Image Noise and Noise Images in Computer Vision, Photography and Embedded Vision

What is Image Noise?

Image Noise is the variation in signal  from the ground trust, from pixel to pixel or frame to frame.

How Does A Noisy Image Impact Human Viewing and Computer Vision?

Noise is commonly thought of as Salt-and-Pepper noise. In a still image, one may say the image appears to be "Too Grainy"

In this sailboat example, researchers show that the confidence of class recognition drops rapidly  multi-pixel / spatial noise is present in an image.

Motion Blur and Computer Visiona Exposure Value

Dodge et al. "Understanding How Image Quality Affects Deep Neural Networks"  

What Types of Noise Exist in Cameras?

There are numerous types of noise in cameras. There are two main categories:

  • Single pixel noise can be thought of as temporal or random. Single Pixel noise is a variation in signal (or pixel value) from frame to frame. 
  • Multi-pixel noise can be thought of as spatial or fixed pattern noise, with variation from pixel to pixel in a single frame. 

The specific types of noise in a camera system are:

  • Readout Noise
  • Photon Shot Noise
  • Fixed Pattern Noise
  • Reset Noise

What About Denoising?

Denoising can be applied to mitigate noise. The approach is different for each of the two categories of noise.

Many multi-pixel (Spatial) denoising algorithms use a frequency filter to reduce the variation in pixel intensity. This filter also filters out information included in the image.

Hasinoff, et. al. "Burst Photography for high dynamic range and low light cameras"

Denoising (Spatial) Creates Texture Blur and Loss 

Localized denoisingcreates texture loss, which is particularly visible with mobile phone cameras.

This texture loss is noticeable to the human visual system when zooming in on the image.

For computer vision, the impact can be even more noticeable depending on your filter size.

This example by Chen et al shows a brick wall building and the output from an edge detection network before and after filtering. The high frequency noise filter greatly reduces the texture in the image, particularly in regions where color is constant.

Chen, S.-C.; Chiu, C.-C. Texture Construction Edge Detection Algorithm. Appl. Sci. 2019, 9, 897. https://doi.org/10.3390/app9050897

References and Related Links

Dodge et al. "Understanding How Image Quality Affects Deep Neural Networks" 

Stanford EE 392B lecture notes

View Other Image Quality and Computer Vision Topics

Trying to Determine Your Camera Requirements? 

Use our free web-based AoV Calculator to determine your system's Field of View Requirements. Then, use the M12 Lens calculator to match your requirements with the available lenses. Our Depth of Field Calculator also provides the hyperfocal distance and depth of field for every sensor and lens combination.

Camera Module Angle of View Calculator. Camera AoV Calculator.
Basler Camera Depth of Field Calculator. DoF Calculator.

We also have a couple of other calculators that many engineers find interesting.

Jetson Nano Mipi Camera Lens Focal Length Calculator. EFL Calculator.
Raspberry Pi HQ FoV Calculator for Vision System Cameras
Lens Focal Length Calculator. EFL Calculator.
Camera Angle of View Calculator. Camera AoV Calculator.
Camera Depth of Field Calculator. DoF Calculator.
An FoV Calculator for Vision System Cameras

Here are a Few M12 Lenses. Search all 50+ Using Our M12 Lens Calculator

190°@5.7mm Fisheye M12 Lens

CIL290-F2.2-M12A660

190°@5.7mm Fisheye M12 Lens

Low Distortion 2.2mm M12 Lens

CIL023-F2.2-M12B650

Low Distortion 2.2mm M12 Lens

GoPro 3.0mm M12 Lens

CIL331-F2.5-M12B650

GoPro 3.0mm M12 Lens

Low Distortion 1.8mm M12 Lens

CIL018-F2.8-M12A650

Low Distortion 1.8mm M12 Lens

200°@6.3mm Fisheye M12 Lens

CIL219-F2.5-M12A650

200°@6.3mm Fisheye M12 Lens

We Also have Cost Effective 12MP+ C-Mount Lenses for Machine Vision and Factory Automation.

135° 4K+ low distortion M12 lens for IMX335 and AR0521
135° 4K+ low distortion M12 lens for IMX335 and AR0521
135° low distortion S-Mount Lens
No Distortion Wide Angle M12 Lens
CIL018-F2.8-M12A650
Low Distortion 1.8mm M12 Lens
$39.00
200° M12 Fisheye Lens
200° M12 Fisheye Lens
200° Mini Fisheye Lens
Mini M12 Fisheye Lens
CIL219-F2.5-M12A650
200°@6.3mm Fisheye M12 Lens
$79.00
5mm M12 Lens for IMX334
5mm M12 Lens for IMX334
5mm M12 Lens IMX334
5mm S Mount Lens IMX334
CIL046-F2.0-M12A650
IR Corrected 4.4mm M12 Lens CIL046
$79.00
Wide Angle Waterproof M12 Lens
Wide Angle Waterproof M12 Lens
IMX678 sturdEcam genicam GMSL lens
Stereocam
CIL341-F2.0-M12A650
Wide-Angle 4mm M12 Lens
$79.00
8mm M12 Lens CIL078 Nvidia Camera
8mm M12 Lens CIL078 Nvidia Camera
8mm M12 Lenses for Nvidia Camera
8mm S Mount Lens for Nvidia cameras
Low Distortion 7.8mm M12 Lens
CIL078-F2.0-M12A650
Low Distortion 7.8mm M12 Lens
$59.00
Telephoto 12mm M12 Lens
Telephoto 12mm M12 Lens
Telephoto M12 Lens 12mm
Arducam usb cameras Telephoto 12mm M12 Lens
Telephoto 12mm S-Mount Lens
CIL125-F2.4-M12A650
Telephoto 12mm M12 Lens
$39.00