Inarguably, camera performance has become increasingly important across multiple industrial applications to solve real-world business challenges and meet customer expectations. Hence, camera manufacturers have been working doubly hard to enhance image quality while adding new embedded functionalities.
One of the important yet complicated parts of the process is capturing light from the camera sensor before transforming it into high-quality images. It involves a significant amount of processing expertise. Fortunately, embedded vision cameras come equipped with a dedicated ISP to handle the process effectively and effortlessly.
As the name implies, the Image Signal Processor (ISP) is used for processing images in embedded vision camera systems. The ISP also performs other operations on the captured image such as demosaicing, denoising, and auto functions that help deliver an enhanced image. Through this blog, we hope to bring to light some of the basics regarding ISP tuning, as well as the significance of using an external ISP in your imaging solution.
What is ISP Tuning?
ISP tuning is the process of adjusting an image signal processor to optimize performance and convert RAW images from image sensors into high-quality images.
Let’s look at the image processing pipeline used by ISPs.
In an image sensor, each pixel records only one of three colors (Red, Green, Blue) filtered by the Bayer filter mosaic. ISP interpolates a set of complete red, green, and blue values for each point. Demosaicing is, basically, a part of the image processing pipeline used by ISPs to reconstruct a full-color image from the Bayer pattern images.
With the presence of noise, possible subsequent image processing tasks, such as video processing, image analysis, and tracking, are adversely affected. Image signal processors apply denoising techniques to the data of images to mitigate noise.
ISP ensures auto-exposure capabilities, which is the automatic fine-tuning of image brightness – according to the amount of light that reaches the camera sensor.
Auto white balance:
ISP applies color correction matrices in the captured camera image to adjust the colors and ensure proper color fidelity in the captured image.
Importance of using an external ISP in imaging solutions
Not all application processors come with ISPs. Using one which doesn’t have an ISP can lead to decreased application performance. In such scenarios, an external image signal processor can be used to get the best out of the image sensor. Since ISPs in processors have limited functionalities and tuning is not supported to a great extent, it causes time-to-market delays and disruptions. In the case of Internal ISPs, some may not support key features such as High Dynamic Range (HDR). It is recommended that an external ISP should be leveraged to get the desired quality images.
External ISP camera modules from e-con Systems: