What Is a Soft Copy?

A hard copy is a plate-like entity that holds compressed information in two dimensions, while a soft copy represents invisible information that is otherwise stored (memorized). The storage mentioned here means that the information is more irreversible than soft copy and maintains a stable state ^[1] .

Chinese name: Soft copy hard copy

Soft copy hard copy soft copy and hard copy overview

Image hard copy output is ^one of the important functions of the PACS system ^[1] . Medical images are generated by various digital medical equipment and finally stored in the system server. However, sometimes in order to meet the joint consultation of various hospitals or according to the requirements of patients, it is necessary to have a hard copy output method of the images in the PACS system, which can print the diagnostic images of patients in the form of films.

The image hard copy output function is to output various medical image files to medical film or medical printing paper using a dicom network printer. Its main functions include: dicom film and paper printing; adjusting the window width of the image, zooming and rotating the window alert image , Reverse, position, etc. Can print effect preview, overlay information (patient, image, examination) printing; image gaze information printing, set network connection with dicom printer; set display information of output image, set printing parameters, number of rows and columns, etc.

When the data is output to the paper via the printer, it is called a hard copy, and if the data is displayed on the screen, it is called a soft copy. Part of a screen-type computer monitor (monitor), which also includes a housing for electronic components. In the computer industry, the output of a screen is considered a soft copy because it is invisible And it is temporary, unlike hard copy, it is printed on paper by a printer, which is tangible and durable. Popularly speaking, hard copy is to print data with a printer. Soft copy is to copy the data in memory.

The difference between hard copy and hard copy

Hard copy itself is complete as a recording medium, that is, it has both storage and display functions; soft copy is only meaningful when it is combined with information storage means. It can be explained that it only serves as a display function.

With the development of digital technology, there are more and more occasions where hard copies are used as instantaneous display of digital data. But it becomes a hard copy and loses its reversibility at the same time, so it has the storage function, which is different from soft copy. In short, the difference between hard copy and soft copy lies in the high ground of its reversibility ^[2] .

Classification of soft-copy hard-copy images

There are various types of images, as shown in the general classification diagram. Soft copies do not have the light distribution of material structure, while hard copies are two-dimensional plate-like material entities. People who deal with it use touch and other sense organs in addition to vision. The difference between the two is very large. This is the first basis of classification.

The so-called "soft copy does not have a material structure". For example, there is no material difference between the bright and dark areas of the composition image. If it is a CRT, it means that the difference in the excitation state of the same fluorescent substance is reflected.

The original design idea of the display system is to display dynamic images, so the images are further classified into still image mode and dynamic image mode. Moving images in hard copy are not easy to imagine. But you can imagine that when you were a kid, you draw some misaligned pictures at the cutout of the notebook and look at the notebook continuously.

The film is projected on the screen by quickly changing the transmission hard copy method, and the afterimage effect of the eye is used to make people see the dynamic image. But the projection image is the shadow of the pigment distribution on the film, that is, soft copy ^[2] .

Hard copies can be divided into transmissive and reflective. As described above, the transmission type appears mostly as a soft copy via an optical system, so a typical hard copy is a reflection type.

Soft copy Hard copy Hard copy and soft copy intermediate image

The groping politics of images between soft copy and hard copy, that is, the advantages of both. In the field of rewritable records, looking back at history, there have been several hard copies based on the difference in status in the 1970s ^[2] .

Soft copy hard copy status like hard copy

A typical example is a thermosensitive recording material developed under the trade name Thermofax developed by the 3M company in the United States. It is a method of heating a transparent film to make an opaque image according to an image, or a thin plate with a fine light scattering particle interface to make a transparent image according to an image using a heating method to make it a contrasting projection image. Also, the melting of solids is accompanied by direct thermal recording of hard copy materials for document copying ^[2] .

Soft copy hard copy method using electronic photo

The initial response of the electronic photo is the photoelectric effect inside the solid. It does not contain all chemical changes and is a pure physical process. So essentially its reversibility is very high. How to check the initial response is directly related to the problem of designing a rewritable photo.

Electronic photos tend to form soft copies, so the irreversibility imparted by toner development and thermal fixing is the exception. A common problem with these methods of electronic photographs is that they require larger equipment, and therefore have more constraints on viewing conditions than hard copies. When hard copying, the information update time is often large, so it only corresponds to special uses, and there are cases where the repeated use life is very short ^[2] .