The scanning quality is a comprehensive manifestation of various characteristics of the scanner. We should not only proceed from a certain characteristic of the scanner, but emphasize its advantages one-sidedly. In fact, the scan quality is the result of a combination of scanner software and hardware. Software and hardware specifications are the key to verifying the quality of different types of scanners. Below we make an overall description of the various aspects affecting the quality of the scan.
First, the hardware drum scanner and platform scanner use completely different scanning principles, resulting in different scanning quality. Among them, the development of the scanning technology of the photomultiplier tube is relatively early, but the development is not as fast as the CCD technology. As we all agree, the photomultiplier tube represents a high-quality scan quality. What are the reasons?
1. The method of scattering spot scanning is as follows: a strong light shines on a small area of ​​the manuscript on the drum, and the area around it is still black, and the local area of ​​the manuscript is copied through a small scanning hole mirror during scanning. This method actually eliminates scattering and does not generate unwanted signals.
What is the photography principle of the platform scanner? The example shown on the lower left shows that the entire object is projected on the CCD array as if it were a photograph. There are several factors that affect the generation of scattered light, where the internal structure of the platform scanner plays a major role. For the problem of scattered light, we have to solve two problems: First, is excess light around the original document absorbed or reflected on a light wall that is not masked? Second, is the CCD array placed in an unenclosed space or in a dark box with scattered light? The mechanical design of the folding cassette in the imaging system and the components designed to reduce scattered light are all related to this problem. All of these designs greatly reduce the intensity of scattered light. For example, a 0.01% scattered light component will reduce the dynamic density range D1.0.
2. Signal-to-noise ratio The photomultiplier tube has a relatively complex structure, the price is relatively expensive, and the electrical noise signal is also low. In comparison, the CCD array exhibits a higher internal electrical noise level, which is further amplified by the heat absorption of the scanning light. This effect can in principle be reduced by means of insulation, thermal insulation cassette designs, humidity sensors or temperature monitoring devices. Therefore, compared with photomultiplier tubes, the disadvantage of CCD is the sensitivity to scattered light.
3, optical and interpolation resolution (scanning accuracy)
From this perspective, the important difference between the two technologies is that the DPI value itself is not comparable. The optical resolution of the roller scanner is determined by the size of the scanning aperture. The surface looks like this parameter is small, but it has no direct correlation with the actual scanning process. During the continuous scanning process, 50% overlap in the scanning direction produces optical interpolation resolution, which is caused by the scanning speed (scanning drum longitudinal and The horizontal scanning speed is determined by the processing speed of the computer, which can result in a scanning resolution of up to 20000 DPI.
In contrast, the optical resolution of the platform scanner is determined by the CCD array, and the resolution of “mathematical interpolation†can reach 14,000 DPI. Scan quality is largely determined by the quality of all mathematical algorithms. In general, optical interpolation is better than mathematical interpolation.
4. Signal Processing In signal processing, there are major differences between the two technologies. The drum scanner utilizes analog signals from the opto-isolator amplifier and performs analog-to-digital conversion by logarithmic compression. This process intensifies the image signal, especially in shadows. After the digitization process, the scanner will express a richer level.
The digital processing of the platform scanner is based on the principle of digital linearity. We can understand this process as this: Half of the depth translates into a D0.3 density. We use an example to explain, 16-bit color can produce 65536 tone. Half of 65536 is 32768, which shows the density range from D0.00 to D0.3. Half of 32678 is 16384, further exhibiting a density of D0.3 to 0.6. By analogy, only 4 levels remain from D3.9 to D4.2. If the density of the original is large, the scanner with a smaller depth cannot discern the dark details. In summary, the scanner's dynamic range is the most important variable. The quality of the scan is determined by a series of design details and the principle of tracing.
