acldvppImgToTensor

Applicability

Function Usage

• Description: normalizes images by subtracting the mean value and then dividing the result by the standard deviation, where the mean value is fixed at 0 and the standard deviation is fixed at 255. Therefore, this operator is used only to normalize UINT8 images with range [0, 255] to FLOAT images with range [0.0, 1.0].
• Formula:

  out = (self - mean) / std

Prototype

Each operator has two-phase API calls. First, acldvppImgToTensorGetWorkspaceSize is called to calculate the required workspace size based on the computation process. Then, acldvppImgToTensor is called to perform computation. The two-phase APIs are as follows:

• First-phase API:

  1	acldvppStatus acldvppImgToTensorGetWorkspaceSize(const aclTensor* self, aclTensor* out, uint64_t* workspaceSize, aclOpExecutor** executor)

• Second-phase API:

  1	acldvppStatus acldvppImgToTensor(void* workspace, uint64_t workspaceSize, aclOpExecutor* executor, aclrtStream stream)

acldvppImgToTensorGetWorkspaceSize

• Parameters:
  • self: input tensor of the operator, which is of the aclTensor type created by calling aclCreateTensor (the tensor data is stored on the device). The value of dataType of the input tensor can be UINT8, the value of Format can be NCHW or NHWC, and non-contiguous tensors are not supported. The value of N can be 1 or left empty, and the value of C can be 1 or 3 (1: input GRAY image; 3: input RGB image).
  • out: output tensor of the operator, which is of the aclTensor type created by calling aclCreateTensor (the tensor data is stored on the device). The value of dataType of the output tensor can be FLOAT, non-contiguous tensors are not supported, and the values of Format and Shape must be the same as those of self.
  • workspaceSize: size of the workspace to be allocated on the device.
  • executor: operator executor, containing the operator computation process.
• Returns:

  acldvppStatus status code. For details, see acldvpp Return Codes.

acldvppImgToTensor

• Parameters:
  • workspace: address of the device memory allocated by calling aclrtMalloc. The size of the device memory is specified by workspaceSize.
  • workspaceSize: The value must be the same as that obtained by calling acldvppImgToTensorGetWorkspaceSize.
  • executor: op executor, which contains the operator computation process and is the same as the executor of the acldvppImgToTensorGetWorkspaceSize API.
  • stream: stream for executing a task, which can be a created stream for saving resources or newly created by calling aclrtCreateStream.
• Returns:

  acldvppStatus status code. For details, see acldvpp Return Codes.

Constraints

The supported image resolution ranges from 6 x 4 to 4096 x 8192.