Q:
I see the term "CMOS Camera" quite often. Is this the same as a CCD?
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A:
Hello,
first of all, CCD does not mean digital camera. CCD just means older technology. CMOS sensors are getting a larger and larger market part in the world of digital imaging. Right now CMOS sensors are used in Cell Phones and high end professional cameras. CMOS sensors are also more often used in industrial imaging where they are in the process of taking the largest part of the market.
In automotive the CMOS sensors will not be the only players. In some particular applications where we can cope with blooming and complex electronics but noise and sensitivity are key criterias, then some CCD are very competitive, even if the module cost is higher.
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Q:
Do you have a side-by-side comparison? I also heard CMOS will do night vision. Is this true?
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A:
CMOS is a completely different fab process but basically the CCD and CMOS sensors "look" the same.
As they are operated in a very different way, the two kind of image sensors cannot be compared. The external electronics of a CCD is also usually big compared to the requirements of a CMOS, CCD blooms,...
Both can be used in night vision.
CCD will not work when another car comes in front of you with headlamps on for example.
A good CMOS is also a bit less sensitive than a good CCD.
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Q:
Hello,
tks for the comparesion. CCD application is digital Camera as i understand. what is the application of CMOS Camera? do you have application notes? what is Melexis part number on CMOS Camera?
tks,
cheng Yuan
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A:
CMOS is also digital camera. Application notes are available at www.melexis.com. It is used in night vision, wide dynamic range applications (see from dark garage into bright driveway, etc.). there are several melexis cmos cameras depending on your requirements, please visit www.melexis.com and search on "camera"
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A:
i assume that you have installed the EVB normally and included the development libraries.
The driver (SYS and INF) is then installed and all you need to do is to copy the CCAPI.DLL and CCAPI.H files from the development directory to your project directory. Include the H file to your software to have access to all the high level functions. Those functions are described in the user's manual together with an example code in C.
If you link the DLL statically, we also provide a LIB file in the development directory.
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Q:
I've just bought the evb90267 & mlx75007.
I want to use dll in my software (I don't know how to do it). But the user's manual is not clear.
(Those are my first melexis products)
I'd like tot have some informations about it.
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Q:
Is there exist datasheet on the sensor MLX75007?
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Q:
I'm intrested in the next parameters:
1. Dynamic range
2. Dark current
3. Noise
4. Quantum efficiency (at 850nm)
5. price
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Q:
Hi!
When I send a Frame Request, I get a Frame valid (that's nice). Then I send a Line Request, and than I get... no Line Valid (not so nice).
Could someone tell me how this is possible?
Thanks!
C
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Q:
By the way, Line Request Out stays NULL too. Could it have something to do with wrong SPI settings? Or should the MLX75007 put line valid high even if the SPI is default (all zero)?
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A:
Check the SPI settings, if the window size settings are 0 or non-sense there will not be any line data.
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Q:
I've been able to get some data out of the MLX75007, I use the line request out as the line request in. Although this sounds nice, it is all rubbish. The output isn’t what it should be. When I open the data in a hex-editor the line’s are of the correct size (X-size), as are the amount of lines (Y-size).
By the way, in between two line readout’s there are about 200 0x00 of data, what could this be?
Kind regards,
Coen
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A:
The output bus is forced low when it is not used.
Data is valid only when LINE_VALID AND FRAME_VALID = 1
Connecting line_request_in to line_request_out is the recommended operation.
If the image is not correct, check your SPI settings and check the data timings
- SPI_CS falling edge vs frame request
- SPI programming
- Data sampling point vs clock
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Q:
If the image is not correct, check your SPI settings and check the data timings
- SPI_CS falling edge vs frame request
What should be the condition? The datasheet informs me to upload a SPI when Frame Request is high, although exceptions exist. So what I do is upload a SPI prior to streaming data. So the first thing what I do is reset the MLX75007, then an SPI upload and then an frame request occurs. Is this right to do so?
- SPI programming
- Data sampling point vs clock
With data sampling point you mean the clock that drives the snapshot? What should be this condition?
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A:
Do you mean that you reset before each frame? This is really not recommended.
The datasheet specifies the relation between SPI_CS falling and FRAME_VALID falling. SPI_CS should fall after FRAME_VALID. For the first frame, it should fall before FRAME_REQUEST.
- Data sampling point vs clock
=> i mean falling edge vs rising edge
Read the datasheet more carefully.
Also check your waveforms on VDD_PIX.
