by multiplying the read data from the line sensor 20 by the correction value K _i is transmitted to the image information reading means 30. Output. The image information reading means 30 displays the corrected data of each read line on a sheet 50.
And output to the image processing apparatus later.

As described above, according to the radiation image information reading apparatus of the present embodiment, the moving distance in the sub-scanning direction is measured while reading each reading line for a fixed reading time, The width of each read line is determined, and according to the width of the read line, the larger the width of the read line,
Since the output of the line sensor for the read line is corrected to be small, the influence on the reading due to the non-uniformity of the moving speed in the sub-scanning direction can be reduced. Also,
When correcting, a table showing the relationship between the width of the read line and the correction value is prepared in advance based on the relationship between the amount of stimulated emission from the phosphor sheet and the excitation energy, enabling accurate correction In addition, the calculation for correction is simplified, and the efficiency of the entire reading is improved.

FIG. 3 is a perspective view showing a radiation image information reading apparatus according to a second embodiment of the present invention, and FIG. 4 is a cross-sectional view showing a cross section taken along line II of the radiation image information reading apparatus shown in FIG. .

The illustrated radiographic image information reading apparatus includes a scanning belt 40 on which a stimulable phosphor sheet 50 on which radiographic image information is stored and conveyed is placed in a direction indicated by an arrow Y, and a linear secondary excitation light (hereinafter referred to as a secondary excitation light). A broad area laser (hereinafter, referred to as BLD) 11, which emits the excitation light L substantially in parallel to the surface of the sheet 50, a collimator lens for condensing the linear excitation light L emitted from the BLD 11, and a beam only in one direction. 12, optical system consisting of a combination of toric lenses
A dichroic mirror 14 disposed at an angle of 45 degrees with respect to the surface 50 and set to reflect the excitation light L and transmit a stimulating light M described later, and a linear mirror reflected by the dichroic mirror 14. The excitation light L is applied to the sheet 50 by an arrow X
While the light is condensed in a linear shape extending along the direction, the stimulated emission light M according to the accumulated and recorded radiation image information emitted from the sheet 50 by condensing the linear excitation light L is converted into a parallel light flux. A gradient index lens array (a lens in which a number of gradient index lenses are arranged, hereinafter, referred to as a first Selfoc lens array) 15 and a parallel light flux formed by the first Selfoc lens array 15 Then, the stimulated emission light M transmitted through the dichroic mirror 14 is slightly condensed by the second selfoc lens array 16 for condensing the light on the line sensor 20 and the stimulated emission light M transmitted through the second selfoc lens array 16. An excitation light cut filter 17 that cuts the excitation light L reflected on the surface of the sheet 50 and transmits the stimulated emission light M, and receives and emits the stimulated emission light M transmitted through the excitation light cut filter 17. A line sensor 20 for conversion, a control unit 32a for controlling a read time for each read line, and a correction unit 32b for performing a correction process on data obtained by reading each read line within the read time; Is provided with image information reading means 30 for outputting the data corrected by the above to the image processing apparatus in correspondence with the portion of the sheet 50.

A magnetic scale 60 is attached to one edge of the sheet 50.
a is provided, and a magnetic detector 60b installed near the line sensor 20 with a small gap between the magnetic scale 60a detects a change in the magnetic signal of the scale 60a.

The first selfoc lens array 15 has the function of forming, on the dichroic mirror 14, the light emission area of the photostimulated light M on the sheet 50 as an image plane for forming an image with a one-to-one size. The second selfoc lens array 16 has a dichroic mirror 14 on the light receiving surface of the line sensor.
The image of the photostimulated luminescence light M above is formed into an image plane on which the image is formed in a one-to-one size.

The optical system 12 composed of a collimator lens and a toric lens expands the excitation light L from the BLD 11 onto a dichroic quick mirror 14 to a desired irradiation area.

Next, the operation of the radiation image information reading apparatus of this embodiment will be described.

First, by moving the scanning belt 40 in the direction of the arrow Y, the sheet 50 on which the radiation image information is stored and conveyed is conveyed in the direction of the arrow Y. At the same time as the sheet 50 moves in the arrow Y direction, the scale 60a also moves. The magnetic detector 60b detects a change in the polarity of the magnetic signal on the scale 60a, and outputs a pulse signal according to the movement of the sheet 50 and the scale 60a,
The moving distance of the sheet in the Y direction is obtained from the pulse signal, and the distance is determined by the image information reading means 30 and the control means 32a.
Output to

On the other hand, the BLD 11 emits the linear excitation light L substantially in parallel with the surface of the sheet 50 for a reading time T _i (excitation time) determined by the control means 32a to be described later. L is converted into a parallel beam by an optical system 12 including a collimator lens and a toric lens provided on the optical path, is reflected by the dichroic mirror 14, and travels in a direction perpendicular to the surface of the sheet 50. Arrow X on the sheet 50 by the selfoc lens 15
Light is collected in a linear shape extending along the direction.

