How does a scanner measure vision?

In the hand-held scanner of the roller vision scanning platform, the scanning effect is not good but the price is low.

Rotatingdrumimagescanner is the most precise scanning instrument at present, and it has always been the best choice for high-precision color printing. Also called "electronic color separator". Its working process is to scan the positive film or manuscript with a color separator and store it in the computer. Because the color information of a positive film or manuscript is recorded in the form of C, M, Y, K or R, G and B after color separation, this process is called "color separation" or "electronic color separation". In fact, "electricity division" is what we call scanning with a roller scanner.

How to use the scanner and matters needing attention

Scanner is a device that uses photoelectric technology and digital processing technology to convert graphic or image information into digital signals through scanning. Let me share with you the usage and precautions of the scanner. Welcome to read!

First, scanner index detection.

1. Detection of photosensitive elements:

Scan a group of horizontal thin lines (such as hair or metal lines), then browse in ACDSee32 and set the scale to 100% for observation. If there is a broken line in the longitudinal direction, it means that the photosensitive elements are unevenly arranged or have bad blocks.

2. Test the transmission mechanism:

Scan a scanner-wide picture, browse it in ACDSee32, and set the scale to 100% for observation. If there is tearing in the transverse direction or the horizontal line can be observed, it means that there is a mechanical failure in the transmission mechanism.

3. Detection resolution:

Scan the color photos with the scanner's nominal resolution (such as 300dpi and 600dpi), then browse in ACDSee32, and set the scale to l00% for observation. The mixed color block will not be observed as qualified, otherwise the resolution is not enough.

4. Gray detection:

Select the nominal gray scale of the scanner, scan a night scene photo with light, and pay attention to the hierarchy between light and dark. Scanners with high gray levels will show better image details (especially dark areas).

5. Detect the number of color bits:

Select the number of nominal color bits of the scanner, scan a color photo, set the display mode of the monitor to true color, and compare it with the original to see if the color is full. It should be noted that there is no complete agreement with the original. The display may have a color cast, which affects observation, and the photosensitive system of the scanner may also have a certain color cast. Most high-end and mid-range scanners are equipped with color correction software, but only a few low-end scanners are equipped with color correction software. Please calibrate the color of the monitor and scanner before the test.

6.OCR character recognition input detection:

Use black-and-white binary and nominal resolution to scan independent printed originals. A 300dpi scanner can correctly identify the fifth word in a newspaper, and a 600dpi scanner can almost identify the seventh word on a business card.

Second, the daily use and maintenance of the scanner

As an ordinary user, it is very important not only to buy qualified, convenient and durable scanner products, but also to learn to use them correctly and carry out simple maintenance.

1. Once the scanner is powered on, never hot plug the cables with SCSI and EPP interfaces, which will damage the scanner or computer, except USB interface, of course, because it supports hot plug.

2. Please don't cut off the power when the scanner is working. Generally, it is necessary to wait until the mirror group of the scanner is completely returned, and then cut off the power supply, which is very meaningful for the normal work of the scanner circuit chip.

3. Because some CCD scanners can scan small three-dimensional objects, the instrument should pay attention to: when placing sharp objects, don't move them casually to avoid scratching the glass, including the staples on the reflection manuscript; Don't use too much force when putting down the upper cover, so as not to break the glass.

4. Some scanners are not designed to completely cut off the power switch. When the user is not using it, the tube of the scanner is still on. Because the lamp tube of the scanner is also consumable (comparable to fluorescent lamp, but it takes a long time), users are advised to cut off the power supply when not in use.

The scanner should be placed away from the window, because there is a lot of dust near the window, and direct sunlight will reduce the service life of plastic parts.

6. Because the scanner will generate static electricity at work, it will suck a lot of dust into the body, which will affect the work of the lens group. Therefore, don't cover it with fabrics that are easy to fall off (velvet products, cotton fabrics, etc.). ), it can be covered with silk or batik cloth, and proper indoor humidity can avoid the influence of dust on the scanner.

Three. Frequently asked questions about the use of scanners

1. When the scanner switch is turned on, the scanner makes abnormal noise.

This is because some models of scanners have locks to lock the lens group to prevent vibration during transportation. Therefore, the lock should be opened before turning on the power switch of the scanner.

2. There is no response after the scanner is powered on.

Some models of scanners are energy-saving, and the lights will light up only after entering the scanning interface, and will go out automatically after exiting.

3. "Scanner not found" is displayed during scanning.

This phenomenon may be caused by turning on the host first and then turning on the scanner. You can restart the computer or refresh it in equipment management.

4. Is the resolution of the scanner the same as that of the printer? How to choose a printer according to the resolution of the scanner?

The unit of scanner resolution should be strictly defined as ppi, not dpi. Ppi refers to the number of pixels per inch. For the scanner, each pixel is not a simple description of 0 or 1, but a description of 24bit, 36bit or CMYK( 1004). D in the printer resolution dpi refers to a point in English, and each point has no depth, only the concept of 0 or 1. For the scanner, 1 pixel needs four kinds of dot (CMYK) to describe, that is, the color of a dot is determined by the density of different dots. So the concept of dpi between scanner and printer is different. Output an image of 1: L with a printer of 1440dpi, and scan it with 100- 150dpi.

5. When the scanner scans, there is a prompt of "insufficient hard disk space or insufficient memory".

First confirm whether the hard disk and memory are enough. If the space is large, please check whether the scan resolution you set is too large, resulting in too much file data.

6. Scanning makes a lot of noise.

Disassemble the machine cover, find some sewing machine oil drops on the toilet paper to wipe off the oil stains on the two tracks of the mirror group, then put sewing machine oil drops on the bearings at both ends of the transmission gear group and the belt (pay attention to the moderate amount of oil), and finally adjust the belt tightness properly.

7. The scanning time is too long.

Check the remaining capacity of the hard disk, optimize the hard disk space, delete the useless TMP file first, make Scandisk, and then make Defrag or SpeedDisk. Please note: If the final actual scan resolution setting is higher than the optical resolution of the scanner, the scanning speed will slow down, which is normal.

Ten points for attention when using scanner

1, do not forget to lock the scanner.

Because the scanner adopts precision optical system including optical lens, its structure is fragile; In order to avoid damaging optical elements, scanners are usually equipped with special locking/unlocking mechanisms. Before moving the scanner, the optical components should be locked, but it is important to pay special attention to that before using the scanner again, it must be unlocked first, otherwise it is likely to damage the transmission mechanism of the scanner due to negligence!

2. Do not use organic solvents to clean the scanner, so as not to damage the scanner housing and optical components.

Don't let the scanner work in a dusty environment.

Be sure to keep the scanner glass clean and undamaged, because it is directly related to the scanning accuracy and recognition rate of the scanner; If there is dust on it, it is best to use the leather tiger that we usually dust the camera lens.

4. Do not power on the scanner.

When installing the scanner, especially the scanner with EPP parallel port, in order to prevent the motherboard from burning out, the computer must be turned off before plugging in.

5. Don't ignore the update of the scanner driver.

Many users usually only pay attention to upgrading the drivers of devices such as graphics cards, but often ignore upgrading the drivers of scanners, which directly affects the performance of scanners and involves the compatibility of various software and hardware systems. In order to make scanners work better, they should often download updated drivers from the manufacturer's website.

6. Don't use too high a resolution.

When using the scanner, many users set the resolution of the scanner to be very high, hoping to improve the recognition rate. But in fact, when scanning ordinary manuscripts, the resolution of about 300DPI is enough. Too high resolution may reduce the recognition rate, because too high resolution will scan the details of printed words more carefully, and it is easier to identify the defects and defects of printed manuscripts, which will lead to a decrease in the recognition rate.

7. Do not turn off the system virtual memory.

When scanning images in computers with low memory configuration, the system memory is often insufficient. At this time, the remaining space on the hard disk can be used as virtual memory to complete the scanning work, but when the virtual memory is disabled, the scanner cannot continue to work.

8. Don't set the compression ratio too small.

After completing the image scanning task with a scanner, we often need to choose an appropriate image saving format to save files. When some users choose JPEG format, they always think that the smaller the compression ratio is, the easier it is to save and transmit, but if it is set too small, the image information will be seriously lost.

9. Then the scanner needs to consume extra power to find the ideal scanning entry point during its work. Even so, it is difficult to ensure the ideal vertical resolution of the scanner.

10, don't switch scanners frequently.

Some scanners are very demanding. Before each use, please make sure that the scanner is turned on before turning on the computer. In this case, the direct consequence of switching the scanner frequently is to start the computer frequently, which is also extremely unfavorable to the scanner itself.

How to use the Apple Lidar scanner?

The usage of Apple Lidar scanner is as follows:

1. Turn on the rangefinder, aim the origin of the lens at the starting point of the measured object, and press+to mark the starting point. Move the phone slowly, and when it reaches the end point, click the+sign to end the measurement.

2. Open it and click to enter "Camera". Adjust the position of iPhone so that the tested person is displayed on the screen from head to toe. After waiting for a moment, a line is displayed on the top of a person's head (or the top of a hair or hat), and the height measurement results are displayed directly below this line.

3. To take a measurement photo, please click the "Take a photo" button. To save the photo, tap the screenshot in the lower-left corner, tap Done, and then choose Save to Photo or Save to File. You can easily access and * * * enjoy the height measurement images in photos or files at any time on the iPhone.

IPhone lidar features:

The function of lidar is accurate ranging. The lidar scanner has both a laser generator and a laser receiver. The principle is to emit a laser. When the laser touches an actual object, it will form a reflection, and then the receiver can feel the reflected laser.

Since the time of laser emission and reception is recorded and the speed of laser is known, the time of laser reflection can be converted into the actual distance from the object. Not only that, the accuracy of lidar ranging can be as accurate as a few centimeters.

The function of lidar is to obtain the actual distance and orientation of the object, and the camera is undoubtedly capturing the picture. So when the two are combined by software, the picture on the screen is not only an image, but also the data such as the distance of the object are recorded in iPhone 13Pro.

Because AR itself is a combination of virtual and reality, iPhone 13Pro can capture real objects more accurately and obtain more data, and the application of AR technology can be more accurate and mature.

Everyone's impression of eye health examination probably stays on the eye chart and optical examination, but in fact, the eye is a very complicated organ, and its requirements and accuracy are no less than other physical examinations. One of the most important points is "visual field examination", which is often overlooked by everyone, but can see the disease factors.

Basic ophthalmological examination

Generally speaking, there will be eye examination, intraocular pressure examination and fundus examination. In addition to looking at the eye chart, you should also sit on the optometry instrument and look at the balloon or small house in the machine to confirm the degree of hyperopia, myopia and astigmatism. This kind of inspection is very common, and basically professional optical shops can operate it, which is very convenient to use when matching glasses.

However, in addition to myopia and hyperopia, eye diseases include glaucoma, cataracts and retinal detachment. The early symptoms of these diseases are not obvious, or even easily overlooked, which may be the complications of other diseases. Therefore, when you go to the physical examination center, you are likely to do intraocular pressure examination and fundus examination again.

There are two ways to measure intraocular pressure. The first contact tonometer measures the hardness of eyeball, that is, the pressure of eyeball itself is converted by the force required to flatten cornea. When doing this test, be sure to keep your eyes straight ahead, don't deliberately open your eyes wide or narrow your eyes, and keep them open and closed normally. Another method is a non-contact tonometer, which uses jet air to flatten the cornea.

Usually, the intraocular pressure below 20~2 1mmHg is called normal intraocular pressure, and there is a risk of glaucoma if it exceeds this standard, but in fact, everyone's optic nerve has different tolerance standards for intraocular pressure, so the proportion of glaucoma caused by low intraocular pressure is also very high. It is suggested that attention should be paid if the intraocular pressure difference between the two eyes exceeds 4mmHg, or the value at regular examination is much higher than that at the last examination.

Fundus examination and visual field examination

Fundus refers to retina, optic nerve and choroid. Retina is responsible for visual projection, while choroid is the source of nutrition and oxygen. Through the photographic examination of fundus, we can clearly see whether the blood vessels, shapes and colors of retina, macula, optic nerve and choroid are abnormal, and then check out various problems.

For example, retinal breaks, retinal detachment, macular degeneration, optic neuritis, and even eye wind, diabetes, and hypertension can all be seen through subtle changes in fundus blood vessels. Some people find that they have diabetes simply because of blurred vision. Conversely, diabetic patients can also understand how their physical condition is controlled through fundus examination.

Visual field examination refers to the range that the eyes can see, generally speaking, it is 50 degrees upward, 60 degrees toward the nose, 90 degrees outward and 70 degrees downward. If you can't see clearly on both sides, it may be a visual field defect. For example, if you can't see around your eyes, or in the middle of your eyes, you can't see what is on your right. It may be glaucoma, cataract, retinal detachment, macular degeneration, etc. Even a blood clot formed by brain tumor or stroke pressing the optic nerve.

The way to check is to use a visual field scanner. The inspection process takes about 10 minutes. After leaning your head against the machine, you must always look at the center of the screen, but the machine will flash bright spots in all directions. When you see a bright spot in which direction, be sure to press the button in that direction to confirm where the field of vision is missing.

What kind of physical examination do you want? Click here to find out.

How to use the scanner

Many users usually only pay attention to upgrading the drivers of devices such as graphics cards, but often ignore upgrading the drivers of scanners, which directly affects the performance of scanners and involves the compatibility of various software and hardware systems. In order to make scanners work better, they should often download updated drivers from the manufacturer's website. What are the ways to use the scanner? Come and have a look with me!

First, scanner index detection.

1. Detection of photosensitive elements:

Scan a group of horizontal thin lines (such as hair or metal lines), then browse in ACDSee32 and set the scale to 100% for observation. If there is a broken line in the longitudinal direction, it means that the photosensitive elements are unevenly arranged or have bad blocks.

2. Test the transmission mechanism:

Scan a scanner-wide picture, browse it in ACDSee32, and set the scale to 100% for observation. If there is tearing in the transverse direction or the horizontal line can be observed, it means that there is a mechanical failure in the transmission mechanism.

3. Detection resolution:

Scan the color photos with the scanner's nominal resolution (such as 300dpi and 600dpi), then browse in ACDSee32, and set the scale to l00% for observation. The mixed color block will not be observed as qualified, otherwise the resolution is not enough.

4. Gray detection:

Select the nominal gray scale of the scanner, scan a night scene photo with light, and pay attention to the hierarchy between light and dark. Scanners with high gray levels will show better image details (especially dark areas).

5. Detect the number of color bits:

Select the number of nominal color bits of the scanner, scan a color photo, set the display mode of the monitor to true color, and compare it with the original to see if the color is full. It should be noted that there is no complete agreement with the original. The display may have a color cast, which affects observation, and the photosensitive system of the scanner may also have a certain color cast. Most high-end and mid-range scanners are equipped with color correction software, but only a few low-end scanners are equipped with color correction software. Please calibrate the color of the monitor and scanner before the test.

6.OCR character recognition input detection:

Use black-and-white binary and nominal resolution to scan independent printed originals. A 300dpi scanner can correctly identify the fifth word in a newspaper, and a 600dpi scanner can almost identify the seventh word on a business card.

Second, the daily use and maintenance of the scanner

As an ordinary user, it is very important not only to buy qualified, convenient and durable scanner products, but also to learn to use them correctly and carry out simple maintenance.

1. Once the scanner is powered on, never hot plug the cables with SCSI and EPP interfaces, which will damage the scanner or computer, except USB interface, of course, because it supports hot plug.

2. Please don't cut off the power when the scanner is working. Generally, it is necessary to wait until the mirror group of the scanner is completely returned, and then cut off the power supply, which is very meaningful for the normal work of the scanner circuit chip.

3. Because some CCD scanners can scan small three-dimensional objects, the instrument should pay attention to: when placing sharp objects, don't move them casually to avoid scratching the glass, including the staples on the reflection manuscript; Don't use too much force when putting down the upper cover, so as not to break the glass.

4. Some scanners are not designed to completely cut off the power switch. When the user is not using it, the tube of the scanner is still on. Because the lamp tube of the scanner is also consumable (comparable to fluorescent lamp, but it takes a long time), users are advised to cut off the power supply when not in use.

The scanner should be placed away from the window, because there is more dust near the window, which will be exposed to direct sunlight, which will reduce the service life of plastic parts.

6. Because the scanner will generate static electricity at work, it will suck a lot of dust into the body, which will affect the work of the lens group. Therefore, don't cover it with fabrics that are easy to fall off (velvet products, cotton fabrics, etc.). ), it can be covered with silk or batik cloth, and proper indoor humidity can avoid the influence of dust on the scanner.

Three. Frequently asked questions about the use of scanners

1. When the scanner switch is turned on, the scanner makes abnormal noise.

This is because some models of scanners have locks to lock the lens group to prevent vibration during transportation. Therefore, the lock should be opened before turning on the power switch of the scanner.

2. There is no response after the scanner is powered on.

Some models of scanners are energy-saving, and the lights will light up only after entering the scanning interface, and will go out automatically after exiting.

3. "Scanner not found" is displayed during scanning.

This phenomenon may be caused by turning on the host first and then turning on the scanner. You can restart the computer or refresh it in equipment management.

4. Is the resolution of the scanner the same as that of the printer? How to choose a printer according to the resolution of the scanner?

The unit of scanner resolution should be strictly defined as ppi, not dpi. Ppi refers to the number of pixels per inch. For the scanner, each pixel is not a simple description of 0 or 1, but a description of 24bit, 36bit or CMYK( 1004). The resolution of the printer D in dpi refers to the points in English, and each point has no depth, only the concept of 0 or 1. For the scanner, 1 pixel needs four kinds of dot (CMYK) to describe, that is, the color of a dot is determined by the density of different dots. So the concept of dpi between scanner and printer is different. Output an image of 1: L with a printer of 1440dpi, and scan it with 100- 150dpi.

5. When the scanner scans, there is a prompt of "insufficient hard disk space or insufficient memory".

First confirm whether the hard disk and memory are enough. If the space is large, please check whether the scan resolution you set is too large, resulting in too much file data.

6. Scanning makes a lot of noise.

Disassemble the machine cover, find some sewing machine oil drops on the toilet paper to wipe off the oil stains on the two tracks of the mirror group, then put sewing machine oil drops on the bearings at both ends of the transmission gear group and the belt (pay attention to the moderate amount of oil), and finally adjust the belt tightness properly.

7. The scanning time is too long.

Check the remaining capacity of the hard disk, optimize the hard disk space, delete the useless TMP file first, make Scandisk, and then make Defrag or SpeedDisk. Please note: If the final actual scan resolution setting is higher than the optical resolution of the scanner, the scanning speed will slow down, which is normal.