JP2695339B2 - Image reading device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reader for irradiating an X-ray photographic film with light and reading an image on the film by the amount of transmitted light. More specifically, the present invention provides an improved image reading apparatus that irradiates light only in a range adapted to the width of the radiographic film to be read.

[0002]

2. Description of the Related Art As an application example of image reading of an X-ray film, an X-ray film obtained by irradiating a bone to be inspected with an X-ray film is used to measure the density of an image on the film by a microdensitometer. MD method for bone measurement using "Bone metabolism" Vol. 13, 187-195 (0980
, "Bone metabolism," Vol. 14, pp. 91-104 (1981).
Year))).

Incidentally, the MD method is easy to adopt because it uses an X-ray photographic film which can be easily obtained by using an X-ray image radiographing apparatus which is widely used as an apparatus for diagnosing a bone fracture or the like, and is gradually widened. It is becoming popular.

Japanese Unexamined Patent Publication No. 3-215256 discloses an image reading apparatus for the MD method. As a band-shaped light generating means for irradiating an X-ray photographic film, a band-shaped LED (light) is used. emittin
g diode), a high-frequency lighting rod-shaped fluorescent tube, a DC lighting rod-shaped lamp, and a band-shaped light source that irradiates the lamp from the opposite end face by arranging the end faces of the optical fiber in a band shape.

However, there are cases where various widths of the X-ray photographic film are used, and when the width of the X-ray photographic film is narrower than the area irradiated with light by the strip-shaped light source, the film at the edge of the film is Accurate image reading is difficult due to adverse effects on the detection result of the transmitted light amount detection means near the edge of the film due to light passing through the film such as exposure and light leakage. In particular, when measuring the bone, an image of a standard material made of aluminum or the like in the form of steps or slopes is used near the edge of the film, which is used to convert the shadow degree of the image of the bone to be inspected in the X-ray film into bone density. Is often located, and it is necessary to accurately read the image in the radiographic film up to the vicinity of the edge of the film.

[0006]

When the length of the strip-shaped light source exceeds the width of the X-ray photographic film, the inventors of the present invention have diligently studied in order to eliminate the irradiation light in the area exceeding the width. The present invention has been found to be extremely effective when the width of the X-ray photographic film is detected and the light generation area of the strip-shaped light source is adjusted in accordance with the detected width, and the present invention has been reached.

A means for mechanically limiting the irradiation area only to the film width by inserting a light shielding plate or the like into the area of the optical light source that exceeds the width of the X-ray film is conceivable.
Mechanical operations such as putting in and out of the light-shielding plate and the like are liable to have a complicated structure and are likely to cause malfunction, which is not preferable.

[0008]

That is, the present invention relates to a film running means for running an X-ray photographic film containing an image to be read, and a strip-like light source capable of partially illuminating light for irradiating the X-ray photographic film. Means, a transmitted light amount detecting means for detecting a transmitted light amount obtained by irradiating the X-ray photographic film with light, and a predetermined one end side parallel to the traveling direction of the X-ray photographic film is substantially the band-shaped light source means. When it is located at a predetermined position on the upper end portion, at any one of predetermined film end portion equivalent positions corresponding to the other end portion parallel to the running direction of the film corresponding to the film widths of a plurality of types, A film width detecting means for detecting a film width in a direction perpendicular to the running direction of the X-ray photo film by detecting a change in the amount of transmitted light at the end of the film position, and the film width detecting means. An image reading apparatus characterized by having a light-generating region control means for controlling the light generating region of the strip-shaped light source means based on a detection result by Lum width detecting means.

In a preferred mode, the X-ray photo film is properly positioned when a change in the amount of transmitted light at the other end of the film is not detected at any of the predetermined positions corresponding to the end of the film. There is an image reading apparatus equipped with an alarm generating means for generating an alarm indicating that there is no alarm.

As the shape of the X-ray photographic film in the present invention, a generally used rectangle can be mentioned. The image to be read on the film is not particularly limited, and specific examples thereof include an X-ray photographic image of bone as described above. As the traveling means of the film, an automatic traveling means is preferable, and in particular, after the width of the film is detected while the X-ray film is mounted at a predetermined position, the automatic traveling means is automatically operated at a predetermined speed adapted to the detection speed of the transmitted light amount. It is desirable that the film be made to run.

As the band-shaped light source means, X to be applied
Any one can be used as long as the lighting area can be changed according to the width of the radiographic film. Specific examples thereof include one in which a large number of LEDs are arranged in a substantially strip shape, and one of a large number of optical fibers. An example is one in which the end faces are arranged in a strip shape and light is incident on the other end face.
The strip-shaped light source means is installed at a position extending in a direction perpendicular to the running direction of the X-ray photographic film.

The transmitted light amount detecting means may be any as long as it can detect the transmitted light amount of the light from the band-shaped light source means which is transmitted through the X-ray photographic film. Licensor CC
D (charge coupled device)
And the like.

