JPH01228279A - Image pickup devce - Google Patents

Abstract

PURPOSE: To process an X-ray image obtained by two X-ray radiation energies by forming each row of imaging devices from two areas and providing a reading means for each area. CONSTITUTION: Single rows 1 by (n) pieces which consists of (m) pieces of imaging devices 2a-2m are provided adjacent to each other, and a perfect image pickup unit is formed by the matrix of (m×n) pieces of imaging devices. A bus 3 transfers image information from the image point of a tested object to be irradiated by X-rays from imaging device 2a to imaging device 2m in the row direction. An X-ray source operated along with the image pickup unit consists of hard radiation and soft radiation. A switch 4 controlled by a clock signal is provided at the position of the imaging device 2i in the row 1, the transfer of electric charge from imaging device 2a to imaging device 2m is performed at the 1st position of the switch 4, and reading of electric charge from the imaging device 2a is performed by the horizontal shift register 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention provides a matrix with horizontal rows and vertical columns of image sensors and a method for transferring image information in the column direction in a time-delay-integration mode. The present invention relates to an imaging apparatus that is fully equipped with means for supplying all clock signals to a matrix of iron sensing elements, and means for continuously reading out image information from one column.

[Conventional technology]

In radiography, - directing a flat fan-shaped beam of X-ray radiation from a number of imaging elements arranged in a straight line through a subject to an imaging device is described in U.S. Pat. No. 41'
No. 79100. In this case, each imaging element receives radiation transmitted via a corresponding part of the subject, if desired after post-processing. As for the post-processing.

This includes converting the radiation into visible light, for example in an X-ray detector, before it is detected by the imaging device. For example, the dimensions are 0. In the case of an imaging device consisting of a large number of image sensors arranged in a straight line of IXo, 1 mm, the exposure time for each image sensor is very short relative to the normal scanning speed of the subject. The signal-to-noise ratio of the resulting image is either very low or, in order to increase this ratio, the loading of the x-ray source must be increased to an undesirably high level. However, to obtain an acceptable signal-to-noise ratio for relatively low x-ray source loads, the It is necessary to use an X-ray source.

An imaging device with a multi-IJ circuit including rows and columns of imaging elements is used, and the charge on these elements is determined by the amount of charge received by the elements during a certain period of time in the imaging element. It is known from U.S. Pat. No. 4,383,327 to form a radiation as a result of which is transferred to an adjacent associated vertical shift register during a readout period.

This occurs for all image sensors in each row during their readout period. Relative movement between the subject and the imaging device also occurs between successive periods, so that the same portion of the subject is imaged by the next row of imaging elements during the first period. It is also possible in a known manner to combine the function of converting radiation into charge and the function of transferring charge in a vertical COD shift register. As the charge in the shift register advances, charge is thus accumulated in the shift register associated by successive imagers in a column within successive time periods. The accumulated charge is the sum of the charges transmitted through a particular part (image point) of the object during one successive period.

This scanning method uses one-time delay integration or TD (Time
It appears to be particularly suitable for use in examining objects with X-ray radiation. Although each image sensor itself generates only a very small amount of charge depending on the radiation received, it is capable of forming a sufficiently usable image.

For a general explanation of TDI principles, see U.S. Pat.
See No. 83327.

Two different high voltage values e.g. 70 kVp and 13
Generate so-called dual-energy X-ray images by alternately feeding 0 kVp eXl sources, each high voltage value generating Xi miskrills with different energy center points (often referred to as different hardnesses). Koeman (J.

Ceuvna et al., "Computer-generated multiple energy image and its technical explanation," Medicamundi, Volume 27, No. 3 (
, 1982). An X-ray image obtained by sequentially irradiating an object with X-ray radiation having a first energy center point and X-ray radiation having a second energy center point? For example, when processed by a computer, a tissue can be made more clearly as a result of not being able to image the bones in the human body, but instead being able to image tissue parts behind the ribs, for example. This is based on the fact that, for example, when irradiating a human body, different substances in the body have different absorptions for X-rays with different hardness.

In addition to obtaining different X-ray radiation energies by switching the supply voltage of the X-ray radiation source.

Xi radiation beam emitted by an X-ray radiation source.

Before it reaches the object, multiple different radiant energies are radiated separately.

It is also possible to obtain from this source of X-ray radiation driven by a single supply voltage. As a result, an actual x-ray radiation beam will result from the first and second sub-beams with the first x-ray radiation energy and the second x-ray radiation energy. In this case, since the soft radiation in the F-wave beam is removed by the filter,
fundamentally.

An unwavering beam of hard x-ray radiation contains both hard and soft radiation.

[Summary of the invention]

The object of the invention is suitable for processing X-ray images obtained by two X-ray radiation energies. An object of the present invention is to provide an imaging device that operates according to the TDI principle.

To this end, the present invention provides an imaging device of the type mentioned at the outset, in which each row of imaging elements is taken from at least two regions containing imaging elements, and each row of imaging elements is provided with a pad for each said region. The means include a congratulation means coupled to read image information from the associated area.