The excitation of the linear excitation light L incident on the sheet 50 causes the stimulated emission light M having an intensity in accordance with the accumulated and recorded radiation image information to be emitted from the condensing area of the sheet 50 and its vicinity. You. The stimulated emission light M is converted into a parallel light beam by the first selfoc lens 15, passes through the dichroic mirror 14, and is condensed on each pixel area of the line sensor 20 by the second selfoc lens array 16. . At this time, the excitation light L slightly reflected on the stimulated emission light M transmitted through the second selfoc lens array 16 and reflected on the surface of the sheet 50 is cut by the excitation light cut filter 17.

In the present embodiment, the optical system between the sheet 50 and the line sensor 20 is set to a 1: 1 imaging system for the sake of simplicity, but it is a matter of course that an enlargement / reduction optical system may be used. . However, from the viewpoint of increasing the light-collecting efficiency, it is preferable to use the same-size or magnifying optical system.

The line sensor 20 emits light from the sheet 50.
Receives light, performs photoelectric conversion, and
The read data is output to the correction means 32b. In addition, line
The reading of each reading line by the sensor 20 is performed by the excitation light L.
The line sensor 20 is controlled synchronously with the excitation
Reading time T for each reading line determined by the means 32a _i
To read each read line.

[0079] On the other hand, the control unit 32a is equal width H _i of each read line (e.g., H ₀₎ so as to, and controls the reading time T _i for each read line. Control means 32a is be notified to the moving distance of the sheet 50 from the magnetic detector 60b, while performing the reading for a reading line, when the moving distance of the sheet 50 becomes H _0, reading stop instruction To stop the reading by the line sensor 20 and the excitation by the excitation light L. At the same time, the time T _{i at} which reading was performed on the reading line is output to the correction means 32b.

On the other hand, when the width of each read line is constant, the correction means 32b calculates the read time T _i and the correction value G _i for each read line, which are created in advance based on the curve shown in FIG. be one having a conversion table showing the correspondence, when receiving the read data from the line sensor 20, based on the read time of the corresponding read line T _i, determines a correction value G _i from the conversion table, the line sensor 20 the corrected data obtained by multiplying the correction value G _i to read data from and outputs to the image information reading means 30. The image information reading means 30
The corrected data of each read line is output to the image processing device later, with the portion of the sheet 50 corresponding.

As described above, according to the radiation image information reading apparatus of the present embodiment, the moving distance in the sub-scanning direction is measured, and the reading time for each reading line is controlled according to the moving distance. Therefore, it is possible to eliminate the variation in the width of each reading line due to the variation in the moving speed in the sub-scanning direction, that is, to make the width of each reading line constant. Further, based on the relationship between the amount of stimulated light emission from the phosphor sheet and the excitation energy, a table indicating the relationship between the reading time for each reading line and the correction value is prepared in advance. The longer the read time of the read line, the smaller the output of the line sensor for the read line is, so that the unevenness of the read data density due to the uneven moving speed in the sub-scanning direction is eliminated, and the accurate Not only to obtain accurate image data, but also to simplify calculation for correction,
The efficiency of the entire reading is good.

The present invention is not limited to the above-described embodiments, but includes various known structures such as a light source, a condensing optical system between the light source and the sheet, an optical system between the sheet and the line sensor, and a line sensor. Can be adopted. In addition, the image processing apparatus further includes an image processing device that performs various signal processing on signals output from the image information reading unit, and an erasing unit that appropriately emits radiation energy still remaining on the sheet whose excitation has been completed. An equipped configuration can also be adopted.

Further, in the above-described embodiment, a configuration is adopted in which the optical path of the excitation light L and the optical path of the stimulating light M are partially overlapped to further reduce the size of the device. However, the present invention is not limited to such a configuration. For example, as shown in FIG. 5, the optical path of the excitation light L and the optical path of the stimulated emission light M do not overlap at all, and
Alternatively, a configuration to which the second embodiment is applied can be applied.

