/**
 * Image Preprocessor for TFLite Models
 *
 * Converts images to the format expected by TFLite models:
 * - Resized to model input size (e.g., 640x640)
 * - Normalized to [0, 1] range
 * - As Float32Array in NHWC format (batch, height, width, channels)
 *
 * This implementation uses react-native-skia for image manipulation.
 * Install with: npm install @shopify/react-native-skia
 */
export interface PreprocessOptions {
    /** Target width (default: 640) */
    width?: number;
    /** Target height (default: 640) */
    height?: number;
    /** Normalize to [0, 1] range (default: true) */
    normalize?: boolean;
    /** Whether to apply letterboxing to maintain aspect ratio (default: true) */
    letterbox?: boolean;
}
export interface PreprocessResult {
    /** Preprocessed pixel data as Float32Array */
    data: Float32Array;
    /** Original image width */
    originalWidth: number;
    /** Original image height */
    originalHeight: number;
    /** Scale factors for mapping back to original */
    scale: {
        x: number;
        y: number;
    };
    /** Padding applied (if letterboxing) */
    padding: {
        x: number;
        y: number;
    };
}
/**
 * Preprocess an image for TFLite model inference
 *
 * @param uri Image URI (file:// or http://)
 * @param options Preprocessing options
 * @returns Preprocessed image data
 */
export declare function preprocessImage(uri: string, options?: PreprocessOptions): Promise<PreprocessResult>;
/**
 * Preprocess a VisionCamera frame for TFLite inference
 *
 * This requires vision-camera-resize-plugin to be installed:
 * npm install vision-camera-resize-plugin
 *
 * Usage in a frame processor:
 * ```
 * const frameProcessor = useFrameProcessor((frame) => {
 *   'worklet';
 *   const resized = resize(frame, {
 *     size: { width: 640, height: 640 },
 *     pixelFormat: 'rgb',
 *     dataType: 'float32',
 *   });
 *   const result = model.runSync([resized]);
 *   // Process result...
 * }, [model]);
 * ```
 */
export declare function getFrameProcessorInstructions(): string;
/**
 * Convert Float32Array from HWC to NHWC format (add batch dimension)
 */
export declare function addBatchDimension(data: Float32Array): Float32Array;
/**
 * Check if Skia is available for image preprocessing
 */
export declare function isSkiaAvailable(): boolean;
/**
 * Initialize Skia module (call before using Skia-dependent functions)
 * @returns true if Skia was loaded successfully
 */
export declare function initSkia(): Promise<boolean>;
/**
 * Check if resize plugin is available for frame processing
 */
export declare function isResizePluginAvailable(): Promise<boolean>;
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