It is preferable that the band-shaped lens means and the band-shaped light source and the band-shaped detection means are preferably arranged so that the light from the band-shaped light source passes through the X-ray photographic film and is focused at the detection portion of the band-shaped detection means. It is preferably arranged between the film and the detector. As a specific example of the belt-shaped lens means,
An example is a rod lens in which a large number of short optical fibers are bundled and fixed with a resin or the like, and a cross-sectional shape perpendicular to the axial direction of the fiber is formed into a band shape.

When a band-shaped CCD is used as the detection means, a band-shaped CC is used to enable more accurate detection.
There is a method of intermittently moving the film at a fine pitch of about 100 μm in the direction perpendicular to D. A bals motor is preferably used for such intermittent running. In the case of intermittent running, the light source is not turned on while the film is moving, and the light source is turned on and off so that the light source is turned on only when the film is stationary. The detection accuracy and the traveling accuracy can be improved.

Further, as the detecting means of the film width detecting means for detecting the film width in the direction perpendicular to the traveling direction of the X-ray photographic film, any means can be used as long as the width of the X-ray photographic film can be detected. It may be one specifically, a means for mechanically detecting the detection ends by contacting the detection ends with the positions of both ends of the film, or a film of the amount of transmitted light or passing light at both ends of the film irradiated with light. There is a non-contact type detecting means for detecting a change in the width direction.

In the film width detecting means of the present invention, one end side of the film is placed at a predetermined position,
Only the other end side is contacted, and more preferably non-contactly, the film width is detected by detecting the position of the film end, which has a basic structure, and corresponds to a plurality of kinds of film widths. The configuration is such that a change in the amount of transmitted light with respect to the film position end portion is detected at any one of predetermined film end portion equivalent positions corresponding to the other end portion parallel to the traveling direction of the film.

Particularly, when the X-ray film to be read is a predetermined type of standard film, one end side of the film is positioned at a predetermined position and the other end side should be positioned at several predetermined positions. In order to determine the film width from the position where the predetermined change in the light receiving amount in the width direction corresponding to the edge of the film is detected by detecting the light receiving amount of the light from the band light source by the band light receiving amount detecting means. Practically desirable ones are used.

In this case, it is indispensable that one end of the film is located at a predetermined position, and the other end of the film should be located at several predetermined positions as positions to be located. When a predetermined change in the amount of received light corresponding to the end portion is not detected, it is wrong to provide a means for judging that the one end side of the film is not located at the predetermined position and issuing an alarm to that effect. It is more preferable for preventing image reading.

In the present invention, as the light generation area control means for controlling the light generation area of the strip light source means based on the detection result of the film width detection means, the film width detection result from the film width detection means is used. Any signal can be used as long as it receives the signal of (1) and generates a signal designating a region to be turned on in the band-shaped light source means capable of partial lighting to partially turn on the band-shaped light source means. As a specific example of the light generation area control means, there is one in which an output interface is provided in a portion of the belt-shaped light source means that is desired to be partially lit so that the light can be partially lit according to a signal from the MPU.

Further, when the strip-shaped light source means partially illuminates in a block shape such as an LED, when the other end of the film cannot be aligned with the end of the partially lit region of the strip-shaped light source, the other part of the film is Regarding the narrowest area outside the end portion, the band-shaped light source means such as an LED is additionally turned on to perform image reading, and the obtained image reading data relates to the amount of received light close to the saturation value near the other end of the film. A read data processing unit for deleting the read data area may be provided. An example of a specific read data processing means in that case is an MPU as shown in the figure.

FIG. 1 shows a bone measuring device incorporating a preferred embodiment of the image reading device of the present invention. As shown in the figure, the automatic reading means 1 relating to the image reading apparatus is a light generating means (light source) such as a partially illuminable LED for irradiating an X-ray photographic film.
And a detection means such as a CCD for detecting the amount of light transmitted from the light source through the X-ray photographic film and a film automatic running means such as a roller for automatically running the X-ray photographic film. It is a thing.

Further, in the figure, there is shown an MPU which functions as a film width detecting means for detecting a film width in a direction perpendicular to the running direction of the X-ray photographic film. In the film width detecting means, all of the LEDs are attached to the film inserted close to one side of the tray-shaped film inserting means (not shown) so that one end of the X-ray photo film is inserted at a predetermined position. Is turned on and the amount of received light is detected by the CCD, and the position corresponding to the other end portion of the film that has been determined in advance is detected, so that one of the film widths of a plurality of types of standard films can be taken as its X-ray photograph. It is used as a film width detection value.

When it is determined by the detecting means that the corresponding film width cannot be detected, C in FIG.
By RT, the alarm generation means issues an alarm indicating that one end of the film is not inserted so as to be in a predetermined position. In that case, it is necessary to insert the film again.

Further, in FIG. 1, a light generation area control for controlling an area where a strip-shaped LED made up of a plurality of blocks is partially turned on is based on the information about the film width detected by the film width detecting means. An MPU and LED controller as a means are shown.

When the film width and the LED partial lighting area do not match and the LED partial lighting area exceeds the width of the film and is additionally lighted, the obtained image reading data indicates the vicinity of the other end portion of the film. The MPU includes a data processing function for deleting data close to the saturation value of the received light amount detection.