That is, the radiation image information reading apparatus shown in FIG. 5 has a scanning belt 40, a BLD 11 that emits linear excitation light L at an angle of approximately 45 degrees with respect to the surface of the sheet 50, and a linear excitation light emitted from the BLD 11. An optical system 12 for irradiating a linear excitation light L on the surface of the sheet 50, comprising a combination of a collimator lens for condensing the light L and a toric lens for expanding the beam in only one direction, approximately 45 degrees with respect to the surface of the sheet 50 And has an optical axis substantially perpendicular to the advancing direction of the excitation light L,
Lens array 1 for condensing the photostimulated light M emitted from the sheet 50 by the irradiation of light onto the line sensor 20
6. Excitation light cut filter 17 for cutting excitation light L mixed with stimulable emission light M incident on selfoc lens array 16, stimulable emission light M transmitted through excitation light cut filter 17.
And a line sensor 20 that receives and photoelectrically converts the received light, and an image information reading unit 30.

A magnetic scale 60 is provided on one edge of the sheet 50.
a is provided, and a magnetic detector 60b installed near the line sensor 20 with a small gap between the magnetic scale 60a detects a change in the magnetic signal of the scale 60a.

The SELFOC lens array 16 functions to set the light emitting area of the photostimulated light M on the sheet 50 on the light receiving surface of the line sensor 20 as an image plane for forming an image with a one-to-one size.

The optical system 12 including a collimator lens and a toric lens transmits the excitation light L from the BLD 11 to the sheet 5.
Expand to the desired irradiation area above zero.

When the first embodiment described above is applied to the configuration shown in FIG. 5, the image information reading means 30 includes a correcting means 31 for performing a correction process on data obtained by reading each reading line. The data corrected by the correction means 31 is output to the image processing apparatus later, with the data corresponding to the part of the sheet 50.

Next, the operation of the radiation image information reading apparatus when the first embodiment is applied to the configuration shown in FIG. 5 will be described.

First, as the scanning belt 40 moves in the direction of the arrow Y, the sheet 50 on which the radiation image information is stored and conveyed is conveyed in the direction of the arrow Y. At the same time as the sheet 50 moves in the arrow Y direction, the scale 60a also moves. The magnetic detector 60b detects a change in the polarity of the magnetic signal on the scale 60a, and outputs a pulse signal according to the movement of the sheet 50 and the scale 60a,
The moving distance of the sheet in the Y direction is obtained from the pulse signal, and this distance is output to the image information reading means 30 and the correcting means 31.

On the other hand, the BLD 11 emits the linear excitation light L in a direction inclined at an angle of approximately 45 degrees with respect to the surface of the sheet 50, and the excitation light L is supplied to a collimator lens provided on the optical path. The light is converted into a parallel beam by the optical system 12 composed of a toric lens, and is incident on the sheet 50 at an angle of approximately 45 degrees with respect to the surface of the sheet 50. At this time, the excitation light L irradiates a linear region extending along the arrow X direction on the surface of the sheet 50. In addition, the control is performed so that the excitation time by the excitation light L is equal for each reading line.

The excitation of the linear excitation light L incident on the sheet 50 causes the stimulated emission light M of an intensity corresponding to the accumulated and recorded radiation image information to be emitted from the irradiated area of the sheet 50 and its vicinity. Is done. The stimulated emission light M passes through the excitation light cut filter 17, cuts the mixed excitation light L, enters the selfoc lens 16, and is condensed on the light receiving surface of the line sensor 20.

The operation after receiving light by the line sensor 20, the measurement of the width of each read line by the moving distance sensor (the magnetic scale 60a and the magnetic detector 60b), and the correction to the read data for each read line by the correction means 31 are as follows. Since the operation is the same as that of the radiation image information reading apparatus of the first embodiment described above, the description thereof is omitted.

As described above, even if the radiation image information reading apparatus of the present embodiment is configured, the reading distance is measured in the sub-scanning direction while reading each reading line at a constant reading time. The width of the read line is obtained, and the output of the line sensor with respect to the read line is corrected to be smaller as the width of the read line is larger in accordance with the width of the read line. It is possible to reduce the influence of gender on reading. In addition, when performing the correction, a table indicating the relationship between the width of the read line and the correction value is prepared in advance based on the relationship between the amount of stimulated light emission from the phosphor sheet and the excitation energy. And the calculation for the correction is simplified, and the efficiency of the entire reading is good.

When the above-described second embodiment is applied to the configuration shown in FIG. 5, the image information reading means 30 includes a control means 32a for controlling a reading time for each reading line and a reading time within the reading time. It has a correction means 32b for performing a correction process on data obtained by reading each reading line, and outputs the data corrected by the correction means 32b to the image processing device later by associating the data with the part of the sheet 50. is there.

Next, the operation of the radiation image information reading apparatus when the second embodiment is applied to the configuration shown in FIG. 5 will be described.

