/**
 * WebGPU inference engine for PP-OCRv6 small detection model.
 *
 * Architecture (small_det):
 *   MobileNetV3-like backbone (SE blocks, GELU activations)
 *   → FPN neck with 6x Resize+Conv
 *   → DB head with 2× ConvTranspose (stride=2) up to full resolution
 *   → Sigmoid → probability map [1, 1, H, W]
 *   → CPU: DBPostProcess → bounding boxes
 */
export interface DetBox {
    x0: number;
    y0: number;
    x1: number;
    y1: number;
    confidence: number;
}
export interface DetResult {
    boxes: DetBox[];
    timeMs: number;
}
export interface PaddleDetOptions {
    modelUrl: string;
    onProgress?: (stage: string, pct?: number) => void;
}
export declare class PaddleDetEngine {
    device: GPUDevice;
    private pipelines;
    private initializers;
    private activations;
    private parsedGraph;
    private onProgress?;
    private uniformBuffers;
    private shadowShapeValues;
    private resolveTensor;
    init(options: PaddleDetOptions): Promise<void>;
    private compileShaders;
    private loadModel;
    private uploadAsF32;
    private alloc;
    private allocTensor;
    private makeUniform;
    private makeZeroUniform;
    private parseGraph;
    /**
     * Run detection on a canvas. Returns detected text region boxes.
     */
    detect(image: HTMLCanvasElement | HTMLImageElement): Promise<DetResult>;
    /**
     * Resize so shorter side = 736 (preserving aspect ratio, max long side = 4000),
     * convert to BGR float32 [1,3,H,W] with ImageNet normalization.
     */
    private preprocessToTensor;
    private walkGraph;
    private dispatchNode;
    private dispatchConv;
    private dispatchUnaryElementwise;
    private dispatchRelu;
    private dispatchHardSigmoid;
    private dispatchSigmoid;
    private dispatchTanh;
    private dispatchErf;
    private dispatchExp;
    private dispatchSqrt;
    private dispatchNeg;
    private dispatchBinaryBroadcast;
    private dispatchGlobalAveragePool;
    private dispatchMaxPool;
    private dispatchReduceMean;
    private dispatchResize;
    private dispatchConvTranspose;
    private dispatchConcat;
    private dispatchShape;
    private dispatchGather;
    private dispatchBatchNorm;
}
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