How to optimise imperfect camouflage

Camouflage is key to survival for many animals in nature, from insects and crustaceans to reptiles and birds, living in a wide range of habitat types. It is also of great value to humans, from its longstanding use by the military to areas of recreation (e.g. wildlife watching) and art and design. In simple terms, concealment prevents detection of an object, or recognition of what an object truly is. While intuitively simple, camouflage is a rich and complex subject. This is because there are many different ways that an object could be concealed, ranging from resembling the general background, to disruptive markings that break up the body outline. In the last 10-15 years considerable research has been conducted into understanding what types of camouflage exist, how they work, and their value in preventing detection and recognition. However, despite considerable progress, a major area remains largely unexplored: how should camouflage be made effective when an object is seen against more than one type of background? Most previous research has focussed on how camouflage types (e.g. background matching, disruptive coloration) work when an object is seen against one background (e.g. a tree trunk). However, in reality, in many instances (both natural and human made) objects need to be concealed against several different visual scenes, such as foliage and rocks. The main aim of this project is to understand how types of camouflage work in such cases, and how the features of camouflage colour patterns should be optimised for maximal effectiveness across a range of visual scenes encountered.
This project will involve two main approaches to address the above aim. First, we will conduct experiments with human observers searching on touch screens for hidden targets against different background images. We will create carefully controlled artificial targets of different colours and patterns conforming to different types of camouflage. Some targets will be made to match one background type alone, whereas other targets will represent a blend of features from two different background types (a compromise or intermediate form). Other targets will possess features of disruptive coloration, with markings placed to break up the outline of the body, or to create false internal shapes and patterns inside the body. These targets will also vary in their level of visual contrast. We will then present these defined target types to participants in scenarios where they can be seen against two different types of background. We will measure detection times to determine how successful each target is against each background used, and overall against the range of backgrounds involved. This will determine what types and features of camouflage minimise detection risk over the range of visual scenes encountered. Second, we will conduct artificial evolution experiments. The targets in part 1 above are fixed in nature and defined by us. This allows precise control of visual properties but limits the range of possible camouflage appearances that can be tested. Here, we will create populations of artificial targets with their colour patterns encoded by a 'genome'. Human participants will search for targets, and those that are found least often or more slowly will 'survive' and reproduce to form the next generation. Over time, the populations of targets will evolve to match the backgrounds better. We will conduct versions of the experiments whereby populations evolve in scenarios where they are seen against several background types. This will allow us to determine the types of camouflage that arise in these circumstances, and how they parallel the results of the fixed target experiments above. Overall, these experiments will provide valuable findings on how camouflage can be optimised in the many situations, both natural and human-made, where objects and animals are seen against more than one type of visual scene.

Camouflage includes strategies that prevent detection and recognition. These are of substantial importance in numerous animal species and to humans in applications ranging from military defence to art and design. In the last 10-15 years, much research has sought to understand what types of camouflage exist and how they are made effective. This includes strategies such as background matching, resembling the appearance of the background scene, and disruptive coloration, to break up an object's body edges. While substantial progress has been made, a major aspect of camouflage effectiveness has been comparatively neglected. Most previous research has focussed on camouflage strategies used on one background type only. In contrast, in many situations, both natural and human-made, objects will be seen against a range of backgrounds and visual scenes differing in appearance. The question is, in such cases how should camouflage be made most effective across all backgrounds encountered and what types of camouflage are most effective? This project will answer these questions in two ways. First, we will create targets of fixed appearance presented on computer screens to human subjects against various background types. We will create targets that match one background type alone, represent an intermediate form between two background types, or which have properties of disruptive coloration. We will compare success in preventing detection against each background type and overall against all backgrounds to determine how camouflage should be optimised. Second, we will create artificial evolution experiments. Here, targets will be made with a 'genome' controlling their appearance. Human subjects will search for them and over time populations of targets will evolve and change based on which colour patterns are most effective in preventing detection. Targets will be seen against either one background type (specialists) or against a range of backgrounds (generalists).

This project will have implications in a number of areas, both applied aspects of camouflage design and breaking, and outreach and public understanding of science.
1) Economic and commercial.
Camouflage has for decades had significant importance in human lives. This most notably includes military applications, but also in recreation and commerce, including art, wildlife watching, and hunting. It is also increasingly used in urban contexts to disguise unattractive functional objects such as mobile phone transmission masts and satellite dishes. This project will provide key information about how objects can be camouflaged in a diversity of complex visual scenes, especially when objects are likely to be seen against a range of background types. Importantly, this is an Industrial Partnership application with QinetiQ, a company with extensive work related to applied aspects of camouflage, especially for the armed forces. We will therefore work together to ensure that the dissemination of the findings of this work are effectively passed onto those organisations (e.g. the MoD and defence companies) regarding how best to design camouflage materials when faced with the need for concealment in different visual scenes and scenarios. This will include workshops and presentations with stakeholders and industry partners, as well as QinetiQ reports.
2) Outreach, education, and widening participation.
Predator-prey relationships and animal coloration are topics with a long history, stemming back to the very first evolutionists, of stimulating public interest and attracting broad attention. They have great potential to inspire future generations about science and learning because the concepts are readily understandable, easy to demonstrate, and benefit from being highly visual. Furthermore, there is a clear link between the fundamental science of understanding camouflage to applied benefits, which helps to illustrate the value of scientific research. Camouflage remains a textbook - and widely used - example of natural selection and is regularly covered in the media. This has significantly increased in recent years, with the subject often covered in television and radio programmes (including involving the PI), art and design exhibitions, public lectures, and several recent popular science books. The PI has a wide range of experience dealing with media interest, setting up websites and interactive online games about his research, collaborating with media offices to make videos, and corresponding Twitter and Facebook accounts for disseminating his work in social media (see Pathways to Impact). He is currently a BBSRC Schools Regional Champion for the South West. A key aim is to communicate with and inspire the general public, especially school/college children about the subject and science in general. Therefore, we will: i) coordinate with press offices about press releases from our papers and communicating our research in general, ii) apply to present at the Royal Society Summer Science Exhibition, iii) make an interactive website containing videos and images from our work, as well as computer games demonstrating the key concepts of our work, iv) set up a database of videos and images to be used in outreach and to give to the media and other scientists, v) give talks at various public/outreach events, in particular to local schools in Cornwall, and vi) use our Facebook and Twitter accounts to disseminate our work and interesting materials (pictures, videos), and the subject area in general, to a wide audience.