First, as the scanning belt 40 moves in the direction of the arrow Y, the sheet 50 on which the radiation image information is stored and conveyed is conveyed in the direction of the arrow Y. At the same time as the sheet 50 moves in the arrow Y direction, the scale 60a also moves. The magnetic detector 60b detects a change in the polarity of the magnetic signal on the scale 60a, and outputs a pulse signal according to the movement of the sheet 50 and the scale 60a,
The moving distance of the sheet in the Y direction is obtained from the pulse signal, and the distance is determined by the image information reading means 30 and the control means 32a.
Output to

On the other hand, the BLD 11 applies the linear excitation light L to the surface of the sheet 50 at approximately 45 ° with respect to the reading time T _i (excitation time) determined by the control means 32a. The excitation light L is converted into a parallel beam by an optical system 12 including a collimator lens and a toric lens provided on the optical path, and is approximately 45 degrees with respect to the surface of the sheet 50. And enters the sheet 50. At this time, the excitation light L irradiates a linear region extending along the arrow X direction on the surface of the sheet 50.

The excitation of the linear excitation light L incident on the sheet 50 causes the stimulated emission light M having an intensity corresponding to the accumulated and recorded radiation image information to be emitted from the irradiated area of the sheet 50 and its vicinity. Is done. The stimulated emission light M passes through the excitation light cut filter 17, cuts the mixed excitation light L, enters the selfoc lens 16, and is condensed on the light receiving surface of the line sensor 20.

The operation after the light reception by the line sensor 20, the control of the reading time of the line sensor 20 by the control means 32a, and the correction to the read data for each read line by the correction means 32b are described in the second embodiment. Since the operation is the same as that of the radiation image information reading apparatus, the description is omitted.

In this way, even in the radiation image information reading apparatus in which the second embodiment is applied to the configuration shown in FIG. 5 as in this example, the moving distance in the sub-scanning direction is measured, and Accordingly, since the reading time for each reading line is controlled, it is necessary to eliminate the variation in the width of each reading line caused by the variation in the moving speed in the sub-scanning direction, that is, to make the width of each reading line constant. Can be possible. Also,
A table showing the relationship between the read time for each read line and the correction value is prepared in advance based on the relationship between the amount of stimulated light emission from the phosphor sheet and the excitation energy, and the table is read in accordance with the read time for each read line. As the line reading time is longer, the output of the line sensor for the read line is corrected so as to be smaller, so that the unevenness of the read data density due to the uneven moving speed in the sub-scanning direction is eliminated, and an accurate image is obtained by precise correction. The data can be obtained, the calculation for correction is simplified, and the efficiency of the entire reading is good.

In the radiation image information reading apparatus of each of the above embodiments, both the light source of the excitation light and the line sensor are arranged on the same side of the sheet, and the stimulated emission light emitted from the sheet surface on which the excitation light is incident. The radiation image information reading apparatus of the present invention is not limited to such a configuration, and the support is made of a material capable of transmitting photostimulated light. By using the stimulable phosphor sheet formed as described above, the light source of the excitation light and the line sensor are arranged on different sides of the sheet as shown in FIG. It is also possible to adopt a configuration of a transmitted light condensing type configured to receive stimulated emission light emitted from the side surface.

That is, the radiation image information reading apparatus shown in FIG. 6 uses the stimulable phosphor sheet 50 at the front end and the rear end (whether a radiation image is not recorded at the front end and the rear end or is not recorded). Transport belt 40 'for supporting the sheet in the direction of arrow Y while supporting the sheet, and BLD11 and BLD11 for emitting linear excitation light L in a direction substantially perpendicular to the surface of the sheet 50. A combination of a collimator lens for condensing the linear excitation light L emitted from the lens and a toric lens for expanding the beam only in one direction,
An optical system 12 for irradiating the surface of the sheet 50 with the linear excitation light L, having an optical axis substantially orthogonal to the surface of the sheet 50, and irradiating the excitation light L with the back surface of the sheet 50 (with respect to the incident surface of the excitation light L Photostimulated light M 'emitted from the opposite side
A selfoc lens array 16 condensed at 20, an excitation light cut filter 17 for cutting excitation light L mixed with the stimulated emission light M 'incident on the selfoc lens array 16, a photostimulant transmitted through the excitation light cut filter 17. The apparatus includes a line sensor 20 that receives the emitted light M ′ and performs photoelectric conversion, and an image information reading unit 30.

The selfoc lens array 16 has a function of making the light emitting area of the stimulated emission light M 'on the back surface of the sheet 50 into an image plane for forming an image with a one-to-one size on the light receiving surface of the line sensor 20. . The optical system 12 including a collimator lens and a toric lens transmits the excitation light L from the BLD 11 to a sheet 50.
Expand above to the desired irradiation area.

