import { S as SsimOptions } from './types-ClU9XBY2.js';

/**
 * Hitchhiker's SSIM (Structural Similarity Index)
 *
 * Reference:
 * A. K. Venkataramanan, C. Wu, A. C. Bovik, I. Katsavounidis, and Z. Shahid,
 * "A Hitchhiker's Guide to Structural Similarity,"
 * IEEE Access, vol. 9, pp. 28872-28896, 2021.
 * DOI: 10.1109/ACCESS.2021.3056504
 *
 * Reference implementation (C): https://github.com/utlive/enhanced_ssim
 * Licensed under BSD-2-Clause-Patent (Netflix, Inc.)
 *
 * This TypeScript implementation is independent, based on the published algorithm.
 * See ../../licenses/HITCHHIKERS-SSIM.md for detailed license information.
 *
 * Key improvements over standard SSIM:
 * 1. Uses rectangular windows instead of Gaussian windows
 * 2. Uses integral images (summed area tables) for O(1) window computation
 * 3. Uses Coefficient of Variation (CoV) pooling instead of mean pooling
 * 4. Self-Adaptive Scale Transform (SAST) for viewing distance adaptation
 * 5. Significantly faster than Gaussian-based SSIM (~4x speedup)
 */

/**
 * Hitchhiker's SSIM options
 */
interface HitchhikersSsimOptions extends SsimOptions {
    /** Dynamic range of the images (default: 255) */
    L?: number;
    /** Window stride for non-overlapping windows (default: windowSize for non-overlapping) */
    windowStride?: number;
    /** Use Coefficient of Variation pooling instead of mean (default: true) */
    covPooling?: boolean;
}
/**
 * Compute Hitchhiker's SSIM between two images using integral images
 *
 * @param image1 - First image data (RGBA format, 4 bytes per pixel)
 * @param image2 - Second image data (RGBA format, 4 bytes per pixel)
 * @param output - Optional output buffer for SSIM map visualization (RGBA format)
 * @param width - Image width in pixels
 * @param height - Image height in pixels
 * @param options - SSIM computation options
 * @returns SSIM score (0-1, where 1 is identical)
 *
 * @example
 * ```typescript
 * // Basic usage with default CoV pooling
 * const score = hitchhikersSSIM(img1, img2, undefined, width, height);
 *
 * // With mean pooling (traditional)
 * const score = hitchhikersSSIM(img1, img2, undefined, width, height, { covPooling: false });
 * ```
 */
declare function hitchhikersSSIM(image1: Uint8ClampedArray | Uint8Array | Buffer, image2: Uint8ClampedArray | Uint8Array | Buffer, output: Uint8ClampedArray | Uint8Array | Buffer | undefined, width: number, height: number, options?: HitchhikersSsimOptions): number;

export { type HitchhikersSsimOptions, hitchhikersSSIM as default, hitchhikersSSIM };