According to a preferred embodiment of the present invention, these regions of each image sensor row are arranged on the same straight line in the row direction.

According to another exemplary '41M aspect of the present invention, the imaging elements in the first region extend the entire length of one row.

The imaging elements of each next region always extend only a fraction of the length of the smaller row.

Although the invention is particularly adapted to the simultaneous processing of two X-ray images obtained with different X-ray radiation energies, the invention is not limited to radiography alone. The invention can be applied in all cases where images are acquired alternately in different spectral regions and these images are scanned in TDI mode. Note that these different spectral regions may be in the X-ray region, visible light region, or infrared region. The separation into separate spectral bands can be effected in the visible or infrared region, in these cases by F-waves, for example. At the same time, it is also possible to divide the radiation into two or more spectral regions, for example to divide visible light into red, blue and green parts.

Next, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[Implementation]

FIG. 1 shows a single column 1 from 1m image sensors 2a-2m. Since a complete imaging device operating according to the TDI principle comprises a very large number, for example n, of such columns adjacent to each other.

A complete imaging device is formed by a matrix of (mXn) imaging elements. The bus 3 is provided for supplying a clock signal to each imaging element and each column of the imaging device, thereby transmitting image information from an image point of a subject to be irradiated by X-rays in one column direction. The data is transferred from the image sensor 2a to the image sensor 2m as is known in EMODE.

Each imaging element in each column 1, for example column 1, has the function of converting light into charge and the function of transferring charge in the column direction under the control of a clock signal using known COD techniques;
It can be configured to operate. However, each shot 1
On the other hand, a vertical COD shift register is provided adjacent to the image sensor in each column, and this shift register is configured to perform the function of converting light into charge only. It receives a charge and transfers it column-wise in steps, thereby.

It may be possible to add the charges representing a particular image point of the subject during each delivery step from said image points of successive image sensors.

An X-ray source, not shown, operating in conjunction with an imaging device according to FIG. 1, delivers two flat X-ray beams.

One beam consists of relatively hard P-wave radiation and the other beam consists of 1 e.g. Dutch Patent Application No. 84019
It is a combined beam of hard and soft radiation as described in No. 46.

In this case, the arrangement of the imaging device for the two beams is such that the light generated under the influence of soft radiation is placed on the imaging device 2.
a-2i (1 km here), and the light generated from the combined beam reaches the image sensor 21+1...2m (
Here, for example, i=m/2) is reached.

At the position of the image sensor 21 in the column 1, a switch 4, for example a MOSFET, controlled by a clock signal is arranged. 1 normal TD in the first position of switch 4
According to the I mode, charge is transferred from the image sensor 2a to the image sensor 2m.

The horizontal shift register 6 reads charges from the image sensor 2m. The horizontal shift register 6 is configured to read out the charge of the last image sensor in each column and transfer it to the output bus. Therefore, the image information of each image point of the object is

It is sent to the output bus as a line, that is, to represent a straight line part of the object. In this first position of the switch 4, as can be seen, the hard X-ray radiation energy and the combination
It is not possible to distinguish between the image information produced by the linear radiation energy and the linear radiation energy.

However, if switch 4 is in the second position.

Transfer of charge from the image sensor 21 to the image sensor 21+1 is not possible. However, the switch 4 is connected in such a way that the charge from the imaging element 21 is then transferred to the conduction channel 8 . A conduction channel 8 is formed within the semiconductor body containing the imaging device.

Image information is transferred from the image sensor 21 to a second horizontal shift register 9 equipped with an output terminal 10. Image sensor 2a-2
The information from i represents the amount of hard X-ray radiation transmitted through the image point of the object.

The shift register 9 can read out the information from the image pickup elements 21 of each of the columns 1a-In and send it out one after another to the output terminal 10 in the usual manner.

Since the imaging elements 2i+1-2m receive only the light formed by one combined X-ray radiation in the second position of the switch 4, the shift register 6 is an imaging element representing the amount of combined radiation transmitted by the image point of the object. 2 i
+ Image information from 1-2 m.

Received from image sensor 2m.

If desired, a shift register 6. is formed on the semiconductor substrate.
By combining the output signals from 9, image information of hard X-ray radiation and image information of soft X-ray radiation can be obtained from 11111.
A simple subtraction operation allows them to be separated from each other and processed further.

In order to compensate for differences in the sensitivity of the imager to hard and combined The position can be determined so that i=m/2 does not necessarily hold.

A number of switches 4 may be provided for a certain number of imagers in the row 1, with the first row section detecting the first X-ray radiation energy and the second row section detecting the first X-ray radiation energy, if desired. 2 to detect X-ray radiant energy.

It is also possible to set one of the switches 40 to the second position, if desired. In this case, a conduction channel 8 is of course provided which can receive the charge from each image sensor to which a switch 4 is attached.

Shift register 6 at one end of the column, shift register 9 at one end of the column
instead of placing each on the other end.