When the above-described first embodiment is applied to the configuration shown in FIG. 6, the image information reading means 30 performs correction processing on data obtained by reading each reading line. And outputs the data corrected by the correction means 31 to the image processing device later, while associating the parts of the sheet 50 with each other.

Next, the operation of the radiation image information reading apparatus in which the above-described first embodiment is applied to the configuration shown in FIG. 6 will be described.

First, as the transport belt 40 'moves in the direction of the arrow Y, the sheet 50 on which the radiation image information is stored and supported by the transport belt 40' is transported in the direction of the arrow Y. At the same time as the sheet 50 moves in the arrow Y direction,
The scale 60a also moves at the same time. The magnetic detector 60b detects a change in the polarity of the magnetic signal on the scale 60a, and
And a pulse signal corresponding to the movement of the scale 60a, and the moving distance of the sheet in the Y direction is obtained from the pulse signal, and this distance is used as the image information reading means 30 and the correcting means 31.
Output to

On the other hand, the BLD 11 emits the linear excitation light L in a direction substantially orthogonal to the surface of the sheet 50, and the excitation light L is composed of a collimator lens and a toric lens provided on the optical path. The light is converted into a parallel beam by the optical system 12 and is incident on the sheet 50 substantially perpendicularly. At this time, the excitation light L
Irradiates a linear region extending along the arrow X direction on the surface of the sheet 50.

The irradiation of the linear excitation light L incident on the sheet 50 emits photostimulated light M having an intensity corresponding to the accumulated and recorded radiation image information from the irradiation area of the sheet 50 and its vicinity. . At the same time, the stimulated emission light M ′ that has passed through the transparent support of the sheet 50 is emitted also from the back side of the sheet 50. In addition, the control is performed so that the excitation time by the excitation light L is equal for each reading line.

The stimulated emission light M ′ emitted from the portion on the back side of the sheet 50 passes through the excitation light cut filter 17 and
After being cut off, the mixed excitation light L enters the selfoc lens 16 and is collected on the light receiving surface of the line sensor 20.

The operation after the light reception by the line sensor 20, the measurement of the width of each read line by the moving distance sensor (the magnetic scale 60a and the magnetic detector 60b), and the correction to the read data for each read line by the correction means 31 are as follows. Since the operation is the same as that of the radiation image information reading apparatus of the first embodiment described above, the description thereof is omitted.

As described above, even if the radiation image information reading apparatus of the present embodiment is configured, the reading distance is measured in the sub-scanning direction while reading each reading line for a fixed reading time. The width of the read line is obtained, and the output of the line sensor with respect to the read line is corrected to be smaller as the width of the read line is larger in accordance with the width of the read line. It is possible to reduce the influence of gender on reading. In addition, when performing the correction, a table indicating the relationship between the width of the read line and the correction value is prepared in advance based on the relationship between the amount of stimulated light emission from the phosphor sheet and the excitation energy. And the calculation for the correction is simplified, and the efficiency of the entire reading is good.

When the above-described second embodiment is applied to the configuration shown in FIG. 6, the image information reading means 30 includes a control means 32a for controlling a reading time for each reading line and a reading time within the reading time. It has a correction means 32b for performing a correction process on data obtained by reading each reading line, and outputs the data corrected by the correction means 32b to the image processing device later by associating the data with the part of the sheet 50. is there.

Next, the operation of the radiation image information reading apparatus in which the above-described second embodiment is applied to the configuration shown in FIG. 6 will be described.

First, as the transport belt 40 'moves in the direction of the arrow Y, the sheet 50 on which the radiation image information is stored and supported by the transport belt 40' is transported in the direction of the arrow Y. At the same time as the sheet 50 moves in the arrow Y direction,
The scale 60a also moves at the same time. The magnetic detector 60b detects a change in the polarity of the magnetic signal on the scale 60a, and
And a pulse signal corresponding to the movement of the scale 60a, and the moving distance of the sheet in the Y direction is obtained from the pulse signal, and this distance is used as the image information reading means 30 and the control means 32.
Output to a.

On the other hand, the BLD 11 makes the linear excitation light L substantially orthogonal to the surface of the sheet 50 for the reading time T _i (excitation time) determined by the control means 32a. The excitation light L is directed to an optical system including a collimator lens and a toric lens provided on the optical path.
The beam is made into a parallel beam by 12 and is incident on the sheet 50 substantially perpendicularly. At this time, the excitation light L irradiates a linear region extending along the arrow X direction on the surface of the sheet 50.

