JPH05110849A - Picture scanning reader - Google Patents

Abstract

PURPOSE:To minimize a memory capacity required to generate shading correction data and to relieve the load onto the software. CONSTITUTION:Reference data obtained by reading a stimulable phosphor sheet IP to which a radiant ray is uniformly radiated are stored sequentially to a shading memory 54 via an adder 52 for each main scanning line. Thus, the shading correction data are stored in the shading memory 54. Then the stimulable phosphor sheet IP on which desired picture information is recorded is read and the shading correction data whose polarity is inverted by an inverter 60 are added to the picture data by using an adder 40 to obtain the corrected picture data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image scanning / reading apparatus for correcting image data obtained by photoelectrically reading an image recording medium with shading correction data.

[0002]

2. Description of the Related Art For example, in an image scanning and reading apparatus, an image recording medium on which image information is recorded is mainly scanned by a light beam deflected by an optical deflecting means such as a galvanometer mirror, and the image recording medium is scanned in the main scanning direction. Sub-scanning is performed by moving the recording medium relatively in a direction substantially orthogonal to the two-dimensional scanning, and the recording medium is two-dimensionally scanned to obtain optical information. Has been converted to.

In this case, the optical scanning system including the light deflector has shading due to uneven scanning speed with respect to the scanning position of the image recording medium, uneven light intensity, and the like.
Further, the photoelectric conversion means has shading due to uneven photoelectric conversion characteristics. When the obtained image data is reproduced without correcting this shading, streak-like unevenness occurs in the sub-scanning direction of the reproduced image, or
There is an inconvenience that uneven density occurs over the whole area.

In order to eliminate such inconvenience, shading correction data is created and image data is corrected by this shading correction data. Therefore, a method of creating shading correction data will be described with reference to FIG.

The laser beam L output from the laser light source 2 is deflected by the galvanometer mirror 4 and main-scans on the stimulable phosphor sheet IP which is sub-scanned and conveyed.
Here, the stimulable phosphor sheet IP means radiation (X
Radiation, α-rays, β-rays, γ-rays, electron rays, ultraviolet rays, etc.) accumulates a part of this radiation energy, and when it is subsequently irradiated with excitation light such as visible light, it emits light in accordance with the accumulated energy. A sheet having a layer made of a phosphor that emits exhausted light. In this case, as the stimulable phosphor sheet IP, one that is uniformly irradiated with radiation is used.

Therefore, stimulated emission light is generated from the stimulable phosphor sheet IP irradiated with the laser beam L. This stimulated emission light is guided to the photomultiplier 6 via the light guide 5 whose end portion is arranged in proximity to the main scanning line of the stimulable phosphor sheet IP, and is converted into an electric signal. The electric signal is converted into a digital signal by the A / D converter 8 and then stored in the image memory 10 as reference data for the entire surface of the stimulable phosphor sheet IP. Image memory 10
The reference data stored in the shading memory 14 is stored in the shading memory 14 as the shading correction data corresponding to the main scanning line of the stimulable phosphor sheet IP by being averaged in the image processing unit 12, for example. It

Next, the stimulable phosphor sheet IP on which desired image information is recorded is scanned by the laser beam L in the same manner as in the case of the above-mentioned reference data, and the obtained electric signal is processed by the A / D converter 8. Converted to digital signal. In this case, the gain of the A / D converter 8 is adjusted by the shading correction data stored in the shading memory 14. As a result, the digital signal converted by the A / D converter 8 is stored in the image memory 10 as shading-corrected image data.

The image data obtained as described above is
After the desired processing is performed by the image processing unit 12, the D / A converter 16 converts the analog signal into an analog signal, which is displayed on the display unit 18.

[0009]

In this case, all the reference data are once stored in the image memory 10 and then the image processing unit 12 is used.
In order to create the shading correction data by software, in addition to the shading memory 14 for storing the shading correction data, the image data for the number of lines necessary for creating the shading correction data of the stimulable phosphor sheet IP is generated. An image memory 10 for storing is required. Therefore, it cannot be applied to such an image scanning and reading apparatus without the image memory 10 having a relatively large capacity. Further, since the image processing unit 12 requires software for creating shading correction data, there is a disadvantage that the software configuration of the image processing unit 12 becomes complicated.

Therefore, the present invention overcomes the above-mentioned inconvenience, reduces the cost of the apparatus by eliminating the need for a large-capacity storage means for temporarily storing the reference data for creating the shading correction data, and further reduces the shading. An object of the present invention is to provide an image scanning / reading device capable of reducing the load of software for creating correction data.

