JP3088006B2 - Image data reading method of solid-state imaging device in radiation diagnostic apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention is used for reading out image data of a solid-state imaging device applied to a solid-state imaging device such as a CCD imaging device used in a radiation diagnostic apparatus. The present invention relates to a method, and more particularly to an improvement in a method of transferring image data in a solid-state imaging device.

(Prior Art) Conventionally, when reading image data from a CCD imaging device, a vertical transfer register (hereinafter referred to as a V transfer register) is used.
Each time one vertical line of image data is stored in the memory, one vertical transfer clock (hereinafter referred to as V transfer clock)
After collectively transferring image data for one horizontal line in the transfer register to a horizontal transfer register (hereinafter referred to as an H transfer register), one horizontal line in the H transfer register is transferred by a plurality of horizontal transfer clocks (hereinafter referred to as an H transfer clock). The sequential transfer of the image data to the outside is repeated until one vertical line of the V transfer register is completed.

(Problems to be Solved by the Invention) However, according to the above-described conventional image data reading method, it is necessary to increase the frequency of a read clock in order to read image data of a CCD imaging device in a short time. On the other hand, in order to increase the frequency of the read clock, the CCD imaging device must have an expensive and complicated system configuration.

Therefore, in the conventional case, when a CCD imaging device having a relatively inexpensive and simple system configuration is adopted, the CCD
There is a problem that the time for reading image data from the imaging device cannot be further reduced.

Further, this type of conventional image data reading method is applied to a radiation diagnostic apparatus such as a three-dimensional CT apparatus. In this case, a visible image obtained by an image intensifier (hereinafter referred to as II) is obtained. An image is picked up by a CCD image pickup device combining the V transfer register and the H transfer register as described above, and the image data stored in the CCD image pickup device is sequentially read to obtain a plurality of tomographic images.

When reconstructing one tomographic image of a plurality of tomographic images, signals corresponding to a large number of scanning lines on the V transfer register are added to obtain a signal corresponding to one tomographic image. is there.

In such a case, a tomographic image is obtained by fine scanning, so that the photographing time becomes long and the number of data is enormous, so that there is a problem that a huge amount of memory is required.

SUMMARY OF THE INVENTION The present invention has been made to solve each of the above-described problems, and a first object of the present invention is to significantly reduce image data reading time in a solid-state imaging device having a relatively simple system configuration. An object of the present invention is to provide an image data readout method for a solid-state imaging device that can perform the above.
A second object is to reduce the imaging time required for reconstructing a tomographic image and to reduce the amount of memory for storing image data in a radiation diagnostic apparatus such as a three-dimensional CT apparatus. An object of the present invention is to provide an image data reading method for a solid-state imaging device.

[Configuration of the invention]

(Means for Solving the Problems) According to the present invention, in order to achieve the above object, a visible image obtained by an image intensifier is read every time one vertical line of image data is stored in a vertical transfer register. A solid-state imaging device that captures image data for one vertical line horizontally from a horizontal transfer register to an external device and sequentially reads out image data stored in the solid-state imaging device to obtain a plurality of tomographic images. In the image data reading method of the imaging device, after transferring image data of a plurality of horizontal lines corresponding to one slice of a subject from the vertical transfer register to the horizontal transfer register by a plurality of vertical transfer clocks, a charge is stored in the horizontal transfer register. By repeatedly transferring the added image data to the outside horizontally, the predetermined The image data for one vertical line of the vertical transfer register corresponding to the chair is read out to the outside.

(Operation) If the configuration for achieving the object according to the present invention is V
The image data necessary to obtain one slice of the subject is sent from the transfer register to the H transfer register all at once, and the added image data is obtained by adding charges in the H transfer register. The image data for a predetermined slice of the subject is read from the solid-state imaging device by repeating the reading of the image data. In this case, the number of scans required to reconstruct a tomographic image is drastically reduced, so that the photographing time is greatly reduced, and the memory amount can be significantly reduced due to the reduction in the number of data.

(Embodiment) FIG. 1 is a configuration diagram schematically showing a CCD imaging device of a first embodiment to which the image data reading method of the present invention is applied.

The CCD image pickup device according to the first embodiment is configured such that each time image data for one vertical line (one screen) is stored in the V transfer register 1 which performs photoelectric conversion and accumulation operation, the V
The horizontal transfer of the image data for the vertical lines is performed by the H transfer register 2 according to a timing chart schematically shown in FIG. 2 (ie, non-interlace driving).

That is, FIG. 2 shows the transfer timing when image data is transferred from the V transfer register 1 to the H transfer register 2 by two horizontal lines. In the case of this transfer timing, the V transfer register 1 is driven by two V transfer clocks.
, To the H transfer register 2 sequentially, one horizontal line at a time, and after transferring two horizontal lines, the image data for the two horizontal lines stored in the H transfer register 2 is horizontally transferred to the outside by a predetermined number of H transfer clocks. By repeating the transfer, the image data for one vertical line of the H transfer register 1 can be read out to the outside.

Therefore, according to the CCD imaging device of the first embodiment of the present invention, when the frequency of the H transfer clock for reading the image data from the H transfer register is the same as that of the related art, the number of times of reading is halved. Can read image data from the CCD imaging device.