The irradiation of the sheet 50 with the linear excitation light L causes the stimulated emission light M having an intensity corresponding to the accumulated and recorded radiation image information to be emitted from the irradiation area of the sheet 50 and its vicinity. . At the same time, the stimulated emission light M ′ that has passed through the transparent support of the sheet 50 is emitted also from the back side of the sheet 50.

The stimulated emission light M ′ emitted from the back side of the sheet 50 passes through the excitation light cut filter 17 and
After being cut off, the mixed excitation light L enters the selfoc lens 16 and is collected on the light receiving surface of the line sensor 20.

In this way, even in the radiation image information reading apparatus in which the second embodiment is applied to the configuration shown in FIG. 6 as in this example, the moving distance in the sub-scanning direction is measured, and the moving distance is measured. Accordingly, since the reading time for each reading line is controlled, it is necessary to eliminate the variation in the width of each reading line caused by the variation in the moving speed in the sub-scanning direction, that is, to make the width of each reading line constant. Can be possible. Also,
A table showing the relationship between the read time for each read line and the correction value is prepared in advance based on the relationship between the amount of stimulated light emission from the phosphor sheet and the excitation energy, and the table is read in accordance with the read time for each read line. As the line reading time is longer, the output of the line sensor for the read line is corrected so as to be smaller, so that the unevenness of the read data density due to the uneven moving speed in the sub-scanning direction is eliminated, and an accurate image is obtained by precise correction. The data can be obtained, the calculation for correction is simplified, and the efficiency of the entire reading is good.

In all of the above-described radiographic image information reading apparatuses, the magnetic detector 60b is installed near the line sensor 20, but in order to receive pulse signals from the magnetic scale 60a well, the scale 60a is used. Any position may be used as long as the position is close to the line sensor with a minute gap and the position relationship with the line sensor is known.

In all the above-described radiographic image information reading apparatuses, a magnetic moving distance sensor (magnetic scale 60a and magnetic detector 60b) is used as an example of a moving distance sensor. A device capable of measuring a relative moving distance with respect to, for example, an optical moving distance sensor or the like may be used.

Further, the sheet used in the radiation image information reading apparatus of each of the above-mentioned embodiments is an ordinary sheet which is used both as a phosphor for absorbing radiation and a phosphor for storing radiation energy, ie, radiation image information. Although a stimulable phosphor sheet may be used, as described above, the use of a sheet containing a phosphor dedicated to storage can further improve the image quality.

In the above-described radiographic image information reading apparatus, the magnetic scale 60a is provided on the edge side of the sheet 50. May be provided along the edge side direction.

Further, as a sheet used in the above-described radiation image information reading apparatus, two image information items of the same subject having different radiation energy absorption characteristics are stored and recorded. A stimulable luminescent light can be separately emitted from its front and back surfaces, and a stimulable phosphor sheet for radiation energy subtraction is used, and line sensors are separately arranged on both sides of the sheet, respectively. The image information read from both sides may be a device provided with a reading unit that performs a subtraction process by making the pixels on the front and back surfaces of the sheet correspond to each other. In this case, the radiation image information reading method and device according to the present invention are also provided. Can be applied.

Also, as a stimulable phosphor sheet for radiation energy subtraction, for example, a so-called sheet having a structure subdivided into a large number of microcells by an excitation light reflecting partition member extending in the thickness direction of the sheet is used. An anisotropic sheet can also be used.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a radiation image information reading apparatus according to a first embodiment of the present invention;

FIG. 2 is a sectional view of the radiation image information reading apparatus shown in FIG.
Sectional view showing a line section

FIG. 3 is a schematic diagram illustrating a radiation image information reading apparatus according to a second embodiment of the present invention;

FIG. 4 is a sectional view of the radiation image information reading apparatus shown in FIG.
Sectional view showing a line section

FIG. 5 is a diagram for explaining the configuration of another radiation image information reading apparatus to which the first and second embodiments of the present invention are applied;

FIG. 6 is a diagram for explaining the configuration of another radiation image information reading apparatus to which the first and second embodiments of the present invention are applied;

FIG. 7 is a diagram for explaining the influence of uneven moving speed in the sub-scanning direction.

FIG. 8 is a diagram showing the relationship between the amount of stimulated emission light per unit area of the phosphor sheet and the excitation energy per unit area.

FIG. 9 is a view for explaining reading with a fixed width of each reading line.