Second, software We talked about the hardware factors needed to ensure good scanning quality. The software also has the same, sometimes even more important, status. Software factors that affect scan quality include the computer's internal color space, color correction digital algorithms, gradation calculations, UCR, GCR, USM, and color separation tables. The friendly interface provides users with intelligent help to ensure that even beginners can achieve good scanning quality.
1. Color Space Most Cylinder Scanners and many commercially available platform scanners use the CMYK color space, which may be some historical reasons. Because the original scanner was used only in the printing industry, "CMYK - printed colors". In practice, the proven algorithm is thus continued. Scanners using the CMYK color space internally have provided the HSL user interface to interface with new users and new markets. We can't deny that traditional electricity division operators can achieve a very good copying effect by adjusting the CMYK value. For example, using the rather complex CMYK degree on the CHROMAGRAPH DC3000 system can achieve a very good scanning effect.
This includes a number of well-rehearsed and proven correction options, such as basic corrections and selective corrections to control master color reproduction; fine-level corrections are used to define any color in the CMYK color space.
Programmable scanning software is now especially popular among people from the multimedia and design communities who use CIELAB color space. This is a standard, independent visual color space beyond the device, covering all colors that can be seen by the human eye, based on the color of the LCH system (H hue, C saturation, L brightness) The psychological attributes of color, and independent of the device.
In this respect, it is necessary to convert the data stored before the output to the output format. The output device profile needed for the printout is generated by the Printability Profiles Generator. The "printability profile" includes all information for a particular printing device, such as: printing method, printing material and ink characteristics, ink sequence, ink layer thickness, and ink absorption. Because the print space is smaller than the LAB color space, a good color gamut conversion method is needed so that the loss of color is not visually seen. This conversion can only be seen when the scan data is displayed on the screen or printed on paper. The quality of the gamut conversion method reflects the quality of the scanning software.
2. Sharpness Control Professional Scanners actually handle sharpness processing from 10% to 3000% throughout the day, thereby avoiding image loss due to density compression. Highlights, shadows, and midtones are all expected to achieve the best clarity, depending on the scaling and screening conditions. The clarity of the outline of the bright and dark parts of the image must be combined with the smoothness. Good software automatically guarantees good sharpness and smoothness of the scan. The "smooth, clear" contradiction can obviously be solved by intelligent software. For sharp outlines, complex structures, and bright and dark junctions, good sharpness is a must, and for large color smoothness with similar colors is especially important.
The sharpness control function of the scanner provides such control: For example, in the reproduction of a fashion magazine, the smoothness and the sharpness need to have four benefits; the model must have non-slip, soft skin, and the texture of the fabric or fur must be Emphasis is coming. The sharpening function controlled by the color value during the scanning phase can easily meet this quality requirement.
3. Color Management In the open system, color management is required at all stages of the workflow. The Macintosh's COLORSYNC 2.5 and WINDOWS ICM meet this requirement.
4. The intelligent person's assistant must ensure that the scanning quality is set correctly for the highlight and dark tone values. After calculation, these settings are converted into computer original tone values ​​to ensure that the copy is visually consistent with the original. The tone of highlights, shadows, and manuscripts must be preserved. The color cast of any color must be corrected, and the complex layers must emphasize the subject. In the past, experienced electric sub-operators were required to complete the above functions. We called us to achieve the same purpose with intelligent aids such as COLORASSISTANT. GEOASSISTANT confirmed the position of the original on the original holder or roller and automatically defined it. Original Frame, JOBASSISTANT organizes batch and background scanning functions. The "Intelligent Assistant" supports re-digitized multifunction units, such as COPIXASSISTANT, to determine screening definition and film density. REGISTER ASSISTIST automatically edits each color separation.
In short, when it comes to scanning quality, it is not possible to consider only one index of the scanner's technical parameters. The scanning quality is the result of a combination of all hardware optimized combinations and user-friendly software packages. Roller scanners and flatbed scanners reflect the different needs of customers. The platform scanner is easy to operate and the roller scanner represents a high quality scan. We still give this choice the final decision to the customer!