[0011]

In order to achieve the above object, the present invention performs main scanning of an image recording medium in a one-dimensional direction and moves the image recording medium in a direction substantially orthogonal to the main scanning direction. In this way, in the image scanning reading device that subscans to two-dimensionally scan the recording medium and photoelectrically reads the information recorded on the recording medium to obtain image data,
Storage means for storing reference data obtained by reading a reference image recording medium on which uniform image information is recorded in main scanning units, and the reference image with respect to the reference data in main scanning units stored in the storage means. Based on the reference data stored in the storage means, the addition means for sequentially adding the reference data of the next main scanning unit of the recording medium and the image data obtained by reading the image recording medium on which desired image information is recorded And a correction unit that corrects.

[0012]

In the image scanning / reading apparatus according to the present invention, the shading correction data is created by adding the reference data read from the reference image recording medium in the main scanning unit and storing it in the storage means. In this case, the storage means may have a capacity to store data corresponding to the main scanning line of the reference image recording medium. Then, based on the shading correction data, the data obtained from the stimulable phosphor sheet IP on which desired image information is recorded is corrected.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image scanning reading apparatus according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the configuration of the image scanning and reading apparatus of this embodiment. This image scanning / reading apparatus outputs a laser light source 20 that outputs a laser beam L, a galvanometer mirror 22 that deflects the laser beam L in the main scanning direction, and guides the deflected laser beam L to a synchronization signal generator 24. A half mirror 26, a light guide 28 whose ends are arranged in proximity to each other along a main scanning line of the stimulable phosphor sheet IP, and a photomultiplier that converts stimulated emission light from the stimulable phosphor sheet IP into an electric signal. A pliers 30 and a control circuit for processing the electric signal are provided. The synchronization signal generating unit 24 includes a grid 32 in which light transmitting portions and light non-transmitting portions are arranged alternately along the scanning direction of the laser beam L,
A cylindrical condensing bar 34 that condenses the light that has passed through the grid 32, and photodetectors 36a and 36b that are provided at both ends of the condensing bar 34 and that detect the light are provided.

The control circuit comprises a photomultiplier 3
A logarithmic converter 38 for logarithmically converting the image signal from 0, an A / D converter 42 for A / D converting the logarithmically converted image signal via an adder 40, and an A / D-converted switch 44.
An image processing unit 46 for performing a predetermined image processing on the image signal supplied via the image processing apparatus, a D / A converter 48 for D / A converting the image signal subjected to the image processing, and the D / A conversion. And a display unit 50 for displaying image data composed of the generated image signal on a CRT or the like. Further, the control circuit is a switch 44.
A shading memory 54 for storing the image signal from the above as shading correction data in units of main scanning lines via an adder 52, a D / A converter 56 for D / A converting the correction signal as the shading correction data, and D / A
An inverter 60 that inverts the sign of the converted correction signal and supplies the inverted signal to the adder 40 via a switch 58. The switch 44, the shading memory 54, and the switch 58 are controlled by the controller 62. Further, the control circuit includes a sync signal generator 64 that generates a sync signal based on signals from the photodetectors 36a and 36b that form the sync signal generator 24. The synchronization signal generated by the synchronization signal generator 64 is the A / D converter 42.
And D / A converters 48 and 56.

The image scanning / reading apparatus of this embodiment is basically constructed as described above, and its operation will be described below.

First, a procedure for creating shading correction data will be described.

Therefore, the stimulable phosphor sheet IP having the entire surface uniformly irradiated with radiation is used as a reference image recording medium, and the stimulable phosphor sheet IP is irradiated with the laser beam L. In this case, the laser beam L output from the laser light source 20 is irradiated onto the stimulable phosphor sheet IP which is sub-scanned and conveyed through the galvanometer mirror 22 and the half mirror 26, and is reflected by the half mirror 26. Then, the light is guided to the condensing bar 34 via the grit 32 that constitutes the synchronization signal generation unit 24. Light collecting bar 34
The laser beam L guided to the
a and 36b, which are converted into electric signals to generate a synchronization signal generator 64.
And a sync signal is generated. This synchronization signal is A
It is supplied to the / D converter 42 and the D / A converters 48 and 56.

On the other hand, the stimulated emission light is output from the portion of the stimulable phosphor sheet IP irradiated with the laser beam L, which corresponds to the main scanning line, and the stimulated emission light is photoed through the light guide 28. It is guided to the multiplier 30 and converted into an electric signal. The electric signal is logarithmically converted by the logarithmic converter 38, and then is added through the adder 40 to the A / D converter 4
At 2, it is converted into reference data as a digital signal. Here, the controller 62 turns off the switching device 58, controls the switching device 44, and controls the A / D converter 42.
And the adder 52 are connected. Therefore, the reference data obtained from the portion corresponding to the main scanning line of the stimulable phosphor sheet IP is stored in the shading memory 54 via the adder 52. In this case, the shading memory 54 is set to a capacity for storing only reference data for one main scanning line of the stimulable phosphor sheet IP.

