Scintigraphic image contrast-enhancement techniques: Global and local area histogram equalization

Verdenet, J.; Cardot, J; Baud, Michel; Chervet, H.; Duvernoy, J.; Bidet, R

doi:10.1007/bf00251349

Cited by 14 publications

(6 citation statements)

References 4 publications

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“…Many proven contrast-enhancement methods have been described in the literature, but their use in bone scintigraphy has not been investigated (4,5). Studies to improve the quality of bone scintigraphy images have been previously published (6)(7)(8). Verdenet et al (6) used a global histogram equalization technique to enhance bone scintigraphy images.…”

Section: Discussionmentioning

confidence: 99%

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Role of an Intensity-Transformation Function in Enhancement of Bone Scintigraphy Images

Pandey

Dhiman

Sharma

et al. 2018

J. Nucl. Med. Technol.

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Bone scintigraphy images might exceed the dynamic range (the ratio between the highest and the lowest displayable brightness) of the monitor. In such a case, a high-intensity area accompanied by loss of detail in other structures in the displayed image make the clinical interpretation challenging. We have investigated the role of an intensity-transformation (IT) function in enhancement of these types of images. Forty high-dynamic-range bone scintigraphy images were processed using an IT function. The IT function has 2 parameters: threshold and slope. With the threshold kept equal to the mean count of the image, the slope was varied from 1 to 20. A software program developed in-house was used to process the images. Twenty output images corresponding to one input image were visually inspected by 2 experienced nuclear medicine physicians to select images of diagnostic quality, and from their selection was determined the standardized slope that produced the maximum number of diagnostic images. The 2 physicians also scored the quality of the input and output images (at the standardized slope) on a scale of 1-5. The Student test was used to determine the significance of differences in mean score between the input and output images at an α significance level of 0.05. Application of the IT function with standardized parameters significantly improved the quality of high-dynamic-range bone scintigraphy images ( < 0.001, with α = 0.05). A slope of 8 maximized the number of diagnostic images. The IT function has a significant role in enhancing high-dynamic-range bone scintigraphy images.

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Section: Discussionmentioning

confidence: 99%

“…Studies to improve the quality of bone scintigraphy images have been previously published (6)(7)(8). Verdenet et al (6) used a global histogram equalization technique to enhance bone scintigraphy images. They found that the technique improves the readability of the images.…”

Section: Discussionmentioning

confidence: 99%

Role of an Intensity-Transformation Function in Enhancement of Bone Scintigraphy Images

Pandey

Dhiman

Sharma

et al. 2018

J. Nucl. Med. Technol.

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“…Such output images may produce false-positive results in some cases if the reporting is made solely based on histogram equalization followed by contrast stretch and the normalization as authors have mentioned in the study. [ 9 ] Since this was a retrospective study, number of false-positive results were not considered or investigated in this study. This technique can be applied on low contrast studies and can be, especially, useful if one is not interested in looking for contrast between bone tissue uptakes and is only interested in looking for the presence of a lesion.…”

Section: Discussionmentioning

confidence: 99%

“…have used GHE technique for the enhancement of bone scintigraphic images. [ 9 ] They found that the technique improves the readability of data and is suitable to bone scintigraphy. However, they have also mentioned observation of few false positive results as application of this technique.…”

Section: Introductionmentioning

confidence: 99%

Investigating the role of global histogram equalization technique for ^99mTechnetium-Methylene diphosphonate bone scan image enhancement

et al. 2017

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Purpose of the Study:99mTechnetium-methylene diphosphonate (99mTc-MDP) bone scan images have limited number of counts per pixel, and hence, they have inferior image quality compared to X-rays. Theoretically, global histogram equalization (GHE) technique can improve the contrast of a given image though practical benefits of doing so have only limited acceptance. In this study, we have investigated the effect of GHE technique for 99mTc-MDP-bone scan images.Materials and Methods:A set of 89 low contrast 99mTc-MDP whole-body bone scan images were included in this study. These images were acquired with parallel hole collimation on Symbia E gamma camera. The images were then processed with histogram equalization technique. The image quality of input and processed images were reviewed by two nuclear medicine physicians on a 5-point scale where score of 1 is for very poor and 5 is for the best image quality. A statistical test was applied to find the significance of difference between the mean scores assigned to input and processed images.Results:This technique improves the contrast of the images; however, oversaturation was noticed in the processed images. Student's t-test was applied, and a statistically significant difference in the input and processed image quality was found at P < 0.001 (with α = 0.05). However, further improvement in image quality is needed as per requirements of nuclear medicine physicians.Conclusion:GHE techniques can be used on low contrast bone scan images. In some of the cases, a histogram equalization technique in combination with some other postprocessing technique is useful.

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“…Thus, pupil removal is left for this step to be performed; with only iris and pupil, the contrast enhancement method would yield better performance (Verdenet, Cardot et al 1981). As shown in Figure 4.13, image (a) is the outcome from the previous step (outer iris and upper and lower eyelid boundary delineation).…”

Section: Pupil Eyelash Detection and Results Reliability Verificationmentioning

confidence: 99%

A Highly Efficient Biometrics Approach for Unconstrained Iris Segmentation and Recognition

Adjouadi

Chen

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The first part of the dissertation introduces a robust and fast segmentation approach using still images contained in the UBIRIS (version 2) noisy iris database. The results show accuracy estimated at 98% when using 500 randomly selected images from the UBIRIS.v2 partial database, and estimated at 97% in a Noisy Iris Challenge Evaluation (NICE.I) in an international competition that involved 97 participants worldwide involving 35 countries, ranking this research group in sixth position. This accuracy is achieved with a processing speed nearing real time.The second part of this dissertation presents an innovative segmentation and recognition approach using video-based iris images. Following the segmentation stage which delineates the iris region through a novel segmentation strategy, some pioneering experiments on the recognition stage of the less-constrained video iris biometrics have been accomplished. In the vi video-based and less-constrained iris recognition, the test or subject iris videos/images and the enrolled iris images are acquired with different acquisition systems. In the matching step, the verification/identification result was accomplished by comparing the similarity distance of encoded signature from test images with each of the signature dataset from the enrolled iris images. With the improvements gained, the results proved to be highly accurate under the unconstrained environment which is more challenging. This has led to a false acceptance rate (FAR) of 0% and a false rejection rate (FRR) of 17.64% for 85 tested users with 305 test images from the video, which shows great promise and high practical implications for iris biometrics research and system design.

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Scintigraphic image contrast-enhancement techniques: Global and local area histogram equalization

Cited by 14 publications

References 4 publications

Role of an Intensity-Transformation Function in Enhancement of Bone Scintigraphy Images

Role of an Intensity-Transformation Function in Enhancement of Bone Scintigraphy Images

Investigating the role of global histogram equalization technique for ^99mTechnetium-Methylene diphosphonate bone scan image enhancement

A Highly Efficient Biometrics Approach for Unconstrained Iris Segmentation and Recognition

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Scintigraphic image contrast-enhancement techniques: Global and local area histogram equalization

Cited by 14 publications

References 4 publications

Role of an Intensity-Transformation Function in Enhancement of Bone Scintigraphy Images

Role of an Intensity-Transformation Function in Enhancement of Bone Scintigraphy Images

Investigating the role of global histogram equalization technique for 99mTechnetium-Methylene diphosphonate bone scan image enhancement

A Highly Efficient Biometrics Approach for Unconstrained Iris Segmentation and Recognition

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Investigating the role of global histogram equalization technique for ^99mTechnetium-Methylene diphosphonate bone scan image enhancement