Also, after sequentially transferring one horizontal line from the V transfer register 1 to the H transfer register 2 by three or more V transfer clocks and transferring image data of three or more horizontal lines, the image data of three or more horizontal lines is transferred. Is read out from the H transfer register 2 to the outside with a predetermined number of H transfer clocks. At the same read clock frequency as in the related art, the number of times of reading can be reduced to less than 1/3. Image data can be read from the imaging device. Note that the spatial resolution decreases as the number of transfer horizontal lines from the V transfer register 1 to the H transfer register 2 increases. This is because the number of transfer horizontal lines is determined depending on the required spatial resolution. Become.

Thus, the CCD imaging device according to the first embodiment of the present invention has a relatively simple system configuration,
There is an advantage that the read time of image data can be significantly reduced as compared with the related art.

FIG. 3 is a configuration diagram schematically showing a radiation diagnostic apparatus according to a second embodiment to which the image data reading method of the present invention is applied.

The radiation diagnostic apparatus according to the second embodiment includes an X-ray generating unit 3 that can radiate X-rays in a space including a required diagnostic site, and is provided corresponding to the X-ray generator 3 and has a required diagnostic function. An X-ray detector 6 combining an II4 and a CCD imaging device 5 for detecting X-rays passing through the site, and a reconstruction process for reconstructing a tomographic image based on the detection information of the X-ray detector 6 A storage unit 8 for storing three-dimensional pixel group information corresponding to a required diagnostic site obtained by the reconstruction processing unit 7; and a tertiary pixel based on the three-dimensional pixel group information stored in the storage unit 8. A three-dimensional image reconstruction processing unit 9 for reconstructing an original image, and a display unit 10 for displaying a processing result of the three-dimensional image reconstruction processing unit 9 are provided.

Then, in the X-ray detector 6, the solid-state imaging device 5
Has a V transfer register 1 and an H transfer register 2 as shown in FIG. 1 for capturing the visible image obtained in II4, and operates as follows.

That is, the solid-state imaging device 5 used in the radiation diagnostic apparatus of the second embodiment transfers 32 horizontal lines corresponding to one slice of a diagnostic region from the V transfer register 1 to the H transfer register 2 by 32 V transfer clocks. After transferring the image data,
By repeating the horizontal transfer of the added image data obtained by adding the charges in the H transfer register 2 to the outside, the image data of one vertical line of the V transfer register 1 corresponding to a predetermined slice of the diagnostic region is read out. ing.

This is an example of constructing an X-ray detector 6 suitable for irradiating a diagnosis part with a cone beam from the X-ray generator 3 to enable simultaneous multi-slice data acquisition.

That is, the number of scanning lines in a CCD imaging device is usually 500 to 1000, whereas the number of slices by CT imaging is usually 10 to 20, so the number of slices is larger than the number of scanning lines. Is also overwhelmingly small.

For example, a CCD imaging device with 1024 scanning lines and one
When combined with 4 "aperture II, the slice width S given by one scan line is It just becomes.

On the other hand, the slice width S _{1 that} is usually considered practical is S ₁ S10 mm, and when 32 scanning lines are bundled, a slice width of 0.34 mm / scanning line × 32 = 10.94 mm is obtained. be able to.

Therefore, as described above, when charge addition of 32 scanning lines is realized in the H transfer register 2 of the CCD imaging device 5, the amount of memory required for reconstructing a tomographic image is 1
This can be reduced to 1/32 as compared with the conventional case where image data is horizontally transferred for each scanning line, which is practically convenient.

Further, since the added image data for 32 scanning lines is output from the H transfer register 2 to the outside, the imaging time is greatly reduced.

〔The invention's effect〕

As described above, in the image data reading method of the solid-state imaging device according to the present invention, each time one vertical line of image data is stored in the V transfer register, the image data is transferred from the V transfer register to the H transfer register at one time. Since the number of lines is equal to or greater than the number of horizontal lines, the time required for reading from the solid-state imaging device to the outside can be significantly reduced, and a good image can be obtained without a shift due to a time difference unlike the case of interlace driving. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a CCD image pickup device according to a first embodiment to which the image data reading method of the present invention is applied, and FIG.
FIG. 3 is a timing chart schematically showing the transfer timing of image data to the transfer register, and FIG. 3 is a configuration diagram schematically showing a radiation diagnostic apparatus of a second embodiment to which the image data reading method of the present invention is applied. 1 V transfer register 2 H transfer register 3 X-ray generator 4 II 5 CCD imaging device 6 X-ray detector

Claims (1)

(57) [Claims] 1. A visible image obtained by an image intensifier is transferred from a horizontal transfer register to a vertical transfer register each time one vertical line of image data is stored in a vertical transfer register. In a method of reading image data of a solid-state imaging device in a radiation diagnostic apparatus that captures an image with a solid-state imaging device to be transferred and sequentially reads out image data stored in the solid-state imaging device to obtain a plurality of tomographic images, a plurality of vertical transfer clocks are used. After transferring image data for a plurality of horizontal lines corresponding to one slice of a subject from the vertical transfer register to the horizontal transfer register, the added image data obtained by adding the charges in the horizontal transfer register is repeatedly transferred horizontally to the outside. One vertical line of the vertical transfer register corresponding to a predetermined slice of the subject Image data reading method for a solid-state image pickup device in the image data of the radiodiagnostic and wherein the reading to the outside.