encompassed many people. The camera phone further helped popularize digital photography, along with the Internet, social media, and the JPEG image format. The first cell phones with built-in digital cameras were produced in 2000 by Sharp and Samsung. Small, convenient, and easy to use, camera phones have made digital photography ubiquitous in the daily life of the general public. Digital camera Sensors Image sensors are arrays of electronic devices that convert the optical image created by the camera lens into a digital file that is stored in some digital memory device, inside or outside the camera. Each element of the image sensor array measures the intensity of light hitting a small area of the projected image (a pixel) and converts it to a digital value. The two main types of sensors are charge-coupled devices (CCD)—in which the photocharge is shifted to a central charge-to-voltage converter—and CMOS or active pixel sensors. Most cameras for the general consumer market create color images, in which each pixel has a color value from a three-dimensional color space like RGB. Although there is light-sensing technology that can distinguish the wavelength of the light incident on each pixel, most cameras use monochrome sensors that can only record the intensity of that light, over a broad range of wavelengths that includes all the visible spectrum. To obtain color images, those cameras depend on color filters applied over each pixel, typically in a Bayer pattern, or (rarely) on movable filters or light splitters such as dichroic mirrors. The resulting grayscale images are then combined to produce a color image. This step is usually performed by the camera itself, although some cameras may optionally provide the unprocessed grayscale images in a so-called raw image format. However, some special-purpose cameras, such as those for thermal mapping, or low light viewing, or high speed capture, may record only monochrome (grayscale) images. The Leica Monochrom cameras, for example, opted for a grayscale-only sensor to get better resolution and dynamic range. The reduction from three-dimensional color to grayscale or simulated sepia toning may also be performed by digital post-processing, often as an option in the camera itself. On the other hand, some multispectral cameras may record more than three color coordinates for each pixel. Multifunctionality and connectivity In most digital camera (except some high-end linear array cameras and simple, low-end webcams), a digital memory device is used for storing images, which may be