Radiation Tomography Shadow Removal via Boundary Identification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional radiation tomography apparatuses suffer from image blurring due to shadows of collimators in fluoroscopic images, which affects the quality of tomographic images, especially at the boundaries where the radiation source and detector move.
Innovation Solution
A radiation tomography apparatus that includes a collimator for restricting radiation, a boundary identifying device to differentiate between shadow and non-shadow areas, and an image complement device to generate a complement image by using pixel values from non-shadow areas, thereby removing the shadow areas and enhancing image visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the collimator is controlled to emit radiation only to the site of interest, then unnecessary exposure to the subject is suppressed, but the radiation beam becomes narrower causing no radiation to enter the periphery of the FPD and creating shadow areas in the fluoroscopic image
Solution Approach 1:
The shadow area is identified and complemented in advance before the final image reconstruction process. By preliminarily processing the fluoroscopic images to fill shadow areas with pixel values from non-shadow areas, the subsequent image reconstruction is not affected by collimator shadows, thus resolving the contradiction between radiation limitation and image quality.
2Loss of energy
If the collimator restricts radiation to a narrower beam, then radiation exposure is reduced, but shadow areas appear in the fluoroscopic image causing blurring in the tomographic image
Solution Approach 1:
The collimator shadow, which is initially a harmful artifact, is converted into a solvable problem through image processing. By identifying shadow areas and complementing them with pixel values from adjacent non-shadow areas, the harmful shadow effect is transformed into an opportunity to enhance image quality while maintaining the benefits of restricted radiation exposure.
3Area of stationary object
If fluoroscopic images contain the entire FPD area, then the acquired images relate to the whole detector, but the periphery shows dark shadow areas that blur the tomographic image when superimposed
Solution Approach 1:
Different regions of the fluoroscopic image are treated differently through local quality processing. Shadow areas are identified and complemented with pixel values from non-shadow areas, while non-shadow areas remain unchanged. This localized processing ensures that the entire FPD area is utilized for image acquisition while eliminating the harmful effects of shadow areas in the final tomographic image.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus produces tomographic images with superior visibility and reduced blurring by identifying and removing shadow areas, resulting in clearer images without collimator shadows.
Implementation Method 1
a radiation source for irradiating a subject with radiation; a collimator for collimating radiation from the radiation source; a radiation detecting device for detecting radiation applied to the subject
Data Source
AI summary
One object of this invention is to provide a radiation tomography apparatus for acquiring a tomographic image from a plurality of fluoroscopic images. The radiation tomography apparatus can acquire the tomographic image having superior visibility without being influenced by a shadow of a collimator appearing in the fluoroscopic image when radiation is applied only to a portion of an FPD through control of the collimator. In this invention, a boundary between a shadow area where the shadow of the collimator appears in the fluoroscopic image and a non-shadow area is identified, and the shadow area in the fluoroscopic image is complemented by the non-shadow area, etc., whereby a complement image is generated. Then the complement image is used for generating the tomographic image. According to this invention, an extremely dark area where the shadow of the collimator appears is removed and thereafter the tomographic image is generated. As a result, the tomographic image has superior visibility with no blurring due to the shadow of the collimator.