Functions

Function Description

Vision Preprocessing Core (VPC): processes YUV and RGB images. It provides the following key functions:

Cropping: crops one or more selected regions of interest (ROIs) from one or more images.
Resizing: resizes an ROI (supporting uncompressed format) or multiple ROIs from a single image (supporting uncompressed format). 8K resizing and non-8K resizing are supported for images based on resolutions. The resizing modes include resizing an image without cropping it, resizing an image with the aspect ratio preserved, and more.
Overlaying: crops a selected ROI from the input image, resizes the cropped image, and pastes it in the specified region of the output image. The output image may be a blank image (when the allocated output buffer is empty) or an existing image (when an image has been read into the allocated output buffer). Overlaying is performed only when the output image is an existing image.
Stitching: crops selected ROIs from the input image, resizes the cropped ROIs, and loads them to the specified areas in the output image.
Image pyramid: successively downsamples an image using a Gaussian filter.
Histogram analysis: collects statistics on the pixel value distribution of each image channel (RGB/YUV).
Color remapping: remaps an image to a new one based on the given configuration.
Border making (or padding): creates a border around an image.
Format conversion: converts between RGB and YUV.
Image grayscale: converts a color image into a grayscale image. A YUV400 image is output. Note that grayscale input images produce only grayscale output images.
For Atlas training products : only the data of the Y component is extracted from the YUV420SP output image.

Function Support

The following table lists the functions supported by different versions.

Function	Atlas training products	Atlas inference products	Atlas 200I/500 A2 inference products	Atlas A2 training products / Atlas A2 inference products	Atlas A3 training products / Atlas A3 inference products
Cropping	√	√	√	√	√
Resizing	√	√	√	√	√
Overlaying	√	√	√	√	√
Stitching	√	√	√	√	√
Image pyramid	x	√	x	x	x
Histogram analysis	x	√	√	√	√
Remapping	x	√	√	√	√
Border making	x	√	√	√	√
Format conversion	√	√	√	√	√
Image grayscale	√	√	√	√	√

Function Diagrams

The following figures are for reference only. The alignment restrictions vary depending on the product model. For details, see the instructions of each function interface.

Figure 1 VPC function diagram (cropping + resizing + overlaying)

Figure 2 VPC function diagram (stitching)

Figure 3 Resizing with the aspect ratio preserved (paste ROI centered on the output image)

Due to different alignment constraints, Atlas training products and Atlas inference products support the resizing function below.

Figure 4 Resizing with the aspect ratio preserved (paste ROI vertically centered on the output image)

Figure 5 Resizing with the aspect ratio preserved (paste ROI horizontally centered on the output image)

Reference

The following figure shows the component layout of the RGB and YUV formats. Two YUV420SP images are used as examples for semi-planar format and an ARGB image is used as an example for Packed and RGB formats.

Parent topic: VPC