Cameras provide a vast amount of information at high rates and are part of many specialized or general-purpose devices. This versatility makes them suitable for many interaction scenarios, yet they are constrained by geometry and require objects to keep a minimum distance for focusing. We present the LensLeech, a soft silicone cylinder that can be placed directly on or above lenses. The clear body itself acts as a lens to focus a marker pattern from its surface into the camera it sits on. This allows us to detect rotation, translation, and deformation-based gestures such as pressing or squeezing the soft silicone. We discuss design requirements, describe fabrication processes, and report on the limitations of such on-lens widgets. To demonstrate the versatility of LensLeeches, we built prototypes to show application examples for wearable cameras, smartphones, and interchangeable-lens cameras, extending existing devices by providing both optical input and output for new functionality.

翻译：相机能以高帧率提供大量信息，并被集成于众多专用或通用设备中。这种多功能性使其适用于多种交互场景，但受几何结构限制，物体需保持最小距离才能对焦。我们提出LensLeech——一种可直接置于透镜表面或上方的软硅胶圆柱体。透明本体本身作为一个透镜，将其表面的标记图案聚焦至下方的相机传感器，从而实现对旋转、平移及基于形变的手势（如按压或挤压软硅胶）的检测。我们讨论了设计需求，描述了制造工艺，并报告了此类透镜表面交互组件的局限性。为展示LensLeech的通用性，我们构建了应用于可穿戴相机、智能手机及可更换镜头相机的原型示例，通过提供光学输入与输出功能，拓展了现有设备的交互能力。