what is isp ?(image signal processor)

 

Image Signal Processor, "ISP",

is a core device of camera systems.

when the sensor senses the light from the camera then it needs to process it with the help of a processor, it can not be done by the primary processor of the system because it is not optimized for processing the image signals. ISPs are specially designed to process the image signals.

Image Signal Processor, “ISP”, is a core device of camera systems. so it can process efficiently, fastly, and safely without losing any information from the picture.

o wThe ISP equips a high-performance image signal processing engine developed by and executes processes like demosaicing, noise reduction, auto exposure, autofocus, and auto white balance in high speed and high quality. ISP（Image Signal Processor ) 
An image signal processor, also called image processing engine, is a specialized digital signal processor used for image processing in digital cameras, mobile phones or other devices. 

nowadays the cameras are including more and more features like artificial intelligence(AI), beautification mode and more other features. this is possible only because of the dedicated Image Signal Processing(ISP) unit.

So what purpose does ISP have? Well, pixels are sensitive to light between some set of wavelengths, essentially they’re color agnostic. The way to get a color image out is to put a filter on top, usually a bayer pattern color filter, then interpolate the color of the pixels adjacent. Your 8 MP CMOS doesn’t sense red green and blue for each pixel, it senses one color for each, then ISP guesses the color based on what’s next to it. This is called demosaicing, and it’s probably the primary job of ISP, and there are many secret sauce methods to computing this interpolated image. In addition, ISP does all the other housekeeping, it controls autofocus, exposure, and white balance for the camera system. Recently correcting for lens imperfections like vignetting or color shading imparted by the imperfect lens system (which you’ll add right back in with Instagram, you heathen) has been added, along with things like HDR recombining, noise reduction, another filtering, face or object detection, and conversion between color spaces. There’s variance between the features that ISP does, but this is really the controller for getting that bayer data into a workable image array. 

A normal ISP has the following properties.

1. Bayer transformation 
2. Demosaicing
3. Noise reduction
4. image sharpening
5. beautification
6. AI features
7. face detection

some of the ISP manufactures are following.

• Canon - DIGIC (based on Texas Instruments OMAP)
• Casio - EXILIM engine
• Epson - EDiART
• Fujifilm - EXR III or X Processor Pro
• Google - Pixel Visual Core
• Leica - MAESTRO (based on Fujitsu Milbeaut)
• Nikon - Expeed (based on Fujitsu Milbeaut)
• Panasonic - Venus Engine (based on Panasonic MN103/MN103S)
• Ricoh - GR engine (GR digital), Smooth Imaging Engine
• Samsung - DRIMe (based on Samsung Exynos)
• Sharp - ProPix
• Sony - Bionz
• HTC - ImageSense .