AMTBioFeature WASM JS API 文档

所有导出的 C 函数可通过 Module._FunctionName() 在 JavaScript 中直接调用。WASM 模块通过 createAMTBioFeature() 加载。

Module Loading

import createAMTBioFeature from './amtbiofeature.js';
const Module = await createAMTBioFeature({ print, printErr });

Lifecycle

Function	Return	Description
`Module._AMTBioFeatureWasm_Init(model_data, model_size, config_data, config_size)`	`int`	Initialize SDK (pass `null, 0, null, 0` for defaults)
`Module._AMTBioFeature_Init()`	`int`	Alias — same as above with no args; returns 0 on success
`Module._AMTBioFeature_Release()`	`void`	Release SDK and free all internal resources
`Module._AMTBioFeature_ReleaseHandle(handle)`	`void`	Release a detection handle returned by DetectPixels
`Module._AMTBioFeature_Version()`	`char*`	Return version string (use `Module.UTF8ToString()`)

Configuration

Function	Return	Description
`Module._AMTBioFeature_SetMinSize(min_size, cls)`	`void`	Set minimum object size in px (`cls=-1` for all, `1` for palm)
`Module._AMTBioFeature_SetMaxCount(max_count, cls)`	`void`	Set max detections per frame
`Module._AMTBioFeature_SetThreshold(first, second, cls)`	`void`	Set score thresholds (range 0.0–1.0)
`Module._AMTBioFeature_SetInputSize(width, height)`	`void`	Set expected input image dimensions

Detection

Function	Return	Description
`Module._AMTBioFeature_DetectPixels(handlePtr, dataPtr, width, height, channels, format)`	`int`	Zero-copy palm detection from raw RGB pixels. `handlePtr` is output (`int*`), `format=0` for RGB. Returns 0 on success.

Usage:

const rgb = new Uint8Array(pixelCount * 3); // RGB888 pixels
const dataPtr = Module._malloc(rgb.length);
Module.HEAPU8.set(rgb, dataPtr);
const handlePtr = Module._malloc(4);

const ret = Module._AMTBioFeature_DetectPixels(
  handlePtr, dataPtr, width, height, 3, 0
);

if (ret === 0) {
  const handle = Module.getValue(handlePtr, 'i32');
  // ... get results ...
  Module._AMTBioFeature_ReleaseHandle(handle);
}
Module._free(handlePtr);
Module._free(dataPtr);

Results

Function	Return	Description
`Module._AMTBioFeature_GetObjectCount(handle)`	`int`	Number of detected objects
`Module._AMTBioFeature_GetObject(handle, index, objPtr)`	`int`	Populate `TObject` struct at `objPtr`. Returns 0 on success.

TObject struct layout (52 bytes):

Offset	Type	Field
`0`	`i32`	`class_id` (1 = palm)
`4`	`float`	`box.x`
`8`	`float`	`box.y`
`12`	`float`	`box.width`
`16`	`float`	`box.height`
`20`	`i32` (pointer)	`landmarks` pointer to `TLandmark` array
`24`	`i32`	`landmark_count` (9 for palm)
`28`	`float`	`yaw`
`32`	`float`	`roll`
`36`	`float`	`pitch`
`40`	`float`	`score` (0.0–1.0)
`44`	`i32`	`track_id`
`48`	`i32`	`state`

Quality & Direction

Function	Return	Description
`Module._AMTBioFeature_GetQualityColor(handle, index, scorePtr)`	`int`	Get visible-light palm quality score (0–100). Returns > 0 on success.
`Module._AMTBioFeature_GetDetectionQuality(handle, index, scorePtr)`	`int`	Get overall detection quality score. Returns > 0 on success.
`Module._AMTBioFeature_GetPalmDirection(handle, index, scorePtr)`	`int`	Get palm direction: >= 0.5 = left hand, < 0.5 = right hand. Returns 0 on success.

License

Function	Return	Description
`Module._AMTBioFeature_CheckLic()`	`int`	Returns 0 if license is valid
`Module._AMTBioFeature_SetLic(content)`	`int`	Set license key string. Returns 0 on success.

Memory (Low-level)

Function	Description
`Module._malloc(size)`	Allocate `size` bytes in WASM linear memory, return pointer
`Module._free(ptr)`	Free previously allocated memory
`Module.HEAPU8`	`Uint8Array` view of WASM memory for reading/writing pixel data
`Module.getValue(ptr, type)`	Read a value at `ptr` (`'i32'`, `'float'`, etc.)
`Module.UTF8ToString(ptr)`	Convert null-terminated C string to JS string

Complete Example

import createAMTBioFeature from './amtbiofeature.js';

const Module = await createAMTBioFeature();

// Initialize
Module._AMTBioFeature_Init();

// Configure for palm detection
Module._AMTBioFeature_SetMinSize(80, 1);    // cls=1 = palm
Module._AMTBioFeature_SetMaxCount(1, 1);
Module._AMTBioFeature_SetThreshold(0.4, 0.5, 1);

// Prepare RGB888 pixel data
const dataPtr = Module._malloc(width * height * 3);
Module.HEAPU8.set(rgbPixels, dataPtr);

// Detect
const handlePtr = Module._malloc(4);
const ret = Module._AMTBioFeature_DetectPixels(
  handlePtr, dataPtr, width, height, 3, 0
);

if (ret === 0) {
  const handle = Module.getValue(handlePtr, 'i32');
  const count = Module._AMTBioFeature_GetObjectCount(handle);

  for (let i = 0; i < count; i++) {
    const scorePtr = Module._malloc(4);

    Module._AMTBioFeature_GetQualityColor(handle, i, scorePtr);
    const quality = Module.getValue(scorePtr, 'float');

    Module._AMTBioFeature_GetPalmDirection(handle, i, scorePtr);
    const direction = Module.getValue(scorePtr, 'float');
    const hand = direction >= 0.5 ? 'Left' : 'Right';

    Module._free(scorePtr);
  }

  Module._AMTBioFeature_ReleaseHandle(handle);
}

Module._free(handlePtr);
Module._free(dataPtr);