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Q:
Thanks for the quick reply Arnoud,
No, I don't reset before each frame. I only reset at startup and I only load the SPI after that reset, so only one time.
I cant find the relation between SPI_CS falling and Frame_Valid... This is what I did find, and it is conflicting with your post:
-On page 22, Upload must occur during the high state of a frame request.
-On page 38, A whole new SPI can be uploaded during the frame request high state.
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A:
The method on page 38 is the easiest one.
If you upload an SPI during sensor operation, the safest solution if to have SPI_CS falling after FRAME_VALID falling but before FRAME_REQUEST rising.
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A:
the MLX75007 is a product under development. It is only available as samples. For this you have to contact your local Melexis representative.
As the product is still under development, the datasheets and application notes are not published.
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Q:
We want to use MLX 90255 Linear array for application beloow.
Object is polyester filament yarn moving at the speed 5000 meters/ min Diameter is 400 micron. we want to detect Diameter variation .for that we want to take 20000 reading/sec.if measured value goes beyond set limit it will recod as error.
is it possible with above image sensor.
For more information you can visit www.lenzing-instruments.com our compititor. look in PROMPT Software. on line monitoring OLM.
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A:
the MLX90255 at the minimum integration time will be dominated by readout and will reach 7000 frames per second with 1MHz clock and 50% duty cycle. In this case the integration time is about 130 microseconds.
To have >20000 reading/sec you need to use three sensors separated in space-time by 45microseconds. To do this, you have to have the sensors synchronized (parallel operation) but located at different positions on the wire.
To increase the accuracy of the measurement, the sensor must be placed with an angle to the wire (diagonally), so that the amount of pixels affected by the presence of the wire is higher.
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Q:
Please make me clear regading relation
Between
1, Clock frequency
2, No of reading can be taken
3, No of pixel like 128x1 ,256x1
How integration time is calculated.
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A:
1. 90255BCR can run up to 1MHz in your case (50% duty cycle, reduced temperature range i assume).
2. At the maximum clock speed you will read one pixel per clock. One frame in integrated when the previous one is read out, so integration time = readout time - 18 clocks + idle time between two readouts (0 in this case).
3. (128 real + 4)x1 pixels
http://www.melexis.com/Asset.aspx?nID=4833
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A:
About the calculation of frame rate:
1 frame = 10us SI + 133 clocks@1MHz = 6993fps
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A:
Here is a brief application note on wire width measurement for your application.
http://www.melexis.com/Asset.aspx?nID=5270
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Q:
As you told 3 Sensor required and connected parellel.
Is there any alternative for our aplication.
We have two other company.Can you suggest us other Company Who manufacture 128x1 ,256x1 516x1 1024x1 Haveing Package 8 pin DIP or ClK >5Mhzs.
In MLX90555 Can we shield Pixel IN top and botom . As our normal reqirement 600 to 1500 .
And sensing lenght is <8000 micron. If we Reduce No Of pixel and keep sensor Diagonal(inclined).
Thanks
K.C.PATEL
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Q:
We acually requre No of PXEL in Central region of MLX 90255. If we reduce No pixel as SENSING DIE SIZE IS more than 8 mm. and we want to measure maximum .6mm to 1.5 mm.So if we use central area and in reading if we can mange to read only Centrally located Pixel.I think At one MHZ CLOCK we can fulfill our application. Please Confirm.
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A:
If you provide an SI pulse before the end of readout, the sensor will stop the current frame and start a new one. You cannot use only the central part of the sensor, but you can use the left part.
If you take for example 32 pixels, you will get a frame rate of
1 frame = 10us SI + 35 clocks@1MHz = 22222fps
but your integration time is also reduced.
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A:
Integration cannot be abbridged, it always consist of 128 pixels. Readout itself can be aborted though. The simultaneuos integration though is fawlty.?
Clock frequency should not be less than a few 100 kHz.
The dead space between the pixels is of course the pixel pitch minus the pixel active area:
63.5 um - 56.4 um = 7.1 um.
what do think regarding IC haus IC -LF 1401.
can we compare with MLX 90255 performance and all data.
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Q:
Pl reply. MLX 90255 is compitible IC-LF1401 128x1 linear array by competitor
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Q:
Can we measure 10 micron Diameter of object?
What is Minimum Measurement in MICRON?
Can OPTICAL LENS Make our aplication possible?
We have SIZE 30 MM to USE light sorce preferably LED
Can You suggest Smallest optical system for our aplication?
