Edge Detection of COVID-19 CT Image Based on GF_SSR, Improved Multiscale Morphology, and Adaptive Threshold

Edge detection is an effective method for image segmentation and feature extraction.Therefore,extracting weak edges with the inhomogeneous gray of Corona Virus Disease 2019(COVID-19)CT images is extremely important.Multiscale morphology has been widely used in the edge detection of medical images due to its excellent boundary detection accuracy.In this paper,we propose a weak edge detection method based on Gaussian filtering and singlescale Retinex(GF_SSR),and improved multiscale morphology and adaptive threshold binarization(IMSM_ATB).As all the CT images have noise,we propose to remove image noise by Gaussian filtering.The edge of CT images is enhanced using the SSR algorithm.In addition,based on the extracted edge of CT images using improved Multiscale morphology,a particle swarm optimization(PSO)algorithm is introduced to binarize the image by automatically getting the optimal threshold.To evaluate our method,we use images from three datasets,namely COVID-19,Kaggle-COVID-19,and COVID-Chestxray,respectively.The average values of results are worthy of reference,with the Shannon information entropy of 1.8539,the Precision of 0.9992,the Recall of 0.8224,the F-Score of 1.9158,running time of 11.3000.Finally,three types of lesion images in the COVID-19 dataset are selected to evaluate the visual effects of the proposed algorithm.Compared with the other four algorithms,the proposed algorithm effectively detects the weak edge of the lesion and provides help for image segmentation and feature extraction.

Application of Frontotemporal Expanded Flap with Bilateral Superficial temporal vessels in Repair of Large Area Scar Contracture in Face and Neck

Objective To summarize the clinical experience of frontotemporal expanded flap with bilateral superficial temporal vessels in repairing large area scar contracture in face and neck.Methods 14 patients with facial and Cervical scar contracture in our hospital were taken as the research object.With bilateral superficial temporal vessels as pedicles,a 400-600 ml skin dilator was inserted into the forehead and 50-100 ml skin dilator was inserted into the two temporal parts respectively.Within 3-4 months,the water injection volume reaches 2 times of the dilator volume.After maintaining for one month,skin flap transplantation was performed.The frontal flap was reserved for hairline reconstruction,and the flap was cut to cover the area after facial and Cervical scar release to reconstruct the jaw-neck angle.The pedicle division and pedicle trimming were performed 3-4 weeks after operation.Results All the 14 patients completed the operation successfully.The flap expansion time is 5-6 months.The expanded skin flap covers an area of 26 cm×9 cm-42 cm×16 cm,and all the skin flaps survived after operation.Among them,2 patients suffered from flap congestion after flap transplantation.Follow-up for 6-12 months showed that the color and texture of the skin flap were similar to those of facial skin,with natural transition and no obvious bloating.The angle between the lower jaw and the neck is about 90.The anterior flexion,posterior extension,lateral flexion and rotation of the neck are obviously improved compared with the anterior,and the posterior extension is close to normal.Conclusion Frontotemporal expanded flap with bilateral superficial temporal vessels is suitable for patients with large-area scar contracture in face and neck that cannot be repaired after expansion of adjacent local normal tissues.