Test Patterns

LED.FYI includes a comprehensive set of built-in test patterns for display calibration, verification, and troubleshooting.

Available Patterns

Surface Info

Displays a grid overlay with metadata about the surface, including its name, resolution, and specifications. Useful for identifying surfaces in multi-screen setups.

Panel Map

The most feature-rich test pattern. Visualizes the physical panel grid with data path overlays:

• Panel coordinates — Shows grid position labels (e.g., A1, B2) on each panel
• Data path arrows — Arrows showing the signal flow direction between panels
• String numbers — Numbered markers at the start of each string
• String colors — Each string gets a unique color for easy identification
• Disabled panels — Shown as black boxes with a red X

Panel Map Options

Extensive customization is available:

Option	Values
Background	Checkerboard, solid color, or gradient
Panel borders	Show/hide borders between panels
Screen border	Show/hide the outer screen border
Coordinates	Show/hide panel coordinate labels
Coordinate style	A,1 (alpha-numeric) / 1,A / 1,1 / A,A
Coordinate position	Center, top-left, top-right, bottom-left, bottom-right
Delimiter	Comma, period, space, or none
Data path	Show/hide arrows and string numbers
Surface name	Show/hide surface name overlay
Scale overlay	Concentric circles and diagonal lines

When the surface is linked to a screen, the Panel Map uses actual panel data — reflecting your real wiring configuration, string assignments, and disabled panel status.

Solid Color

Fills the entire surface with a user-selected color. Useful for:

• Testing uniform brightness across the LED wall
• Identifying dead pixels or module issues
• Verifying color accuracy

SMPTE RP 219 HD Bars

Professional broadcast-standard color reference bars following the SMPTE RP 219-2002 specification:

• Top section — 75% color bars (white, yellow, cyan, green, magenta, red, blue)
• Middle section — Chroma setting signal
• Lower section — Luminance ramp (black to white gradient)
• Bottom section — PLUGE (Picture Line-Up Generation Equipment) for black level calibration
• Side panels — 40% and 15% gray for 16:9 adaptation

This is the industry standard for display calibration and color accuracy verification.

Scrolling Lines (Horizontal)

Animated horizontal white stripes scrolling across a black background. Useful for:

• Verifying smooth motion rendering
• Checking for tearing or stuttering
• Testing refresh rate performance

Scrolling Lines (Vertical)

Same as horizontal but with vertical stripes. Useful for testing in the perpendicular direction.

Scrolling Lines (Diagonal)

45-degree diagonal scrolling lines. Tests both horizontal and vertical refresh simultaneously and reveals issues at panel seams.

Grid Pattern

Black background with white grid lines and a red center crosshair with circle. Useful for:

• Alignment and calibration between panels
• Verifying pixel-accurate rendering
• Checking for geometric distortion

Gradient Sweep

Smooth HSL color gradient that animates through the full spectrum. Tests:

• Color transition smoothness
• Banding artifacts
• Bit depth adequacy (8-bit vs 10-bit vs 12-bit)

Checkerboard

Alternating two-color checkerboard pattern. Useful for:

• Pixel-level inspection
• Verifying 1:1 pixel mapping
• Checking for aliasing or scaling artifacts

4:4:4 Chroma Test

A specialized test pattern that detects lossy color compression:

• Section 1 — Red/Cyan 1px alternating lines
• Section 2 — Blue/Yellow 1px alternating lines
• Section 3 — Magenta/Green 1px alternating lines
• Section 4 — Colored blocks with white text

If any color fringing or blurring is visible, the signal path is using chroma subsampling (4:2:0 or 4:2:2) instead of full 4:4:4. This is critical for LED output quality — LED walls require uncompressed 4:4:4 for pixel-perfect rendering.

Customization

Most test patterns support customization options:

• Colors — Custom color selection via hex codes
• Animation speed — For animated patterns
• Line width / Grid size — Pattern dimensions
• Opacity and borders — Visual styling
• Font scaling — Text size for coordinate labels