Figure 1. Xilinx Zynq-7000 [1]

According to Xilinx [1], Field Programmable Gate Arrays (FPGAs) are semiconductor devices that are based around a matrix of configurable logic blocks (CLBs) connected via programmable interconnects. FPGAs can be reprogrammed to desired application or functionality requirements after manufacturing. This feature distinguishes FPGAs from Application Specific Integrated Circuits (ASICs), which are custom manufactured for specific design tasks. Although one-time programmable (OTP) FPGAs are available, the dominant types are SRAM based which can be reprogrammed as the design evolves.

Figure 2. OV7670 Camera [2]

In this project, FPGA (Figure 1) was applied to complete the gesture recognition work. This requires well combination of camera, monitor and strict algorithm. The specific aim of this project is providing a primary version of a game 'Fruit Ninja'. Although this game is simple with ARM, considerable work should be done on FPGA because students can only manipulate the logic gates to complete functions.
Moreover, the camera model is OV7670, which can be seen in Figure 2, is a low cost image sensor + DSP that can operate at a maximum of 30 fps and 640 x 480 ("VGA") resolutions, equivalent to 0.3 Megapixels. This preprocess can be configured via the Serial Camera Control Bus (SCCB) [2].

Reference:

[1] Xilinx, What is an FPGA? [Online]. Available: https://www.xilinx.com/products/silicon-devices/fpga/what-is-an-fpga.html
[2] Thaoyu Electronics, OV7670 Camera Module (With the AL433 FIFO) [Online]. Available: https://www.hotmcu.com/ov7670-camera-module-with-the-al433-fifo-p-304.html