TELEPATHOLOGY

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TELEPATHOLOGY

• Prof. Dr. O. Ferrer-Roca
• 1998

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INTRODUCTION TO TELEPATHOLOGY (I)
TELEPATHOLOGY IS PATHOLOGY APPLIED AT DISTANCE,
i. e. THE DIAGNOSIS OF PATIENTS TISSUE
PATHOLOGIES WITHOUT DIRECT MANIPULATION.
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Specimen under study
DATA SENDING
CSCW
TELEDIAGNOSIS
ACQUISITION
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INTRODUCTION TO TELEPATHOLOGY (II)

• .- STATIC TELEPATHOLOGY
• FTP, WWW, videotelephone, modem.
• Static images
• 2.- KINETIC TELEPATHOLOGY
• Remote controlof the microscope.
• Static or live compressed images
• 3.- DYNAMIC TELEPATHOLOGY
• Real Time interaction.
• Live , high quality images

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BASIC REQUIREMENTS FOR TELEPATHOLOGY
The basic requirements for Telepathology are

• . MULTIMEDIA DATABASE.

• . COLOR IMAGES - RESOLUTION.

• . INTERACTIVE CONTROL OF COLOR.

• . CONTROLLED SAMPLING.

• . SECURITY / CONFIDENTIALITY tools

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REQUIREMENTS FOR TELEPATHOLOGY 1.MULTIMEDIA
DATABASE

• NO PATIENT will be correctly diagnosed without
  his/her PREVIOUS BIOPSIES and MEDICAL DATA
  available .
• DATABASE
• MEDICAL/BIOPSIES INFORMATION
• COMPARISONS/QUERY,
• BY PATIENT
• BY DIAGNOSIS

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REQUIREMENTS FOR TELEPATHOLOGY 2. IMAGE
COLOR/RESOLUTION
IMAGE QUALITY FACTORS

• . DYNAMIC RANGE.

• . SPATIAL RESOLUTION.

• . COMPRESSION .

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COLOR IMAGES OF SUFFICIENT RESOLUTION 1. DYNAMIC
RANGE
Is the DIFFERENCE between MAX."SATURATION LEVEL"
MIN."signal DETECTION LEVEL ", DIVIDED BY the
"DIFF to DETECT signal CHANGES".
DrSmax-Smin/Sdif BUT LINEAR RESPONSE of the
video camaras is compensated for the LOGARITHMIC
non-linear response of the human eye using a
GAMMA-CORRECTION VIDEO-CAMARAS output is gamma
corrected.
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GAMMA CORRECTION
RESPONSE TO GAMMA CORRECTION ORIGINAL IMAGE
GAMMA CORRECTED IMAGE. Imagen cedida por
Pedro Arconada con permiso de IDG, S.L.
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COLOR IMAGES OF SUFFICIENT RESOLUTION 2. SPATIAL
RESOLUTION
Max. Spatial Frequency (Fmax) able to be detected
or transmitted x/y 43 aspect ratio
pixel
SF information present in one dimention unit
DEPENDS ON MICROSCOPIC POWER
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SPATIAL RESOLUTION 2 SHANONS SAMPLING THEORY
TO ASSURE THAT A DISCRETE SAMPLE (DIGITAL) WILL
REPRODUCE AN ANALOG (CONTINOUS) IMAGE
SAMPLES SHOULD BE TAKEN AT 2Fmax
CONSECUENCES 1.- 512x512 matrix could be
sufficient at high power, but unacceptable at low
power, where the amount of information per space
unit is much higher. 2.- High resolution camaras
allow digital zooming
PROVIDED THE BEST QUALITY M/O OPTICS
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COLOR IMAGES OF SUFFICIENT RESOLUTION 3.
COMPRESSION
REDUCE AMOUNT DATA WITHOUT SENSIBLE LOSS OF
IMPORTANT INFORMATION
DEPENDS SUBSEQUENT ANALYSIS 1.- Visual diagnosis
2.- Image analysis 3.- Image quantitation

• COLOR REDUCTION YUV, Median cut, palette
  c.reduct.
• SPATIAL RESOLUTION REDUCTION yes/no
  interpolation
• DATA REDUCTION lossy/lossless compression

