otsu filter  (MathWorks Inc)

Journal: Alzheimer's Research & Therapy

Article Title: Retinal mid-peripheral capillary free zones are enlarged in cognitively unimpaired older adults at high risk for Alzheimer’s disease

doi: 10.1186/s13195-023-01312-8

Figure Lengend Snippet: Montaged 20 × 20°OCTA images of the central foveal region and paired arterioles and venules in the superficial vascular plexus of a 60-year-old cognitively unimpaired low-risk female. a Raw montaged OCTA image before image processing. b Vesselness filtered image in MATLAB. c Vesselness filtered and Otsu thresholded image in MATLAB. Red “A” and blue “V” represent paired arterioles and venules, respectively. Periarteriole CFZ can be seen as dark gaps around the arteriole (red “A”) while the perivenule CFZ can be seen as dark gaps around the venule (blue “V”). Periarteriole CFZ can be seen as larger than the perivenule CFZ

Article Snippet: Fig. 1 Montaged 20 × 20°OCTA images of the central foveal region and paired arterioles and venules in the superficial vascular plexus of a 60-year-old cognitively unimpaired low-risk female. a Raw montaged OCTA image before image processing. b Vesselness filtered image in MATLAB. c Vesselness filtered and Otsu thresholded image in MATLAB.

Techniques:

Journal: Alzheimer's Research & Therapy

Article Title: Retinal mid-peripheral capillary free zones are enlarged in cognitively unimpaired older adults at high risk for Alzheimer’s disease

doi: 10.1186/s13195-023-01312-8

Figure Lengend Snippet: A vesselness filtered and Otsu thresholded montaged 20 × 20°OCTA image of the superficial vascular plexus in MATLAB of a 60-year-old cognitively unimpaired low-risk female. The image shows the central fovea (FAZ area = 0.48 mm 2 ; FAZ effective diameter = 782 µm) and a paired arteriole (red “A”) and venule (blue “V”), 14.1° and 15.4°, respectively, inferior to the fovea. Evenly sampled points around the arteriole or venule showing the periarteriole (71.3 µm) and perivenule (58.5 µm) CFZs are shown. The arteriole diameter = 75.1 µm and the venule diameter = 124 µm. Arteriole linear distance of sampling for the periarteriole CFZ = 7.41 mm and venule linear distance of sampling for the perivenule CFZ = 6.67 mm

Article Snippet: Fig. 1 Montaged 20 × 20°OCTA images of the central foveal region and paired arterioles and venules in the superficial vascular plexus of a 60-year-old cognitively unimpaired low-risk female. a Raw montaged OCTA image before image processing. b Vesselness filtered image in MATLAB. c Vesselness filtered and Otsu thresholded image in MATLAB.

Techniques: Sampling

Journal: Alzheimer's Research & Therapy

Article Title: Retinal mid-peripheral capillary free zones are enlarged in cognitively unimpaired older adults at high risk for Alzheimer’s disease

doi: 10.1186/s13195-023-01312-8

Figure Lengend Snippet: Computation of vessel density in a 20 × 20° macular-centered OCTA image of a 74-year-old cognitively unimpaired high-risk female. a Processed (cropped, vesselness filtered, and Otsu thresholded) image. b Corresponding reversed contrast/negative image. A customized MATLAB script was used to count the number of white pixels in both the original processed ( a ; designated as vessels) and the reversed contrast images ( b ; designated as the non-perfused background). The number of pixels was then converted to mm 2 based on the micron‐to‐pixel ratio in the x and y directions, as computed from the fiducial marks acquired from the HEYEX software as done previously [ – ]. The area of white pixels in mm 2 designated as vessels was then added to that of the background to compute the total area of the image (~ 36 mm 2 ). The vessel density was then computed as the ratio of the area of white pixels designated as vessels ( a ) to the total area of the image. Scale bar: 200 µm

Article Snippet: Fig. 1 Montaged 20 × 20°OCTA images of the central foveal region and paired arterioles and venules in the superficial vascular plexus of a 60-year-old cognitively unimpaired low-risk female. a Raw montaged OCTA image before image processing. b Vesselness filtered image in MATLAB. c Vesselness filtered and Otsu thresholded image in MATLAB.

