According to Abbreviationfinder, JPEG stands for Joint Photographic Experts Group. One of the most popular formats to save our digital images, let’s know a little more about its origin, characteristics that differentiate it from other image formats. Let’s start by understanding where the name JPEG derives from, this format was created by the Joint Photographic Experts Group, the acronyms of this group are those that give the name of the JPEG format or also called JPG. JPEG (of the English Joint Photographic Experts Group, Joint Group of Experts in Photography) is the name of an expert committee that created a standard for compressing and encoding still image files.
This committee was integrated from the beginning by the merger of various groups in an attempt to share and develop their experience in digitizing images. ISO, three years earlier (April of 1983), had started its investigations in the area. Besides being a compression method, it is often thought of as a file format. JPEG / Exif is the most common image format used by digital cameras and other image capture devices, along with JPEG / JFIF, which is also another format for storing and transmitting photographic images on the World Wide Web. These format variations are often indistinguishable, and are called JPEGs. Files of this type are usually named with the extension.jpg.
Format characteristics
Before the need for web design, development, programming and usability arose, graphic designers insisted that the greater the weight of the image, for example 300 KB, the better the resolution and printing of the image. Then, the need arises to make a transition from printed design to design on the web, and one of the surprises is that those gigantic images that were printed in full color, on the web needed to be compressed and reduced in weight, so that they easily load. It is in this compression action, where the JPEG format plays a role. important, because it allows the compression level of each of the images to be graduated in this way we can decide between a low-quality image, which implies a smaller file size, or a high-quality image, which represents a greater weight. The compression system that JPEG uses is based on reducing information by averaging it in the gradient areas. In other words, the color value of some pixels is calculated based on the color of the pixels that surround them. Due to these characteristics, this format is very efficient when it comes to storing images that have many gradients and color nuances. Although it is also necessary to bear in mind that it is almost useless when we want to save drawings with large extensions of flat and uniform colors or with very well defined edges in this format, it is definitely not recommended.
The characteristics of this graphic format are quite different from those of the GIF format, hence these 2 formats are used by the HTML language, since one tries to complement the other and vice versa.
The characteristics of the JPEG graphic format are:
- Bitmap graphic format.
- True color support, also known by its English namesake true color (24 Bit).
- Compression algorithm (lossy) that supports high pack rates (1/20 and more).
The support of true color (24 bits) of JPEG offers us the possibility of offering images with a depth of 16,777,216 colors.
It is clear that a bitmap with this color depth reaches huge memory sizes, but this is supplemented by the compression algorithm that the format offers.
This compression algorithm, although very powerful (reduces the size of the bitmap to 5% of the original or less), offers information losses as we increase its compression rate. The compression rate is adjusted when we save the file, for example, from our image processor.
This loss of information occurs as we increase its compression rate and is noticeable in the resolution of the image.
P-JPEG
It is an extension of the JPEG format that owes its name to Progressive JPEG (Progressive JPEG).
Its main advantage is that it allows the progressive display of images.
The progressive display that incorporates P-JPEG is based on displaying, while the graphic is loaded, the image from lower to higher quality. We should not confuse it with the interlacing system of the GIF format, since GIF is based on showing alternating lines of the graphic during loading, while the progressive display system of P-JPEG we see all the lines from the beginning, only that of blurred, until it reaches its maximum sharpness when charging is complete.
JPEG (Joint Photographic Experts Group) is an algorithm designed to compress images with 24-bit depth or grayscale. JPEG is also the file format that this algorithm uses to store compressed images. JPEG only handles still images, but there is a related standard called MPEG for videos. The JPEG file format is often abbreviated.jpg because some operating systems only accept three letter extensions. JPEG is a lossy compression algorithm. This means that when decompressing the image we do not obtain exactly the same image that we had before compression.
One of the characteristics that make JPEG very flexible is being able to adjust the degree of compression. If we specify very high compression, a significant amount of quality will be lost, but we will get small files. With a low compression rate we obtain a quality very similar to that of the original, and a larger file.
This loss of quality accumulates. This means that if you compress an image and decompress it you will get image quality, but if you compress it again and decompress it again you will get a greater loss. Every time you compress and unzip the image, it will lose some quality.
JPEG / JFIF is the most widely used format for storing and transmitting photo files on the Web. But lossy compression of the format is not suitable for diagrams that include text and lines.
The JPEG compression algorithm is based on two visual defects of the Human Eye, one is the fact that it is much more sensitive to change in luminance than chrominance, that is, we notice changes in brightness more clearly than in color. The other is that we notice small changes in brightness more easily in homogeneous areas than in areas where the variation is large, for example at the edges of the bodies of objects.
