Video Cassette Recorders (VCR) Information
Industrial video cassette recorders (VCRs) receive video input and capture the data onto analog or digital videotape. . They are widely used in industrial applications such as machine vision and other fields such as security, forensic, and medical uses. The devices covered here are of medical, scientific, professional, or industrial grade and do not include consumer grade VCRs. This does not include consumer grade products. Video cassette recorders can operate in monochrome or color. Monochrome is black and white, or grayscale; the image is presented in black, white, and grayscale. The range of colors is generated with varying combinations of different discrete colors. One common technique is sensing the red, green, and blue components (RGB) and combining them to create a wide spectrum of colors.
Important performance specifications to consider when searching for video cassette recorders include number of video inputs, maximum real time recording, time lapse recording, maximum time lapse recording, horizontal resolution, and signal-to-noise ratio. The maximum number of input video channels typically, would be cameras or other signal sources; inputs may include items like video players, computers, VCRs, etc. This specification includes inputs from all types of connectors. Time-lapse recording records frames at specified time intervals; this feature can increase recording time. Horizontal resolution is the maximum number of individual picture elements that can be distinguished in a single scanning line. It is most common to characterize horizontal video resolution corrected for the image aspect ratio, or specify the resolution in the largest circle than can fit in a rectangular image. Thus, for example a 640 x 480 image would be specified as 480 horizontal lines. Signal-to-Noise ratio is defined as the peak-to-peak camera signal output current to the RMS noise in the output current. This ratio represents how prevalent the noise component of a signal, and thus the image uncertainty, is in the total signal. Noise sources include sensor "dark current", electromagnetic interference, and any other spurious non-image signal elements. Higher SNR numbers represent less image degradation from noise.