Image Processing Filters

Edges & Gradient (9)

• Canny edge detection — classic two-threshold edge detector with hysteresis
• Sobel edges — first-order gradient magnitude
• Scharr edges — better small-kernel alternative to Sobel
• Laplacian edges — second-order edge response
• Hough lines — detect straight lines
• Hough circles — detect circular shapes
• Contour outlines — find and draw region boundaries
• Harris corners — classic corner detector
• Good features to track — Shi-Tomasi corners

Thresholding (2)

• Binary threshold — fixed-cutoff black/white
• Adaptive threshold — local-mean threshold for uneven lighting

Morphology (7)

• Erode — shrink bright regions
• Dilate — grow bright regions
• Opening — erode then dilate
• Closing — dilate then erode
• Morphological gradient — dilation minus erosion
• Top-hat — isolate bright details
• Black-hat — isolate dark details

Smoothing & Sharpening (7)

• Gaussian blur — smooth noise with a Gaussian kernel
• Median blur — salt-and-pepper noise removal
• Box blur — uniform-kernel averaging
• Bilateral filter — edge-preserving smoothing
• Unsharp mask — photographic sharpening
• Sharpen — 3×3 sharpening kernel
• Emboss — raised-relief effect

Color & Tone (11)

• Grayscale — convert to luminance
• Invert — photo-negative
• Sepia — warm vintage tone
• Histogram equalization — stretch contrast
• CLAHE — adaptive contrast equalization
• Gamma correction — non-linear brightness
• Color isolation — HSV range mask
• Channel split — R, G, B side-by-side
• HSV view — visualize the HSV channels
• Posterize — reduce intensity levels
• White balance — gray-world correction

Geometry (5)

• Rotate — rotate around center
• Flip — mirror horizontally / vertically
• Resize — scale up or down
• Perspective warp — 4-point transform
• Affine shear — 2×3 affine transform

Effects (6)

• Pencil sketch — photo to pencil drawing
• Cartoon effect — smoothed colors plus edge mask
• Pixelate — blocky downscale
• Vignette — radial darkening
• Oil paint — bilateral plus quantize
• Denoise — non-local means / bilateral

Analysis (3)

• FFT magnitude — frequency-domain spectrum
• RGB histogram — per-channel intensity chart
• K-means color quantize — cluster pixels into K colors