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Q:
We also Need NON CONTACT TEMPERATURE MEASUREMENT OF POLYESTER FILAMENT YARN HAVING DIAMETER .8 to 1.3 MM. .Temperature Range 40 to 300 C.
We want to mesure yarn temperature at heater exit with accuracy +-1C.
Pl Suggest suitable product.
There is very huge requirement in Draw Texturising Machine. This parameter to be monitor on linein Texturising machine having 240 Position. only Thing is we requre Copact assembley.Pl reply earlier post MLX90255.
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A:
The MLX90255 has a pixel width of 66um and a small dead area between the pixels. By software you can subsample to s smaller pitch, but the accuracy depends on your software and the sub-sampling rate. There is of course a limit to this method and it has to be tested in the real application.
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Q:
Can we use MLX75006 or MLX 75007.
What is its Die size? Can we take 20000 reding/sec.IN MLX90255 IT sown 385 DPI what dose it actually mean?
We need to insure first 10 Micron Image.Can be taken.
What optical lens required.Micro optical array is available for MLX90255 ? will it help ?
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A:
MLX75006 has a pixel pitch of 10um and alows for programming of the readout region you need and is a snapshot sensor, but even under strong light you will have difficulties to reach 4000 frames per second.
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A:
After a few more investigations, you can push the 90255 up to 1.6MHz at ambient temperature and 50% duty cycle of the clock. In order to stop the readout sooner than the end, you will have to run a fast clock (6MHz) to clear the digital readout before applying a new SI pulse.
By doing so, you will get a frame rate of:
1 frame = 10us SI + 35 clocks@1.6MHz + 98 clocks@6MHz = 20743fps
For 20000 fps, you need to use a maximum of
10us + (x+2)/1600000 + (131-x)/6000000 = 1/20000
=> x=36 pixels
Now if you want to have these 36 pixels fitting your maximum sensing area of 1.3mm, you need to put the sensor at an angle vs the wire. 36 pixels is 2.31mm => 75 degrees
If you don't like to use this angle due to pixel inclination, you can do spatial subsampling by software.
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Q:
Can we use MLX90271 for our aplication As discussed above ?
we are not finding Data Sheet and application note and other detail.
I recieve some data sheet from your Indian Representive.
Thanks for your co-operation.
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Q:
Please send Data sheet and application note of
MLX90271
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A:
the datasheet has been sent to your e-mail address about 1 week ago.
Note the minimum order quantity of 50000 devices / year for this part.
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Q:
Thanks but I was interested in its application note if available.
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A:
There is no application note available for MLX90271.
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Q:
Which one is better and best for my application.
MLX90255 OR MLX90271
which one give precise reading of filament yarn.
can we measure 2 micron ?
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A:
I think MLX90255. If you need two lines, you can place them where you need, and you can also readout the two sensors in parallel to increase speed.
Also from a commercial point of view, there is no MOQ on the MLX90255.
For 2 microns measurement, you need to have a very good design of your illumination, no vibrations in the system and a good interpolation in your software. The sensor has an SNR of 8 bits avec very good linearity, so interpolation down to 2um should be possible. You have to test it in your particular situation.
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Q:
I would like to use MLX90255 for designing One-dimensional bar code Reader.
Could you tell me how to design the function?
Which other components we still are needed except for MLX90255?
Whether there are some reference design about MLX90255 to come true such function of One-dimensional bar code reader?
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A:
Asuming that you are talking about the electronics, there are extra components needed for the optical path.
On the electronic side a microcontroller with ADC is the only thing you need. You have to provide some timings to the sensor and read the analog output. Some bypass capacitors are required.
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Q:
I use linear sensor MLX90255 in the SMD8 package. I was surprised to read in a recent datasheet (the Rev008 of november 05) that the max frequency is 500 KHz. The old SMD8 sensors (datasheet rev 006) are assumed to work at 1024 KHz! Why are performances of the new products weaker than the old sensors? And how will I do when I will have used all my old sensors. I really need this max speed of 1024KHz!
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A:
the sensor did not change, if you used to buy the MLX90255BA, you still have the same sensor in the current orders, we only changed the datasheet.
The reason is that, if you use a duty cycle of the clock far from 50%, the sensor will have to be limited to 500kHz. We have thus changed the datasheet so that the max frequency corresponds to the worst duty cycle.
If you use a standard 50% duty cycle, you can use the sensor at 1MHz.
However, we have developed a new sensor called MLX90255BC, backward compatible with BA, that can operate up to 800kHz at short or long duty cycles (still 1MHz for 50% duty cycle).
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