export type ColorHex = string;
/** @internal */
export declare function colorDistance(a: ColorHex, b: ColorHex): number;
/** @internal */
export declare function concealmentScore(entityColors: readonly ColorHex[], backgroundColors: readonly ColorHex[]): number;
export interface ConcealmentTarget {
    id: string;
    entityColors: readonly ColorHex[];
    backgroundColors: readonly ColorHex[];
}
export interface ConcealmentSample {
    id: string;
    score: number;
    concealed: boolean;
    dwellSeconds: number;
}
/** Plain JSON state of a {@link ConcealmentSensor}: seconds each target has stayed concealed. */
export interface ConcealmentSensorState {
    dwell: Record<string, number>;
}
export interface ConcealmentSensor {
    tick(targets: readonly ConcealmentTarget[], dt: number): ConcealmentSample[];
    reset(id?: string): void;
    snapshot(): ConcealmentSensorState;
    restore(next: ConcealmentSensorState): void;
}
/** @internal */
export declare function createConcealmentSensor(config?: {
    threshold?: number;
}): ConcealmentSensor;