The MIPI CSI-2 receiver capture pipeline is shown in This Figure.
This pipeline consists of eight components, six of which are controlled by the APU via an AXI4-Lite based register interface, one is controlled by the APU via an I2C register interface, and one is configured statically:
•The Sony IMX274 is a 1/2.5 inch CMOS digital image sensor with an active imaging pixel array of 3864H x2196V. The image sensor is controlled via an I2C interface using an AXI I2C Controller in the PL. It is mounted on a FMC daughter card and has a MIPI output interface that is connected to the MIPI CSI-2 RX Subsystem inside the PL. For more information, see the LI-IMX274MIPI-FMC data sheet [Ref 3].
•The MIPI CSI-2 Receiver Subsystem (CSI RX) includes a MIPI D-PHY core that connects four data lanes and one clock lane to the sensor on the FMC card. It implements a CSI-2 receive interface according to the MIPI CSI-2 standard v1.1. The subsystem captures images from the IMX274 sensor in RAW10 format and outputs AXI4-Stream video data. For more information, see the MIPI CSI-2 Receiver Subsystem Product Guide (PG232) [Ref 14].
•The AXI subset converter is a statically configured IP core that converts the raw 10-bit (RAW10) AXI4-Stream input data to raw 8-bit (RAW8) AXI4-Stream output data by truncating the two least significant bits (LSB) of each data word.
•The Demosaic IP core reconstructs sub-sampled color data for images captured by a Bayer color filter array image sensor. The color filter array overlaid on the silicon substrate enables CMOS image sensors to measure local light intensities that correspond to different wavelengths. However, the sensor measures the intensity of only one principal color at any location (pixel). The Demosaic IP receives the RAW8 AXI4-Stream input data and interpolates the missing color components for every pixel to generate a 24-bit, 8bpc RGB output image transported via AXI4-Stream. A GPIO is used to reset the IP between resolution changes.
•The Gamma LUT IP core is implemented using a look-up table (LUT) structure that is programmed to implement a gamma correction curve transform on the input image data. A programmable number of gamma tables enable having separate gamma tables for all color channels, in this case red, green, and blue. The Gamma IP takes AXI4-Stream input data and produces AXI4-Stream output data, both in 24-bit RGB format. A GPIO is used to reset the IP between resolution changes.
•The Video Processing Subsystem (VPSS) is a collection of video processing IP subcores. This instance is uses the Color Space Converter (CSC) configuration to perform color correction tasks including contrast, brightness, and red/green/blue gain control. The CSC takes AXI4-Stream input data and produces AXI4-Stream output data, both in 24-bit RGB format. A GPIO is used to reset the subsystem between resolution changes. For more information, see the Video Processing Subsystem Product Guide (PG231) [Ref 13].
•The Video Processing Subsystem (VPSS) is a collection of video processing IP subcores. This instance uses the VPSS only configuration, which provides scaling, color space conversion, and chroma resampling functionality. The VPSS takes AXI4-Stream input data in 24-bit RGB format and converts it to a 16-bit, 8bpc YUV 4:2:0 output format using AXI4-Stream. A GPIO is used to reset the subsystem between resolution changes.
•The Video Frame Buffer Write IP uses the same configuration as the one in the TPG and HDMI RX capture pipelines. It takes YUV 4:2:0 sub-sampled AXI4-Stream input data and converts it to memory-mapped AXI4 format which is written to memory as 16-bit packed YUYV. The memory-mapped AXI interface is connected to the HP1 high performance PS/PL port via an AXI interconnect. For each video frame transfer, an interrupt is generated. A GPIO is used to reset the IP between resolution changes.
Similar to the TPG and HDMI RX capture pipelines, all the IPs in this pipeline are configured to transport 2ppc, enabling up to 2160p60 performance.