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COLOR IMAGES OF SUFFICIENT RESOLUTION 3.
COMPRESSION METHODS-JPEG
99
35
60
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INTERACTIVE CONTROL OF COLOR

• TO CONTROL CAMARAS DISPLAY
• SPECTRAL RESPONSE
• WHITE BALANCE
• GAMMA CORRECTION

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INTERACTIVE CONTROL OF COLOR
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OPTIMAL LINEARITY is obtained because the O.D.
IMAGES are operated PIXEL BY PIXEL with a
COMPLETE BACKGROUND IMAGE -- gamma correction do
not affect the result --
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CONTROLLED SAMPLING (I)
DIAGNOSTIC DISCREPANCIES DUE TO SAMPLING 9 - 6. 3

LIABILITY ISSUES
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CONTROLLED SAMPLING (II) LIABILITY ASPECTS

• 1.- LIABILITY FORMULAES
• "based on the images received"
• "if confirmed and contrasigned by the
  responsable
• pathologist"
• 2.- CONTROL OVER THE STUDIED AREA

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CONFIDENTIALITY AND SECURITY TOOLS
MANDATORY

• 1.- DIGITAL SIGNATURE
• 2.- Dg system based on the data available
• AUTHENTICATION of data
• Control Register of any modification

OTHERS

• ORGANIZATIONAL REQUIREMENTS
• Appointment management
• CSCW

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Specimen under study
DATA SENDING
CSCW
TELEDIAGNOSIS
ACQUISITION
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(No Transcript)
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DISTANCE TELEQUANTITATION DENSITOMETRY ASPECTS (I)
Light spectrum sensitivity of the detector is of
less importance on densitometric measurements
based on TRANSMITTED LIGHT since it has to be
performed on the maximum ABSORVANCE peak ( 1/Tmax
), and it is normalized against the white
background or incident light
If final Intensity OD -log T
-log(If/Io) OD Optical Density Io
background Int.
Each color has its maximum absorvance at a
specific range of de light spectrum . MAX
ABSORVANCE of PIGMENT has to be known in advance
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DENSITOMETRY ASPECTS (II) MAXIMUM ABSORVANCES
a narrow band pass filter ( 20nm wave lenght )
stabilized light ( 100W halogen)
STAINING (DYE ) MAXIMUM ABSORVANCE Toluidine
Blue 640 nm Feulgen 560 nm DAB (Diamino
Bencidine) 547 nm Gallocianine 580
nm Haemathoxyline alone 600 nm Haemathoxyline-
Eosine 530 nm Haemathoxyline-Light Green 635
nm PAP standard 545 nm Thionine 570
nm Metile Green 660 nm
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DENSITOMETRY ASPECTS (III)
TRANSMISSION DENSITOMETRY ACHROMATIC SPACE
LIGHT INTENSITY Green input ( in general )
Other problems 1.- SURROUNDING EFFECT Light
arround the object

Glare effect
Contrast
OD

• 2.- CONTRAST RATIO relation gain (W) and offset
  (B)
• Depends on the digitizing board ( each individual
  board )
• Depends on the enviromental light - Cinema room
  801
• - CTR office 51

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DENSITOMETRY ASPECTS (IV)
3.- SATURATION LEVEL of the detector
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DENSITOMETRY ASPECTS (V)
DENSITOMETRY IN THE CHROMATIC SPACE
GAMMA CORRECTION DEPENDING COLOR SPACES
Hdominant wavelenght S white present in the
H I Intensity or brightness
A.- HSI model
B.- RGB model
L mapped in 8 bits (0-255) LUT per color
gamma LLuminance L(Vepsilon)
Vvoltage
eblack offset
GAMMA CORRECTION INDEPENDENT C. SPACES
Y 0.299 R 0.587 G 0.114 B U 0.596 R 0.275
G 0.321 B V 0.212 R 0.523 G 0.311 B
C.- YUV model
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DENSITOMETRY ASPECTS (VI)
REFLECTION DENSITOMETRY The densitometric
measurements of colours based on reflected light
are standardised in the ISO 5TC42
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THANK YOU FOR YOUR ATTENTION
PROF.Dr. O.Ferrer-Roca 1998