Imaging system with four different wavelengths obtained from LEDs

In order to evaluate skin pigmentation in different skin layers, there is a special light adapter needed to take multispectral pictures of skin. As there are different optical properties of skin pigments, four different light sources have been chosen. blue λ= 470 nm – highly absorbed by epidermal melanin green λ= 576 nm – hemoglobin peak red  λ= 660nm – epidermal-dermal boundary IR λ= 865 nm – low absorption, sensitive to scattering to measure papillary dermis thickness. There was lighting source for “Nikon Coolpix E3100” digital camera developed to take multispectral images of skin. Making adapter The drawing of  lighting adapter The lighting adapter isn’t very hard to build. You need to make a circular PCB and solder LEDs with protective resistors. The PCB image:

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Histological Skin Structure Diagram

Skin is a brilliant structure of our body. It is very elastic and pretty strong to protect internal tissue. It also acts as thermoregulator of our entire body protecting from overheats when we sweat and when there is cold – the blood flow is reduced to skin tissues to save heat to inner organs of the body. Skin is pretty resistive to harmful chemicals, microorganisms and if dry it has high electrical receptivity. From biochemical side – skin can produce vitamin D when exposed to sunlight, which is essential for the growth and maintenance of our bones. The extensive network of nerves within the skin feeds information continuously to the brain concerning our surroundings. So it is full of sensors to know the external world like temperature, pressure. Don’t even let me start about skin importance in the fashion industry. About how much there is attention paid to cosmetics, beauty…

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About melanoma

Melanoma is one of the fastest spreading lesions. Melanoma is curable if it is diagnosed in early stages. If melanoma is diagnosed in the early stages, the curability reaches about 90 percent of patients. In another hand, if melanoma is diagnosed in late stages, then curability is less than 50 percent. To attain better curing result it is not enough to diagnose the disease, but there is permanent monitoring needed before and after procedures. In this website, you will find information about melanoma from the technical side. Let us say, how lesions are dedicated, how photographed and what do doctors do to make a diagnose. There are many techniques for making melanoma diagnoses. The most widely used by dermatologists is the ABCD(E) rule, where skin images are taken, and then shape, color, and structure analysis of lesion is made. This rule is so simple that everyone can do it by…

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Pointers to structures in embedded C

Sometimes you might like to manipulate the members of C structures in more generalized way. This can be done by using pointer reference to structure. Normally it is easier to pass pointer to structure than passing entire structure to function. Structure pointer can be declared very easily: struct structure_tag_name *variable; For instance: struct position{ int x; int y; }pos1, *pos2; we can assign first structure address to structure pointer like this: pos2=&pos1; now we can access first structure members by using structure pointer: pos2->x=10; or we can write (*pos2).x=10; Structures can contain member pointers to other structures or to structures of same type. This way we can create lists – dynamic structure: struct list{ int listNo; struct list *next; //pointer to another structure }item1, item2; This way you can assign the pointer with address to another structure: item1.next=&item2; Read more about dynamic structures in C tutorials on internet.

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Interfacing MPXV5100 pressure sensor to Atmega8

The MPX5100 series piezoresistive transducer is a state-of-the-art monolithic silicon pressure sensor designed for a wide range of applications, but particularly it is convenient to interface to microcontroller or microprocessor with A/D inputs. This is thin-film metallization, and bipolar processing to provide an accurate, high level analog output signal that is proportional to the applied pressure. More details can be found here MPXV5100 This sensor measures differential pressure comparing to atmospheric so when there is no pressure applied it shows 0kPa;

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