[Explanation of symbols]

11 Broad-area laser (BLD) 12 Optical system consisting of collimator lens and toric lens 14 Dichroic mirror 15, 16 Selfox lens array 17 Excitation light cut filter 20 Line sensor 30 Image information reading means 31 Correction means 32a Control means 32b Correction means 40 scanning belt 50 stimulable phosphor sheet 60a magnetic scale 60b magnetic detector H read line width L excitation light M stimulated light K _{i, G i} correction value P excitation light intensity S reading line area T reading time S reading line of E Emission amount of stimulated emission light per unit area W Excitation energy per unit area Z Length of read line in main scanning direction

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G083 AA03 BB04 BB05 CC09 CC10 DD11 DD15 DD16 DD18 EE02 2H013 AC04 AC05 5B047 AA17 AB02 BA01 BB02 CA23 CB07 DA06 5C072 AA01 CA06 FB09 NA01 UA05 VA01

Claims (22)

[Claims] 1. A part of the surface of a stimulable phosphor sheet on which radiation image information is stored is linearly irradiated with excitation light, and the stimulable phosphor sheet is irradiated with the linearly irradiated part or the irradiated part. The stimulated emission light emitted from the back surface side portion of the stimulable phosphor sheet corresponding to the irradiated portion is received by using a line sensor divided into a plurality of pixel regions in the length direction of the irradiated portion. Performs photoelectric conversion, and a line light source and the line sensor that irradiate the excitation light, and one of the phosphor sheets is moved relative to the other in a direction different from the length direction, and the phosphor sheet is moved for each reading line. In the radiation image information reading method of sequentially reading the output of the line sensor in accordance with the movement and obtaining the output of each of the pixel regions for each of the moved read lines, the reading of each of the read lines is performed. Perform the above reading with a constant interval,
A radiation image information reading method, comprising: measuring a width of each of the read lines; and correcting the read line so that the larger the width, the smaller the output of the line sensor. 2. The stimulable phosphor sheet is capable of absorbing light in an ultraviolet to visible region and storing its energy, and is excited by light in a visible to infrared region to stimulate the energy. 2. The radiation image information reading method according to claim 1, further comprising a stimulable phosphor capable of emitting the emitted light. 3. A scale is provided on any side edge of the phosphor sheet or on a member integrated with the phosphor sheet along a direction in which the edge side extends, and a scale is provided on the line sensor or on the line sensor. At a position where the positional relationship is known, a pulse signal generator that generates a pulse signal corresponding to the distance of the movement corresponding to the scale is provided,
3. The radiation image information reading method according to claim 1, wherein a distance of the movement is measured from the pulse signal generated from the pulse signal generator, and a width of each of the read lines is obtained. 4. A conversion table showing a relationship between a width of each of the read lines and a correction value for an output of the line sensor, and the output of the line sensor is corrected using the conversion table. The radiation image information reading method according to claim 1. 5. The radiation image information reading method according to claim 4, wherein the conversion table is created based on the relationship between the amount of stimulated emission from the phosphor sheet and the excitation energy. 6. A part of the surface of the stimulable phosphor sheet on which the radiation image information is stored is linearly irradiated with excitation light, and the linearly irradiated part of the stimulable phosphor sheet or the irradiated part is irradiated with the excitation light. The stimulated emission light emitted from the back surface side portion of the stimulable phosphor sheet corresponding to the irradiated portion is received by using a line sensor divided into a plurality of pixel regions in the length direction of the irradiated portion. Performing photoelectric conversion, the line light source and the line sensor for irradiating the excitation light, and moving one of the phosphor sheets relative to the other in a direction different from the length direction, and In a radiation image information reading method of sequentially reading the output of a line sensor in accordance with the movement and obtaining an output of each of the pixel regions for each of the moved read lines, the distance of the movement is measured. A radiation image information reading method, wherein a reading time for each of the reading lines is controlled in accordance with the moving distance so that a width of the reading line is constant. 7. The stimulable phosphor sheet is capable of absorbing light in an ultraviolet to visible region and storing its energy, and is excited by light in a visible to infrared region to stimulate the energy. 7. The radiation image information reading method according to claim 6, further comprising a stimulable phosphor capable of emitting light as emitted light. 8. A scale is provided on any side edge of the phosphor sheet or on a member integrated with the phosphor sheet along a direction in which the edge side extends, and a scale is provided on the line sensor or the line sensor. At a position where the positional relationship is known, a pulse signal generator that generates a pulse signal corresponding to the distance of the movement corresponding to the scale is provided,
7. The distance of the movement is measured from the pulse signal generated from the pulse signal generator.
Or the radiation image information reading method according to 7. 9. The radiation image information reading method according to claim 6, wherein the correction is performed so that the output of the line sensor decreases as the reading time for each of the reading lines increases. . 10. A conversion table showing a relationship between a read time for each of the read lines and a correction value for an output of the line sensor, and correcting the output of the line sensor using the conversion table. Claim 9
