YUV400_U8 to Gray

Assume that AIPP inputs a YUV400_U8 image and outputs a gray image. The input image size is 224 x 224, and the valid data region starts from the (0, 0) pixel coordinates in the upper-left corner. For the original network model, C is 1, and H and W are 220.

• Enable the cropping (crop) function.
• Set the horizontal and vertical coordinates (load_start_pos_h and load_start_pos_w) of the cropping start position to 0.
• Do not need to configure the crop_size_w and crop_size_h parameters. In this case, the width and height of the cropped image size (crop_size[W|H]) are obtained from the width and height of the --input_shape option used during model conversion, and the 220 x 220 region is selected starting from the (0, 0) coordinates.
• Do not need to configure the csc_switch. For the same original network model, if AIPP inputs a YUV420SP_U8 image, the same set of AIPP configurations can be used. In other words, only the data of Y channel is selected.

aipp_op{
    aipp_mode: static
    csc_switch: false
    crop: true
    input_format: YUV400_U8
    load_start_pos_h: 0
    load_start_pos_w: 0
    src_image_size_w: 224
    src_image_size_h: 224
    # The normalization parameters are set as required. The following values are examples only.
    mean_chn_0: 128
    min_chn_0: 0.0
    var_reci_chn_0: 0.00390625
}