First, the hardware drum scanner and platform scanner use completely different scanning principles, resulting in different scanning quality. Among them, the development of the scanning technology of the photomultiplier tube is relatively early, but the development is not as fast as the CCD technology. As we all agree, the photomultiplier tube represents a high-quality scan quality. What are the reasons?
1. The method of scattering spot scanning is as follows: a strong light shines on a small area of ​​the manuscript on the drum, and the area around it is still black, and the local area of ​​the manuscript is copied through a small scanning hole mirror during scanning. This method actually eliminates scattering and does not generate unwanted signals.
What is the photography principle of the platform scanner? The example shown on the lower left shows that the entire object is projected on the CCD array as if it were a photograph. There are several factors that affect the generation of scattered light, where the internal structure of the platform scanner plays a major role. For the problem of scattered light, we have to solve two problems: First, is excess light around the original document absorbed or reflected on a light wall that is not masked? Second, is the CCD array placed in an unenclosed space or in a dark box with scattered light? The mechanical design of the folding cassette in the imaging system and the components designed to reduce scattered light are all related to this problem. All of these designs greatly reduce the intensity of scattered light. For example, a 0.01% scattered light component will reduce the dynamic density range D1.0.
2. Signal-to-noise ratio The photomultiplier tube has a relatively complex structure, the price is relatively expensive, and the electrical noise signal is also low. In comparison, the CCD array exhibits a higher internal electrical noise level, which is further amplified by the heat absorption of the scanning light. This effect can in principle be reduced by means of insulation, thermal insulation cassette designs, humidity sensors or temperature monitoring devices. Therefore, compared with photomultiplier tubes, the disadvantage of CCD is the sensitivity to scattered light.
3, optical and interpolation resolution (scanning accuracy)
From this perspective, the important difference between the two technologies is that the DPI value itself is not comparable. The optical resolution of the roller scanner is determined by the size of the scanning aperture. The surface looks like this parameter is small, but it has no direct correlation with the actual scanning process. During the continuous scanning process, 50% overlap in the scanning direction produces optical interpolation resolution, which is caused by the scanning speed (scanning drum longitudinal and The horizontal scanning speed is determined by the processing speed of the computer, which can result in a scanning resolution of up to 20000 DPI.
In contrast, the optical resolution of the platform scanner is determined by the CCD array, and the resolution of “mathematical interpolation†can reach 14,000 DPI. Scan quality is largely determined by the quality of all mathematical algorithms. In general, optical interpolation is better than mathematical interpolation.
4. Signal Processing In signal processing, there are major differences between the two technologies. The drum scanner utilizes analog signals from the opto-isolator amplifier and performs analog-to-digital conversion by logarithmic compression. This process intensifies the image signal, especially in shadows. After the digitization process, the scanner will express a richer level.
The digital processing of the platform scanner is based on the principle of digital linearity. We can understand this process as this: Half of the depth translates into a D0.3 density. We use an example to explain, 16-bit color can produce 65536 tone. Half of 65536 is 32768, which shows the density range from D0.00 to D0.3. Half of 32678 is 16384, further exhibiting a density of D0.3 to 0.6. By analogy, only 4 levels remain from D3.9 to D4.2. If the density of the original is large, the scanner with a smaller depth cannot discern the dark details. In summary, the scanner's dynamic range is the most important variable. The quality of the scan is determined by a series of design details and the principle of tracing.
Second, software We talked about the hardware factors needed to ensure good scanning quality. The software also has the same, sometimes even more important, status. Software factors that affect scan quality include the computer's internal color space, color correction digital algorithms, gradation calculations, UCR, GCR, USM, and color separation tables. The friendly interface provides users with intelligent help to ensure that even beginners can achieve good scanning quality.