Techniques: Software

Journal: Scientific Reports

Article Title: OCTA reveals remodeling of the peripheral capillary free zones in normal aging

doi: 10.1038/s41598-021-95230-0

Figure Lengend Snippet: Montaged 20 × 20-degree OCTA images of the central foveal region and paired arterioles and venules in the superficial vascular plexus of a 63-year-old cognitively unimpaired male. ( a ) Raw montaged OCTA image before image processing. ( b ) Vesselness filtered image in Matlab. ( c ) Vesselness filtered and Otsu thresholded image in Matlab. Red “A” and blue “V” represent paired arterioles and venules, respectively. Periarteriole CFZ can be seen dark gaps around the arteriole (Red “A”) while the perivenule CFZ can be seen as dark gaps around the venule (Blue “V”). Periarteriole CFZ can be seen as larger than the perivenule CFZ.

Article Snippet: Figure 2 A vesselness filtered and Otsu thresholded montaged 20 × 20-degree OCTA image of the superficial vascular plexus in Matlab of a 63-year-old cognitively unimpaired male.

Techniques:

Journal: Scientific Reports

Article Title: OCTA reveals remodeling of the peripheral capillary free zones in normal aging

doi: 10.1038/s41598-021-95230-0

Figure Lengend Snippet: A vesselness filtered and Otsu thresholded montaged 20 × 20-degree OCTA image of the superficial vascular plexus in Matlab of a 63-year-old cognitively unimpaired male. The image shows the central fovea (FAZ area = 0.27 mm 2 ; FAZ effective diameter = 586 µm) and a paired arteriole (Red “A”) and venule (Blue “V”), 13.6 and 17.3 degrees, respectively, inferior to the fovea. Evenly sampled points around the arteriole or venule showing the periarteriole (70.2 µm) and perivenule (53.5 µm) CFZs are shown. The arteriole diameter = 96.0 µm and the venule diameter = 129 µm. Evenly sampled points include coordinates from the center of the fovea (green dot), points on the top/bottom edge of an arteriole (red dots) or venule (blue dots), and points from the middle of a capillary superior/inferior to an arteriole (red dots) or venule (blue dots).

Article Snippet: Figure 2 A vesselness filtered and Otsu thresholded montaged 20 × 20-degree OCTA image of the superficial vascular plexus in Matlab of a 63-year-old cognitively unimpaired male.

Techniques:

Journal: Scientific Reports

Article Title: OCTA reveals remodeling of the peripheral capillary free zones in normal aging

doi: 10.1038/s41598-021-95230-0

Figure Lengend Snippet: Raw and processed OCTA images showing a sex-matched example of the remodeling of the pCFZ in normal aging for a 20 × 20-degree region of the retina. ( a ) and ( d ) represent raw OCTA images of a 28 and 66-year-old cognitively unimpaired female, respectively. ( b ) and ( e ) represent corresponding vesselness filtered images in Matlab. ( c ) and ( f ) represent corresponding vesselness filtered and Otsu thresholded images in Matlab. Red “A” and blue “V” represent paired arterioles and venules, respectively. The dark gaps around the arteriole (periarteriole CFZ; 111 µm; vessel distance from fovea = 14.2 degrees) and venule (perivenule CFZ; 93.2 µm; vessel distance from fovea = 13.9 degrees) of the cognitively unimpaired older adult can be observed as larger than that around the arteriole (periarteriole CFZ; 73.4 µm; vessel distance from fovea = 13.8 degrees) and venule (perivenule CFZ; 57.4 µm; vessel distance from fovea = 16.1 degrees) of the young participant. Scale bar: 200 µm.

Article Snippet: Figure 2 A vesselness filtered and Otsu thresholded montaged 20 × 20-degree OCTA image of the superficial vascular plexus in Matlab of a 63-year-old cognitively unimpaired male.

