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Year : 2018  |  Volume : 9  |  Issue : 2  |  Page : 137-138  

Use of filters in dermatoscopy to capture better images

Department of Dermatology, Christian Medical College, Vellore, Tamil Nadu, India

Date of Web Publication19-Mar-2018

Correspondence Address:
Balakrishnan Nirmal
Department of Dermatology, Christian Medical College, Vellore, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/idoj.IDOJ_345_16

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How to cite this article:
Nirmal B. Use of filters in dermatoscopy to capture better images. Indian Dermatol Online J 2018;9:137-8

How to cite this URL:
Nirmal B. Use of filters in dermatoscopy to capture better images. Indian Dermatol Online J [serial online] 2018 [cited 2021 Dec 5];9:137-8. Available from: https://www.idoj.in/text.asp?2018/9/2/137/227796


Dermatoscopy has expanded its utility from skin tumors to infective and inflammatory disorders.[1] Though its utility is continuously increasing in dermatological disorders, capturing good quality images are equally important.[2] Filters are transparent or translucent glass material used in front of lens to alter the light passing through it for better photography. The basic filters used in photography include ultraviolet filter, polarizing filter, fluorescent light filter, and neutral density filter [Figure 1], with cost ranging from 1000 to 5000 INR (Indian rupees).
Figure 1: Image showing various filters: ultraviolet filter, polarizing filter, fluorescent light filter, and neutral density filter (Opteka TM, USA)

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Fluorescent light filters (FLD) are used to improve images taken under bright fluorescent light.[3] Dermatoscope is a useful tool to detect early nail involvement in psoriasis showing dilated vessel with a prominent halo, streaky capillaries, splinter hemorrhages, linear onycholysis, and oil-drop sign.[4] The vascular nail bed findings can be obscured by high back reflection of the translucent nail plate even with contact fluid and polarized light dermatoscopes. This back reflection can be overcome by using FLD filters (Opteka TM, USA) [Figure 2]. These filters have become less important as most cameras automatically adjust for white balance, however, sometimes there may be such an overwhelming amount of white light, as seen with reflection from nail plate that no amount of white balance can restore full color.
Figure 2: Dermatoscopy of nail psoriasis (×10) showing dilated globose vessels, streaky capillaries, and linear onycholysis (a) without filter (b) and with FLD filter. Nail bed vascular features are better captured with FLD filter

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Neutral density filter (ND) are grey-colored filters that reduce the light reaching the sensor. This effectively decreases the camera shutter speed and increases exposure time to absorb maximum detail. ND filters are named according to the fraction of light the filters allows to pass. An ND2 filter blocks one-half of the incident light and allows the rest to pass through, whereas an ND4 filter blocks only one-fourth of the light to pass.[5] ND filters are used in pigmented lesions to capture even the finest details by increasing the exposure time which is decreased by faster closure of aperture due to reflection of white light from dermal collagen in the absence of ND filter (Opteka TM, USA) [Figure 3].
Figure 3: Dermatoscopy of lichen planus pigmentosus (×10) showing diffuse peppering pigment pattern on a brown background (a) without filter (b) and with ND filter (ND4) Pigment pattern detail is well appreciated with ND filter with less reflected light from dermal collagen

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Filters incorporate very slight but noticeable changes in the image captured. Though filters have their advantages, because it is a piece of glass between the lens and the object, it can affect the quality of the image.[5] Hence, they have to be used only when required and offer distinct advantages. However, the use of filters in dermatoscopy for better images is a potential research area that should be explored in the future.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Lallas A, Argenziano G. Dermatoscope-the dermatologist's stethoscope. Indian J Dermatol Venereol Leprol 2014;80:493-4.  Back to cited text no. 1
[PUBMED]  [Full text]  
Kaliyadan F. The scope of the dermoscope. Indian Dermatol Online J 2016;7:359-63.  Back to cited text no. 2
[PUBMED]  [Full text]  
Mansurov N. Lens Filters Explained. Available from: https://photographylife.com/lens-filters-explained. [Last accessed date on: 2016 Sep 23].  Back to cited text no. 3
Yadav TA, Khopkar US. Dermoscopy to detect signs of subclinical nail involvement in chronic plaque psoriasis: A study of 68 patients. Indian J Dermatol 2015;60:272-5.  Back to cited text no. 4
[PUBMED]  [Full text]  
Camera lens filters. Available from: http://www.cambridgeincolour.com/tutorials/camera-lens-filters.htm. [Last accessed date on 2016 Sep 23].  Back to cited text no. 5


  [Figure 1], [Figure 2], [Figure 3]


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