Hexagon is a Digital Signal Processor, which is a 32-bit based multi-threaded CPU Architecture developed by Qualcomm technologies. The Hexagon Architecture was developed to deliver performance for the low power over a variety of applications. It has features such as hardware assisted multi-threading, privilege levels, VLIW(Very Large Instruction Word) , SIMD(Single Input Multiple Data) and instructions geared toward efficient signal processing.
on 24th August 2015 @Hotchips,Qualcomm revealed about their new Digital Signal Processor(DSP) in Snapdragon 820.Have a Look at the architecture.
This new compute DSP consist of Vector Extensions Coprocessor,able to process audio,video and images at low power.If talk about its performance,it can achieve performance/mW better than the CPU.
The main problem of today’s smartphone camera is how compute engine is achieved for producing Low Light Photos. The result is noisy. This new DSP outcast previous generations processing using HVX acceleration and local tone mapping and temporal noise reduction to brighten dark videos and photos.
HVX is a 1024-bit wide extensions set used for pixel data parallelism. It has emphasis on Low power precision fixed point and special Instruction set Architecture. It also has large primary cache is used for Image processing. HVX is better than existing “Neon” which is compliant with co-processor FPU for SIMD processing. The advantage in computing is 8 times more compute/cycle,L1 Efficient Data Sharing. Neon or CPU used L1 & L2 for image data, but HVX uses L2 cache for image Data processing. This processing will create low overhead on the CPU.
In above comparison, Quad core Krait CPU with Neon optimizations which is clocked at 2.65 GHz and a single DSP/HVX clocked at 725 MHz, HVX performs better in terms of latency and consuming less power.
Qualcomm snapdragon 820 which is the high-end chipset coming from qualcomm with Hexagon Vector eXtensions(HVX) is going to bring new image processing and computer vision capabilities. It will improve capturing low light , Detail Enhancement in images.