Visual (optical) illusions. Revaluation of vertical lines

VISUAL (OPTICAL) ILLUSIONS
Visual (optical) illusions / Revaluation of vertical lines

Re-evaluation of vertical lines. Encyclopedia of visual illusions

visual illusions

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Obviously, due to historically accumulated experience, on the one hand, and due to the location of the line connecting a person’s eyes in a horizontal plane, on the other hand, a person has the ability to more accurately determine horizontal distances by eye than the height of objects. It turns out that visual acuity "in the horizontal direction" is greater than in the vertical one, and an eye comparison of the length of parallel horizontal lines can be made with an accuracy of 1%, while for vertical lines such an accuracy is unattainable.

Turning the eye in the vertical plane requires more muscle tension than a similar turn in the horizontal plane, and since muscle tension can act as a measure of the path, vertical distances seem to us greater than horizontal ones. Therefore, most people have the ability to exaggerate vertical dimensions as compared to horizontal ones, and this also leads to visual illusions. Here are some examples of these illusions (Fig. 53-58).

Visual (optical) illusions / Overestimation of vertical lines
Rice. 53. The height of the hat-cylinder seems to be greater than the width of the brim, although they are equal

Visual (optical) illusions / Overestimation of vertical lines
Rice. 54. The height CD of a figure seems to be greater than its base AB, although AB=CD

Visual (optical) illusions / Overestimation of vertical lines
Rice. 55. The height of the black comb seems to be greater than its width, although they are equal. By turning the figure on its side, it is easy to achieve the disappearance of the illusion.

Visual (optical) illusions / Overestimation of vertical lines
Rice. 56. The lower rectangle seems shorter and thicker than the upper one, although these figures are equal.

Visual (optical) illusions / Overestimation of vertical lines
Rice. 57. The three vertical stripes on the left are of the same height, but when placed as shown in the center of the figure, or as shown on the right, the narrow strip appears to be longer than the two wide ones.

Visual (optical) illusions / Overestimation of vertical lines
Rice. 58. The upper parts of the typographic signs seem to be equal in height to the lower ones, although they are actually smaller than the lower ones, as can be seen by turning the picture over.

If you ask a number of people to draw vertical and horizontal lines of the same length, then in most cases the drawn vertical lines will be shorter than the horizontal ones. When dividing a vertical line in half by eye, the middle is usually too high (see Fig. 40).

Visual (optical) illusions / Overestimation of vertical lines
Fig. 40

Vertical parallel lines, with their considerable length, usually seem to diverge slightly in the upper part. Note that the horizontal ones always seem to converge. This circumstance is taken into account, among other things, in architecture, where high columns, in order for them to appear correctly parallel to us, are made slightly convergent at the top. For example, the colonnade of the Parthenon was built in Greece.

Note that due to the exaggeration of vertical lines in architecture, one also has to reckon with this circumstance. If the eye fixes a horizontal line that is at the same level, then the lines lying above appear curved. Appropriate measures must be taken to eliminate this apparent architectural flaw.

The illusions of the filled space closely adjoin the considered group of illusions (Fig. 59-61). The filled space, over which the eye slides horizontally, lengthens. Thus, for example, on the sea, all distances seem smaller, since the boundless expanse of the sea is an undivided space. Buildings decorated with figures and ornaments seem to us larger than their actual size.

Visual (optical) illusions / Overestimation of vertical lines
Rice. 59. Filled space seems longer than unfilled space.

Visual (optical) illusions / Overestimation of vertical lines
Rice. 60. The right shaded square appears narrower and taller than the left.

Visual (optical) illusions / Overestimation of vertical lines
Rice. 61. Shaded sectors appear smaller than unshaded ones. They are actually equal quadrants of the same circle. Our gaze involuntarily slides to the center of the circle and moves more easily horizontally than vertically (by force of habit)

On fig. 60 it seems to us that the right figure B is narrower and taller (the gaze slides along the vertical) of the left figure A. In fact, both A and B are regular shaded squares.

Does this mean that filled space always seems to us wider than unfilled space both horizontally and vertically? However, this is not always the case, and much depends on the direction in which our gaze slides, trying to perceive the figure (Fig. 61).

Among other things, cases of incorrect perception and comparison of horizontal lines are possible (Fig. 62).

Visual (optical) illusions / Overestimation of vertical lines
Rice. 62. Pipe illusion. The left dashes appear to be longer than the right ones, although both are the same length. Similarly, the area of the right figure seems to be larger, although it is clear that the areas are equal

Author: Artamonov I.D.

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Synchronous DC-DC Regulators Texas Instruments LM76002/3 18.04.2018

Texas Instruments has released new buck converters with up to 60 V input and up to 2.5 A output for the LM76002 and up to 3.5 A for the LM76003.

With a wide input voltage range, it is possible to simplify input protection circuits for 24V applications in industrial and automotive systems. Switching frequency adjustable over a wide range (350...2200 kHz) allows you to optimize the device either in terms of power loss or in terms of the space occupied by the solution on the board. The ICs have a large pad on the bottom of the package, which is designed to absorb power losses, which ensures excellent thermal behavior.

The presence of special grooves inside the pins of the microcircuit improves the quality of the solder joint and provides 100% visual control of the assembly process.

Technical specifications:

input voltage range: 3,5...60 V (maximum 65 V);
output voltage from 1,0 V to 95% of Vin;
rated output current: up to 2,5 A (LM76002) and up to 3,5 A (LM76003);
frequency is adjusted in the range: 350...2200 kHz;
low self-consumption current: 15 μA;
maximum efficiency reaches 97%;
configurable soft start (6,3ms by default);
the presence of a Power-Good output;
the ability to select the operating mode with forced PWM (FPWM);
high efficiency at low load (Light-Load Architecture mode);
operating temperature range -40...150°С;
case WQFN-30 size 4x6 mm;
there are versions of microcircuits with automotive qualifications.

Typical applications:

automotive electronics;
telecommunication equipment;
CCTV;
software logic controllers;
power supply systems from tires 24/48 Volt.

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