Ridge Counting
Definition
For loop patterns: the number of ridges crossing an imaginary straight line drawn from core to delta, excluding the core and delta ridges themselves. The resulting integer is part of the Henry sub-classification formula.
- Applies to
- Loop patterns
- Counted
- Ridges crossing the core-to-delta line
- Excluded
- The core and delta ridges themselves
- Use
- Henry sub-classification formula
Common questions
Why are the core and delta ridges themselves excluded from the count?+
Including them would make the count inconsistent between examiners depending on how the core or delta boundary is defined, so the convention excludes both endpoints and counts only the ridges crossing the line between them.
How does ridge count affect Henry sub-classification?+
Loops are further divided into groups based on whether the ridge count falls above or below a set threshold, which refines the classification beyond the basic loop, whorl or arch pattern type.
Related terms
- ACE-V
- Analysis, Comparison, Evaluation, Verification: the four-stage method for latent print examination used by accredited forensic fingerprint laboratories. Analysis examines the latent in...
- Arch
- A fingerprint pattern in which ridges flow across from one side to the other without recurving and without enclosing a central area....
- Core
- The approximate centre of a fingerprint pattern. In a loop, it is identified as the innermost recurving ridge's peak or the tip...
- Delta (Triradius)
- The point of convergence of three ridge systems in a loop or whorl, visible as a Y-junction or triangular confluence. Loops have...
- Henry Classification System
- The fingerprint filing and retrieval system developed by Edward Henry with Haque and Bose in Bengal in the 1890s and adopted by...
- Level 1 Detail
- In ACE-V, the broadest level of information extracted from a fingerprint: the overall ridge flow and pattern type (arch, loop, whorl). Level...
- Loop
- A fingerprint pattern in which ridges enter from one side, recurve, and exit on the same side. The most common pattern type...
- Ridge Tracing
- For whorl patterns: following the ridge issuing from the inner side of the left delta toward the right delta and recording whether...
- Whorl
- A fingerprint pattern in which at least one ridge makes a complete circuit around a central area, or forms a related closed...