Techniques:

Journal: Scientific Reports

Article Title: OCTA reveals remodeling of the peripheral capillary free zones in normal aging

doi: 10.1038/s41598-021-95230-0

Figure Lengend Snippet: Montaged 20 × 20-degree OCTA images of the central foveal region and paired arterioles and venules in the superficial vascular plexus of a 63-year-old cognitively unimpaired male. ( a ) Raw montaged OCTA image before image processing. ( b ) Vesselness filtered image in Matlab. ( c ) Vesselness filtered and Otsu thresholded image in Matlab. Red “A” and blue “V” represent paired arterioles and venules, respectively. Periarteriole CFZ can be seen dark gaps around the arteriole (Red “A”) while the perivenule CFZ can be seen as dark gaps around the venule (Blue “V”). Periarteriole CFZ can be seen as larger than the perivenule CFZ.

Article Snippet: Figure 5 Raw and processed OCTA images showing a sex-matched example of the remodeling of the pCFZ in normal aging for a 20 × 20-degree region of the retina. ( a ) and ( d ) represent raw OCTA images of a 28 and 66-year-old cognitively unimpaired female, respectively. ( b ) and ( e ) represent corresponding vesselness filtered images in Matlab. ( c ) and ( f ) represent corresponding vesselness filtered and Otsu thresholded images in Matlab.

Techniques:

Journal: Scientific Reports

Article Title: OCTA reveals remodeling of the peripheral capillary free zones in normal aging

doi: 10.1038/s41598-021-95230-0

Figure Lengend Snippet: A vesselness filtered and Otsu thresholded montaged 20 × 20-degree OCTA image of the superficial vascular plexus in Matlab of a 63-year-old cognitively unimpaired male. The image shows the central fovea (FAZ area = 0.27 mm 2 ; FAZ effective diameter = 586 µm) and a paired arteriole (Red “A”) and venule (Blue “V”), 13.6 and 17.3 degrees, respectively, inferior to the fovea. Evenly sampled points around the arteriole or venule showing the periarteriole (70.2 µm) and perivenule (53.5 µm) CFZs are shown. The arteriole diameter = 96.0 µm and the venule diameter = 129 µm. Evenly sampled points include coordinates from the center of the fovea (green dot), points on the top/bottom edge of an arteriole (red dots) or venule (blue dots), and points from the middle of a capillary superior/inferior to an arteriole (red dots) or venule (blue dots).

Article Snippet: Figure 5 Raw and processed OCTA images showing a sex-matched example of the remodeling of the pCFZ in normal aging for a 20 × 20-degree region of the retina. ( a ) and ( d ) represent raw OCTA images of a 28 and 66-year-old cognitively unimpaired female, respectively. ( b ) and ( e ) represent corresponding vesselness filtered images in Matlab. ( c ) and ( f ) represent corresponding vesselness filtered and Otsu thresholded images in Matlab.

Techniques:

Journal: Scientific Reports

Article Title: OCTA reveals remodeling of the peripheral capillary free zones in normal aging

doi: 10.1038/s41598-021-95230-0

Figure Lengend Snippet: Raw and processed OCTA images showing a sex-matched example of the remodeling of the pCFZ in normal aging for a 20 × 20-degree region of the retina. ( a ) and ( d ) represent raw OCTA images of a 28 and 66-year-old cognitively unimpaired female, respectively. ( b ) and ( e ) represent corresponding vesselness filtered images in Matlab. ( c ) and ( f ) represent corresponding vesselness filtered and Otsu thresholded images in Matlab. Red “A” and blue “V” represent paired arterioles and venules, respectively. The dark gaps around the arteriole (periarteriole CFZ; 111 µm; vessel distance from fovea = 14.2 degrees) and venule (perivenule CFZ; 93.2 µm; vessel distance from fovea = 13.9 degrees) of the cognitively unimpaired older adult can be observed as larger than that around the arteriole (periarteriole CFZ; 73.4 µm; vessel distance from fovea = 13.8 degrees) and venule (perivenule CFZ; 57.4 µm; vessel distance from fovea = 16.1 degrees) of the young participant. Scale bar: 200 µm.

Article Snippet: Figure 5 Raw and processed OCTA images showing a sex-matched example of the remodeling of the pCFZ in normal aging for a 20 × 20-degree region of the retina. ( a ) and ( d ) represent raw OCTA images of a 28 and 66-year-old cognitively unimpaired female, respectively. ( b ) and ( e ) represent corresponding vesselness filtered images in Matlab. ( c ) and ( f ) represent corresponding vesselness filtered and Otsu thresholded images in Matlab.

Techniques: