Architecture

In the OS system, the ISP firmware consists of the kernel driver and user mode ISP SDK. In this document, we only discuss the ISP SDK part. The ISP SDK consists of the IOCTL library, device library, control library, module library, sensor library, pipeline library, and ISP flow control application.

  • The IOCTL library provides the ISP register read/write and buffer allocate/release functions to service the module unit.
  • The device objects provide the basic device operations. For example, open/close/ioctl/init/allocate buffer/release buffer, etc.
  • The control objects include the 3A algorithm and other basic algorithms for adaptive control. For example, AE/AWB/SAT, etc. These adaptive controls are based on the ISO and color temperature.
  • The module objects provide the parameter conversion and the ISP register program.
  • The sensor library provides the exposure time and sensor gain calculation and program.
  • The pipeline objects provides the device/control/module management.
  • The “stf_isp_ctrl” application monitors the video device stream on/off and establishes/tears down the pipeline for the ISP adaptive control.
Figure 1. ISP SDK Architecture