What Is Image Communication?

Image communication is the field concerned with the capture, compression, transmission, storage, and display of still and moving visual information. It encompasses the technical methods by which images travel from a source to a destination across communication systems, whether those images are photographs, medical scans, video frames, or documents. The field draws on signal processing, information theory, and communications engineering, and it has been shaped significantly by standards developed through IEEE and related bodies. As imaging has become central to medicine, broadcasting, remote sensing, and everyday digital life, image communication has grown into one of the most practically significant areas of electrical and communications engineering.

Compression Standards: JPEG, HEVC, and Beyond

Compression is foundational to image communication because raw image data is too large to transmit efficiently over most networks. The JPEG standard, developed through a collaboration involving the ISO/IEC Joint Photographic Experts Group and drawing on decades of IEEE-published research in transform coding, remains the dominant format for still image compression. JPEG uses the discrete cosine transform to reduce spatial redundancy, achieving substantial size reductions with controlled quality loss. For video, the High Efficiency Video Coding (HEVC) standard, also known as H.265, offers roughly double the compression efficiency of its predecessor H.264 at equivalent visual quality. HEVC is used in streaming services, broadcast television, and video conferencing. Research on newer codecs, including AV1 and Versatile Video Coding (VVC), continues to be published in IEEE journals and presented at IEEE conferences.

Picture Archiving and Communication Systems

Picture archiving and communication systems (PACS) are the networks of hardware and software used in medical imaging to acquire, store, distribute, and display medical images. A PACS connects imaging modalities such as CT scanners, MRI machines, and digital X-ray systems to radiologists and clinicians who need to review images for diagnosis. PACS rely on the DICOM (Digital Imaging and Communications in Medicine) standard to ensure interoperability across equipment from different manufacturers. Medical image transmission within PACS must balance compression efficiency against diagnostic fidelity: lossy compression that is acceptable for consumer photographs may be inappropriate for images used in clinical diagnosis. The IEEE Engineering in Medicine and Biology Society has contributed significantly to research on medical imaging systems, including PACS architecture and image quality assessment.

Facsimile Transmission

Facsimile (fax) technology is one of the earliest forms of image communication over telephone networks. Fax systems convert a scanned document image into a signal suitable for transmission over the public switched telephone network and reconstruct it at the receiving end. The CCITT Group 3 and Group 4 fax standards, developed through international coordination, define the compression and transmission protocols used by fax machines worldwide. Although fax has been largely displaced by email and digital document sharing in most contexts, it remains in active use in healthcare and legal settings where signed document transmission has regulatory significance.

Video Compression and Streaming

Beyond individual codecs, video communication systems integrate compression, packetization, and adaptive bitrate control to deliver video across variable-bandwidth networks. Adaptive bitrate streaming protocols allow video players to switch between quality levels in real time based on available bandwidth, ensuring continuous playback. IEEE research in this area covers rate control algorithms, perceptual quality metrics, and the interaction between codec design and network protocols. The IEEE Transactions on Image Processing is a primary venue for research on image and video coding, quality assessment, and transmission.

Applications

• Medical imaging: PACS and DICOM-based systems transmit radiological images between scanners, archives, and clinicians across healthcare networks.
• Video streaming: HEVC and AV1 compression enables high-quality video delivery over internet connections with limited bandwidth.
• Digital photography: JPEG and its successors compress still images for storage and sharing across cameras, smartphones, and web platforms.
• Document transmission: Facsimile standards allow scanned documents to be transmitted over telephone networks, with ongoing use in regulated industries.
• Remote sensing: Compressed image communication enables satellites and aerial platforms to transmit high-resolution imagery to ground stations.
• Video conferencing: Real-time video codecs and transmission protocols support audio-visual communication over internet and cellular networks.