Next, when the reference data corresponding to the next main scanning line of the stimulable phosphor sheet IP is read, this reference data is stored in the shading memory 54 in the adder 52 when the controller 62 is activated. The shading memory 54 after being added to the immediately preceding reference data.
Stored in. This operation is performed by an area for a line required to obtain the shading correction data of the stimulable phosphor sheet IP (for example, 64 in the vicinity of the center of the stimulable phosphor sheet IP).
(Area for line). Where, for example,
The reference data is 10 bits, and the shading memory 5
If the memory capacity of each pixel of 4 is set to 16 bits,
The reference data of each pixel can be added up to 64 times by the adder 52 (10-bit data × 64 = 16-bit data). Furthermore, it is possible to automatically perform averaging by taking out the required number of bits of data from the higher order of the 16-bit data. In this way, the data finally stored in the shading memory 54 is
Hereinafter, this is referred to as shading correction data.

As described above, in the present embodiment, the adder 52
And a shading memory 54 capable of storing the shading correction data for one line of the stimulable phosphor sheet IP.
And, shading correction data is created.
In this case, even if the image scanning and reading apparatus does not have a large-capacity image memory, the shading correction data can be created if the shading memory 54 for finally storing the shading correction data is provided.
Therefore, it is possible to reduce the memory capacity. Further, since the shading correction data can be created by hardware, for example, the image processing unit 46
However, it is not necessary to prepare software for creating shading correction data.

Next, the stimulable phosphor sheet IP on which desired image information is recorded is set in the image scanning / reading apparatus, and the scanning / reading operation is started.

Therefore, the image data obtained by reading the stimulable phosphor sheet IP is logarithmically converted by the logarithmic converter 38, and then the adder 40 adds the shading correction data. That is, the controller 62 controls the switch 58 to connect the inverter 60 and the adder 40, and controls the switch 44 to connect the A / D converter 42 and the image processing unit 46.

The shading correction data stored in the shading memory 54 is converted into the shading correction data as a digital signal by the D / A converter 56, the polarity of the shading correction data is inverted by the inverter 60, and the shading correction data is converted by the inverter 58. It is supplied to the adder 40. Therefore, in the adder 40, the shading correction data is actually subtracted from the image data from the logarithmic converter 38, and the corrected image data is supplied to the A / D converter 42. In addition, from the image data corrected in this way, for example, the unevenness of the signal due to the galvanometer mirror 22,
The unevenness of the sensitivity of the photomultiplier 30 will be removed. The corrected image data is converted into a digital signal by the A / D converter 42 and then guided to the image processing unit 46 via the switch 44.

In the image processing section 46, desired image processing is performed on the image data. Then, this image data is converted into an analog signal by the D / A converter 48 and displayed on the display unit 50.

In the above-described embodiment, a divider is used instead of the logarithmic converter 38 and the adder 40, and the shading correction data from the switch 58 is introduced into this divider, and the shading correction data is used for the image. It can also be configured to perform data division.

[0027]

According to the image scanning / reading apparatus of the present invention, the following effects can be obtained.

That is, the shading correction data is created by providing the adding means and the storage means for storing the shading correction data, and sequentially adding the reference data obtained from the reference image recording medium by the adding means and storing the result in the storage means. Therefore, a large-capacity storage means such as a frame memory is unnecessary. Further, the hardware can be easily configured, and the load on the software can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an image scanning and reading apparatus according to the present invention.

FIG. 2 is a configuration block diagram of an image scanning reading device according to a conventional technique.

[Explanation of symbols]

 20 ... Laser light source 22 ... Galvanometer mirror 24 ... Synchronization signal generation part 30 ... Photomultiplier 40, 52 ... Adder 44, 58 ... Switcher 46 ... Image processing part 54 ... Shading memory 62 ... Controller

Claims (1)

[Claims] 1. An image recording medium is main-scanned in a one-dimensional direction, and the image recording medium is moved in a direction substantially orthogonal to the main-scanning direction so as to be sub-scanned so that the recording medium is two-dimensionally scanned and recorded. In an image scanning reading device that obtains image data by photoelectrically reading information recorded on a medium, a memory for storing reference data obtained by reading a reference image recording medium on which uniform image information is recorded in main scanning units. Means, adding means for sequentially adding reference data of the next main scanning unit of the reference image recording medium to the reference data of the main scanning unit stored in the storage means, and desired image information recorded An image scanning reading apparatus comprising: a correction unit that corrects image data obtained by reading an image recording medium based on reference data stored in the storage unit.