The process of electronic acquisition, the equivalent of taking a photograph, is often referred to as image capture. Light intensity is detected in a digital camera by a photosensor. This is normally a charge-coupled device CCD, although complementary metal oxide silicon CMOS) devices are beginning to appear in some systems. When photons strike the sensor, they give up energy. This causes electrons to be emitted, turning the energy of the photons into electrical energy. The number of electrons that are emitted can be measured to determine how many photons struck the capture element, and from this, the scanner can generate a value for the intensity of light arriving from the point on the original being analyzed.
The aim of the digitization stage is to capture all the information from an original that will be needed in the reproduction and convert it into an array of binary numbers that a computer can process. The human visual system actively seeks cues that will give it information about the objects within the visual field, and a reproduction of an image that contains a large amount of detail is almost always preferred to one in which some of the detail has been lost. Like conventional cameras, digital cameras come in compact, single-lens reflex, and large-format varieties. Low-resolution compacts are useful for producing classified advertisements and tend to have relatively simple optics, image-sensing electronics, and controlling software. Digital cameras are often based on existing single-lens reflex camera designs with the addition of CCD backs and storage subsystems. The capture resolution of these cameras is ideal for news photography and other applications with similar quality requirements.
The process of electronic acquisition, the equivalent of taking a photograph, is often referred to as image capture. Light intensity is detected in a digital camera by a photo sensor. This is normally a charge-coupled device CCD, although complementary metal oxide silicon CMOS) devices are beginning to appear in some systems.
When photons strike the sensor, they give up energy. This causes electrons to be emitted, turning the energy of the photons into electrical energy. The number of electrons that are emitted can be measured to determine how many photons struck the capture element, and from this the scanner can generate a value for the intensity of light arriving from the point on the original being analyzed.
The aim of the digitization stage is to capture all the information from an original that will be needed in the reproduction and convert it into an array of binary numbers that a computer can process. The human visual system actively seeks cues that will give it information about the objects within the visual field, and a reproduction of an image that contains a large amount of detail is almost always preferred to one in which some of the detail has been lost.
Like conventional cameras, digital cameras come in compact, single-lens reflex, and large-format varieties. Low-resolution compacts are useful for producing classified advertisements and tend to have relatively simple optics, image-sensing electronics, and controlling software. Digital cameras are often based on existing single-lens reflex camera designs with the addition of CCD backs and storage subsystems.
The capture resolution of these cameras is ideal for news photography and other applications with similar quality requirements.
