Digital cameras were initially developed as video memo devices and televisions with cameras and had appearances and designs that differed from film-based cameras. However, improvements in pixel number led to them becoming replacements for film-based cameras. Radical innovations, such as the function of optical zoom and image stabilization that were required to take quality photographs, were then developed. At the same time, digital cameras took on the appearance of film-based cameras, leading to frame that they could replace film-based cameras for consumers. In this manner, though film-based cameras came to be replaced by digital cameras, the appearance of film-based cameras became their dominant “industrial” design.