Underwater imaging is a fascinating yet highly demanding field from a technical standpoint. Whether it’s exploring the seabed, inspecting infrastructures or capturing the beauty of aquatic ecosystems, the challenges encountered are numerous. In this article, we explore the main obstacles of underwater imaging and the technological solutions developed to overcome them.
pressure management
Underwater pressure increases rapidly with depth, reaching around 10 times atmospheric pressure every 100 metres. Imaging equipment must be designed to withstand these extreme mechanical constraints. Cameras are often housed in hermetically sealed casings made from highly resistant materials such as aluminium, titanium or specialised polymers. Additionally, each product is tested in hyperbaric chambers to ensure that no defects occurred during manufacturing. A single hair in a seal groove or a scratch on a seal face can compromise the watertightness. A poorly dimensioned product that implodes under pressure could destroy all the surrounding equipment, some of which may cost millions of euros.
light distortion
In the aquatic environment, light behaves very differently to air. Water absorbs the different wavelengths of light unevenly, with reds and oranges disappearing within the first few metres, while blues and greens predominate. This degrades the natural colours of underwater objects. In addition, suspended particles diffuse and disperse light, reducing image contrast and sharpness. To compensate for these limitations, artificial light sources, such as powerful LED lamps, are used to restore visibility. These lights must be strategically positioned to minimize glare from particles that can blind cameras.
colour distortion
Colour distortion, caused by the refraction and absorption of light, poses a major challenge in producing accurate underwater images. The refractive index of water alters not only the colours but also the perception of the shapes and sizes of objects. This distortion requires post-processing adjustments to correct both colour bias and optical aberrations. Modern imaging software incorporates algorithms that automatically adjust white balance according to the environment (ambient lighting, water turbidity, etc.). However, the quality of these corrections depends on the calibration data collected during capture, which makes underwater operations even more complex.
buoyancy and stability
The underwater environment is dynamic and unpredictable. Cameras, often operated by divers or mounted on remotely operated vehicles (ROVs), must remain stable to avoid shaking and produce sharp images. To achieve this, the systems are generally calibrated to achieve near-neutral buoyancy, enabling them to remain stationary without sinking or rising to the surface. In addition, integrated gyroscopes and advanced stabilization algorithms help to compensate for movement due to underwater vehicle currents or vibrations.
suspended particles
Underwater environments, whether clear or turbid, always contain suspended particles, such as sediment or plankton. These particles create a ‘fog’ or ‘marine snow’ effect in images, reducing their quality and clarity. To limit this effect, cameras use indirect lighting positioned to reduce reflections from particles. At the same time, image processing algorithms are used to attenuate the visual disturbance caused by turbidity, thereby enhancing image contrast and sharpness.
communication and storage limitations
Communication and data storage represent another challenge in underwater imaging. Radio or WiFi signals, commonly used on land, do not propagate efficiently in water. Data must therefore be transmitted via cables or, where this is not possible, through acoustic technologies. However, acoustic methods are limited in bandwidth and speed, often capable of transmitting only around 4 images per second at a resolution of 0.15MP. To overcome these constraints, underwater cameras often include high-capacity internal storage systems, enabling images and videos to be saved until they are retrieved at the surface.
maintenance and longevity
Marine environments, particularly salt water, are extremely corrosive to equipment. Underwater cameras must therefore be made from corrosion-resistant materials, such as special alloys or protective coatings. Additionally, modular designs allow for quick replacement of faulty components, minimizing costs and downtime. Regular maintenance is essential to ensure durability, especially in extreme environments.
towards excellence in underwater imaging
Underwater imaging is a field where the technical challenges are both numerous and diverse. Pressure, lighting, colour distortion, stability and the constraints related to communication and maintenance require advanced technical solutions. By combining robust engineering with sophisticated image processing technologies, it is now possible to capture accurate, high-quality images in this demanding environment. These advances not only reveal the secrets of the deep, but also meet the growing needs of scientific exploration, industrial inspection and the preservation of marine ecosystems.