Читать книгу Small Animal Laparoscopy and Thoracoscopy онлайн

132 страница из 232

Medical cameras contain a computer “chip,” which transforms the optical image into an electronic signal transmitted to the CCU. Recent improvements in miniaturization of complementary metal‐oxide‐semiconductor (CMOS) “chips” have led to standardization of CMOS cameras as high‐end quality devices whose performance and image quality are equivalent or superior to earlier CCD (charge‐coupled device) cameras [1–5].

Although endoscopic camera quality has previously been defined by single‐chip or three‐chip technology, it is currently more relevant to embrace HD image technology. An HD image can be produced with either a single CMOS chip or three‐chip camera, which provides a wide screen display (ssss1a). The HD aspect ratio of 16 : 9 more closely approximates the human visual field than the historical 4 : 3 standard and allows the surgeon to observe instruments entering the surgical field sooner than with a traditional monitor [1–5].

However, HD cameras differ in resolution and light sensitivity, performance characteristics that affect detail recognition, color, features, and price. Some newer cameras, for example, have integrated image capturing capabilities or image processing options that enhance contrast or brighten dark areas (see Enhanced Contact Endoscopy section below). Full HD cameras deliver superior picture resolution (1920 × 1080 pixels) and progressive scanning, as opposed to interlaced scanning. The progressive scanning method simultaneously displays all 1080 lines for every frame, thus producing the smoothest, clearest image, especially when the video content is motion intensive.