Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Hottawa Stuff > Week 1 > Flashcards

Week 1 Flashcards

1
Q

Digital Camera Sensor - Describe

A

A matrix of millions of microscopic light sensitive photodiodes

These create pixels by sensing light intensity

Do not record colours, only intensity of light (grey scale)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

2 types of digital camera sensors

A

CCD - solid state sensor called Charge Coupled Device

CMOS - Complementary Metal Oxide Semiconductor - Nikon uses this

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Exam Question

Pixels - define and name 3 properties

A

Pixel = Picture Element

A digital square composed of a number value based on the intensity of light received from a sensor

3 Properties:

  • Location
  • Colour Value
  • Size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

File formats - Loss of Information

A

Common formats

  • JPEG
  • TIFF
  • RAW

TIFF & PSD files do not lose detail; TIFF is a very large file size; lossless

RAW is uncompressed, but an enhanced image cannot be saved in RAW format; use this format when you are enhancing a file

JPEG takes up less space, easily shared, but loses information when saved; each change/save further compresses file; lossy file

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

File size of images - affected by…

A

1) Number of pixels
2) Colour Depth
- 8, 12, 14, 16 bit per channel

3) Colour Mode
- CMKY (4 channels)
- RGB (3 channels)
- Grayscale (1 channel)

4) File Format
- RAW (lossless)
- JPEG (lossy)
- TIFF (lossless)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Exam Question

Image Quality - Factors that affect

A

Resolution
Colour bit depth (16 bit vs 8 bit)
Lens (quality of)
Size of CCD (full frame vs crop)
File format (JPEG, RAW, TIFF)
Colour interpolation (how colour is processed)
Processing of image(changes made; contrast, etc)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

3 layers of human skin

A

Epidermis

Dermis

Hypodermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Epidermis

A

Outermost layer

  • Composed mainy of keratinocytes
  • protective barrier
  • reduces water loss through evaporation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

2 Types of Skin

A

Smooth skin:

  • has hair
  • Sebaceous glands (greastest around head/face)
  • NO friction ridges

Volar (FR) skin:

  • only sweat glands
  • completely covered in ridges (no voids)
  • fingers/palms & bottoms of feet
  • sweat of FR skin increases grip
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the Basement Membrane

A

Between Dermis & Epidermis

  • Fibrous sheet
  • fibres are interwoven
  • structural support for epidermis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

5 Layers of Epidermis

A

1) Stratum Corneum
2) stratum Lucidum
3) stratum Granulosum
4) stratum Spinosum
5) stratum Basale

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Stratum Basale

A

Last layer - CLGSB

  • single layer of columnar shaped cells
  • mitosis - the generation of new cells (cells split)
  • new cells pushed towards surface
  • are blueprint of what you see on the surface
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Stratum Spinosum

A

2nd Last layer - CLGSB

  • 2-4 cells thick
  • exhibit first changes in cell structure
    Synthesis of keratin process
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Stratum Granulosum

A

Middle layer - CLGSB

  • Last of the living cells
  • first precursors of keratin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Stratum Lucidum

A

2nd layer - CLGSB

Keratin fills inside of cell

Keratin is an insoluable protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Stratum Corneum

A

1st layer - CLGSB

  • Up to 100cells thick
  • cells have accumulation of Keratin
  • cell death has occurred
  • cells large and flat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Dermis

A 
Middle layer
Made up of:
- cells, fibres, blood vessels and gelatinous material
- energy reserve of Epidermis
- sensory reception
- temperature regulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Desmosomes

A

Protein Bundles that keep cells together as they migrate from the Basale to the surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why is friction skin unique and persistent?

A

Persistency:

1) Basal Cell Mitosis
2) Structural Elements

Uniqueness:

1) Random timing
2) Random growth
3) Random pressures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe Basale Cell Mitosis

A

Occurs in Basale layer of epidermis.

Is blueprint for cell regeneration

Cell replicates, splits, moves up through epidermis to surface

Can take up to 30 days

Stay together with Desmosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the 4 structural elements relating to persistency

A

1) desmosomes bind newly formed cells together until they reach surface
2) basale cells (bottom of epidermis) attached to bsmt membrane with Fibrils/microfibrils and hemidesmosomes
3) bsmt membrane attached to dermis with fibrils/microfibrils
4) surface of dermis, dermal papillae fit into ‘pockets’ of underside of epidermis beside PR’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Desribe uniqueness of FR skin

A

1) Random timing:
- PR’s develop during 10.5-12 weeks
- volar pads regress
- time of differentation occurs
Ie: end of PR development, SE develoment occurs

2) Random growth:
- # of ridge units that form a FR
- path a FR takes
- Start/stop of FR
- Thickness/thinness of FR
- alignment, bifurcation or misalignment of FR
- height of a ridge
- size and location of pores

3) Random Pressures
- stress on the skin surface can affect size and shape of volar pads
- pressures in the womb
- neighboring ridges
- genetic & physical pressures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Dermal Papillae (Papillary Pegs)

A

Peg like projections on top of dermis, that fit into pockets on the underside of epidermis

Run in 2 rows between PR & SR; hug PR

Increase surface area of attachment between dermis and epidermis

Break down into smaller units due to aging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Whose extensive research of fetal skin cross sections showed the development of dermal papillae?

A

Alfred Hale 1952

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Whose research showed the dermal papillae are in 2 rows ok the underside of the epidermis and break down as people age?
Michio Okajima 1976
26
Describe scars
Permanent damage to the basal layer or beyond - cuts - genetic condition (diseases) - may appear as voids or partial voids Damages the ‘blue print’ - basal layer
27
Friction skin development (fetal)
3 weeks: - epidermis is 1 cell thick 6 weeks: - hand is paddle like - volar pads appear (transient bulges of tissue) on palms/fingers - 5 on fingers, 4 on interdigital, 1 on thenar & 1 on hypothenar area of palm 8 weeks: - digits have seperated - thumb has rotated - flexion creases appear (first on palm, then fingers) 10. 5 to 12 weeks: - volar pad regression - PR on underside of epidermis begin to form as result of rapid cell division of basal cells - longest ridges & bifurcations form first - later in develop, less area to cover, short ridges (islands/dots) appear 15-17 weeks: - secondary ridges begin to appear - form between existing PR - PR develop ceases in that area * Time of Differentation!!! 20 weeks: - SR locations are established - FR are visible on surface - Final FR config is established & will not change by week 20 (as early as 16 weeks) 20-24 weeks: - SR develop of same depth as PR (into the dermis) - 23 weeks dermal papillae form on top of dermis between PR & SR hugging PR - 24 weeks entire system mature
28
Who described the evolution of the friction ridge skin of mammals including that mammals have the same arrangement of volar pads on the hands and feet?
Inez Whipple 1904
29
3 types of Flexion creases
Digital Transverse Crease - top Proximal Transverse Crease - middle Thenar Crease - bottom
30
Whose extensive research on friction ridge skin showed volar pad regression occurs almost concurrently with the beginning of primary ridge development?
Harold Cummins 1929
31
Whose study of thin cross sections of fetal skin determined the timing and development of primary and secondary ridges?
Alfred Hale 1952
32
Who was the first to suggest these centers of disturbance of primate friction ridge skin formations represents the locations of the volar pads?
Harrison Hawthorne Wilder | Early 20th century
33
What affects pattern types?
The size shape and symmetry of volar pads direct ridge flow and thus pattern formations The timing between the start of PR development and volar pad regression affects ridge count (core to delta distance) - Early ridge development = higher volar pads (less regression) and higher ridge count/core-delta distance - PR development after volar pad mostly regressed = low ridge count/core-delta distance
34
Whose extensive research of friction ridge skin showed the size, location, growth and configuration of the volar pads affect friction ridge develop and the overall fingerprint pattern?
Harold Cummins 1929
35
Ridge Formation - Occurence order
1) top/apex of volar pad 2) tip 3) base (platform ridges) 3 can be used for digit orientation, as they are generally horizontal ridges
36
Volar Pads and Patterns
1) Large even shaped volar pads = circular type patterns (whorls) 2) Volar pads offset to one side = loops - height of the volar pad dictates core to delta distance 3) PR develop much later in process after volar pads have fully regressed (low/small volar pads) = arch/tented arch
37
Minutiae - Gaulton Points
1) FR made up of individual ridge units 2) Each ridge unit contains: pore, pore duct & sweat gland 3) length of ridge unit is ~same as its width
38
Who is credited with being the first to recognize that although specific friction ridge arrangements may be similar, they are never duplicated?
JCA Mayer 1788
39
Incipient Ridges
Correspond to PR Immature ridge Did not have time to fully develop prior to start of SR develop ( T of D) Based on same structure of mature PR’s Thinner than mature ridge Usually do not have developed pore
40
Who studied incipient ridges and determined they are primary ridges that did not fully develop?
Michio Okajima 1976
41
Define Ridgeology
The study of uniqueness of the friction skin and its use for personal identification.
42
3 basic pattern types
Arches Whorls Loops
43
3 main areas of the palm
Interdigital Hypothenar Thenar
44
3 main creases of the palm
Digital Transverse crease Promixal Transverse crease Thenar crease
45
Ulna and Radial bones
Ulna is on the little finger side Radial is on the thumb side
46
Image quality on camera determined by...
ISO Shutter Speed Aperature Aperature Priority is the preferred setting on our cameras
47
What does CSWIM stand for?
C = Compensation S = Size (Quality) W = White Balance (light source setting) I = ISO (higher = digital noise) M = Metering (turn back to Matrix each time)
48
Resizing in Photoshop does...
Changes the number of pixels per inch (PPI) Physical size of the image changes, but the total number of pixels remains the same The pixels rendered become larger or smaller, have the same colour and location info
49
Re-sampling an image in photoshop does...
Changes the number of pixels in an image Allows the size of an image to remain constant
50
Calibration
Method of resizing an image so that it correlates to an actual given value (measurement) Must have a properly photographed scale present
51
Differential Growth - Friction Skin Development
The random growth aspects of friction skin development that occurs from the onset of Primary Ridge development (10.5-12 weeks) until the appearance of Secondary Ridge development (15-17 weeks; Time of Differentation)
52
Preferred camera mode for Forensic Photography and why?
Aperature Priority so you can control the amount of Depth of Field
53
Why do we calibrate images
1) to look professional in Court 2) to enhance the image 3) to print the image life sized
54
Described the formation and development of volar pads on the human fetus. Found that volar pads regress at the same time friction ridges develop.
Harold Cummins
55
Found that all mammals have the same morphological arrangement of the formation of friction ridges. Found that ridge patterns are affected by external forces and pressures by neighbouring developing ridges
Alfred Hale
56
Described the anatomical formation of friction ridges. Established uniqueness by detailing how ridge units are subjected to differential growth
Inez Whipple
57
Detailed the various stages of friction ridge development, particuarly how the primary and secondary ridges are formed. Detailed the developement of papillary pegs and major ridge path deviations
Harrison Hawthorne Wilder
58
F Stops - Aperature
1) Controls the volume of light 2) Controls the depth of field Smaller the number - More light = Less depth of field - Moving up 1 stop halves the light Larger the number - Less light = More depth of field - Moving down 1 stop doubles the light F/2.8, F/4, F/5.6, F/8, F/11, F/16, F/22, F/32
59
Shutter Speed
Controls the amount of time the sensor is exposed to light Displayed as seconds and fractions of seconds 1”, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500 Moving up 1 stop halves the light Moving down 1 stop doubles the light
60
Polarizing filters
Filter that transmits light rays in one direction Used to eliminate glare
61
Channels (Contrast Filters)
Selected channel will allow own colour to pass while blocking other colours Used to create contrast, greatly beneficial for fingerprints between the impression and the background
62
Colour Models/Modes
Mathematical representation of colour values which gives a set of colours Main colour models we use; RGB and CMYK Used to give the best contrast between an inpression and a background. CMYK used primarily for Ninhydren as you cam select the colour Majenta
63
RGB Colour Model
Additive model Transmitted Primary colours: Red, Green and Blue All 3 together create white In RGB, red lightens red, etc
64
CMYK Model
Subtractive model Reflected light CMYK: Cyan, Magenta, Yellow and K(Key) Mixing all 3 creates black Cyan darkens Cyan, etc
65
Tonal Ranges
1) Highlights 2) Midtones 3) Shadows
66
ISO
Light sensitivity of the sensor 100, 200, 400, 800, 1600, 3200, 6400, etc Higher the ISO, creates digital noise (reduced quality of an image)
67
Camera Lens
Gathers light rays and brings them into focus on the sensor
68
Increasing Depth of Field
1) Use a SMALLER Aperature (larger number) 2) Increase camera to subject distance - Move away from subject! 3) Use a SHORTER focal length
69
Hand Held and Motion Blur
The Shutter Speed should equal the reciprocal of the chosen Focal length 200 = 100 = 50 =
70
Metering Modes
1) Matrix - Everything 2) Center weighted - Focus on the object in the center 3) Spot - Focus on a central spot in the center
71
Manual Focus - Used when
1) Night photography 2) Close-up photography 3) Fingerprint photography
72
Inverse Square Law
The intensity of light reaching an object is inversely proportional to the square of the distance between the object and the light source ``` 1 = 1 2 = 4 3 = 9 4 = 16 5 = 25 6 = 36 Etc... ```
73
Flash
Referred to as a Speedlight Can be attached to the ‘hot shoe’ Can be attached via flash sync cord Can be triggered remotely
74
Flash Modes
Synchronized flash Slow sync flash Rear curtain sync
75
Flash Techniques ****Exam Question****
Direct flash Oblique/grazed Feathered Bounce Flill (lightens up shadowed areas!)
76
Perspective
Where the camera was positioned when a photo was taken Changing focal length does not change perspective, changing location does 50mm is what a person saw/witnessed Picture angle of 46 degrees Most appropriate for forensic photography for depicting what a witness saw Focal length is equal to the diagonal of the sensor

Hottawa Stuff (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions