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X-RAY DETECTOR INTERMITTENT DEFECT CORRECTION

IP.com Disclosure Number: IPCOM000199837D
Publication Date: 2010-Sep-17

Publishing Venue

The IP.com Prior Art Database

Abstract

A technique for identification and elimination of intermittent defective line and a line segment from the processed image either at an x-ray system or a Picture Archiving and Communications System (PACS) station is disclosed. A system operator marks the defective line segment with a rectangular box. Subsequently, a location of the defective line or line segment is determined by means of the maximum or minimum of the defective line identification curve that is generated by averaging the pixels along the length of the rectangular box. The location of the defective line in the processed image is mapped onto the location on the detector by means of the rotation, flipping, and edge cutting information stored in the Digital Imaging and Communications in Medicine (DICOM) header of the image.

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Page 1 of 12

X-RAY DETECTOR INTERMITTENT DEFECT CORRECTION

FIELD OF INVENTION

The invention generally relates to x-ray systems and more particularly to identifying and correcting intermittent defective line and line segment in a processed image.

BACKGROUND OF THE INVENTION

In the domain of x-ray detector systems, a defect line in a processed image is a significant problem. A majority of defect lines and line segments are intermittent defects, which cannot be detected through detector system calibration. Further, field data shows that the defective pixels, especially defective line and line segments, are among the persistent complaints pertaining to the digital detectors.

A conventional digital x-ray detector is a two-dimensional pixel array used to obtain a two-dimensional x-ray image that is represented by the following equation:

{

p j

i L

0L , (1)

where I and J are, respectively, the numbers of rows and columns of the image.

Due to manufacturing limitations, a detector may have defective pixels. Such defective pixels are typically identified and corrected by interpolating with their neighboring good pixels. As a result, each x-ray detector is calibrated at the detector manufacture to identify the initial defective pixels. The manufacturing calibration covers the whole specified working environment range and x-ray techniques. The following equation represents a manufacturing bad pixel map:

,

i

= J

j

I

,

1

,

,

;

1

=

,

1

,

0

,

1

}

,

{

bp Mji L

0L , (2)

{

,

,

i

}= J

j

I

,

1

,

,

;

1

=

,

1

,

0

,

1

}

Page 2 of 12

bp j

i

{

, =

M j

}

1

p , 0

bp

{

, =

M j

}

i

i

Where if the corresponding pixel is a defective pixel and if the

corresponding pixel is not a defective pixel. The detector system is also calibrated in the field regularly to identify any newly developed defective pixels. Field calibration is performed in typical field working environmental conditions. Let,

i

p ,

j

bp Cji L

0L (3)

be the field calibrated bad pixel map where if the corresponding pixel is a defective one and if the corresponding pixel is not a defective one.

1

{

{

,

,

i

}= J

j

I

,

1

,

,

;

1

=

,

1

,

0

,

1

}

bp j

i

p ,

0

{

, =

C j

}

i

bp j

i

p ,

However, intermittent defective pixels are not identified by means of either calibration described above. Intermittent defective pixels appear in a clinical image randomly.

Hence there exists a need for a method that identifies and corrects an intermittent defective line and line segment in the processed image.

BRIEF DESCRIPTION OF THE INVENTION

The embodiments described herein provide identification and correction of intermittent defective line and line segment in a processed image, either at the x-ray system, or the Picture Archiving and Communications System (PACS) station. The method described herein eliminates intermittent defect pixels.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments described herein provide a method for identifying and correcting an intermittent defective line and a line segment, in a...