1. Color Space Most Cylinder Scanners and many commercially available platform scanners use the CMYK color space, which may be some historical reasons. Because the original scanner was used only in the printing industry, "CMYK - printed colors". In practice, the proven algorithm is thus continued. Scanners using the CMYK color space internally have provided the HSL user interface to interface with new users and new markets. We can't deny that traditional electricity division operators can achieve a very good copying effect by adjusting the CMYK value. For example, using the rather complex CMYK degree on the CHROMAGRAPH DC3000 system can achieve a very good scanning effect.
This includes a number of well-rehearsed and proven correction options, such as basic corrections and selective corrections to control master color reproduction; fine-level corrections are used to define any color in the CMYK color space.
Programmable scanning software is now especially popular among people from the multimedia and design communities who use CIELAB color space. This is a standard, independent visual color space beyond the device, covering all colors that can be seen by the human eye, based on the color of the LCH system (H hue, C saturation, L brightness) The psychological attributes of color, and independent of the device.
In this respect, it is necessary to convert the data stored before the output to the output format. The output device profile needed for the printout is generated by the Printability Profiles Generator. The "printability profile" includes all information for a particular printing device, such as: printing method, printing material and ink characteristics, ink sequence, ink layer thickness, and ink absorption. Because the print space is smaller than the LAB color space, a good color gamut conversion method is needed so that the loss of color is not visually seen. This conversion can only be seen when the scan data is displayed on the screen or printed on paper. The quality of the gamut conversion method reflects the quality of the scanning software.
2. Sharpness Control Professional Scanners actually handle sharpness processing from 10% to 3000% throughout the day, thereby avoiding image loss due to density compression. Highlights, shadows, and midtones are all expected to achieve the best clarity, depending on the scaling and screening conditions. The clarity of the outline of the bright and dark parts of the image must be combined with the smoothness. Good software automatically guarantees good sharpness and smoothness of the scan. The "smooth, clear" contradiction can obviously be solved by intelligent software. For sharp outlines, complex structures, and bright and dark junctions, good sharpness is a must, and for large color smoothness with similar colors is especially important.
The sharpness control function of the scanner provides such control: For example, in the reproduction of a fashion magazine, the smoothness and the sharpness need to have four benefits; the model must have non-slip, soft skin, and the texture of the fabric or fur must be Emphasis is coming. The sharpening function controlled by the color value during the scanning phase can easily meet this quality requirement.
3. Color Management In the open system, color management is required at all stages of the workflow. The Macintosh's COLORSYNC 2.5 and WINDOWS ICM meet this requirement.
4. The intelligent person's assistant must ensure that the scanning quality is set correctly for the highlight and dark tone values. After calculation, these settings are converted into computer original tone values ​​to ensure that the copy is visually consistent with the original. The tone of highlights, shadows, and manuscripts must be preserved. The color cast of any color must be corrected, and the complex layers must emphasize the subject. In the past, experienced electric sub-operators were required to complete the above functions. We called us to achieve the same purpose with intelligent aids such as COLORASSISTANT. GEOASSISTANT confirmed the position of the original on the original holder or roller and automatically defined it. Original Frame, JOBASSISTANT organizes batch and background scanning functions. The "Intelligent Assistant" supports re-digitized multifunction units, such as COPIXASSISTANT, to determine screening definition and film density. REGISTER ASSISTIST automatically edits each color separation.
In short, when it comes to scanning quality, it is not possible to consider only one index of the scanner's technical parameters. The scanning quality is the result of a combination of all hardware optimized combinations and user-friendly software packages. Roller scanners and flatbed scanners reflect the different needs of customers. The platform scanner is easy to operate and the roller scanner represents a high quality scan. We still give this choice the final decision to the customer!
Pet Training & Behavior Products,Dog Training & Behaviour Aids,Dog Training Equipment Items,Dog Training Behavior
Ningbo Yinzhou Hengxi Winbate Household Product Manufacturer , https://www.nbwinbate.com