JPS6321858B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring the electrophoretic velocity of visible suspended particles in a liquid.

When an electric field is applied to a solution containing suspended visible particles such as red and white blood cells, these particles undergo electrophoresis. The movement speed of suspended particles by electrophoresis is measured as follows. The floating particles are strongly illuminated to form an image of the floating particles on the light receiving surface of the imaging device to obtain a video signal. In this way, when two video signals are obtained at an appropriate time interval and a correlation function between the two video signals is determined, the position of the peak is located at the light-receiving surface of the imaging device of the floating particle image during the above-mentioned appropriate time interval. Since it represents the distance traveled above,
From this, the electrophoretic movement speed of suspended particles can be calculated.

In the method described above, the video signal contains a strong background due to light scattering by the solution itself in which visible particles are suspended or by colloidal particles suspended in the solution, and the image of the suspended particles is not focused. The signals of blurred images located at outlying positions are included, and these are unnecessary signals for calculating the moving speed of floating particles as described above and interfere with the signal processing of the video signal. The object of this invention is to provide a device for removing signals of background and out-of-focus suspended particles from a video signal.

The present invention differentiates a video signal, extracts a signal of one polarity, levels-sorts this, removes the background, and generates a peak signal with a width wider than a certain width depending on the width of each peak in the remaining signal. The object of the present invention is to provide an apparatus that calculates the above-mentioned correlation function for the signal of the remaining peak after removing the signal. The present invention will be explained below with reference to Examples.

FIG. 1 shows an embodiment of the present invention, in which 1 is an electrophoresis tube containing a liquid in which visible particles are suspended;
Reference numerals 2 and 3 denote electrodes, and a voltage is applied between the electrodes to cause visible particles within the tube 1 to undergo electrophoresis. 4 is a laser light source that illuminates the liquid in the electrophoresis tube 1 from above, 5 is a projection lens placed on the side of the electrophoresis tube 1, and P is a diode array element in which a large number of minute photodiodes are arranged. An image of floating particles in the migration tube 1 by the lens 5 is formed on this array element. The electrophoresis speed of floating particles is about 20μ/sec, and the electrophoresis speed is measured over a period of about 10 seconds, so particles remain floating for the time required to scan the array element and obtain one scan's worth of video signals. The particles can be considered to be almost stationary. The array element P is scanned at a certain point, and the output at that time is A-D.
It is digitized by converter AD and stored in memory M1. This scan is repeated at 1 second intervals. Between these scans, the following operations are performed in the circuits below the memory M1.

From memory M1, two adjacent addresses n, n
+1 data is read out and the subtraction circuit Su calculates (n+1
The subtraction operation (data) - (data n) is performed, and the result is stored again at address n in the memory M1. This operation is performed for all addresses. As a result, a signal obtained by differentiating the video signal is stored in the memory M1. Next, this differential signal is read out sequentially, and only positive data above a certain level is extracted by a level selector L. When data is extracted, it is determined as a signal "1", and when no data is extracted, it is determined as a signal "0". Send to circuit J. The configuration and operation of the discriminating circuit J will be described in detail later, but it detects and outputs a signal only when "1" appears three times in a row in the output signal of the level discriminator L.

The meaning of the above operation in terms of signal processing will be explained. Figure 2 A shows the video signal read out from the array element P, b is the background, and a wide peak d
is a signal of an out-of-focus floating particle image, and f is a signal of an in-focus floating particle image. As mentioned above, the memory M1 finally stores the signal shown in FIG. 2B, which is obtained by differentiating the signal shown in FIG. 2A. If we select from this signal a portion having a level l or higher on the positive side, the result will be as shown in Fig. 2C. When the time axis of the signal C is enlarged, it becomes a pulse train as shown in FIG. 2D, and this is the output of the level selector L. Background signals are removed by differential operation and next level selection. Since the discrimination circuit J outputs a signal when the signal "1" (one pulse) from the level selector L is output up to three consecutive times, the signal shown in FIG. It does not output a signal for ', but outputs a signal only for the two pulse trains f' originating from the focused particle image, and the output is as shown in Figure 2 (e), which is stored in memory M2. Forced to remember. In this way, the data (E) in FIG. 2 obtained in one scan of the array element P is stored in the memory M2, and the data (E) in FIG. The same process is performed for each scan of the array element, and the data shown in FIG. 2E for each scan is sequentially stored in the memory M2''.

In FIG. 1, Mp is a multiplier, and the circuit portions below this are circuits for calculating the correlation between the data in FIG. Due to movement of the particle image between one scan and the next scan, the signal a in FIG. 2E has reached the position b in FIG. 2E'. At this time, the address difference between addresses a and b in memories M2 and M2' is m. Data at address n of memory M2' and data at address n+x of memory M2 are read out and multiplied by multiplier Mp. Since the data is "0" or "1", the result of multiplication is "0" or "1". This multiplication is performed on all addresses in the memory M2', and the results of this multiplication are accumulated by an adder S. When the above calculation is completed for all addresses of memory M2', the integration result is the address x of memory M3.
address and the adder S is cleared. This operation is repeated over an appropriate range of values of x.
This range is appropriately determined around the predicted value of m shown in FIG. The above calculation operation can be expressed mathematically as performing the calculation F(x)=∫f(u+x)g(u)du for the functions f(u) and g(u), and the memory M3 The above function F(x) will be stored in . The value of x at which this function value becomes maximum indicates the amount of movement of the floating particle image on the array element in one second, and from this the moving speed of the floating particles can be determined. Memory M2, M
Since there are a large number of 2',..., the above operation is performed between adjacent memories and the sum is accumulated in memory M3.
3, the correlation functions obtained each time are superimposed and averaged.

