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

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

Lens Focal Length Calculator. EFL Calculator.
An 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

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CIL030-F2.1-M12A650

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A 2.1mm M12 Lens for 1/3
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Wide Angle Low Distortion 2mm S-Mount Lens CIL023
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Low Distortion 2.7mm M12 Lens

CIL027-F2.8-M12IR

2.7mm M12 Lens for IMX226
2.7mm M12 Lens for IMX226
A 2.7mm M12 Lens for S-Mount FLIR
Arducam IMX477 2.7mm M12 Lens

GoPro 3.0mm M12 Lens

CIL331-F2.5-M12A660

3.1mm Wide Angle M12 Lens
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Large Format 3.5mm M12 Lens

CIL334-F2.2-M12A660

3.5mm M12 Lens for IMX226 AR0821 IMX537
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S-Mount Drone Lens for Wide Angle IMX226
Wide Angle Drone Lens for IMX226

Low Distortion 6mm M12 Lens

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A 6mm M12 lens for 4K+ sensors
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7mm M12 Lens
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Telephoto 12mm M12 Lens

CIL125-F2.4-M12IR

Telephoto 12mm M12 Lens
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Telephoto M12 Lens 12mm
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Telephoto 26mm M12 Lens

CIL260-F2.0-M12IR

25mm M12 Lens
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25mm lens for FLIR Cameras

185°@7.8mm Fisheye M12 Lens

CIL227-F2.5-M12ANIR

Wide Angle Fisheye Lens for S Mount
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Fisheye Wide Angle M12 Lens
Board Mount Lens Wide Angle Fisheye
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
Fisheye Lens for 1/2.3
Fisheye Lens for 1/2.3
M12 Fisheye Lens for 20MP cameras
195 degree S Mount Lens for AR1820HS
CIL216-F2.2-M12A650
195°@4.7mm Fisheye M12 Lens
$59.00
Mini Fisheye S Mount Lens
Mini Fisheye S Mount Lens
Mini Fisheye M12 Lens
Miniature Fisheye M12 Lens
CIL222-F2.0-M12A650
195°@6.8mm IP67 M12 Fisheye
$39.00
IP65 M12 Lens
IP65 M12 Lens
IP67 M12 Lens
IP67 FLIR S-Mount Lens M12 Lens
CIL034-F2.7-M12A660
IP67+ No Distortion 3.2mm Lens
$49.00
3mm m12 lens
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CIL030-F2.1-M12A650
Low Distortion 3.0mm M12 Lens
$59.00
A 2.1mm M12 Lens for 1/3
A 2.1mm M12 Lens for 1/3
Tiny Pinhole Lens for S-Mount Cameras
15mm TTL Short M12 Lens for Surveillance
CIL821-F2.4-M12B650
Stereographic 2.1mm M12 Lens
$39.00