As observed from television news, surveillance footage from most Closed-Circuit Television System, also known as CCTV cameras, footages are of poor quality and have low resolution. Aside from this, CCTV cameras are short ranged devices and can only view limited spaces and short distances. The previously mentioned flaws of CCTV cameras affect our lives in many different ways for it has important applications in areas such as public safety, law enforcement, and homeland security.
This project aims to improve CCTV video quality by replicating the characteristics of an animal deemed to have outstanding eye vision— an eagle.
The genus Aquila, commonly known as the eagle, is considered to have the best vision within the animal kingdom and it can be studied to learn how to make improvements. Researchers have discovered that the eagle's eye possesses distinctive characteristics that contribute to its superior visual quality, such as high-density photoreceptor cells, a larger and more spherical lens, and a good blood supply. In order to achieve better results, it is important that the image-processing portion of the CCTV camera, which contains the video file of the obtained footage, should not be overlooked even though these alterations only affect the image-receiving part of the camera. Some parts of a Camera function just like a human eye. For example, a camera's sensor and an eye's retina function similarly since both are responsible for receiving light to process into an image, among others. We can presume that the human eye is alike to the quality of an ordinary camera, meaning that using better eyes as a reference for mechanism, like that of an eagle's, can result in better and improved camera quality.
Science Concepts Involved
An eagle's eye is deemed better than a human eye because of several factors related to its structure. According to Journey North Bald Eagles (n.d.): An example is its high-density photoreceptor cells, such as cone and rod cells, in their retinas responsible for detecting light and transmitting visual information to the brain. The foveas, small areas in the retina, contain a high concentration of these cells, allowing eagles to perceive fine details and distinguish colors at long distances. Compared to humans, eagles have multiple foveas with around a million photoreceptor cells per square millimeter, while humans only have a single fovea comprising 200 thousand photoreceptor cells per square millimeter, which makes them better at perceiving details than us.
Furthermore, an eagle's eye has three eyelids, two of which function for closing the bird's eye, whereas the third eyelid is called the Nictitating membrane (Hay, 2016). The Nictitating membrane is responsible for protecting and moisturizing the eyes, producing immunoglobulins, and is part of the precorneal tear film, which is composed of oil, water, and mucin layers (Nictitating Membrane - an Overview | ScienceDirect Topics, n.d.). The oil or lipid layer is composed of a glycerol backbone, two hydrophobic fatty acid tails, and a hydrophilic phosphate group. Thus, lipids are amphipathic, which is a term to describe substances with hydrophilic and hydrophobic parts. The bilayer arrangement of phospholipids in the cell membrane protects the cell and acts as a barrier to some chemicals. The hydrophobic portion is facing in, while the hydrophilic portion is facing out. This aids in controlling which molecules can enter and leave the cell (Ahmed et al., 2022).
Secondly, a CCTV camera's primary function is to capture light and convert it into a video signal. A camera sensor (formerly CCDs, replaced by APS) is the essential component of a CCTV camera and it converts light into an electric signal. The lens of an eagle's eye is also larger in proportion to its body size than in most other animals, allowing more light to enter the eye. The physics of light is important for seeing in low-light conditions and enhances the sharpness of their vision. The electrical signal is converted by electric signal processing into a video signal that can be captured or presented on screen. Electrons from the silver foil collectors can be ejected by light with enough energy to produce an action-reaction effect resulting in the cross spin. In accordance with the light intensity, electrons are released when light photons "hit" the silicon region. Essentially, this is how information from light is transformed into an electrical signal (Damjanovski, 2012). Aside from size, the shape of their lenses is also unique and more spherical than in most other birds of prey, reducing spherical aberration, which is a distortion of the image that can occur when light passes through a curved surface. They can also change the shape of their lenses and corneas through accommodation, making them thinner to focus on far objects and thicker to focus on near objects.Additionally, their eyes also have a good blood supply, which helps maintain the health of the photoreceptor cells in the foveas. Together, these factors contribute to the excellent visual quality of an eagle's eye, allowing it to see with much greater clarity and detail than humans (Journey North Bald Eagles, n.d.).
Bayer filter, by Cburnett, December 28, 2006 CC BY-SA 3.0
On the other hand, CCTV cameras function through the involvement of data cables and several electrical connections. An example is Ethernet cables, which allow data to travel between wires through a set of protocols (Optimum, 2022). The transmission of data across a cable is similar to electrical conduction through metal. It is translated into binary code, a collection of 1s and 0s. The data transmission device will send two distinct voltages of current over the cable (for example, zero volts and 5 volts), with one voltage standing in for one and the other for zero. Data is then translated into binary code, which will be converted back to its original format. The Ethernet Standards encompass the volume and speed of processing data over a defined time. Like electrical lines, fiber optic cables convey pulses of light down a cable rather than electrons (picture turning a torch on and off; when the light is on, you are transmitting a one, and when it is off, you are transmitting a zero). Fiber optic cables can transfer far more data than copper cables because light travels farther and faster than electrons and electricity (Eland Cables. n.d).
How to Use the Final Output
By studying the features of the eagle eye, researchers can gain insights into improving the quality of CCTV cameras and other imaging technologies. A CCTV can be divided into two parts, the image-receiving part, and the image-processing and -transmission part. The image-receiving part is the sensor with photosites, which are light-sensitive cavities or small areas responsible for recording an image's pixels. These photosites can be likened to photoreceptor cells, such as cone and rod cells of animals with an optical system. As the CCTVs we currently have could be likened to human eyes, we could say that the improved model of CCTVs could be likened to eagle eyes. Modifications to these small channels of light include one, making their size smaller to accommodate more photosites; and two, making the density of the photosites larger by reducing the distance between each photosite. As for other specific parts, we are to suggest the following modifications: one, merge the fovea and retina functions into one, thus leading to the sensor and film being one also in a CCTV system (this can be observed in contemporary models); two, since we can liken an iris to a camera diaphragm, the proportions of the iris and diaphragm size of an eagle and a CCTV, respectively, must be similar or equal; three, an aperture can be likened to a pupil, which are both openings that the iris and diaphragm form, respectively, after adjustment. A CCTV likened to an eagle can only get to as far as the image-receiving part; however, the image-processing part is also one that is not worth neglecting as it contains the part wherein the video file of gathered images must be compressed. It is our suggestion that the CCTV system we are trying to come up with must not compress files or at least minimize such action of file distortion to preserve the quality and resolution of the file gathered using such innovation.
Shen, Wei-wei & Chen, Lin & Liu, Shuai & Zhang, Yudong. (2022). An image enhancement algorithm of video surveillance scene based on deep learning. IET Image Processing. 16. 10.1049/ipr2.12286.