The radiation image information reading method described in the above. 11. The radiation image information reading method according to claim 10, wherein the conversion table is created based on a relationship between the amount of stimulated emission from the phosphor sheet and the excitation energy. 12. A line light source for linearly irradiating a part of the surface of the stimulable phosphor sheet on which radiation image information is stored and recorded with excitation light, and a part of the stimulable phosphor sheet linearly radiated. Or the photostimulable light emitted from the back surface side portion of the stimulable phosphor sheet corresponding to the irradiated portion is received and subjected to photoelectric conversion, and a plurality of pixel regions are arranged in the length direction of the irradiated portion. Scanning means for moving one of the divided line sensor, the line light source and the line sensor, and the stimulable phosphor sheet relative to the other in a direction different from the length direction of the irradiated portion. When,
A radiation image information reading apparatus for sequentially reading the output of the line sensor in accordance with the movement for a certain reading time for each reading line and obtaining an output of each pixel area for each of the moved reading lines. A moving distance sensor for measuring the distance of the movement, and obtaining the width of each of the read lines from the distance of the movement in the fixed reading time,
A radiation image information reading apparatus, comprising: a correction unit that corrects the output of the line sensor so as to decrease as the width of the reading line increases. 13. The stimulable phosphor sheet is capable of absorbing light in the ultraviolet to visible region and storing its energy, and is excited by light in the visible to infrared region to stimulate the energy. 13. The radiation image information reading device according to claim 12, wherein the radiation image information reading device contains a stimulable phosphor capable of emitting as emission light. 14. The scale, wherein the moving distance sensor is provided on any side edge of the phosphor sheet or on a member integrated with the phosphor sheet along a direction in which the edge side extends, and A pulse signal generator which is provided on the sensor or at a position where the positional relationship with the line sensor is known, and which generates a pulse signal corresponding to the scale and corresponding to the distance of the movement. 14. The radiation image information reading device according to claim 12 or 13. 15. The correction means has a conversion table indicating the relationship between the width of each read line and a correction value for the output of the line sensor, and corrects the output of the line sensor using the conversion table. 15. The radiation image information reading device according to claim 12, wherein the radiation image information reading device is a reader. 16. The radiation image information reading apparatus according to claim 15, wherein the conversion table is created based on the relationship between the amount of stimulated emission from the phosphor sheet and the excitation energy. 17. A linear light source for irradiating a part of the surface of a stimulable phosphor sheet on which radiation image information is stored and recorded with excitation light, and a linearly irradiating part of the stimulable phosphor sheet. Or, the photostimulable light emitted from the back surface side portion of the stimulable phosphor sheet corresponding to the irradiated portion is received and subjected to photoelectric conversion. Scanning means for moving one of the divided line sensor, the line light source and the line sensor, and the stimulable phosphor sheet relative to the other in a direction different from the length direction of the irradiated portion. When,
A radiation image information reading apparatus that sequentially reads the output of the line sensor for each reading line in accordance with the movement, and obtains an output of each of the pixel regions for each of the moved reading lines, wherein the movement distance is Radiation comprising: a moving distance sensor for measuring; and reading time control means for controlling a reading time for each of the reading lines according to a distance of the movement so that a width of each of the reading lines is constant. Image information reading device. 18. The stimulable phosphor sheet is capable of absorbing light in the ultraviolet to visible region and storing its energy, and is excited by light in the visible to infrared region to stimulate the energy. 18. The radiation image information reading device according to claim 17, wherein the radiation image information reading device contains a stimulable phosphor capable of emitting as emission light. 19. The scale, wherein the moving distance sensor is provided on any side edge of the phosphor sheet or on a member integrated with the phosphor sheet along a direction in which the edge side extends, and A pulse signal generator which is provided on the sensor or at a position where the positional relationship with the line sensor is known, and which generates a pulse signal corresponding to the scale and corresponding to the distance of the movement. The radiation image information reading device according to claim 17. 20. The apparatus according to claim 17, further comprising a correction unit configured to correct the output of the line sensor so as to decrease as the reading time for each of the reading lines increases. Radiation image information reading device. 21. The correction means has a conversion table indicating a relationship between a read time for each of the read lines and a correction value for an output of the line sensor, and corrects an output of the line sensor using the conversion table. 21. The method for reading radiation image information according to claim 20, wherein: 22. The radiation image information reading apparatus according to claim 21, wherein the conversion table is created based on a relationship between the amount of stimulated emission from the phosphor sheet and the excitation energy.