The configuration and operation of the discrimination circuit J will be explained with reference to FIG. The output signal of the level selector L shown in FIG. Counter C is a ternary counter, and when the fourth pulse is input, it outputs a carry signal and returns to 0. The output of the level selector L is input to a 3-bit shift register R. Shift register R is shifted in synchronization with reading data from memory M1. If the output of the level selector L continues to be ``1'' for four or more signals as shown in Figure 2 d', the counter C outputs a carry signal at the count of 4 and sets the flip-flop F, so the AND gate U closes. Data pushed out from shift register R is blocked at U and does not go to memory M2 or the like. Flip-flop FF is reset when the output signal of shift register R becomes "0". Therefore, when the signal "1" continues for four or more times in the output of L, the AND gate U is closed with a delay of three pulses, and the shift register R remains closed until the output signal train of L becomes zero, which is delayed by three pulses. When the output of L is 3 or less times as the signal "1" continues as shown in f' in Figure 2D, the carry signal is not output from the counter C and the gate U remains open, so there is a delay of 3 pulses. The signal f' in FIG. 2D is output from the shift register R and input to the memory M2 and the like. Counter C is reset when the output of L becomes "0".

The operation of the discrimination circuit J described above is to remove signals of out-of-focus floating particle images from the video signal, and the correlation function is ultimately determined only for sharp floating particle images, and the peak of the correlation function is Become sharp.

Although the above-described embodiment shows a configuration for determining a correlation function between two temporally distant video signals, the present invention is not limited to this configuration. For example, the signal read out from the memory M2, M2', etc. at any same address will be the output signal of the photoelectric conversion element when one slit is placed at the array element P and a photoelectric conversion element is placed behind it. Equivalent to.
Therefore, a method may be adopted in which data at the same address different from the above address is read out from the memory M2, M2', . Alternatively, data at the same address in the memories M2, M2', etc. is read out and added, and data at an address a certain number of addresses away from that address is read out and added, and in this way, the data in the memories M2, M2', etc. are read out and added up by a certain number of addresses. The value obtained by reading the data of M2', . In the explanation of the above embodiments, various arithmetic circuits, memories, counters, registers, etc. are described as separate devices, but these are functions of a microcomputer in which the same device operates various functional circuits at different times. It is.

Since the electrophoresis measuring device of the present invention has the above-described configuration and the background is removed, images of suspended particles can be detected with high sensitivity, and signal processing for determining migration speed is facilitated. Furthermore, the removal of the signal of the out-of-focus floating particle image has the following meaning. In other words, in the electrophoresis tube, a negative charge appears on the tube wall side and a positive charge appears on the solution side at the contact surface between the solution inside the tube and the tube wall, and the solution near the tube wall flows toward the negative electrode side due to the action of the electric field. A flow is generated along the tube axis toward the positive electrode, and a convection current in the tube axis direction, that is, an electroosmotic flow is generated within the tube. Electrophoresis of suspended particles must be measured in a layer where the electroosmotic flow is 0, and the first
The lens 5 in the figure is focused on that layer. Therefore, the floating particles that are out of focus are particles outside this layer of zero electroosmotic flow, so their moving speed is the overlap of the electrophoretic speed and the electroosmotic flow speed, and does not indicate the correct electrophoretic speed. do not have. According to the present invention, since signals of such out-of-focus floating particle images are removed, accurate electrophoretic velocity can be determined.

[Brief explanation of the drawing]

FIG. 1 shows a perspective view of the optical part and a block diagram of the electrical part of a device according to an embodiment of the present invention, FIG. 2 shows signal waveform diagrams at each stage of the device, and FIG.
FIG. 2 is a block diagram showing the configuration of the determination circuit shown in the figure. 1... Electrophoresis tube, 4... Light source, 5... Projection lens, P... Diode array element, M1, M
2, M2',...M3...Memory, L...Level selector, J...Judgment circuit.

Claims (1)

[Claims] 1. A means for forming an image of suspended particles in an electrophoresis tube on a light-receiving surface of an imaging device, and a means for scanning the imaging device at regular intervals and differentiating the obtained video signal to detect a signal that is higher than a certain level. means for selecting a signal; means for removing signals of a certain width or more from the signals selected by the means; a memory for storing the video signal converted by the means; A visible particle electrophoresis measuring device comprising means for performing arithmetic processing to obtain, as electrophoretic velocity information, a variable value giving the maximum value of the cross-correlation function between the two video signals converted over time.