Both shift registers 6.9 may be arranged at one end of the column.

A second embodiment of the present invention is shown in FIG. 2, in which only a single TDI column 110 surface of the imager is shown for simplicity of illustration, while the associated shift registers and clock bus.

The first step is to process the image information obtained by the configuration shown in Figure 2.
Since this is done in the same manner as in the configuration shown in the figure, it has also been omitted.

Column 11 is area 11 that accommodates image sensors 12a-12m.
a and an area 11b that accommodates the imaging elements 12'i - 12'm (1 mm).

In this embodiment as well, the X-ray source is such that one row of one section 1, for example, section A in FIG.
It is positioned relative to the row 11 so that one section B receives only p-wave radiation, that is, hard X-ray radiation. Image sensor 12a in section A of area 11a in column 11
-12i extends over a wider width than the imaging elements in the area 11a and area 11b of one section B in this case.

The image sensor 12m in the area 11a of the column 11 is the image sensor 12m.
A charge representing the sum of light generated by the combined Xi radiation received by a-12i and light generated by the hard X-ray radiation received by image sensor 121-12m is transmitted. Column 1
The image sensor 12'm in the area 11b of 1 is the image sensor 12'm.
1-12'm sends out a charge representing the light generated by the hard X-ray radiation received.

The surface area of region 11a is as shown in FIG.

If the surface area of the region 11b is three times that of the region 11b, and the surface area of the region 11b is selected as one unit, the image sensor 12b has a hard X
A charge containing three times the information resulting from radioactive radiation and twice the information resulting from soft X-ray radiation is transmitted to the image sensor 12'm.
delivers a charge containing one times the information resulting from hard x-ray radiation. Information from the imagers 12m, 12'm can be processed in the same manner as the embodiment of FIG. 1 on the chip containing the imager, if desired. An advantage of the embodiment of FIG. 2 is that no special conduction channels are required to transfer charge from a row of compartments to the shift register, and no switches are required to connect the imager to the conduction channels. Exists.

In FIG. 2, the area ratio of regions 11a-11b in one row 11 is 3:1, but one of these regions receives only one specific X-ray radiation energy, and the other region receives both. Ratios other than those listed above may be used as long as they are designed to receive X-ray radiation and energy.

[Brief explanation of the drawing]

FIG. 1 is a schematic top view of a single TDI array of an imaging device according to a first embodiment of the invention, suitable for detecting two different X-ray radiation energies; FIG. 2 is a schematic top view of a single TDI array of an imaging device according to a second implementation of the invention, suitable for detecting two different X-ray radiation energies. 2a-2m...imaging device, 3...bus. 11...column, lla, llb...area. C, C, flow, ω

Claims (9)

[Claims] (1) a matrix comprising horizontal rows and vertical columns of image sensors, and supply means for supplying a clock signal to the matrix of image sensors for transferring image information in the column direction in a time-delay-integrate mode; reading means for continuously reading out image information from a column, wherein each column of image sensors comprises at least two regions containing image sensors, and wherein each column of image sensors comprises at least two regions including image sensors; Imaging device, characterized in that said readout means comprises readout means coupled to read out image information from its associated area. (2) The imaging device according to claim 1, wherein the different regions are arranged on the same straight line in a column direction. (3) providing switching means belonging to one imaging element in a row, and further providing a conduction channel, which conduction channel is connectable on the one hand to said imaging element via said switching means and on the other hand to said imaging element; 2. The switching means is connected to one readout means, and the switching means is configured to prevent charge transfer in the column direction at the position of the image sensor at one position. imaging device. (4) the switching means, in another position, permit column-wise charge transfer at the position of the imaging element, in which position the switching means allows charge transfer from the imaging element to its associated conduction channel; 4. The imaging device according to claim 3, further comprising: blocking transfer. (5) For each area, a certain number of switching means are provided for a certain number of image sensors out of a certain number of image sensors of said area in said column relationship, said switching means being arranged for one position. , characterized in that charge can be transferred from an associated imaging element to said conduction channel, and only one of said switching means is in said one position during operation, the others being in other positions. The imaging device according to claim 3 or 4. (6) The imaging elements of the first region extend the entire length of the row, and the imaging elements of each subsequent region extend over decreasing sections of the overall length of the row. The imaging device according to item 1. (7) The image pickup device according to claim 6, wherein the last image pickup element in the area as viewed in the transfer direction is arranged on the same straight line near the related readout means. (8) The image sensor in a region spanning a portion of the column length has a width greater than that spanning the remaining portion of the column, and the subsequent region including the image sensor is arranged adjacent to the remaining portion;
The imaging device according to claim 6 or 7, characterized in that: (9) an x-ray radiation source, means for periodically imparting a first or second spectral center point to the x-ray radiation beam emitted by the x-ray radiation source, and detecting the x-ray radiation transmitted from the subject; An apparatus for forming an X-ray image of a subject, characterized in that the detection means includes the imaging device according to any one of claims 1 to 8. X-ray image forming device.