Fließende Überblendung von Endoskopiebildern für die Erstellung eines Mosaiks

Wald, Diana; Reeff, Mireille; Székely, Gábor; Cattin, Philippe C.; Paulus, Dietrich

doi:10.1007/3-540-26431-0_59

Cited by 8 publications

(9 citation statements)

References 4 publications

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“…Also Wald et al [43] presented similar results on whitefield images. However, instead of using a weighting function α = f (x), modeling the pixel-border distance [4][5][6][7]43], a linear approximation l A (x), l B (x) of the specific endoscope illumination characteristic (cf. Fig.…”

Section: Blendingsupporting

confidence: 70%

Real-time image composition of bladder mosaics in fluorescence endoscopy

et al. 2010

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Today, photodynamic diagnostics is commonly used in endoscopic intervention of the urinary bladder. Excited by a narrow band illumination, fluorescence markers enhance the visual contrast between benign and malignant tissue. Since in this modality the endoscope must be moved close to the bladder wall to provide sufficiently exposed images, the field of view (FOV) of the endoscope is very limited. This impedes the navigation and the re-identifying of multi-focal tumors for the physician. Thus, an image providing a larger FOV, composed from single images is highly desired during the intervention for surgery assistance. Since endoscopic mosaicking in real-time is still an open issue, we introduce a new feature-based image mosaicking algorithm for fluorescence endoscopy. Using a multi-threaded software design, the extraction of SURF features, the matching and the image stitching are separated in single processing threads. In an optimization step we discuss the tradeoff between feature repeatability and processing time. After adjusting an optimal thread synchronization, the optimal workload of each thread results in a fast and real-time capable computation of image mosaics. On a standard hardware platform our algorithm performs within the RealTimeFrame framework with an update rate of 8.17 frames per second at full input image resolution (780 × 576). Providing a fast A. Behrens ( ) · M. Bommes · T. Stehle · S. Gross · T. Aach growing image with an extended FOV during the intervention, the mosaic displayed on a second monitor promises high potential for surgery assistance.

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Section: Blendingsupporting

confidence: 70%

Real-time image composition of bladder mosaics in fluorescence endoscopy

et al. 2010

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“…It computes for each pixel the Euclidean distance from the border of a region. Applying the feathering method with similar linear distance maps on endoscopic images, seamless panoramic output images can already be provided, assuming low illumination variations across the input video sequence [3,4,26].…”

Section: Linear Blendingmentioning

confidence: 99%

“…At this point, the overview images must exhibit a sufficient high quality to preserve fine vessel structures and illumination information during the interpolation of overlapping image regions. In white light endoscopy, image mosaics showing seamless overlaps are often provided without any interpolation step [7,[18][19][20], or using only a basic linear blending technique [26]. In the case of PDD illumination, an adequate interpolation method becomes more complex, because the fluorescence intensity can strongly vary across the whole image sequence.…”

Section: Introductionmentioning

confidence: 99%

A non-linear multi-scale blending algorithm for fluorescence bladder images

et al. 2010

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The composition of panoramic images of the internal urinary bladder wall from single endoscope images can strongly support the off-line documentation and surgery planning for cancer treatment, as well as assist the reidentification of multi-focal tumors during a cystoscopy. Unlike white light endoscopy, fluorescence techniques such as photodynamic diagnostics (PDD) lower the risk of missing flat and small tumors due to an enhanced tissue contrast. As a result of the low illumination power and the free hand movement of the endoscope, PDD video sequences usually show strong variations in illumination and resolution. During the subsequent mosaicking and blending process, these effects impede the preservation of original and unbiased input image information in the composed panoramic overview image, and make it difficult to avoid visual interpolation artifacts. Thus, a non-linear intensity based multi-scale blending method for fluorescence images is developed. Based on a highest intensity decision, a region mask modeling the endoscopic illumination characteristic is used to weight the input images on several sub-bands of a Laplacian pyramid. In comparison to basic linear interpolation and standard multiscale methods the new method preserves high fluorescence intensities as well as fine vessel structures in the final image composition. Furthermore the adaptive characteristics of the blending algorithm allow the physician to move the endoscope more freely along the bladder wall during the image mosaicking process.A. Behrens ( ) · M. Guski · T. Stehle · S. Gross · T. Aach

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“…This can be done rather fast since each frame adds only a small new region to the existing mosaic. Currently no special blending occurs but a blending strategy as reported in [5] can be easily incorporated.…”

Section: Methodsmentioning

confidence: 99%

“…Except for [1] they have not yet been applied to endoscopic video. On the other hand, interesting work on combining and improving endoscopic images exist: Wald et al [5] combine two endoscopic frames using manual control points and show how the image quality can be improved by using a smoothing cross dissolve technique. Vogt et al [6] show how to reduce colour errors and mark specular lights in endoscopic images.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Image Mosaic for Endoscopic Video Sequences

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Abstract. We present an algorithm capable of making in real time image mosaics with enlarged field-of-view from the endoscopic video data stream. The algorithm is based on the method of Kourogi et al. (1999) which we extend to the case of endoscopic masks. The algorithm automatically finds the optimal affine transform between video frames and builds the enlarged field-of-view as an intervention-free side task. We apply our algorithm to endoscopic video sequences and compare it to the well-known image-mosaicing algorithm of Szeliski (1994). Our method turns out to be more robust, more than 3 times faster, having at the same time a 4 times smaller average motion estimation error: 0.19 pixel instead of 0.72 pixel between successive frames.

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Fließende Überblendung von Endoskopiebildern für die Erstellung eines Mosaiks

Cited by 8 publications

References 4 publications

Real-time image composition of bladder mosaics in fluorescence endoscopy

Real-time image composition of bladder mosaics in fluorescence endoscopy

A non-linear multi-scale blending algorithm for fluorescence bladder images

Real-Time Image Mosaic for Endoscopic Video Sequences

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