This browser cannot report the window's size in exact display pixels at the current scaling, so the pattern may be resampled and its bar patterns may not show at their true periods. Set browser zoom to 100% and display scaling to 100% or 200%, or use another browser.

PATTERN DESCRIPTION: This pattern provides visual evaluation of display performance based on the AAPM TG18-OIQ specification (equivalent to TG18-QC without Cx patterns). It scales to fill the browser window using a 102-pixel grid pitch referenced to a 1024x1024 pattern. GRAY STEPS: - 16 cells covering gray levels 8–248 in equal steps (16 gray levels per step) - Include low-contrast corner patches (±4 gray levels) - Black cell (0): centered 50% sub-patch at gray 13 (5%) - White cell (255): centered 50% sub-patch at gray 242 (95%) LUMINANCE RAMPS: - Left ramp: 255 (top) → 0 (bottom) - Right ramp: 0 (top) → 255 (bottom) WINDOW RESPONSE BANDS (above gray step grid): - Outer band: black over white - Inner strips: white over black - For evaluating video signal artifacts QUALITY CONTROL PANELS (below gray step grid): - Three regions: black (0), mid-gray (128), white (255) - Each contains "QUALITY CONTROL" text with per-letter contrast - Q = ±14 gray levels, decreasing by 1 to L = ±1 gray level CROSSTALK SECTION (above window bands): - White band over black band - For evaluating pixel crosstalk SPATIAL RESOLUTION FEATURES: - 5 instances: center and four window corners - Left half: high contrast (0/255) - Right half: low contrast (128/130) - Each half has 4 quadrants: vertical 2 px/lp, vertical 4 px/lp, horizontal 2 px/lp, horizontal 4 px/lp - Bar periods are fixed in display pixels and do not change with zoom USAGE: - On a DICOM-conformant display, all low-contrast corner patches should be equally visible - The high-contrast line pairs in the center and corners should appear crisp - All letters of QUALITY CONTROL should be visible - The 0/5% and 95/100% patches are not a reliable indicator of display performance CONTROLS: - Click and drag: Pan - Mouse wheel: Zoom (1x–10x) - ⟲ or R: Reset view - ? or H: Show/hide this help - Window resize: Auto-reset NOTES: - Bar patterns are drawn in display pixels at any OS scaling or browser zoom. A browser that cannot report the exact canvas size at a fractional scaling shows a notice on load. - macOS: use the display's default resolution. Scaled resolutions resample the whole screen after the browser draws, which no web page can detect or undo. - Pattern scales to fit the window dimensions