PPM to JPG converter

.ppm

Portable pixmap images can be stored using the PPM format, which is basic, for example, color (PPM), grayscale (PGM), and black and white (PBM). A portable pixmap can provide a hallway representation of information in the conversion process of bitmap image files of the three types mentioned between different platforms. Jeff Poskanzerom developed the PPM format.

PPM files comprise sequences of a single or more PPM image. Data, padding, and limits do not exist before or after or in the middle of images. Every PPM comprises a single magic number used in identifying the type of file; the magic number for a PPM image is the two-character P6, whitespace (blanks, TABs, CRs, and LFs), and width presented as ASCII characters in decimal. It also comprises whitespace again, which is shown in ASCII decimal. Whitespace, the color value at a maximum (Maxval), is in decimal form, and it should be greater than zero but less than 65536. It is also composed of another single whitespace character, which is on another line. Lastly, it is composed of a raster of height rows found in reverse chronological order. The rows are comprised of width pixels in a left to right format. The samples represented have a pure binary nature, which is by one or two bytes. I byte has a Maxval of less than 256; otherwise, it is 2 bytes. The first byte is the most relevant. The straightforward format is another version of the PPM that exists but is most uncommon.

Jef Poskanzer

.jpg

JPG – is a popular graphic format characterized by a high image compression rate, which leads to a decrease in image quality. It uses the technology of encoding smooth color renditions, providing the ability to frequently reduce the amount of data during the image's recording. Because of the small size, it is requested by the owners of websites, allowing you to save the traffic effectively. It is also frequently used in memory cards of digital video cameras. The JPG algorithm is optimally suitable for compressing photographs and pictures in which realistic scenes with little contrast of colors are present. It is not recommended to use this format for compression of drawings and various kinds of graphics. A strong contrast between several near located pixels provokes the appearance of visible artifacts.

The procedure for compressing the digital images in JPG format is carried out in several stages. First, the photo is transformed into a color space YCbCr, and then it is divided into squares to determine the upper range of the color spectrum. Finally, the colors and brightness are coded. JPEG uses a "lossy" compression system and discrete cosine transform technology. The format acts simultaneously as the standard of ISO and the International Telecommunication Union. The file compression ratio is in the range from 10:1 to 100:1. In this case, the reduction in image quality can vary from insignificant to substantial.

The JPEG Committee