Openmv (I) -- basic introduction and hardware architecture

1. OpenMV Introduce

1.1 What is? OpenMV

OpenMV It is based on MicroPython Sponsored Open source machine vision project , The aim is to create a low cost , Scalable , Use python Driven machine vision module .OpenMV Carrying MicroPython Interpreter , So that it can be carried out on the embedded end python Development , About MicroPython Please refer to my previous blog column ：MicroPython. OpenMV be based on 32 position ,ARM Cortex-M7 Kernel OpenMV-H7, Combined with various cameras , It can realize a variety of machine vision applications , such as Face detection , Object classification etc. .

1.2 OpenMV And OpenCV

OpenMV The full name is open machine vision, Is an open source machine vision framework , and OpenCV yes open computer vision, Is an open source computer vision library , Can run in Linux、Windows、Android and Mac OS On the operating system . The same thing between the two is that they are both tools to realize visual applications , The difference is OpenMV Can run in MCU On , such as ARM Of M Series of chips , and OpenCV It can run in a variety of architectures CPU On .OpenMV The advantage of is lightweight , Can run in MCU On , But when processing high complexity image information and high-speed image information , Ability is obviously weaker than OpenCV. The two correspond to different application scenarios , For occasions that require high-speed processing of complex image information ,OpenCV Be competent for , For product volume , When the cost is relatively high and the processing of image information is relatively simple ,OpenMV It is a very advantageous reference scheme .

2. Hardware architecture

2.1 OpenMV-H7

OpenMV-H7 It is low power consumption Python3 Programmable machine vision hardware , Combined with the camera, it can support a wide range of image processing functions and Neural Networks .OpenMV-H7 Use cross platform IDE Programming , The IDE Allows you to view the frame buffer of the camera 、 Access sensor controls 、 adopt USB Serial （ or WiFi/BLE（ If available ） Upload the script to the camera .OpenMV-H7 The substrate is based on 400MHz Running down STM32H743 MCU, have 1MB SRAM、2MB Flash memory 、FPU、DSP And hardware JPEG Encoder . The base plate adopts modular sensor design , Separate the sensor from the camera . The modular sensor design enables the camera to support multiple sensors , Include OV7725、MT9V03x Global shutter sensors and FLIR Lepton 1、2 and 3 Thermal sensors . chart 1 This is what you see OpenMV-H7 The physical picture of ：

chart 1. OpenMV-H7 The base plate

OpenMV-H7 It can be applied in many fields, such as ： Smart home , Robot navigation , Industrial applications such as object detection and tracking .

2.2 STM32H743

STM32H743 yes OpenMV-H7 Of the substrate MCU, It's a 32 Bit ,Cortex-M7 Core chip , This kernel has Double precision floating-point processing unit FPU, The highest frequency reaches 400MHz, And built in 1M RAM, 2M Flash. chart 2 It shows STM32H743 Chip architecture .

chart 2. STM32H743 framework

2.3 Schematic diagram

OpenMV-H7 The schematic diagram of the base plate is shown in the figure 3 Shown , It can be seen that , The schematic diagram is relatively simple , The core part is STM32H743 The smallest system of , The most basic applications can be done by adding power modules and camera interfaces to the periphery .OpenMV-H7 In addition, the base plate adds USB, I/O Leading out of the interface ,SD card ,RGB Of LED, as well as Debug Interface . In specific project application , We can reasonably design our own OpenMV The base plate , Thereby reducing the volume and cost of circuit boards .

chart 3. OpenMV Schematic diagram