JPS6321859B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring the velocity of electrophoresis of oblate visible particles, such as red blood cells, suspended in a liquid under the action of an electric field.

To measure the electrophoresis of visible suspended particles, an image of the suspended particles is formed on an image pickup tube, the image pickup device is scanned to obtain a video signal, and this video signal is subjected to various calculations to calculate the migration speed. The following method is used. In this case, if the visible particle is flat, the apparent size and brightness of the visible particle as seen from the projection lens will vary depending on the orientation of the particle, and if the particle is rotating, even if the image is of the same particle. The video signal varies over time. If the visible particle image component in the video signal includes fluctuations in signal strength and signal width due to particle rotation other than those caused by electrophoresis, two temporally distant video signals may have different signals for images of the same particle. This may be mistaken for an image signal, or conversely, a signal from an image of another particle may be mistaken for a signal from an image of the same particle, resulting in an error in the calculation of migration speed. Therefore, the present invention was made with the aim of eliminating the influence of particle rotation in electrophoretic measurements of flat visible particles.

The present invention provides an electrophoresis measuring device that converts a particle image signal in a video signal into a single pulse signal regardless of its intensity and width, and performs subsequent arithmetic processing. The present invention will be explained in detail below with reference to Examples.

FIG. 1 shows an embodiment of the present invention. This embodiment is suitable for cases where the floating particle image is small and formed as a bright spot, and only the brightness of the image differs depending on the apparent direction of the particles. 1 is an electrophoresis tube, 2, 3
is an electrode. A solution in which visible particles are suspended is placed in an electrophoresis tube 1, and a voltage is applied between electrodes 2 and 3. 4 is a laser light source that illuminates the inside of the electrophoresis tube 1 from above. A projection lens 5 forms an image of floating particles on the diode array element P by viewing the electrophoresis tube 1 from the side. When array element P is scanned, the second
A video signal as shown in Figure A is obtained. The output of the array element is a series of pulse-like outputs for each unit element, but in order to perform subsequent signal processing in an analog manner, the output is smoothed through a filter and differentiated by a differentiating circuit D. When this differentiated signal is input to the level selector L and a signal of level l or higher is extracted, the background and the signal of the particle image that is slowly out of focus with rising and falling edges (shown as c in Fig. 2 A) are removed. be done. When the one-shot circuit m is triggered by the rising pulses of the signals a and b of the focused particle images thus obtained (FIG. 2(b)), the signal shown in FIG. 2(c) is obtained. The pulses a' and b' in the signal in Figure 2 C are the converted signals a and b of the original particle image,
Regardless of the strength of the signals a and b, the signals have a constant height and width. The array element P is scanned twice at a fixed time interval, and in each scan, the second
The signal shown in FIG. 3C is obtained and stored in memories M1 and M2, and later both memories are read out to find the correlation between both signals. The point of determining this correlation will be explained in the description of the next embodiment.

FIG. 3 shows another embodiment of the invention. This embodiment is suitable when the particle image is large and not only the brightness but also the width of the image differs depending on the direction of the particle. The configuration from the electrophoresis tube 1 to the differential circuit D is the same as the embodiment shown in FIG. FIG. 4A shows the output signal of the array element P, and FIG. 4B shows its differential signal. In Fig. 4A, a and b are video signals of floating particle images, and a is a signal with a large signal width when the flat surface of the particle is directed toward the lens 5, and b is a signal with a large signal width when the flat surface of the particle is directed toward the lens 5. The signal width is narrow when the camera is aimed at c is a signal of an out-of-focus particle image, which has a gradual rise and a large signal width. d is the background. When differentiated, most of the background is removed, and each particle image becomes a signal of a pair of positive and negative pulses. Since the out-of-focus particle image rises slowly, the height of the differential signal is lower than that of the in-focus particle image. This differential signal is sent to level selectors L, L' through diodes r, r' in opposite directions, and those having positive and negative levels equal to or higher than l are selected. Figure 4c,
C' indicates the output signals of L and L'. After being sufficiently amplified, these signals are passed through level detectors C and C' to the fourth level detector.
It is converted into a rectangular wave pulse as shown in Figures D and D'.
The subsequent signal processing is carried out by a microcomputer μ-
Do it with COM.

μ-COM scans the array element P.
This scanning is performed at regular intervals. Since one scan completes in a short time, it can be assumed that the floating particle image does not move during that time. μ-COM counts clock pulses, uses the counted output to designate a unit light receiving element of array element P, and reads out its output.

FIG. 5 is a flowchart of the μ-COM operating program. When scanning of the array element P is started, the signal shown in FIG. 4D is first detected, and when this signal is detected, the count value of the clock pulse is input to the register, and 1/2 counting is started. This adds 1 for every two clock pulses. Next, detect the signal 2', and when this is detected, stop the 1/2 count, check whether the 1/2 count is less than a predetermined value N, and if it is greater than N, clear the 1/2 count. Then, after detecting the end of scanning, the process returns to the second signal detection. When the 1/2 count number is less than N, add the above 1/2 count to the clock count input in the register,
This added value is used as address designation data for memory I, and a signal 1 is sent to that address and the following two addresses.
is memorized and the operation returns to signal detection in step (2). Thus, the operation for one scan is completed by the end of the scan. If the 1/2 count is larger than N, the signal is considered to be a floating substance that is not the target particle, and a check is performed to remove it (1/2 count <N).

In the above operation, each address of the memory corresponds to the address of the unit element of the array element, and regardless of the width of the focused particle image, 3 addresses continue from the center of the width.
Signal 1 is stored at the address. FIG. 4E shows the signals stored in this memory.

Perform the above operation twice at a certain time interval, and
In the second scan, the data shown in FIG. 4(e) is stored in the memory. Next, the memory obtained at each time is read out and the correlation between the two is determined.
To find the correlation, multiply the data at memory address n by the data at memory address n+x (each data is 0 or 1, so the product is also 0 or 1), and apply this multiplication result to all memory Accumulate over addresses and store this in memory at address x. When this operation is performed within an appropriate range of x by changing x by 1, one correlation function is stored in the memory. Since the value of x, which indicates the maximum value of this function, indicates the average distance traveled by the particle image on the array element during two scans, the electrophoretic velocity of the suspended particles can be determined from this value.

The present invention has the above-described structure, and the width of the video signal of a flat particle differs depending on its orientation, and the strength of the video signal also differs because the way illumination light is reflected differs. Since all the signals are converted into signals of the same shape, the shape of the peak of the correlation function becomes uniform, improving the accuracy of measuring electrophoretic velocity.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an optical part and a block diagram of a data processing section of a device according to an embodiment of the present invention, FIG. 2 is a signal waveform diagram at various stages of operation in the device, and FIG. FIG. 4 is a block diagram of the data processing section of another example device; FIG. 4 is a signal waveform diagram at various stages of operation in the device; FIG. be. 1... Electrophoresis tube, 4... Light source, 5... Projection lens, P... Diode array element.

Claims (1)

[Claims] 1 means for forming an image of suspended particles in an electrophoresis tube as a bright spot image on the light receiving surface of an imaging device; a means for detecting the bright spot image in a video signal obtained by scanning the imaging device; A means for converting a point image video signal into a signal with a constant amplitude and a constant time width, regardless of the signal strength, and a video signal obtained by multiple scans at different times, and the above-mentioned floating particle image. An apparatus for measuring electrophoresis of oblate particles, comprising means for determining a correlation between imaging signals converted into signals with a constant amplitude and a constant time width.