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To accomplish this, we will need to take advantage of the IDM by initializing the input and output streams. At the start ofthe function, two instantiations of a new structure dstr_t are declared. You can view the structure contents of dstr_t on p. 2-11 of the IDK Programmer's Guide . The structure contents are defined with calls to dstr_open() . This data flow for the pre-scale is shown in data flow .

Data flow of input and output streams.

To give you a better understanding of how these streams are created, let's analyze the parameters passed in the first callto dstr_open() :

External address: in_image->data

This is a pointer to the place in memory serving as the source of our input data (it's the source because the lastfunction parameter is set to DSTR_INPUT ).

External size: (rows + num_lines) * cols = (240 + 2) * 640

This is the total size of our input data. We will only be taking every other line from in_image->data , so only 240 rows. The extra two rows are for buffer.

Internal address: int_mem

This is a pointer to an 8x640 lexographic array, specifically scratchpad->int_data . This is where we will be putting the data on each call to dstr_get() .

Internal size: 2 * num_lines * cols = 2 * 2 * 640

The size of space available for data to be input into int_mem from in_image->data . Because double buffering is used, num_lines is set to 2.

Number of bytes/line: cols = 640, number of lines: num_lines = 2

Each time dstr_get() is called, it will return a pointer to 2 lines of data, 640 bytes inlength.

External memory increment/line: stride*cols = 1*640

Left as an exercise.

Window size: 1 for double buffered

The need for the window size is not really apparent here. It will become apparent when we do the 3x3 blockconvolution. Then, the window size will be set to 3. This tells the IDM to send a pointer to 3 lines of data when dstr_get() is called, but only increment the stream's internal pointer by 1 (instead of 3) the next time dstr_get() is called. This is not a parameter when setting up an output stream.

Direction of input: dstr_input

Sets the direction of data flow. If it had been set to DSTR_OUTPUT (as done in the next call to dstr_open() ), we would be setting the data to flow from the Internal Address to the External Address.

Once our data streams are setup, we can begin processing by calling the component function pre_scale() (in pre_scale.c ) to operate on one block of data at a time. This function will perform the horizontal scaling byaveraging every two pixels. This algorithm operates on four pixels at a time. The entire function is iterated within pre_scale_image() 120 times, which is the number of rows in each quadrant. Before pre_scale_image() exits, the data streams are closed, and one line is added to the top and bottom of theimage to provide context necessary for the next processing steps. Now that the input image has been scaled to a quarterof its initial size, we will proceed with the four image processing algorithms. In img_proc.c , the set_ptr() function is called to set the variable out_ptr to point to the correct quadrant on the 640x480 output image. Then copy_image() , copy_image.c , is called, performing a direct copy of the scaled input image into the lower right quadrant of theoutput.

Questions & Answers

do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Ece 320 - spring 2003. OpenStax CNX. Jan 22, 2004 Download for free at http://cnx.org/content/col10096/1.2
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