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Dark-frame subtraction

About: Dark-frame subtraction is a research topic. Over the lifetime, 1216 publications have been published within this topic receiving 20763 citations.


Papers
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Journal ArticleDOI
TL;DR: Prior to a systematic compression in a picture archiving and communication system (PACS), two main issues must be addressed: the true information range which exists in a specific type of radiological image, and the costs and benefits of compression for the PACS.
Abstract: Some radiological images with different levels of noise have been studied using various decomposition methods incorporated with Huffman and Lempel-Ziv coding. When more correlations exist between pixels, these techniques can be made more efficient. However, additional noise disrupts the correlation between adjacent pixels and leads to a less compressed result. Hence, prior to a systematic compression in a picture archiving and communication system (PACS), two main issues must be addressed: the true information range which exists in a specific type of radiological image, and the costs and benefits of compression for the PACS. It is shown that with laser film digitized magnetic resonance images, 10-12 b are produced, although the lower 2-4 b show the characteristics of random noise. The addition of the noise bits is shown to adversely affect the amount of compression given by various reversible compression techniques. The sensitivity of different techniques to different levels of noise is examined in order to suggest strategies for dealing with noise. >

45 citations

Patent
30 Nov 1987
TL;DR: In this paper, it is proposed to deform one of the images locally so that the motion of the parts which should remain stationary is compensated for, by subtracting the locally deformed image from the other image, a subtraction image will be obtained which is substantially free from motion artefacts and which contains only the information of the moving contrast medium.
Abstract: Subtraction images formed by digital subtraction angiography contain artefacts due to the motions of the patient. This motion disturbs the condition imposed for subtraction imaging that only the introduced contrast medium is displaced and that the remainder must remain stationary. For example, when ribs of the patient have moved, due to respiration, between the formation of the first image and the second image, this motion will appear as undesirable information (the extent of the motion of the ribs) in the subtraction image. It is proposed to deform one of the images locally so that the motion of the parts which should remain stationary is compensated for. By subtracting the locally deformed image from the other image, a subtraction image will be obtained which is substantially free from motion artefacts and which contains only the information of the moving contrast medium. To achieve this, a shift vector is determined for various pixels and a reliability criterion is calculated for each direction component of said shift vector.

45 citations

Journal ArticleDOI
TL;DR: Experimental results show that the concept of image fusion of filtered noisy images for impulse noise reduction is capable of producing better results compared to individually denoised images.
Abstract: This paper introduces the concept of image fusion of filtered noisy images for impulse noise reduction. Image fusion is the process of combining two or more images into a single image while retaining the important features of each image. Multiple image fusion is an important technique used in military, remote sensing and medical applications. Five different filtering algorithms are used individually for filtering the image captured from the sensor. The filtered images are fused to obtain a high quality image compared to individually denoised images. In-order to better appraise the noise cancellation behavior of our fusion technique from the point of view of human perception, an edge detection is performed using canny filter for the fused image. Experimental results show that this method is capable of producing better results compared to individually denoised images.

44 citations

Journal ArticleDOI
TL;DR: An estimate of the variance of the registration error that can be expected via two approaches is derived, and it is indicated that for most cases registration variances will be significantly less than the diameter of one picture element.
Abstract: When one image (the sigal) is to be registered with a second image (the signal plus noise) of the same scene, one would like to know the accuracy possible for this registration. This paper derives an estimate of the variance of the registration error that can be expected via two approaches. The solution in each instance is found to be a function of the effective bandwidth of the signal and the noise, and the signal-to-noise ratio. Application of these results to LANDSAT-1 data indicates that for most cases registration variances will be significantly less than the diameter of one picture element.

44 citations

Patent
05 Oct 2000
TL;DR: In this article, a method of processing a digital image channel to remove noise, including the steps of identifying a pixel of interest, calculating a noise reduced pixel value from a single weighted average of the pixels in a sparsely sampled local region including the pixel, and replacing the original value of the pixel with the noise reduction pixel value.
Abstract: A method of processing a digital image channel to remove noise, includes the steps of: identifying a pixel of interest; calculating a noise reduced pixel value from a single weighted average of the pixels in a sparsely sampled local region including the pixel of interest; replacing the original value of the pixel of interest with the noise reduced pixel value; and repeating these operations for all of the pixels in the digital image channel.

44 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20238
202221
20213
20202
20192
20187