FIG. 1 shows a bone measuring device including an automatic reading unit 1 and a bone measurement data processing unit 2 as an application example of the image reading device of the present invention. A correction means combining the D conversion means (AD), the REF data storage means (REF) and the DSP is shown.

That is, each time before the reading of the X-ray photo film is started, light is directly supplied from the light source to the line sensor through the rod lens without the X-ray photo film so that the analog output of the line sensor is not saturated. The light amount of the light source is adjusted so that the maximum value at each location is close to the maximum value of full scale, and the line sensor part is the value obtained by converting the detection pattern of the light amount detected by the line sensor in that state with AD conversion means. REF as REF data for each
Store in the storage unit. Then, the detection pattern (the value for each part of the line sensor is referred to as MES data) in which the amount of transmitted light is detected by transmitting the light to the X-ray film and the amount of transmitted light is calculated by the following formula (I) for each part. The corrected value is used as the read data of the X-ray photographic film. It is more efficient to perform such correction each time the X-ray photographic film is intermittently run for a small distance and detects transmitted light, because no special time for correction is required.

[0028]

(Equation 1)

As a preferable bone measuring device,
There is an apparatus in which the automatic reading means is equipped with a light quantity adjusting means of the light source for adjusting the light quantity of the light generated from the light source according to the variation in the light and shade level of the entire X-ray photographic film.

Further, in the automatic reading means of the bone measuring device, a narrow area including the measurement target portion of the image of the bone to be inspected of the X-ray film is automatically specified, and only the image in that area is read. It is desirable to equip the film automatic running means with an automatic positioning control means for carrying out the above.

Thus, the data relating to the transmitted light amount of the image of the bone to be inspected, which is read by the automatic reading means, is a digital signal converted into the number of steps of aluminum stairs, that is, the thickness of aluminum, and is a data group corresponding to the position of the image. Becomes

Further, in such a bone measuring apparatus, a digital signal relating to the light quantity of the transmitted light in the image in the X-ray photo film of the bone to be inspected, which is obtained by the automatic reading means as described above, is stored as the image storage means in the position of the film. A computer means such as an image memory of about 2 Mbytes capable of storing the associated data group is included.

Further, in the bone measuring device, as an image display means, a CRT (Casode) capable of displaying, as an image, a data group stored in the image storage means or obtained by the automatic reading means and having a relationship between the digital signal and the position.
Ray Tube) and the like are included.

Further, the bone measuring device includes, as the point input means, a cursor position display, an instruction control means, a light pen type input means and the like which can specify and input a position as a reference point in the image display means.

Further, in the bone measuring device, as a calculation means,
A reference position input by the point input means is used as a reference to determine a predetermined position to be measured in the image of the bone to be inspected stored in the image storage means, and a group of stored data relating to the image of the bone to be inspected at the predetermined position. ROM for inputting a calculation program for bone measurement capable of performing calculation for bone measurement using R and R for calculation / primary storage
Microcomputer means comprised of AM are included.

As an example of the calculation in the calculation means, as shown in Japanese Patent Laid-Open No. 61-109557, bone measurement is performed on each part of the long bone, and the bone density distribution of the long bone is obtained from the obtained measurement results. May be.

Further, the bone measuring device includes a dot type ink printer, a thermal printer, a laser printer, a video printer, and other CRT screens capable of outputting the measurement result obtained by the calculation as the bone measurement output means. For example, a means for displaying the bone density distribution in different colors for color display as in Japanese Patent Laid-Open No. 61-109557 is an example of what is practically preferable. In FIG. 1, a printer is disclosed as an output means. Further, in FIG. 1, it is connected to communication means such as a telephone line via the MODEM.

[0038]

The image reading apparatus according to the present invention has a mechanically complicated structure by detecting the width of the X-ray photographic film and adjusting the light generating region of the strip light source in accordance with the detected width. In this way, it is possible to eliminate the influence of exposure and light leakage on the edge of the X-ray film and to realize accurate image reading.

[Brief description of the drawings]

FIG. 1 is an illustration of a bone measuring device incorporating an automatic reading means as an embodiment of an image reading device of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-220640 (JP, A) JP-A-3-128567 (JP, A)

Claims (2)

(57) [Claims] 1. A film running means for running an X-ray photographic film containing an image to be read, a strip-like light source means for generating light for irradiating the X-ray photographic film, and the X A transmitted light amount detecting means for detecting the transmitted light amount obtained by irradiating the radiographic film with light, and a predetermined one end side parallel to the traveling direction of the X-ray film is a predetermined position at the substantially upper end of the strip-shaped light source means. The film position end portion at any one of the predetermined film end portion corresponding positions corresponding to the other end portion parallel to the running direction of the film corresponding to the plurality of types of film widths, The film width detecting means for detecting the film width in the direction perpendicular to the running direction of the X-ray photo film by detecting the change in the amount of transmitted light of the film, and the film width detecting means. And a light generation area control means for controlling the light generation area of the strip-shaped light source means based on the detection result. 2. The X-ray photo film is not properly positioned when a change in the amount of transmitted light at the other end of the film is not detected at any of the predetermined positions corresponding to the end of the film. The image reading apparatus according to claim 1, further comprising an alarm generating unit for generating an alarm.