Radiation imaging apparatus

Patent metadata

Field	Value
Publication number	US-10914849-B2
Application number	US-201816180756-A
Country	US
Kind code	B2
Filing date	Nov 5, 2018
Priority date	Nov 10, 2017
Publication date	Feb 9, 2021
Grant date	Feb 9, 2021

Abstract

A radiation imaging apparatus includes a pixel portion in which a plurality of pixels, each pixel including a conversion element configured to convert radiation into charge, are arranged in a matrix, a driving circuit configured to drive a plurality of driving lines and a processing unit configured to process a signal from the pixel portion. The driving circuit performs a reset operation in which the conversion elements of the plurality of pixels are repetitively reset. The pixel portion includes rows in which the pixels have been divided into a plurality of groups. The conversion elements of the plurality of groups are reset at different timings in the reset operation, and the processing unit corrects, by using a signal of a pixel of another group, a signal of a pixel of a group with data deficiency caused by the reset operation.

First claim

What is claimed is:

1. A radiation imaging system comprising:
a pixel portion having a plurality of rows each having a plurality of pixels, each pixel including a conversion element configured to convert radiation into charge and to accumulate the charge and a switch element that connects the conversion element to a signal line;
a driving circuit configured to drive a plurality of driving lines which are respectively provided for the plurality of rows; and
a processing unit configured to process a signal from the pixel portion, wherein
a control terminal of the switch element of each of the plurality of pixels is connected to any one of the plurality of driving lines,
the driving circuit performs a reset operation, by driving the driving lines, in which the conversion elements of the plurality of pixels of each row are repetitively reset until radiation irradiation is detected, stops the reset operation upon detecting the radiation irradiation, causes the conversion elements to accumulate charge, and subsequently causes the conversion elements to output a signal corresponding to an amount of the accumulated charge,
the plurality of pixels of each row are grouped into a plurality of groups, and the plurality of groups are reset at different timings in the reset operation, and
the processing unit corrects, by using a signal of a pixel of another group, a signal of a pixel of a group with data deficiency caused by the reset operation.

2. The system according to claim 1 , wherein the plurality of driving lines are arranged in correspondence with the plurality of groups, respectively.

3. The system according to claim 1 , wherein the plurality of groups include a group formed from pixels belonging to an even column and a group formed from pixels belonging to an odd column.

4. The system according to claim 3 , wherein in conversion elements of the pixels belonging to the odd column and the even column, which are arranged adjacently in each row, are connected to the signal line arranged in common for the pixels belonging to the odd column and the pixels belonging to the even column.

5. The system according to claim 1 , wherein the reset operation includes a first period in which the reset operation is performed sequentially for each row for at least a first group of conversion elements, and a second period in which the reset operation is performed sequentially for each row for a second group of conversion elements different from the first group, and the first period and the second period are repeated.

6. The system according to claim 5 , wherein the reset operation is performed for every other row.

7. The system according to claim 5 wherein the reset operation is performed sequentially for conversion elements of a predetermined group of a plurality of rows at the same timing.

8. The system according to claim 1 , wherein a first driving line and a second driving line are arranged in parallel in a column direction for each row of the pixel portion, and in two continuous rows, the control terminal of the switch element of each of the pixels belonging to an even column is connected to the first driving line and the control terminal of the switch element of each of the pixels belonging to an odd column is connected to the second driving line, and in two continuous rows subsequent to the two continuous rows, the control terminal of the switch element of each of the pixels belonging to the even column is connected to the second driving line and the control terminal of the switch element of each of the pixels belonging to the odd column is connected to the first driving line.

9. The system according to claim 8 , wherein in the reset operation, the driving circuit drives the first driving line in sequence for every other row and drives the second driving line in sequence for every other row, and repeats this.

10. The system according to claim 1 , wherein the correction is performed based on a ratio of the magnitudes of the values of a signal of a group with a low average value and a signal of a group with a high average value.

11. The system according to claim 1 , wherein the correction is performed based on a signal of a pixel belonging to another group of the same row as the pixel of the group with the deficiency.

12. The system according to claim 1 , wherein the correction is performed based on a signal of a pixel belonging to another group which is adjacent to the pixel of the group with the deficiency.

13. The system according to claim 1 , wherein the group with the deficiency is determined based on a timing at which the radiation irradiation is detected.

14. The system according to claim 1 , wherein the plurality of pixels of each row are arranged in a line.

15. The system according to claim 14 , wherein a pixel of one of the plurality of groups is arranged between pixels of another of the plurality of groups in the line.

16. A radiation imaging apparatus comprising:
a pixel portion having a plurality of rows each having a plurality of pixels, each pixel including a conversion element configured to convert radiation into charge and to accumulate the charge and a switch element that connects the conversion element to a signal line;
a driving circuit configured to drive a plurality of driving lines which are respectively provided for the plurality of rows; and
a processing unit configured to process a signal from the pixel portion, wherein
a control terminal of the switch element of each of the plurality of pixels is connected to any one of the plurality of driving lines,
the driving circuit performs a reset operation, by driving the driving lines, in which the conversion elements of the plurality of pixels of each row are repetitively reset until radiation irradiation is detected, stops the reset operation upon detecting the radiation irradiation, causes the conversion elements to accumulate charge, and subsequently causes the conversion elements to output a signal corresponding to an amount of the accumulated charge,
the plurality of pixels of each row are grouped into a plurality of groups, and the plurality of groups are reset at different timings in the reset operation, and
the processing unit corrects, by using a signal of a pixel of another group, a signal of a pixel of a group with data deficiency caused by the reset operation.

17. The apparatus according to claim 16 , wherein the plurality of groups include a group formed from pixels belonging to an even column and a group formed from pixels belonging to an odd column.

18. The apparatus according to claim 17 , wherein in conversion elements of the pixels belonging to the odd column and the even column, which are arranged adjacently in each row, are connected to the signal line arranged in common for the pixels belonging to the odd column and the pixels belonging to the even column.

19. The apparatus according to claim 16 , wherein the reset operation includes a first period in which the reset operation is performed sequentially for each row for at least a first group of conversion elements, and a second period in which the reset operation is performed sequentially for each row for a second group of conversion elements different from the first group, and the first period and the second period are repeated.

20. The apparatus according to claim 19 , wherein the reset operation is performed for every other row or sequentially for conversion elements of a predetermined group of a plurality of rows at the same timing.

Assignees

• Canon Kk

Inventors

• Ofuji Masato
• Watanabe Minoru
• Fujiyoshi Kentaro
• Sato Sho

Classifications

• H04N25/68 Primary

  applied to defects · CPC title

• H04N23/30

  for generating image signals from X-rays · CPC title

• G01T1/247 Primary

  Detector read-out circuitry (for processing gain or off-set correction H04N) · CPC title

• H04N5/32

  Transforming X-rays (cameras or camera modules for generating image signals from X-rays H04N23/30; circuitry of SSIS for transforming X-rays into image signals H04N25/30) · CPC title

• H04N5/367

  Electricity · mapped topic