JPH01101540A - Image information reader - Google Patents

Abstract

PURPOSE:To reduce the size and weight of a device and to obtain a read image signal with high detecting efficiency by using a photoelectric conversion mean constituting a photodetecting means as a line sensor. CONSTITUTION:An accumulative fluorescent sheet 10 is carried in an arrow Y direction for the subscanning of excited beams by a sheet carrying means 11 such as an endless belt and a laser beam 13 to be excited light radiated from a laser light source 12 mainly scans the surface of the sheet 10 in the direction X rectangular to the subscanning direction Y. Stimulated luminescence 15 based upon the radiation of the laser beam 13 is photoelectrically detected by the line sensor 17 obtained by arraying many right receiving elements such as photodiodes in a line. The outputs of respective light receiving elements are added and the added output S1 is integrated by a reading circuit 20 every prescribed time based on a signal S2 synchronized with the main scanning of the read beam 13, so that a result obtained in case of using a photoelectric conversion means having a comparatively wide light receiving face can be obtained. Consequently, the size and weight of the device can be reduced and a read image signal with high detecting efficiency can be obtained.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention irradiates a recording medium on which image information is recorded with reading light, thereby converting the emitted light, reflected light, or transmitted light emitted from the recording medium into a photoelectronic system. The present invention relates to an image information reading device that detects and reads the above-mentioned image information, and particularly relates to an image information reading device that scans a reading light onto a recording medium and performs light detection using a line sensor.

(Prior art) When a certain type of phosphor is irradiated with radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.), a part of the energy of this radiation is accumulated in the phosphor. It is known that when this phosphor is then irradiated with excitation light such as visible light, the phosphor exhibits stimulated luminescence depending on the stored energy. (stimulable phosphor).

Using this stimulable phosphor, radiation image information of a subject such as a human body is transferred to a sheet having a layer of stimulable phosphor (hereinafter referred to as a ``stimulable phosphor sheet'' or simply ``sheet''). This stimulable phosphor sheet is irradiated with excitation light such as a laser beam to generate stimulated luminescent light, and the resulting stimulated luminescent light is read photoelectrically to obtain an image signal. A radiation image information recording and reproducing method has been proposed for processing and obtaining a radiation image of a subject that is suitable for diagnosis (for example, Japanese Patent Laid-Open Nos. 55-12429 and 55-1163).
No. 40, No. 55-163472, No. 56-11395
No. 56-104645, etc.).

Conventionally, in the radiation image information recording and reproducing method as described above, it is known that reading of stimulated luminescence light can be roughly divided into two methods.

That is, in one of them, pixel division is performed on the excitation light scanning side, and the detection of stimulated luminescence light is performed by a photoelectric conversion means (for example, a photomultiplier tube or a photoconductive element) having a wide light-receiving surface. , pixel division is performed in a photoelectric conversion means (for example, a two-dimensional solid-state image sensor, a semiconductor line sensor, etc.), and a time-series image signal is formed by an electric circuit.

(Problem to be solved by the invention) However, in the former method, large photomultiplier tubes,
A complicated condenser is required to guide the stimulated luminescent light there, which poses a problem in that the reading device tends to be large and heavy. On the other hand, in the latter method, since the weak stimulated luminescence light is detected for each pixel, that is, for each light receiving element of the line sensor, there is a problem that the detection efficiency of the read image signal is inferior compared to the former method.

The above explanation has been given using the example of reading the stimulated luminescence light emitted from a stimulable phosphor sheet. However, by irradiating the reading light onto a recording medium on which image information is recorded, the weak light emitted from the recording medium is The above problem similarly occurs in devices that read image information by detecting reflected light or transmitted light.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image information reading device that can be formed to be small and lightweight, and that can obtain read image signals with high detection efficiency.

(Means for Solving the Problems) The image information reading device of the present invention includes a main scanning unit for main-scanning a reading light onto a recording medium on which image information is recorded; Image information having a sub-scanning means that moves relatively in a direction substantially perpendicular to the main scanning direction, and a light detection means that detects emitted light, reflected light, or transmitted light generated from a portion of the recording medium irradiated with the reading light. In the reading device, the above-mentioned light detection means includes a line sensor that faces and extends along the reading light main scanning line on the recording medium, an adding circuit that adds the outputs of each light receiving element of this line sensor, and The present invention is characterized by comprising a reading circuit that integrates the output of the adding circuit at predetermined time intervals based on a signal synchronized with the main scanning of the reading light.

