Compressed images can be sent faster, take up less room, or be sent less frequently, as the bandwidth required to send them is smaller.There are two main types of image compression: lossless and lossy.Īlthough lossy image quality is not as great as lossless compression, the quality difference is almost unnoticeable to human eyes. Once you have compressed an image with an image compressor, you can store it more efficiently, which means you can store more than one image on the same amount of storage space. This proves that a loseless compression was performed.Image compression is a term used to describe the process of reducing the amount of space an image takes up. Technically, almost twice as many images could be stored (if all the pictures were ~500KB to begin with).įigure 3. Comparison of pixels between DICOM and PNG filesĪs demonstrated by the author of the website, in Figure 3, a comparison of the pixels between each image is identical to one another. The implications of this difference is that more images can be stored on the hard drive. How effective was the lossless compression method?Ĭomparing the size of the files, the lossless compression reduced the size by 50%! This method seemed to be very effective because there really is no change in the quality of the image. As defined earlier, “compressed images will be identical to the original image,” meaning that lossless compression methods should not have a loss in information! Between the DICOM and PNG file, there is no change in the quality. The key feature to determine if a lossless compression method was used is to look at the quality of the image. However, a compression into a PNG file does not always guarantee a file was compressed using a lossless compression method. In Figure 2, a DICOM file was compressed into a PNG file, which is a format that supports lossless compression. How can you tell a lossless compression was done? Images can to improve accuracy and to make diagnoses easier Images can be transferred to other departments much faster over the networkĤ. A DICOM file contains the medical image and patient attributes (name, age, ID, etc.)Ģ. This is the most favourable format in medicine mainly due to the following reasons:ġ. In the medical field, it is common to save images as the DICOM format which stands for “Digital Imaging and Communications in Medicine”. large png images often tend to take up storage space only optimal for small imagesĮxample of lossless compression using a medical image.some versions of browsers (like older versions) do not support png formats.supports transparency which allows images to form a gradient from transparent to opaque.as mentioned several times above, the lossless property leads to no loss in image information (quality of photo is unchanged).What are the advantages and disadvantages of using png files? Since it uses a lossless compression format, uncompressed photos can maintain good image quality while reducing the image size. Please see details regarding lossy compression here.Ī PNG, known as Portable Network Graphics, is a lossless compression format that stores digital image information. In lossy compression methods, there is a trade-off between image size and image quality but with lossless compression formats, image quality will be identical to the original uncompressed image. Because no information is lost, the size of the image may not be reduced as much as a lossy compression. No information will be lost – if the compressed image were to be expanded back to the original image, all of the information will be restored. Lossless compression is an image compression scheme where compressed images will be identical to the original image.
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