piikkikuva

Piikkikuva is a Finnish term that translates to "spike image" or "spiky image." It refers to a type of digital image artifact that appears as a series of radiating lines or spikes emanating from a central point. This artifact is most commonly observed in images that have undergone significant compression, particularly with older or less sophisticated compression algorithms.

The appearance of piikkikuva is a result of how these algorithms process areas of uniform color or sharp edges. When certain compression techniques are applied to an image with a distinct boundary or a strong contrast, they can inadvertently create discontinuities or errors in the data representation. These errors manifest as the characteristic spike-like patterns, especially noticeable around high-contrast areas or when the image is viewed at a lower resolution or zoomed in.

While piikkikuva is generally considered an undesirable artifact, it is often a visual indicator of aggressive compression. Modern image compression standards, such as JPEG 2000 or advanced implementations of JPEG, are designed to minimize or eliminate such artifacts. However, in older digital cameras, image editing software, or when dealing with low-quality source material, piikkikuva can still be encountered. It is a phenomenon that highlights the trade-offs between file size and image fidelity in digital imaging.