(Function) In the above configuration, a line sensor is used as the photoelectric conversion means constituting the light detection means, which is advantageous in reducing the size and weight of the reading device, but light detection is performed for each light receiving element. Instead, these respective outputs are added together to form a read signal. In other words, in this configuration, a charge conversion means having a relatively wide light-receiving surface is used, similar to the above-mentioned photomultiplier tube, etc., and a read image signal with high detection efficiency can be obtained.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 shows an image information reading device according to a first embodiment of the present invention. This image information reading device, for example,
It is configured to read radiation image information recorded on a stimulable phosphor sheet as described above. For example, by irradiating radiation that has passed through the subject, the stimulable phosphor sheet 10 on which radiation image information of the subject has been stored and recorded is transferred to a sheet transport means 11 such as an endless belt.
The excitation light is conveyed in the direction of arrow Y for sub-scanning. Further, the laser beam 13 as excitation light emitted from the laser light source 12 is deflected by an optical deflector 14 such as a galvanometer mirror, and main-scans the stimulable phosphor sheet 10 in a direction X substantially perpendicular to the sub-scanning direction Y. do. Stimulated luminescence light 15 is emitted from the portion of the stimulable phosphor sheet 10 irradiated with the laser beam 13 in an amount corresponding to the radiation image information stored and recorded.

This stimulated luminescence light 15 is transmitted to a line sensor 17 formed by arranging a large number of light receiving elements such as photodiodes in a row.
is detected photoelectrically by This line sensor 17 is arranged such that the light receiving element faces the laser beam main scanning line on the stimulable phosphor sheet IO and extends along the line. Also as shown in detail in FIG. 2 above.

A cylindrical lens 18 extending along the line sensor 17 is disposed between the scanning line and the line sensor 17. The stimulated luminescent light 15 emitted from the stimulable phosphor sheet 10 is not converged in the main scanning direction of the laser beam, that is, in the direction in which the light receiving elements 17a are lined up, but is converged by the cylindrical lens 18 in the direction perpendicular thereto, and is then received. Light is efficiently focused onto the element.

The outputs of each light receiving element 17g of the line sensor 17 are added in an adding circuit 19. This added signal S1 changes depending on the recorded information of the stimulable phosphor sheet IO at the irradiation position of the laser beam 13, and is input to the reading circuit 20 where it undergoes processing such as amplification and logarithmic conversion. receive. This signal S1 is also subjected to integration processing at predetermined period intervals based on a synchronization signal S2 synchronized with the scanning of the laser beam 13, and as a result, the reading circuit 20 outputs a pixel-divided time-series analog read image signal S3. Ru. This read image signal S3 is digitized, for example, by an A/D converter 21, and then subjected to gradation processing in an image processing circuit 22.
CR after undergoing signal processing (image processing) such as frequency processing
The radiation image is inputted to an image reproducing device 23 such as a printer, and used for reproducing the radiation image recorded on the stimulable phosphor sheet 10.

Next, referring to FIG. 3, a second embodiment of the present invention will be described. Note that in FIG. 3, elements equivalent to those in FIG. 1 are given the same numbers, and explanations thereof will be omitted unless particularly necessary.

In this embodiment, two line sensors 17A,
17B are arranged side by side in the main scanning direction. The outputs of the line sensors 17A and 17B are input to separate adder circuits 19A and 19B, respectively, and the outputs of these adder circuits 19A and 19B are input to a switching circuit 50.

The laser beam 13 is main-scanned from a portion near the outer end of one line sensor 17A to a portion near the outer end of the other line sensor 17B. The synchronizing signal S2 synchronized with this main scanning is sent to the switching circuit 50.
is man-powered. The switching circuit 50 receives this synchronization signal S.
2, during the period when the laser beam main scanning position is close to one line sensor 17A, the output S1a of one adder circuit 19A is set to a position where the laser beam main scanning position is close to the other line sensor 17B. During a certain period, the output is switched so that the output Slb of the other adder circuit 19B is sent to the reading circuit 20. In this way, the reading circuit 20
A signal S1 obtained by switching the outputs Sla and S1b within one main scanning period is input to the signal S1.

This signal S1 undergoes the same processing as in the first embodiment and is used to reproduce the radiation image recorded on the stimulable phosphor sheet IO.

As mentioned above, the output Sl of the adder circuits 19A and 19B
a. When Slb is switched, only the output of the line sensor 17A or 17B that is closer to the laser beam irradiation position, that is, the output that indicates the stimulated luminescence light amount that correctly corresponds to the radiation image information of the laser beam irradiation position, is used. Therefore, it is possible to eliminate the influence of flare light received by the line sensor 17B or 17A farther from the laser beam irradiation position. Note that the laser beam main scanning position is
Before and after moving from a position close to the line sensor 17A to a position close to the line sensor 17B, it is preferable to weight the outputs of both Sla and Slb at a ratio corresponding to the position and add them. In addition, especially not only at the boundary between line sensors 17A and 17B,
The above-described weighting may be performed by adding the weights over almost the entire main scanning position. In this case, for example, when the main scanning position is near the outermost part of the line sensor 17A, the output S1a may be weighted with a coefficient of 1 and the output Slb may be weighted with a coefficient of 0 (zero). Of course it's a good thing. This also applies to the embodiments described below.

Next, a third embodiment of the present invention will be described with reference to FIG. In this example, two line sensors 17A and 17B are provided as in the second embodiment, and adder circuits 19A and 19B are provided corresponding to each line sensor. In addition, the outputs S1a SS 1 b of each adder circuit 19A and 19B
are manually input to separate reading circuits 2OA and 20B, and undergo the same processing as described above in these reading circuits 2OA and 20B. Thus each reading circuit 2OA, 20
Analog read image signals S3a and S3b output from B
are A/D converters 2LA, respectively.

21B. Each A/D converter 2
The digital read image signal DaSDb output from 1A and 21B is input to the signal processing circuit 60.

This signal processing circuit BO consists of one stimulable phosphor sheet 1
The two series of image signals Da and Db related to 0 are all stored in the internal memory, and then the more appropriate one of the signals DaSDb is read out as the image signal of each pixel, and the image signal representing one radiation image is obtained. Output as .

In order to explain this, a memory storing the above-mentioned image signal is conceptually shown in FIG. In this figure, it is assumed that an image signal Da is stored in an area indicated by symbol A, and an image signal Db is stored in an area indicated by symbol B. Image signal Da
are stored from the signal Da1 for the first main scanning line to the signal Dan for the final n-th main scanning line, and the same is true for the image signal Db. If the number of pixels for the h1 main scanning line is m, the signal for each line is composed of the total amount of signals from the signal for the first pixel to the signal for the m-th pixel. Here, for example, from the first pixel to the (m/2)th pixel in the main scanning direction on the stimulable phosphor sheet 10 is the line sensor 17A.
and the (m/2+1)th pixel to the mth pixel face the line sensor 17B, then the signal processing circuit BO generates an image related to the first pixel to the (m/2)th pixel. Read out the signal Da 1 (signal in the area indicated by the symbol in the figure), and then read out the image signal Db 1 (signal in the area indicated by the symbol R in the figure) related to the (m/2+1)th pixel to the m-th pixel. , these signals are output as image signals for the first main scanning line. In this case as well, it is preferable to weight the data of Da 1 and Db 1 at an appropriate ratio and add them near before and after the transition from the line sensor 17A to 17B. Thereafter, image signals are similarly read out from the second main scanning line to the nth main scanning line, and digital image signals for one image are sent to the image processing circuit 22. This image signal is
The radiation image is reproduced in the same manner as described above.

In the apparatus of this embodiment, by extracting and reading out the image signal D a s D b stored in the memory as described above, the adding circuit 1 in the second embodiment is
The same effect as that obtained by switching the outputs Sla and Slb of 9A and 19B can be obtained.

In this third embodiment, an LED array 61 is used as the excitation light main scanning means, which is composed of a large number of LEDs (light emitting diodes) arranged in a line in the main scanning direction with the stimulable phosphor sheet IO side facing the side. By sequentially lighting up each LED of this LED array 61 one by one, the excitation light 6
A dot-sequential drive circuit B2 for main-scanning 3 is used. If such a main scanning means is used, the reading device can be further miniaturized than when the light beam is deflected using an optical deflector.

In the second and third embodiments described above, two line sensors 17AS17B are used, but three or more line sensors may be provided depending on the reading width.

Even in that case, the output of the adder circuit may be switched as in the second embodiment, or the image signal temporarily stored in the memory may be selected as in the third embodiment. Of course, it may be read out.

Furthermore, although an embodiment formed as a device for reading radiation image information from a stimulable phosphor sheet IO has been described above, the present invention is not limited to this type of radiation image information reading device. Therefore, the present invention is applicable to all image information reading devices in which a line sensor detects emitted light, reflected light, or transmitted light emitted from the recording medium.

(Effects of the Invention) As described in detail above, in the image information reading device of the present invention, a line sensor is used as the photoelectric conversion means constituting the photodetection means, so it is possible to reduce the size and weight.

Further, in the image information reading device of the present invention, since the outputs of a large number of light receiving elements of the line sensor are added to obtain a read signal, a read image signal with high detection efficiency can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing an image information reading device according to a first embodiment of the present invention, FIG. 2 is a side view showing an enlarged main part of the image information reading device, and FIGS. 3 and 4 are Embodiment 2 and 3 of the present invention, respectively.
FIG. 5 is a schematic perspective view showing the image information reading device of the third embodiment. FIG. 10... Stimulable phosphor sheet 11... Sheet transport means 12... Laser light source 13... Laser beam 14... Light deflector 15... Stimulated luminescent light 17.17AS17B... Line Sensor 17a
... Light receiving element 18 ... Cylindrical lens 19.19A, 19B ... Addition circuit 20.20A,
20B...Reading circuit 21, 21A, 21B...A/D converter 50...
Switching circuit 60...Signal processing circuit 81...
・LED array 62... point sequential drive circuit 63
...excitation light

Claims (1)

[Claims] (1) Main scanning means for main-scanning a reading light onto a recording medium on which image information is recorded, and a sub-scanning means for moving the recording medium relative to the reading light in a direction substantially perpendicular to the main scanning direction. In an image information reading device comprising a scanning means and a light detection means for detecting emitted light, reflected light or transmitted light generated from a portion of the recording medium irradiated with the reading light, the light detection means comprises:
A line sensor that faces the reading light main scanning line on the recording medium and extends along the line; an addition circuit that adds the outputs of the respective light receiving elements of this line sensor; 1. An image information reading device comprising: a reading circuit that integrates at predetermined time intervals based on a signal synchronized with the image information reading device.